From 564efd06515edc524a8a1cdf7a3d8a7d9a376c04 Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Mon, 14 Feb 2022 21:27:53 +0100
Subject: [PATCH] Add appeals (#17364)

* Add appeals

* Add ability to reject appeals and ability to browse pending appeals in admin UI

* Add strikes to account page in settings

* Various fixes and improvements

- Add separate notification setting for appeals, separate from reports
- Fix style of links in report/strike header
- Change approving an appeal to not restore statuses (due to federation complexities)
- Change style of successfully appealed strikes on account settings page
- Change account settings page to only show unappealed or recently appealed strikes

* Change appealed_at to overruled_at

* Fix missing method error
---
 app/controllers/admin/accounts_controller.rb  |   4 +-
 app/controllers/admin/dashboard_controller.rb |   1 +
 .../admin/disputes/appeals_controller.rb      |  40 ++++++
 .../auth/registrations_controller.rb          |  11 +-
 .../disputes/appeals_controller.rb            |  25 ++++
 app/controllers/disputes/base_controller.rb   |  18 +++
 .../disputes/strikes_controller.rb            |  17 +++
 .../admin/account_moderation_notes_helper.rb  |   4 +-
 app/helpers/admin/action_logs_helper.rb       |   2 +
 app/helpers/admin/trends/statuses_helper.rb   |  20 +++
 app/javascript/styles/mastodon/admin.scss     |  89 +++++++++++-
 app/mailers/admin_mailer.rb                   |  10 ++
 app/mailers/user_mailer.rb                    |  20 +++
 app/models/account.rb                         |   4 +
 app/models/account_filter.rb                  |   2 +
 app/models/account_warning.rb                 |   8 +-
 app/models/admin/action_log_filter.rb         |   2 +
 app/models/admin/appeal_filter.rb             |  49 +++++++
 app/models/appeal.rb                          |  58 ++++++++
 app/models/user.rb                            |   4 +
 app/policies/account_warning_policy.rb        |  17 +++
 app/policies/appeal_policy.rb                 |  13 ++
 app/services/appeal_service.rb                |  28 ++++
 app/services/approve_appeal_service.rb        |  74 ++++++++++
 .../_account_moderation_note.html.haml        |   7 -
 .../_account_warning.html.haml                |  30 ++++-
 app/views/admin/accounts/show.html.haml       |  21 ++-
 app/views/admin/dashboard/index.html.haml     |   3 +
 .../admin/disputes/appeals/_appeal.html.haml  |  21 +++
 .../admin/disputes/appeals/index.html.haml    |  22 +++
 .../admin/report_notes/_report_note.html.haml |   2 +-
 app/views/admin/reports/show.html.haml        |   2 +-
 app/views/admin_mailer/new_appeal.text.erb    |   9 ++
 .../registrations/_account_warning.html.haml  |  20 +++
 .../auth/registrations/_status.html.haml      |  31 ++---
 app/views/disputes/strikes/show.html.haml     | 127 ++++++++++++++++++
 .../preferences/notifications/show.html.haml  |   1 +
 app/views/statuses/_detailed_status.html.haml |   2 +-
 .../user_mailer/appeal_approved.html.haml     |  59 ++++++++
 .../user_mailer/appeal_approved.text.erb      |   7 +
 .../user_mailer/appeal_rejected.html.haml     |  59 ++++++++
 .../user_mailer/appeal_rejected.text.erb      |   7 +
 app/views/user_mailer/warning.html.haml       |   6 +-
 config/brakeman.ignore                        |  64 +++++----
 config/locales/en.yml                         |  77 ++++++++++-
 config/locales/simple_form.en.yml             |   9 +-
 config/navigation.rb                          |   4 +-
 config/routes.rb                              |  15 +++
 config/settings.yml                           |   1 +
 db/migrate/20220124141035_create_appeals.rb   |  14 ++
 ...19_add_overruled_at_to_account_warnings.rb |   5 +
 db/schema.rb                                  |  23 +++-
 .../admin/disputes/appeals_controller_spec.rb |  53 ++++++++
 .../disputes/appeals_controller_spec.rb       |  27 ++++
 .../disputes/strikes_controller_spec.rb       |  30 +++++
 .../fabricators/account_warning_fabricator.rb |   7 +-
 spec/fabricators/appeal_fabricator.rb         |   5 +
 spec/mailers/previews/admin_mailer_preview.rb |   5 +
 spec/mailers/previews/user_mailer_preview.rb  |   5 +
 spec/models/appeal_spec.rb                    |   5 +
 60 files changed, 1212 insertions(+), 93 deletions(-)
 create mode 100644 app/controllers/admin/disputes/appeals_controller.rb
 create mode 100644 app/controllers/disputes/appeals_controller.rb
 create mode 100644 app/controllers/disputes/base_controller.rb
 create mode 100644 app/controllers/disputes/strikes_controller.rb
 create mode 100644 app/helpers/admin/trends/statuses_helper.rb
 create mode 100644 app/models/admin/appeal_filter.rb
 create mode 100644 app/models/appeal.rb
 create mode 100644 app/policies/account_warning_policy.rb
 create mode 100644 app/policies/appeal_policy.rb
 create mode 100644 app/services/appeal_service.rb
 create mode 100644 app/services/approve_appeal_service.rb
 delete mode 100644 app/views/admin/account_moderation_notes/_account_moderation_note.html.haml
 create mode 100644 app/views/admin/disputes/appeals/_appeal.html.haml
 create mode 100644 app/views/admin/disputes/appeals/index.html.haml
 create mode 100644 app/views/admin_mailer/new_appeal.text.erb
 create mode 100644 app/views/auth/registrations/_account_warning.html.haml
 create mode 100644 app/views/disputes/strikes/show.html.haml
 create mode 100644 app/views/user_mailer/appeal_approved.html.haml
 create mode 100644 app/views/user_mailer/appeal_approved.text.erb
 create mode 100644 app/views/user_mailer/appeal_rejected.html.haml
 create mode 100644 app/views/user_mailer/appeal_rejected.text.erb
 create mode 100644 db/migrate/20220124141035_create_appeals.rb
 create mode 100644 db/migrate/20220210153119_add_overruled_at_to_account_warnings.rb
 create mode 100644 spec/controllers/admin/disputes/appeals_controller_spec.rb
 create mode 100644 spec/controllers/disputes/appeals_controller_spec.rb
 create mode 100644 spec/controllers/disputes/strikes_controller_spec.rb
 create mode 100644 spec/fabricators/appeal_fabricator.rb
 create mode 100644 spec/models/appeal_spec.rb

diff --git a/app/controllers/admin/accounts_controller.rb b/app/controllers/admin/accounts_controller.rb
index e7f56e243..e0ae71b9f 100644
--- a/app/controllers/admin/accounts_controller.rb
+++ b/app/controllers/admin/accounts_controller.rb
@@ -28,7 +28,7 @@ module Admin
       @deletion_request        = @account.deletion_request
       @account_moderation_note = current_account.account_moderation_notes.new(target_account: @account)
       @moderation_notes        = @account.targeted_moderation_notes.latest
-      @warnings                = @account.strikes.custom.latest
+      @warnings                = @account.strikes.includes(:target_account, :account, :appeal).latest
       @domain_block            = DomainBlock.rule_for(@account.domain)
     end
 
@@ -146,7 +146,7 @@ module Admin
     end
 
     def filter_params
-      params.slice(*AccountFilter::KEYS).permit(*AccountFilter::KEYS)
+      params.slice(:page, *AccountFilter::KEYS).permit(:page, *AccountFilter::KEYS)
     end
 
     def form_account_batch_params
diff --git a/app/controllers/admin/dashboard_controller.rb b/app/controllers/admin/dashboard_controller.rb
index f0a935411..e376baab2 100644
--- a/app/controllers/admin/dashboard_controller.rb
+++ b/app/controllers/admin/dashboard_controller.rb
@@ -8,6 +8,7 @@ module Admin
       @pending_users_count   = User.pending.count
       @pending_reports_count = Report.unresolved.count
       @pending_tags_count    = Tag.pending_review.count
+      @pending_appeals_count = Appeal.pending.count
     end
 
     private
diff --git a/app/controllers/admin/disputes/appeals_controller.rb b/app/controllers/admin/disputes/appeals_controller.rb
new file mode 100644
index 000000000..32e5e2f6f
--- /dev/null
+++ b/app/controllers/admin/disputes/appeals_controller.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+class Admin::Disputes::AppealsController < Admin::BaseController
+  before_action :set_appeal, except: :index
+
+  def index
+    authorize :appeal, :index?
+
+    @appeals = filtered_appeals.page(params[:page])
+  end
+
+  def approve
+    authorize @appeal, :approve?
+    log_action :approve, @appeal
+    ApproveAppealService.new.call(@appeal, current_account)
+    redirect_to disputes_strike_path(@appeal.strike)
+  end
+
+  def reject
+    authorize @appeal, :approve?
+    log_action :reject, @appeal
+    @appeal.reject!(current_account)
+    UserMailer.appeal_rejected(@appeal.account.user, @appeal)
+    redirect_to disputes_strike_path(@appeal.strike)
+  end
+
+  private
+
+  def filtered_appeals
+    Admin::AppealFilter.new(filter_params.with_defaults(status: 'pending')).results.includes(strike: :account)
+  end
+
+  def filter_params
+    params.slice(:page, *Admin::AppealFilter::KEYS).permit(:page, *Admin::AppealFilter::KEYS)
+  end
+
+  def set_appeal
+    @appeal = Appeal.find(params[:id])
+  end
+end
diff --git a/app/controllers/auth/registrations_controller.rb b/app/controllers/auth/registrations_controller.rb
index f37e906fd..3b025838b 100644
--- a/app/controllers/auth/registrations_controller.rb
+++ b/app/controllers/auth/registrations_controller.rb
@@ -9,6 +9,7 @@ class Auth::RegistrationsController < Devise::RegistrationsController
   before_action :check_enabled_registrations, only: [:new, :create]
   before_action :configure_sign_up_params, only: [:create]
   before_action :set_sessions, only: [:edit, :update]
+  before_action :set_strikes, only: [:edit, :update]
   before_action :set_instance_presenter, only: [:new, :create, :update]
   before_action :set_body_classes, only: [:new, :create, :edit, :update]
   before_action :require_not_suspended!, only: [:update]
@@ -111,8 +112,10 @@ class Auth::RegistrationsController < Devise::RegistrationsController
   end
 
   def set_invite
-    invite = invite_code.present? ? Invite.find_by(code: invite_code) : nil
-    @invite = invite&.valid_for_use? ? invite : nil
+    @invite = begin
+      invite = Invite.find_by(code: invite_code) if invite_code.present?
+      invite if invite&.valid_for_use?
+    end
   end
 
   def determine_layout
@@ -123,6 +126,10 @@ class Auth::RegistrationsController < Devise::RegistrationsController
     @sessions = current_user.session_activations
   end
 
+  def set_strikes
+    @strikes = current_account.strikes.active.latest
+  end
+
   def require_not_suspended!
     forbidden if current_account.suspended?
   end
diff --git a/app/controllers/disputes/appeals_controller.rb b/app/controllers/disputes/appeals_controller.rb
new file mode 100644
index 000000000..15367c879
--- /dev/null
+++ b/app/controllers/disputes/appeals_controller.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Disputes::AppealsController < Disputes::BaseController
+  before_action :set_strike
+
+  def create
+    authorize @strike, :appeal?
+
+    @appeal = AppealService.new.call(@strike, appeal_params[:text])
+
+    redirect_to disputes_strike_path(@strike), notice: I18n.t('disputes.strikes.appealed_msg')
+  rescue ActiveRecord::RecordInvalid
+    render template: 'disputes/strikes/show'
+  end
+
+  private
+
+  def set_strike
+    @strike = current_account.strikes.find(params[:strike_id])
+  end
+
+  def appeal_params
+    params.require(:appeal).permit(:text)
+  end
+end
diff --git a/app/controllers/disputes/base_controller.rb b/app/controllers/disputes/base_controller.rb
new file mode 100644
index 000000000..865146b5c
--- /dev/null
+++ b/app/controllers/disputes/base_controller.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class Disputes::BaseController < ApplicationController
+  include Authorization
+
+  layout 'admin'
+
+  skip_before_action :require_functional!
+
+  before_action :set_body_classes
+  before_action :authenticate_user!
+
+  private
+
+  def set_body_classes
+    @body_classes = 'admin'
+  end
+end
diff --git a/app/controllers/disputes/strikes_controller.rb b/app/controllers/disputes/strikes_controller.rb
new file mode 100644
index 000000000..d41c5c727
--- /dev/null
+++ b/app/controllers/disputes/strikes_controller.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class Disputes::StrikesController < Disputes::BaseController
+  before_action :set_strike
+
+  def show
+    authorize @strike, :show?
+
+    @appeal = @strike.appeal || @strike.build_appeal
+  end
+
+  private
+
+  def set_strike
+    @strike = AccountWarning.find(params[:id])
+  end
+end
diff --git a/app/helpers/admin/account_moderation_notes_helper.rb b/app/helpers/admin/account_moderation_notes_helper.rb
index 40b2a5289..2f08538ca 100644
--- a/app/helpers/admin/account_moderation_notes_helper.rb
+++ b/app/helpers/admin/account_moderation_notes_helper.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
 module Admin::AccountModerationNotesHelper
-  def admin_account_link_to(account)
+  def admin_account_link_to(account, path: nil)
     return if account.nil?
 
-    link_to admin_account_path(account.id), class: name_tag_classes(account), title: account.acct do
+    link_to path || admin_account_path(account.id), class: name_tag_classes(account), title: account.acct do
       safe_join([
                   image_tag(account.avatar.url, width: 15, height: 15, alt: display_name(account), class: 'avatar'),
                   content_tag(:span, account.acct, class: 'username'),
diff --git a/app/helpers/admin/action_logs_helper.rb b/app/helpers/admin/action_logs_helper.rb
index f3aa4be4f..47eeeaac3 100644
--- a/app/helpers/admin/action_logs_helper.rb
+++ b/app/helpers/admin/action_logs_helper.rb
@@ -33,6 +33,8 @@ module Admin::ActionLogsHelper
       "#{record.ip}/#{record.ip.prefix} (#{I18n.t("simple_form.labels.ip_block.severities.#{record.severity}")})"
     when 'Instance'
       record.domain
+    when 'Appeal'
+      link_to record.account.acct, disputes_strike_path(record.strike)
     end
   end
 
diff --git a/app/helpers/admin/trends/statuses_helper.rb b/app/helpers/admin/trends/statuses_helper.rb
new file mode 100644
index 000000000..d16e3dd12
--- /dev/null
+++ b/app/helpers/admin/trends/statuses_helper.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module Admin::Trends::StatusesHelper
+  def one_line_preview(status)
+    text = begin
+      if status.local?
+        status.text.split("\n").first
+      else
+        Nokogiri::HTML(status.text).css('html > body > *').first&.text
+      end
+    end
+
+    return '' if text.blank?
+
+    html = Formatter.instance.send(:encode, text)
+    html = Formatter.instance.send(:encode_custom_emojis, html, status.emojis, prefers_autoplay?)
+
+    html.html_safe # rubocop:disable Rails/OutputSafety
+  end
+end
diff --git a/app/javascript/styles/mastodon/admin.scss b/app/javascript/styles/mastodon/admin.scss
index 546de1640..f5741bd50 100644
--- a/app/javascript/styles/mastodon/admin.scss
+++ b/app/javascript/styles/mastodon/admin.scss
@@ -578,12 +578,16 @@ body,
 }
 
 .log-entry {
+  display: block;
   line-height: 20px;
   padding: 15px;
   padding-left: 15px * 2 + 40px;
   background: $ui-base-color;
   border-bottom: 1px solid darken($ui-base-color, 8%);
   position: relative;
+  text-decoration: none;
+  color: $darker-text-color;
+  font-size: 14px;
 
   &:first-child {
     border-top-left-radius: 4px;
@@ -596,15 +600,12 @@ body,
     border-bottom: 0;
   }
 
-  &:hover {
+  &:hover,
+  &:focus,
+  &:active {
     background: lighten($ui-base-color, 4%);
   }
 
-  &__header {
-    color: $darker-text-color;
-    font-size: 14px;
-  }
-
   &__avatar {
     position: absolute;
     left: 15px;
@@ -640,6 +641,18 @@ body,
       text-decoration: underline;
     }
   }
+
+  &--inactive {
+    .log-entry__title {
+      text-decoration: line-through;
+    }
+
+    a,
+    .username,
+    .target {
+      color: $darker-text-color;
+    }
+  }
 }
 
 a.name-tag,
@@ -1175,6 +1188,17 @@ a.sparkline {
         font-weight: 600;
         padding: 4px 0;
       }
+
+      a {
+        color: $ui-highlight-color;
+        text-decoration: none;
+
+        &:hover,
+        &:focus,
+        &:active {
+          text-decoration: underline;
+        }
+      }
     }
 
     &--horizontal {
@@ -1451,3 +1475,56 @@ a.sparkline {
     }
   }
 }
+
+.strike-card {
+  padding: 15px;
+  border-radius: 4px;
+  background: $ui-base-color;
+  font-size: 15px;
+  line-height: 20px;
+  word-wrap: break-word;
+  font-weight: 400;
+  color: $primary-text-color;
+
+  p {
+    margin-bottom: 20px;
+    unicode-bidi: plaintext;
+
+    &:last-child {
+      margin-bottom: 0;
+    }
+  }
+
+  &__statuses-list {
+    border-radius: 4px;
+    border: 1px solid darken($ui-base-color, 8%);
+    font-size: 13px;
+    line-height: 18px;
+    overflow: hidden;
+
+    &__item {
+      padding: 16px;
+      background: lighten($ui-base-color, 2%);
+      border-bottom: 1px solid darken($ui-base-color, 8%);
+
+      &:last-child {
+        border-bottom: 0;
+      }
+
+      &__meta {
+        color: $darker-text-color;
+      }
+
+      a {
+        color: inherit;
+        text-decoration: none;
+
+        &:hover,
+        &:focus,
+        &:active {
+          text-decoration: underline;
+        }
+      }
+    }
+  }
+}
diff --git a/app/mailers/admin_mailer.rb b/app/mailers/admin_mailer.rb
index b23bd1296..a9d00c000 100644
--- a/app/mailers/admin_mailer.rb
+++ b/app/mailers/admin_mailer.rb
@@ -15,6 +15,16 @@ class AdminMailer < ApplicationMailer
     end
   end
 
+  def new_appeal(recipient, appeal)
+    @appeal   = appeal
+    @me       = recipient
+    @instance = Rails.configuration.x.local_domain
+
+    locale_for_account(@me) do
+      mail to: @me.user_email, subject: I18n.t('admin_mailer.new_appeal.subject', instance: @instance, username: @appeal.account.username)
+    end
+  end
+
   def new_pending_account(recipient, user)
     @account  = user.account
     @me       = recipient
diff --git a/app/mailers/user_mailer.rb b/app/mailers/user_mailer.rb
index 5221a4892..583c948b0 100644
--- a/app/mailers/user_mailer.rb
+++ b/app/mailers/user_mailer.rb
@@ -173,6 +173,26 @@ class UserMailer < Devise::Mailer
     end
   end
 
+  def appeal_approved(user, appeal)
+    @resource = user
+    @instance = Rails.configuration.x.local_domain
+    @appeal   = appeal
+
+    I18n.with_locale(@resource.locale || I18n.default_locale) do
+      mail to: @resource.email, subject: I18n.t('user_mailer.appeal_approved.subject', date: l(@appeal.created_at))
+    end
+  end
+
+  def appeal_rejected(user, appeal)
+    @resource = user
+    @instance = Rails.configuration.x.local_domain
+    @appeal   = appeal
+
+    I18n.with_locale(@resource.locale || I18n.default_locale) do
+      mail to: @resource.email, subject: I18n.t('user_mailer.appeal_rejected.subject', date: l(@appeal.created_at))
+    end
+  end
+
   def sign_in_token(user, remote_ip, user_agent, timestamp)
     @resource   = user
     @instance   = Rails.configuration.x.local_domain
diff --git a/app/models/account.rb b/app/models/account.rb
index 771cc0b1b..2ad45feda 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -270,6 +270,10 @@ class Account < ApplicationRecord
     true
   end
 
+  def previous_strikes_count
+    strikes.where(overruled_at: nil).count
+  end
+
   def keypair
     @keypair ||= OpenSSL::PKey::RSA.new(private_key || public_key)
   end
diff --git a/app/models/account_filter.rb b/app/models/account_filter.rb
index 86b7f5f41..9da1522dd 100644
--- a/app/models/account_filter.rb
+++ b/app/models/account_filter.rb
@@ -24,6 +24,8 @@ class AccountFilter
     scope = Account.includes(:account_stat, user: [:ips, :invite_request]).without_instance_actor.reorder(nil)
 
     params.each do |key, value|
+      next if key.to_s == 'page'
+
       scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
     end
 
diff --git a/app/models/account_warning.rb b/app/models/account_warning.rb
index fc0d988fd..05d01942d 100644
--- a/app/models/account_warning.rb
+++ b/app/models/account_warning.rb
@@ -12,6 +12,7 @@
 #  updated_at        :datetime         not null
 #  report_id         :bigint(8)
 #  status_ids        :string           is an Array
+#  overruled_at      :datetime
 #
 
 class AccountWarning < ApplicationRecord
@@ -28,12 +29,17 @@ class AccountWarning < ApplicationRecord
   belongs_to :target_account, class_name: 'Account', inverse_of: :strikes
   belongs_to :report, optional: true
 
-  has_one :appeal, dependent: :destroy
+  has_one :appeal, dependent: :destroy, inverse_of: :strike
 
   scope :latest, -> { order(id: :desc) }
   scope :custom, -> { where.not(text: '') }
+  scope :active, -> { where(overruled_at: nil).or(where('account_warnings.overruled_at >= ?', 30.days.ago)) }
 
   def statuses
     Status.with_discarded.where(id: status_ids || [])
   end
+
+  def overruled?
+    overruled_at.present?
+  end
 end
diff --git a/app/models/admin/action_log_filter.rb b/app/models/admin/action_log_filter.rb
index 12136223b..0f2f712a2 100644
--- a/app/models/admin/action_log_filter.rb
+++ b/app/models/admin/action_log_filter.rb
@@ -8,6 +8,8 @@ class Admin::ActionLogFilter
   ).freeze
 
   ACTION_TYPE_MAP = {
+    approve_appeal: { target_type: 'Appeal', action: 'approve' }.freeze,
+    reject_appeal: { target_type: 'Appeal', action: 'reject' }.freeze,
     assigned_to_self_report: { target_type: 'Report', action: 'assigned_to_self' }.freeze,
     change_email_user: { target_type: 'User', action: 'change_email' }.freeze,
     confirm_user: { target_type: 'User', action: 'confirm' }.freeze,
diff --git a/app/models/admin/appeal_filter.rb b/app/models/admin/appeal_filter.rb
new file mode 100644
index 000000000..b163d2e56
--- /dev/null
+++ b/app/models/admin/appeal_filter.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+class Admin::AppealFilter
+  KEYS = %i(
+    status
+  ).freeze
+
+  attr_reader :params
+
+  def initialize(params)
+    @params = params
+  end
+
+  def results
+    scope = Appeal.order(id: :desc)
+
+    params.each do |key, value|
+      next if %w(page).include?(key.to_s)
+
+      scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
+    end
+
+    scope
+  end
+
+  private
+
+  def scope_for(key, value)
+    case key.to_s
+    when 'status'
+      status_scope(value)
+    else
+      raise "Unknown filter: #{key}"
+    end
+  end
+
+  def status_scope(value)
+    case value
+    when 'approved'
+      Appeal.approved
+    when 'rejected'
+      Appeal.rejected
+    when 'pending'
+      Appeal.pending
+    else
+      raise "Unknown status: #{value}"
+    end
+  end
+end
diff --git a/app/models/appeal.rb b/app/models/appeal.rb
new file mode 100644
index 000000000..46f35ae37
--- /dev/null
+++ b/app/models/appeal.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: appeals
+#
+#  id                     :bigint(8)        not null, primary key
+#  account_id             :bigint(8)        not null
+#  account_warning_id     :bigint(8)        not null
+#  text                   :text             default(""), not null
+#  approved_at            :datetime
+#  approved_by_account_id :bigint(8)
+#  rejected_at            :datetime
+#  rejected_by_account_id :bigint(8)
+#  created_at             :datetime         not null
+#  updated_at             :datetime         not null
+#
+class Appeal < ApplicationRecord
+  belongs_to :account
+  belongs_to :strike, class_name: 'AccountWarning', foreign_key: 'account_warning_id'
+  belongs_to :approved_by_account, class_name: 'Account', optional: true
+  belongs_to :rejected_by_account, class_name: 'Account', optional: true
+
+  validates :text, presence: true, length: { maximum: 2_000 }
+  validates :account_warning_id, uniqueness: true
+
+  validate :validate_time_frame, on: :create
+
+  scope :approved, -> { where.not(approved_at: nil) }
+  scope :rejected, -> { where.not(rejected_at: nil) }
+  scope :pending, -> { where(approved_at: nil, rejected_at: nil) }
+
+  def pending?
+    !approved? && !rejected?
+  end
+
+  def approved?
+    approved_at.present?
+  end
+
+  def rejected?
+    rejected_at.present?
+  end
+
+  def approve!(current_account)
+    update!(approved_at: Time.now.utc, approved_by_account: current_account)
+  end
+
+  def reject!(current_account)
+    update!(rejected_at: Time.now.utc, rejected_by_account: current_account)
+  end
+
+  private
+
+  def validate_time_frame
+    errors.add(:base, I18n.t('strikes.errors.too_late')) if Time.now.utc > (strike.created_at + 20.days)
+  end
+end
diff --git a/app/models/user.rb b/app/models/user.rb
index fd1d7049a..517254a91 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -265,6 +265,10 @@ class User < ApplicationRecord
     settings.notification_emails['pending_account']
   end
 
+  def allows_appeal_emails?
+    settings.notification_emails['appeal']
+  end
+
   def allows_trending_tag_emails?
     settings.notification_emails['trending_tag']
   end
diff --git a/app/policies/account_warning_policy.rb b/app/policies/account_warning_policy.rb
new file mode 100644
index 000000000..6b92da475
--- /dev/null
+++ b/app/policies/account_warning_policy.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class AccountWarningPolicy < ApplicationPolicy
+  def show?
+    target? || staff?
+  end
+
+  def appeal?
+    target?
+  end
+
+  private
+
+  def target?
+    record.target_account_id == current_account&.id
+  end
+end
diff --git a/app/policies/appeal_policy.rb b/app/policies/appeal_policy.rb
new file mode 100644
index 000000000..a25187172
--- /dev/null
+++ b/app/policies/appeal_policy.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class AppealPolicy < ApplicationPolicy
+  def index?
+    staff?
+  end
+
+  def approve?
+    record.pending? && staff?
+  end
+
+  alias reject? approve?
+end
diff --git a/app/services/appeal_service.rb b/app/services/appeal_service.rb
new file mode 100644
index 000000000..1397c50f5
--- /dev/null
+++ b/app/services/appeal_service.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class AppealService < BaseService
+  def call(strike, text)
+    @strike = strike
+    @text   = text
+
+    create_appeal!
+    notify_staff!
+
+    @appeal
+  end
+
+  private
+
+  def create_appeal!
+    @appeal = @strike.create_appeal!(
+      text: @text,
+      account: @strike.target_account
+    )
+  end
+
+  def notify_staff!
+    User.staff.includes(:account).each do |u|
+      AdminMailer.new_appeal(u.account, @appeal).deliver_later if u.allows_appeal_emails?
+    end
+  end
+end
diff --git a/app/services/approve_appeal_service.rb b/app/services/approve_appeal_service.rb
new file mode 100644
index 000000000..f76bf8943
--- /dev/null
+++ b/app/services/approve_appeal_service.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+class ApproveAppealService < BaseService
+  def call(appeal, current_account)
+    @appeal          = appeal
+    @strike          = appeal.strike
+    @current_account = current_account
+
+    ApplicationRecord.transaction do
+      undo_strike_action!
+      mark_strike_as_appealed!
+    end
+
+    queue_workers!
+    notify_target_account!
+  end
+
+  private
+
+  def target_account
+    @strike.target_account
+  end
+
+  def undo_strike_action!
+    case @strike.action
+    when 'disable'
+      undo_disable!
+    when 'delete_statuses'
+      undo_delete_statuses!
+    when 'sensitive'
+      undo_sensitive!
+    when 'silence'
+      undo_silence!
+    when 'suspend'
+      undo_suspend!
+    end
+  end
+
+  def mark_strike_as_appealed!
+    @appeal.approve!(@current_account)
+    @strike.touch(:overruled_at)
+  end
+
+  def undo_disable!
+    target_account.user.enable!
+  end
+
+  def undo_delete_statuses!
+    # Cannot be undone
+  end
+
+  def undo_sensitive!
+    target_account.unsensitize!
+  end
+
+  def undo_silence!
+    target_account.unsilence!
+  end
+
+  def undo_suspend!
+    target_account.unsuspend!
+  end
+
+  def queue_workers!
+    case @strike.action
+    when 'suspend'
+      Admin::UnsuspensionWorker.perform_async(target_account.id)
+    end
+  end
+
+  def notify_target_account!
+    UserMailer.appeal_approved(target_account.user, @appeal).deliver_later
+  end
+end
diff --git a/app/views/admin/account_moderation_notes/_account_moderation_note.html.haml b/app/views/admin/account_moderation_notes/_account_moderation_note.html.haml
deleted file mode 100644
index 432fb79a6..000000000
--- a/app/views/admin/account_moderation_notes/_account_moderation_note.html.haml
+++ /dev/null
@@ -1,7 +0,0 @@
-.speech-bubble
-  .speech-bubble__bubble
-    = simple_format(h(account_moderation_note.content))
-  .speech-bubble__owner
-    = admin_account_link_to account_moderation_note.account
-    %time.formatted{ datetime: account_moderation_note.created_at.iso8601 }= l account_moderation_note.created_at
-    = table_link_to 'trash', t('admin.account_moderation_notes.delete'), admin_account_moderation_note_path(account_moderation_note), method: :delete if can?(:destroy, account_moderation_note)
diff --git a/app/views/admin/account_warnings/_account_warning.html.haml b/app/views/admin/account_warnings/_account_warning.html.haml
index 8c9c9679c..ef23c3b77 100644
--- a/app/views/admin/account_warnings/_account_warning.html.haml
+++ b/app/views/admin/account_warnings/_account_warning.html.haml
@@ -1,6 +1,24 @@
-.speech-bubble.warning
-  .speech-bubble__bubble
-    = Formatter.instance.linkify(account_warning.text)
-  .speech-bubble__owner
-    = admin_account_link_to account_warning.account
-    %time.formatted{ datetime: account_warning.created_at.iso8601 }= l account_warning.created_at
+= link_to disputes_strike_path(account_warning), class: ['log-entry', account_warning.overruled? && 'log-entry--inactive'] do
+  .log-entry__header
+    .log-entry__avatar
+      = image_tag account_warning.target_account.avatar.url(:original), alt: '', width: 40, height: 40, class: 'avatar'
+    .log-entry__content
+      .log-entry__title
+        = t(account_warning.action, scope: 'admin.strikes.actions', name: content_tag(:span, account_warning.account.username, class: 'username'), target: content_tag(:span, account_warning.target_account.acct, class: 'target')).html_safe
+      .log-entry__timestamp
+        %time.formatted{ datetime: account_warning.created_at.iso8601 }
+          = l(account_warning.created_at)
+
+        - if account_warning.report_id.present?
+          ·
+          = t('admin.reports.title', id: account_warning.report_id)
+
+        - if account_warning.overruled?
+          ·
+          %span.positive-hint= t('admin.strikes.appeal_approved')
+        - elsif account_warning.appeal&.pending?
+          ·
+          %span.warning-hint= t('admin.strikes.appeal_pending')
+        - elsif account_warning.appeal&.rejected?
+          ·
+          %span.negative-hint= t('admin.strikes.appeal_rejected')
diff --git a/app/views/admin/accounts/show.html.haml b/app/views/admin/accounts/show.html.haml
index f3853d629..9a1f07a06 100644
--- a/app/views/admin/accounts/show.html.haml
+++ b/app/views/admin/accounts/show.html.haml
@@ -246,18 +246,29 @@
   %hr.spacer/
 
   - unless @warnings.empty?
-    = render @warnings
+
+    %h3= t 'admin.accounts.previous_strikes'
+
+    %p= t('admin.accounts.previous_strikes_description_html', count: @account.previous_strikes_count)
+
+    .account-strikes
+      = render @warnings
 
     %hr.spacer/
 
-  = render @moderation_notes
+  %h3= t 'admin.reports.notes.title'
 
-  = simple_form_for @account_moderation_note, url: admin_account_moderation_notes_path do |f|
-    = render 'shared/error_messages', object: @account_moderation_note
+  %p= t 'admin.reports.notes_description_html'
 
-    = f.input :content, placeholder: t('admin.reports.notes.placeholder'), rows: 6
+  .report-notes
+    = render partial: 'admin/report_notes/report_note', collection: @moderation_notes
+
+  = simple_form_for @account_moderation_note, url: admin_account_moderation_notes_path do |f|
     = f.hidden_field :target_account_id
 
+    .field-group
+      = f.input :content, placeholder: t('admin.reports.notes.placeholder'), rows: 6
+
     .actions
       = f.button :button, t('admin.account_moderation_notes.create'), type: :submit
 
diff --git a/app/views/admin/dashboard/index.html.haml b/app/views/admin/dashboard/index.html.haml
index 4b581f5ea..59b75e0e1 100644
--- a/app/views/admin/dashboard/index.html.haml
+++ b/app/views/admin/dashboard/index.html.haml
@@ -46,6 +46,9 @@
       %span= t('admin.dashboard.pending_tags_html', count: @pending_tags_count)
       = fa_icon 'chevron-right fw'
 
+    = link_to admin_disputes_appeals_path(status: 'pending'), class: 'dashboard__quick-access' do
+      %span= t('admin.dashboard.pending_appeals_html', count: @pending_appeals_count)
+      = fa_icon 'chevron-right fw'
   .dashboard__item
     = react_admin_component :dimension, dimension: 'sources', start_at: @time_period.first, end_at: @time_period.last, limit: 8, label: t('admin.dashboard.sources')
 
diff --git a/app/views/admin/disputes/appeals/_appeal.html.haml b/app/views/admin/disputes/appeals/_appeal.html.haml
new file mode 100644
index 000000000..02b8777e1
--- /dev/null
+++ b/app/views/admin/disputes/appeals/_appeal.html.haml
@@ -0,0 +1,21 @@
+= link_to disputes_strike_path(appeal.strike), class: ['log-entry', appeal.approved? && 'log-entry--inactive'] do
+  .log-entry__header
+    .log-entry__avatar
+      = image_tag appeal.account.avatar.url(:original), alt: '', width: 40, height: 40, class: 'avatar'
+    .log-entry__content
+      .log-entry__title
+        = t(appeal.strike.action, scope: 'admin.strikes.actions', name: content_tag(:span, appeal.strike.account.username, class: 'username'), target: content_tag(:span, appeal.account.acct, class: 'target')).html_safe
+      .log-entry__timestamp
+        %time.formatted{ datetime: appeal.strike.created_at.iso8601 }
+          = l(appeal.strike.created_at)
+
+        - if appeal.strike.report_id.present?
+          ·
+          = t('admin.reports.title', id: appeal.strike.report_id)
+        ·
+        - if appeal.approved?
+          %span.positive-hint= t('admin.strikes.appeal_approved')
+        - elsif appeal.rejected?
+          %span.negative-hint= t('admin.strikes.appeal_rejected')
+        - else
+          %span.warning-hint= t('admin.strikes.appeal_pending')
diff --git a/app/views/admin/disputes/appeals/index.html.haml b/app/views/admin/disputes/appeals/index.html.haml
new file mode 100644
index 000000000..dd6a6f403
--- /dev/null
+++ b/app/views/admin/disputes/appeals/index.html.haml
@@ -0,0 +1,22 @@
+- content_for :page_title do
+  = t('admin.disputes.appeals.title')
+
+- content_for :header_tags do
+  = javascript_pack_tag 'admin', async: true, crossorigin: 'anonymous'
+
+.filters
+  .filter-subset
+    %strong= t('admin.tags.review')
+    %ul
+      %li= filter_link_to safe_join([t('admin.accounts.moderation.pending'), "(#{Appeal.pending.count})"], ' '), status: 'pending'
+      %li= filter_link_to t('admin.trends.approved'), status: 'approved'
+      %li= filter_link_to t('admin.trends.rejected'), status: 'rejected'
+
+- if @appeals.empty?
+  %div.muted-hint.center-text
+    = t 'admin.disputes.appeals.empty'
+- else
+  .announcements-list
+    = render partial: 'appeal', collection: @appeals
+
+= paginate @appeals
diff --git a/app/views/admin/report_notes/_report_note.html.haml b/app/views/admin/report_notes/_report_note.html.haml
index 428b6cf59..f9d57c2ae 100644
--- a/app/views/admin/report_notes/_report_note.html.haml
+++ b/app/views/admin/report_notes/_report_note.html.haml
@@ -3,7 +3,7 @@
 
   .report-notes__item__header
     %span.username
-      = link_to display_name(report_note.account), admin_account_path(report_note.account_id)
+      = link_to report_note.account.username, admin_account_path(report_note.account_id)
     %time{ datetime: report_note.created_at.iso8601, title: l(report_note.created_at) }
       - if report_note.created_at.today?
         = t('admin.report_notes.today_at', time: l(report_note.created_at, format: :time))
diff --git a/app/views/admin/reports/show.html.haml b/app/views/admin/reports/show.html.haml
index 02c46e384..e53c180e5 100644
--- a/app/views/admin/reports/show.html.haml
+++ b/app/views/admin/reports/show.html.haml
@@ -57,7 +57,7 @@
         .report-header__details__item__header
           %strong= t('admin.accounts.strikes')
         .report-header__details__item__content
-          = @report.target_account.strikes.count
+          = @report.target_account.previous_strikes_count
 
   .report-header__details
     .report-header__details__item
diff --git a/app/views/admin_mailer/new_appeal.text.erb b/app/views/admin_mailer/new_appeal.text.erb
new file mode 100644
index 000000000..db4529eb7
--- /dev/null
+++ b/app/views/admin_mailer/new_appeal.text.erb
@@ -0,0 +1,9 @@
+<%= raw t('application_mailer.salutation', name: display_name(@me)) %>
+
+<%= raw t('admin_mailer.new_appeal.body', target: @appeal.account.username, action_taken_by: @appeal.strike.account.username, date: l(@appeal.strike.created_at), type: t(@appeal.strike.action, scope: 'admin_mailer.new_appeal.actions')) %>
+
+> <%= raw word_wrap(@appeal.text, break_sequence: "\n> ") %>
+
+<%= raw t('admin_mailer.new_appeal.next_steps') %>
+
+<%= raw t('application_mailer.view')%> <%= disputes_strike_url(@appeal.strike) %>
diff --git a/app/views/auth/registrations/_account_warning.html.haml b/app/views/auth/registrations/_account_warning.html.haml
new file mode 100644
index 000000000..40e7e1296
--- /dev/null
+++ b/app/views/auth/registrations/_account_warning.html.haml
@@ -0,0 +1,20 @@
+= link_to disputes_strike_path(account_warning), class: 'log-entry' do
+  .log-entry__header
+    .log-entry__avatar
+      .indicator-icon{ class: account_warning.overruled? ? 'success' : 'failure' }
+        = fa_icon 'warning'
+    .log-entry__content
+      .log-entry__title
+        = t('disputes.strikes.title', action: t(account_warning.action, scope: 'disputes.strikes.title_actions'), date: l(account_warning.created_at.to_date))
+      .log-entry__timestamp
+        %time.formatted{ datetime: account_warning.created_at.iso8601 }= l(account_warning.created_at)
+
+        - if account_warning.overruled?
+          ·
+          %span.positive-hint= t('disputes.strikes.your_appeal_approved')
+        - elsif account_warning.appeal&.pending?
+          ·
+          %span.warning-hint= t('disputes.strikes.your_appeal_pending')
+        - elsif account_warning.appeal&.rejected?
+          ·
+          %span.negative-hint= t('disputes.strikes.your_appeal_rejected')
diff --git a/app/views/auth/registrations/_status.html.haml b/app/views/auth/registrations/_status.html.haml
index 47112dae0..3546510b2 100644
--- a/app/views/auth/registrations/_status.html.haml
+++ b/app/views/auth/registrations/_status.html.haml
@@ -1,22 +1,17 @@
+- if !@user.confirmed?
+  .flash-message.warning
+    = t('auth.status.confirming')
+    = link_to t('auth.didnt_get_confirmation'), new_user_confirmation_path
+- elsif !@user.approved?
+  .flash-message.warning
+    = t('auth.status.pending')
+- elsif @user.account.moved_to_account_id.present?
+  .flash-message.warning
+    = t('auth.status.redirecting_to', acct: @user.account.moved_to_account.acct)
+    = link_to t('migrations.cancel'), settings_migration_path
+
 %h3= t('auth.status.account_status')
 
-.simple_form
-  %p.hint
-    - if @user.account.suspended?
-      %span.negative-hint= t('user_mailer.warning.explanation.suspend')
-    - elsif @user.disabled?
-      %span.negative-hint= t('user_mailer.warning.explanation.disable')
-    - elsif @user.account.silenced?
-      %span.warning-hint= t('user_mailer.warning.explanation.silence')
-    - elsif !@user.confirmed?
-      %span.warning-hint= t('auth.status.confirming')
-      = link_to t('auth.didnt_get_confirmation'), new_user_confirmation_path
-    - elsif !@user.approved?
-      %span.warning-hint= t('auth.status.pending')
-    - elsif @user.account.moved_to_account_id.present?
-      %span.positive-hint= t('auth.status.redirecting_to', acct: @user.account.moved_to_account.acct)
-      = link_to t('migrations.cancel'), settings_migration_path
-    - else
-      %span.positive-hint= t('auth.status.functional')
+= render partial: 'account_warning', collection: @strikes
 
 %hr.spacer/
diff --git a/app/views/disputes/strikes/show.html.haml b/app/views/disputes/strikes/show.html.haml
new file mode 100644
index 000000000..3dcb19016
--- /dev/null
+++ b/app/views/disputes/strikes/show.html.haml
@@ -0,0 +1,127 @@
+- content_for :page_title do
+  = t('disputes.strikes.title', action: t(@strike.action, scope: 'disputes.strikes.title_actions'), date: l(@strike.created_at.to_date))
+
+- content_for :heading_actions do
+  - if @appeal.persisted?
+    = link_to t('admin.accounts.approve'), approve_admin_disputes_appeal_path(@appeal), method: :post, class: 'button' if can?(:approve, @appeal)
+    = link_to t('admin.accounts.reject'), reject_admin_disputes_appeal_path(@appeal), method: :post, class: 'button button--destructive' if can?(:reject, @appeal)
+
+- if @strike.overruled?
+  %p.hint
+    %span.positive-hint
+      = fa_icon 'check'
+      = ' '
+      = t 'disputes.strikes.appeal_approved'
+- elsif @appeal.persisted? && @appeal.rejected?
+  %p.hint
+    %span.negative-hint
+      = fa_icon 'times'
+      = ' '
+      = t 'disputes.strikes.appeal_rejected'
+
+.report-header
+  .report-header__card
+    .strike-card
+      - unless @strike.none_action?
+        %p= t "user_mailer.warning.explanation.#{@strike.action}"
+
+      - unless @strike.text.blank?
+        = Formatter.instance.linkify(@strike.text)
+
+      - if @strike.report && !@strike.report.other?
+        %p
+          %strong= t('user_mailer.warning.reason')
+          = t("user_mailer.warning.categories.#{@strike.report.category}")
+
+        - if @strike.report.violation? && @strike.report.rule_ids.present?
+          %ul.rules-list
+            - @strike.report.rules.each do |rule|
+              %li= rule.text
+
+      - if @strike.status_ids.present? && !@strike.status_ids.empty?
+        %p
+          %strong= t('user_mailer.warning.statuses')
+
+        .strike-card__statuses-list
+          - status_map = @strike.statuses.includes(:application, :media_attachments).index_by(&:id)
+
+          - @strike.status_ids.each do |status_id|
+            .strike-card__statuses-list__item
+              - if (status = status_map[status_id.to_i])
+                .one-liner
+                  = link_to short_account_status_url(@strike.target_account, status_id), class: 'emojify' do
+                    = one_line_preview(status)
+
+                    - status.media_attachments.each do |media_attachment|
+                      %abbr{ title: media_attachment.description }
+                        = fa_icon 'link'
+                        = media_attachment.file_file_name
+                .strike-card__statuses-list__item__meta
+                  %time.formatted{ datetime: status.created_at.iso8601, title: l(status.created_at) }= l(status.created_at)
+                  ·
+                  = status.application.name
+              - else
+                .one-liner= t('disputes.strikes.status', id: status_id)
+                .strike-card__statuses-list__item__meta
+                  = t('disputes.strikes.status_removed')
+
+  .report-header__details
+    .report-header__details__item
+      .report-header__details__item__header
+        %strong= t('disputes.strikes.created_at')
+      .report-header__details__item__content
+        %time.formatted{ datetime: @strike.created_at.iso8601, title: l(@strike.created_at) }= l(@strike.created_at)
+    .report-header__details__item
+      .report-header__details__item__header
+        %strong= t('disputes.strikes.recipient')
+      .report-header__details__item__content
+        = admin_account_link_to @strike.target_account, path: can?(:show, @strike.target_account) ? admin_account_path(@strike.target_account_id) : ActivityPub::TagManager.instance.url_for(@strike.target_account)
+    .report-header__details__item
+      .report-header__details__item__header
+        %strong= t('disputes.strikes.action_taken')
+      .report-header__details__item__content
+        - if @strike.overruled?
+          %del= t(@strike.action, scope: 'user_mailer.warning.title')
+        - else
+          = t(@strike.action, scope: 'user_mailer.warning.title')
+    - if @strike.report && can?(:show, @strike.report)
+      .report-header__details__item
+        .report-header__details__item__header
+          %strong= t('disputes.strikes.associated_report')
+        .report-header__details__item__content
+          = link_to t('admin.reports.report', id: @strike.report.id), admin_report_path(@strike.report)
+    - if @appeal.persisted?
+      .report-header__details__item
+        .report-header__details__item__header
+          %strong= t('disputes.strikes.appeal_submitted_at')
+        .report-header__details__item__content
+          %time.formatted{ datetime: @appeal.created_at.iso8601, title: l(@appeal.created_at) }= l(@appeal.created_at)
+%hr.spacer/
+
+- if @appeal.persisted?
+  %h3= t('disputes.strikes.appeal')
+
+  .report-notes
+    .report-notes__item
+      = image_tag @appeal.account.avatar.url, class: 'report-notes__item__avatar'
+
+      .report-notes__item__header
+        %span.username
+          = link_to @appeal.account.username, can?(:show, @appeal.account) ? admin_account_path(@appeal.account_id) : short_account_url(@appeal.account)
+        %time{ datetime: @appeal.created_at.iso8601, title: l(@appeal.created_at) }
+          - if @appeal.created_at.today?
+            = t('admin.report_notes.today_at', time: l(@appeal.created_at, format: :time))
+          - else
+            = l @appeal.created_at.to_date
+
+      .report-notes__item__content
+        = simple_format(h(@appeal.text))
+- elsif can?(:appeal, @strike)
+  %h3= t('disputes.strikes.appeals.submit')
+
+  = simple_form_for(@appeal, url: disputes_strike_appeal_path(@strike)) do |f|
+    .fields-group
+      = f.input :text, wrapper: :with_label, input_html: { maxlength: 500 }
+
+    .actions
+      = f.button :button, t('disputes.strikes.appeals.submit'), type: :submit
diff --git a/app/views/settings/preferences/notifications/show.html.haml b/app/views/settings/preferences/notifications/show.html.haml
index d7cc1ed5d..223e5d740 100644
--- a/app/views/settings/preferences/notifications/show.html.haml
+++ b/app/views/settings/preferences/notifications/show.html.haml
@@ -21,6 +21,7 @@
 
       - if current_user.staff?
         = ff.input :report, as: :boolean, wrapper: :with_label
+        = ff.input :appeal, as: :boolean, wrapper: :with_label
         = ff.input :pending_account, as: :boolean, wrapper: :with_label
         = ff.input :trending_tag, as: :boolean, wrapper: :with_label
 
diff --git a/app/views/statuses/_detailed_status.html.haml b/app/views/statuses/_detailed_status.html.haml
index cd5ed52af..1922f53ce 100644
--- a/app/views/statuses/_detailed_status.html.haml
+++ b/app/views/statuses/_detailed_status.html.haml
@@ -49,7 +49,7 @@
     %span.detailed-status__visibility-icon
       = visibility_icon status
     ·
-    - if status.application && @account.user&.setting_show_application
+    - if status.application && status.account.user&.setting_show_application
       - if status.application.website.blank?
         %strong.detailed-status__application= status.application.name
       - else
diff --git a/app/views/user_mailer/appeal_approved.html.haml b/app/views/user_mailer/appeal_approved.html.haml
new file mode 100644
index 000000000..962cab2e2
--- /dev/null
+++ b/app/views/user_mailer/appeal_approved.html.haml
@@ -0,0 +1,59 @@
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.hero
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center.padded
+                              %table.hero-icon{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                                %tbody
+                                  %tr
+                                    %td
+                                      = image_tag full_pack_url('media/images/mailer/icon_done.png'), alt: ''
+
+                              %h1= t 'user_mailer.appeal_approved.title'
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.content-start
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center
+                              %p= t 'user_mailer.appeal_approved.explanation', appeal_date: l(@appeal.created_at), strike_date: l(@appeal.strike.created_at)
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell
+                  %table.column{ cellspacing: 0, cellpadding: 0 }
+                    %tbody
+                      %tr
+                        %td.column-cell.button-cell
+                          %table.button{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                            %tbody
+                              %tr
+                                %td.button-primary
+                                  = link_to root_url do
+                                    %span= t 'user_mailer.appeal_approved.action'
diff --git a/app/views/user_mailer/appeal_approved.text.erb b/app/views/user_mailer/appeal_approved.text.erb
new file mode 100644
index 000000000..290fa24c3
--- /dev/null
+++ b/app/views/user_mailer/appeal_approved.text.erb
@@ -0,0 +1,7 @@
+<%= t 'user_mailer.appeal_approved.title' %>
+
+===
+
+<%= t 'user_mailer.appeal_approved.explanation', appeal_date: l(@appeal.created_at), strike_date: l(@appeal.strike.created_at) %>
+
+=> <%= root_url %>
diff --git a/app/views/user_mailer/appeal_rejected.html.haml b/app/views/user_mailer/appeal_rejected.html.haml
new file mode 100644
index 000000000..75cd9d023
--- /dev/null
+++ b/app/views/user_mailer/appeal_rejected.html.haml
@@ -0,0 +1,59 @@
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.hero
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center.padded
+                              %table.hero-icon{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                                %tbody
+                                  %tr
+                                    %td
+                                      = image_tag full_pack_url('media/images/mailer/icon_warning.png'), alt: ''
+
+                              %h1= t 'user_mailer.appeal_rejected.title'
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell.content-start
+                  .email-row
+                    .col-6
+                      %table.column{ cellspacing: 0, cellpadding: 0 }
+                        %tbody
+                          %tr
+                            %td.column-cell.text-center
+                              %p= t 'user_mailer.appeal_rejected.explanation', appeal_date: l(@appeal.created_at), strike_date: l(@appeal.strike.created_at)
+
+%table.email-table{ cellspacing: 0, cellpadding: 0 }
+  %tbody
+    %tr
+      %td.email-body
+        .email-container
+          %table.content-section{ cellspacing: 0, cellpadding: 0 }
+            %tbody
+              %tr
+                %td.content-cell
+                  %table.column{ cellspacing: 0, cellpadding: 0 }
+                    %tbody
+                      %tr
+                        %td.column-cell.button-cell
+                          %table.button{ align: 'center', cellspacing: 0, cellpadding: 0 }
+                            %tbody
+                              %tr
+                                %td.button-primary
+                                  = link_to root_url do
+                                    %span= t 'user_mailer.appeal_approved.action'
diff --git a/app/views/user_mailer/appeal_rejected.text.erb b/app/views/user_mailer/appeal_rejected.text.erb
new file mode 100644
index 000000000..f47a76818
--- /dev/null
+++ b/app/views/user_mailer/appeal_rejected.text.erb
@@ -0,0 +1,7 @@
+<%= t 'user_mailer.appeal_rejected.title' %>
+
+===
+
+<%= t 'user_mailer.appeal_rejected.explanation', appeal_date: l(@appeal.created_at), strike_date: l(@appeal.strike.created_at) %>
+
+=> <%= root_url %>
diff --git a/app/views/user_mailer/warning.html.haml b/app/views/user_mailer/warning.html.haml
index bda1fef6c..b308e18f7 100644
--- a/app/views/user_mailer/warning.html.haml
+++ b/app/views/user_mailer/warning.html.haml
@@ -77,8 +77,8 @@
                             %tbody
                               %tr
                                 %td.button-primary
-                                  = link_to about_more_url do
-                                    %span= t 'user_mailer.warning.review_server_policies'
+                                  = link_to disputes_strike_url(@warning) do
+                                    %span= t 'user_mailer.warning.appeal'
 
 %table.email-table{ cellspacing: 0, cellpadding: 0 }
   %tbody
@@ -95,4 +95,4 @@
                         %tbody
                           %tr
                             %td.column-cell.text-center
-                              %p= t 'user_mailer.warning.get_in_touch', instance: @instance
+                              %p= t 'user_mailer.warning.appeal_description', instance: @instance
diff --git a/config/brakeman.ignore b/config/brakeman.ignore
index 4245b7192..6ffe12ae0 100644
--- a/config/brakeman.ignore
+++ b/config/brakeman.ignore
@@ -1,25 +1,5 @@
 {
   "ignored_warnings": [
-    {
-      "warning_type": "SQL Injection",
-      "warning_code": 0,
-      "fingerprint": "04dbbc249b989db2e0119bbb0f59c9818e12889d2b97c529cdc0b1526002ba4b",
-      "check_name": "SQL",
-      "message": "Possible SQL injection",
-      "file": "app/models/report.rb",
-      "line": 113,
-      "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
-      "code": "Admin::ActionLog.from(\"(#{[Admin::ActionLog.where(:target_type => \"Report\", :target_id => id, :created_at => ((created_at..updated_at))).unscope(:order), Admin::ActionLog.where(:target_type => \"Account\", :target_id => target_account_id, :created_at => ((created_at..updated_at))).unscope(:order), Admin::ActionLog.where(:target_type => \"Status\", :target_id => status_ids, :created_at => ((created_at..updated_at))).unscope(:order)].map do\n \"(#{query.to_sql})\"\n end.join(\" UNION ALL \")}) AS admin_action_logs\")",
-      "render_path": null,
-      "location": {
-        "type": "method",
-        "class": "Report",
-        "method": "history"
-      },
-      "user_input": "Admin::ActionLog.where(:target_type => \"Status\", :target_id => status_ids, :created_at => ((created_at..updated_at))).unscope(:order)",
-      "confidence": "High",
-      "note": ""
-    },
     {
       "warning_type": "SQL Injection",
       "warning_code": 0,
@@ -27,7 +7,7 @@
       "check_name": "SQL",
       "message": "Possible SQL injection",
       "file": "app/models/status.rb",
-      "line": 100,
+      "line": 104,
       "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
       "code": "result.joins(\"INNER JOIN statuses_tags t#{id} ON t#{id}.status_id = statuses.id AND t#{id}.tag_id = #{id}\")",
       "render_path": null,
@@ -107,7 +87,7 @@
       "check_name": "PermitAttributes",
       "message": "Potentially dangerous key allowed for mass assignment",
       "file": "app/controllers/api/v1/admin/reports_controller.rb",
-      "line": 78,
+      "line": 90,
       "link": "https://brakemanscanner.org/docs/warning_types/mass_assignment/",
       "code": "params.permit(:resolved, :account_id, :target_account_id)",
       "render_path": null,
@@ -140,6 +120,36 @@
       "confidence": "Medium",
       "note": ""
     },
+    {
+      "warning_type": "Cross-Site Scripting",
+      "warning_code": 2,
+      "fingerprint": "afad51718ae373b2f19d2513029fd2afccf58b9148e475934bc6a162ee33c352",
+      "check_name": "CrossSiteScripting",
+      "message": "Unescaped model attribute",
+      "file": "app/views/admin/disputes/appeals/_appeal.html.haml",
+      "line": 7,
+      "link": "https://brakemanscanner.org/docs/warning_types/cross_site_scripting",
+      "code": "t((Unresolved Model).new.strike.action, :scope => \"admin.strikes.actions\", :name => content_tag(:span, (Unresolved Model).new.strike.account.username, :class => \"username\"), :target => content_tag(:span, (Unresolved Model).new.account.acct, :class => \"target\"))",
+      "render_path": [
+        {
+          "type": "template",
+          "name": "admin/disputes/appeals/index",
+          "line": 16,
+          "file": "app/views/admin/disputes/appeals/index.html.haml",
+          "rendered": {
+            "name": "admin/disputes/appeals/_appeal",
+            "file": "app/views/admin/disputes/appeals/_appeal.html.haml"
+          }
+        }
+      ],
+      "location": {
+        "type": "template",
+        "template": "admin/disputes/appeals/_appeal"
+      },
+      "user_input": "(Unresolved Model).new.strike",
+      "confidence": "Weak",
+      "note": ""
+    },
     {
       "warning_type": "Redirect",
       "warning_code": 18,
@@ -194,7 +204,7 @@
         {
           "type": "template",
           "name": "admin/trends/links/index",
-          "line": 37,
+          "line": 39,
           "file": "app/views/admin/trends/links/index.html.haml",
           "rendered": {
             "name": "admin/trends/links/_preview_card",
@@ -213,13 +223,13 @@
     {
       "warning_type": "Mass Assignment",
       "warning_code": 105,
-      "fingerprint": "e867661b2c9812bc8b75a5df12b28e2a53ab97015de0638b4e732fe442561b28",
+      "fingerprint": "f9de0ca4b04ae4b51b74d98db14dcbb6dae6809e627b58e711019cf9b4a47866",
       "check_name": "PermitAttributes",
       "message": "Potentially dangerous key allowed for mass assignment",
       "file": "app/controllers/api/v1/reports_controller.rb",
       "line": 36,
       "link": "https://brakemanscanner.org/docs/warning_types/mass_assignment/",
-      "code": "params.permit(:account_id, :comment, :forward, :status_ids => ([]))",
+      "code": "params.permit(:account_id, :comment, :category, :forward, :status_ids => ([]), :rule_ids => ([]))",
       "render_path": null,
       "location": {
         "type": "method",
@@ -231,6 +241,6 @@
       "note": ""
     }
   ],
-  "updated": "2021-11-14 05:26:09 +0100",
-  "brakeman_version": "5.1.2"
+  "updated": "2022-02-13 02:24:12 +0100",
+  "brakeman_version": "5.2.1"
 }
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 1809f123e..05c64e18a 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -94,7 +94,6 @@ en:
     account_moderation_notes:
       create: Leave note
       created_msg: Moderation note successfully created!
-      delete: Delete
       destroyed_msg: Moderation note successfully destroyed!
     accounts:
       add_email_domain_block: Block e-mail domain
@@ -163,6 +162,11 @@ en:
       not_subscribed: Not subscribed
       pending: Pending review
       perform_full_suspension: Suspend
+      previous_strikes: Previous strikes
+      previous_strikes_description_html:
+        one: This account has <strong>one</strong> strike.
+        other: This account has <strong>%{count}</strong> strikes.
+        zero: This account is <strong>in good standing</strong>.
       promote: Promote
       protocol: Protocol
       public: Public
@@ -227,6 +231,7 @@ en:
       whitelisted: Allowed for federation
     action_logs:
       action_types:
+        approve_appeal: Approve Appeal
         approve_user: Approve User
         assigned_to_self_report: Assign Report
         change_email_user: Change E-mail for User
@@ -258,6 +263,7 @@ en:
         enable_user: Enable User
         memorialize_account: Memorialize Account
         promote_user: Promote User
+        reject_appeal: Reject Appeal
         reject_user: Reject User
         remove_avatar_user: Remove Avatar
         reopen_report: Reopen Report
@@ -276,6 +282,7 @@ en:
         update_domain_block: Update Domain Block
         update_status: Update Post
       actions:
+        approve_appeal_html: "%{name} approved moderation decision appeal from %{target}"
         approve_user_html: "%{name} approved sign-up from %{target}"
         assigned_to_self_report_html: "%{name} assigned report %{target} to themselves"
         change_email_user_html: "%{name} changed the e-mail address of user %{target}"
@@ -307,6 +314,7 @@ en:
         enable_user_html: "%{name} enabled login for user %{target}"
         memorialize_account_html: "%{name} turned %{target}'s account into a memoriam page"
         promote_user_html: "%{name} promoted user %{target}"
+        reject_appeal_html: "%{name} rejected moderation decision appeal from %{target}"
         reject_user_html: "%{name} rejected sign-up from %{target}"
         remove_avatar_user_html: "%{name} removed %{target}'s avatar"
         reopen_report_html: "%{name} reopened report %{target}"
@@ -385,6 +393,9 @@ en:
       media_storage: Media storage
       new_users: new users
       opened_reports: reports opened
+      pending_appeals_html:
+        one: "<strong>1</strong> pending appeal"
+        other: "<strong>%{count}</strong> pending appeals"
       pending_reports_html:
         one: "<strong>1</strong> pending report"
         other: "<strong>%{count}</strong> pending reports"
@@ -402,6 +413,10 @@ en:
       top_languages: Top active languages
       top_servers: Top active servers
       website: Website
+    disputes:
+      appeals:
+        empty: No appeals found.
+        title: Appeals
     domain_allows:
       add_new: Allow federation with domain
       created_msg: Domain has been successfully allowed for federation
@@ -720,6 +735,16 @@ en:
       no_status_selected: No posts were changed as none were selected
       title: Account posts
       with_media: With media
+    strikes:
+      actions:
+        delete_statuses: "%{name} deleted %{target}'s posts"
+        disable: "%{name} froze %{target}'s account"
+        none: "%{name} sent a warning to %{target}"
+        sensitive: "%{name} marked %{target}'s account as sensitive"
+        silence: "%{name} limited %{target}'s account"
+        suspend: "%{name} suspended %{target}'s account"
+      appeal_approved: Appealed
+      appeal_pending: Appeal pending
     system_checks:
       database_schema_check:
         message_html: There are pending database migrations. Please run them to ensure the application behaves as expected
@@ -781,6 +806,17 @@ en:
       empty: You haven't defined any warning presets yet.
       title: Manage warning presets
   admin_mailer:
+    new_appeal:
+      actions:
+        delete_statuses: to delete their posts
+        disable: to freeze their account
+        none: a warning
+        sensitive: to mark their account as sensitive
+        silence: to limit their account
+        suspend: to suspend their account
+      body: "%{target} is appealing a moderation decision by %{action_taken_by} from %{date}, which was %{type}. They wrote:"
+      next_steps: You can approve the appeal to undo the moderation decision, or ignore it.
+      subject: "%{username} is appealing a moderation decision on %{instance}"
     new_pending_account:
       body: The details of the new account are below. You can approve or reject this application.
       subject: New account up for review on %{instance} (%{username})
@@ -871,7 +907,6 @@ en:
     status:
       account_status: Account status
       confirming: Waiting for e-mail confirmation to be completed.
-      functional: Your account is fully operational.
       pending: Your application is pending review by our staff. This may take some time. You will receive an e-mail if your application is approved.
       redirecting_to: Your account is inactive because it is currently redirecting to %{acct}.
     too_fast: Form submitted too fast, try again.
@@ -937,6 +972,32 @@ en:
     directory: Profile directory
     explanation: Discover users based on their interests
     explore_mastodon: Explore %{title}
+  disputes:
+    strikes:
+      action_taken: Action taken
+      appeal: Appeal
+      appeal_approved: This strike has been successfully appealed and is no longer valid
+      appeal_rejected: The appeal has been rejected
+      appeal_submitted_at: Appeal submitted
+      appealed_msg: Your appeal has been submitted. If it is approved, you will be notified.
+      appeals:
+        submit: Submit appeal
+      associated_report: Associated report
+      created_at: Dated
+      recipient: Addressed to
+      status: 'Post #%{id}'
+      status_removed: Post already removed from system
+      title: "%{action} from %{date}"
+      title_actions:
+        delete_statuses: Post removal
+        disable: Freezing of account
+        none: Warning
+        sensitive: Marking as sensitive of account
+        silence: Limitation of account
+        suspend: Suspension of account
+      your_appeal_approved: Your appeal has been approved
+      your_appeal_pending: You have submitted an appeal
+      your_appeal_rejected: Your appeal has been rejected
   domain_validator:
     invalid_domain: is not a valid domain name
   errors:
@@ -1501,6 +1562,15 @@ en:
     recovery_instructions_html: If you ever lose access to your phone, you can use one of the recovery codes below to regain access to your account. <strong>Keep the recovery codes safe</strong>. For example, you may print them and store them with other important documents.
     webauthn: Security keys
   user_mailer:
+    appeal_approved:
+      action: Go to your account
+      explanation: The appeal of the strike against your account on %{strike_date} that you submitted on %{appeal_date} has been approved. Your account is once again in good standing.
+      subject: Your appeal from %{date} has been approved
+      title: Appeal approved
+    appeal_rejected:
+      explanation: The appeal of the strike against your account on %{strike_date} that you submitted on %{appeal_date} has been rejected.
+      subject: Your appeal from %{date} has been rejected
+      title: Appeal rejected
     backup_ready:
       explanation: You requested a full backup of your Mastodon account. It's now ready for download!
       subject: Your archive is ready for download
@@ -1512,6 +1582,8 @@ en:
       subject: Please confirm attempted sign in
       title: Sign in attempt
     warning:
+      appeal: Submit an appeal
+      appeal_description: If you believe this is an error, you can submit an appeal to the staff of %{instance}.
       categories:
         spam: Spam
         violation: Content violates the following community guidelines
@@ -1523,7 +1595,6 @@ en:
         suspend: You can no longer use your account, and your profile and other data are no longer accessible. You can still login to request a backup of your data until the data is fully removed in about 30 days, but we will retain some basic data to prevent you from evading the suspension.
       get_in_touch: If you believe this is an error, you can reply to this e-mail to get in touch with the staff of %{instance}.
       reason: 'Reason:'
-      review_server_policies: Review server policies
       statuses: 'Posts that have been found in violation:'
       subject:
         delete_statuses: Your posts on %{acct} have been removed
diff --git a/config/locales/simple_form.en.yml b/config/locales/simple_form.en.yml
index d6376782d..03eefd0d5 100644
--- a/config/locales/simple_form.en.yml
+++ b/config/locales/simple_form.en.yml
@@ -27,6 +27,8 @@ en:
         scheduled_at: Leave blank to publish the announcement immediately
         starts_at: Optional. In case your announcement is bound to a specific time range
         text: You can use post syntax. Please be mindful of the space the announcement will take up on the user's screen
+      appeal:
+        text: You can only appeal a strike once
       defaults:
         autofollow: People who sign up through the invite will automatically follow you
         avatar: PNG, GIF or JPG. At most %{size}. Will be downscaled to %{dimensions}px
@@ -119,6 +121,8 @@ en:
         scheduled_at: Schedule publication
         starts_at: Start of event
         text: Announcement
+      appeal:
+        text: Explain why this decision should be reversed
       defaults:
         autofollow: Invite to follow your account
         avatar: Avatar
@@ -197,6 +201,7 @@ en:
           sign_up_requires_approval: Limit sign-ups
         severity: Rule
       notification_emails:
+        appeal: Someone appeals a moderator decision
         digest: Send digest e-mails
         favourite: Someone favourited your post
         follow: Someone followed you
@@ -204,8 +209,8 @@ en:
         mention: Someone mentioned you
         pending_account: New account needs review
         reblog: Someone boosted your post
-        report: A new report is submitted
-        trending_tag: A new trend requires approval
+        report: New report is submitted
+        trending_tag: New trend requires review
       rule:
         text: Rule
       tag:
diff --git a/config/navigation.rb b/config/navigation.rb
index fc03a2a77..3fc3747d5 100644
--- a/config/navigation.rb
+++ b/config/navigation.rb
@@ -20,7 +20,7 @@ SimpleNavigation::Configuration.run do |navigation|
     n.item :statuses_cleanup, safe_join([fa_icon('history fw'), t('settings.statuses_cleanup')]), statuses_cleanup_url, if: -> { current_user.functional? }
 
     n.item :security, safe_join([fa_icon('lock fw'), t('settings.account')]), edit_user_registration_url do |s|
-      s.item :password, safe_join([fa_icon('lock fw'), t('settings.account_settings')]), edit_user_registration_url, highlights_on: %r{/auth/edit|/settings/delete|/settings/migration|/settings/aliases|/settings/login_activities}
+      s.item :password, safe_join([fa_icon('lock fw'), t('settings.account_settings')]), edit_user_registration_url, highlights_on: %r{/auth/edit|/settings/delete|/settings/migration|/settings/aliases|/settings/login_activities|^/disputes}
       s.item :two_factor_authentication, safe_join([fa_icon('mobile fw'), t('settings.two_factor_authentication')]), settings_two_factor_authentication_methods_url, highlights_on: %r{/settings/two_factor_authentication|/settings/otp_authentication|/settings/security_keys}
       s.item :authorized_apps, safe_join([fa_icon('list fw'), t('settings.authorized_apps')]), oauth_authorized_applications_url
     end
@@ -41,7 +41,7 @@ SimpleNavigation::Configuration.run do |navigation|
     n.item :moderation, safe_join([fa_icon('gavel fw'), t('moderation.title')]), admin_reports_url, if: proc { current_user.staff? } do |s|
       s.item :action_logs, safe_join([fa_icon('bars fw'), t('admin.action_logs.title')]), admin_action_logs_url
       s.item :reports, safe_join([fa_icon('flag fw'), t('admin.reports.title')]), admin_reports_url, highlights_on: %r{/admin/reports}
-      s.item :accounts, safe_join([fa_icon('users fw'), t('admin.accounts.title')]), admin_accounts_url(origin: 'local'), highlights_on: %r{/admin/accounts|/admin/pending_accounts}
+      s.item :accounts, safe_join([fa_icon('users fw'), t('admin.accounts.title')]), admin_accounts_url(origin: 'local'), highlights_on: %r{/admin/accounts|/admin/pending_accounts|/admin/disputes}
       s.item :invites, safe_join([fa_icon('user-plus fw'), t('admin.invites.title')]), admin_invites_path
       s.item :follow_recommendations, safe_join([fa_icon('user-plus fw'), t('admin.follow_recommendations.title')]), admin_follow_recommendations_path, highlights_on: %r{/admin/follow_recommendations}
       s.item :instances, safe_join([fa_icon('cloud fw'), t('admin.instances.title')]), admin_instances_url(limited: whitelist_mode? ? nil : '1'), highlights_on: %r{/admin/instances|/admin/domain_blocks|/admin/domain_allows}, if: -> { current_user.admin? }
diff --git a/config/routes.rb b/config/routes.rb
index 5edb36519..f59f2a5bb 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -164,6 +164,12 @@ Rails.application.routes.draw do
     resources :login_activities, only: [:index]
   end
 
+  namespace :disputes do
+    resources :strikes, only: [:show] do
+      resource :appeal, only: [:create]
+    end
+  end
+
   resources :media, only: [:show] do
     get :player
   end
@@ -324,6 +330,15 @@ Rails.application.routes.draw do
         end
       end
     end
+
+    namespace :disputes do
+      resources :appeals, only: [:index] do
+        member do
+          post :approve
+          post :reject
+        end
+      end
+    end
   end
 
   get '/admin', to: redirect('/admin/dashboard', status: 302)
diff --git a/config/settings.yml b/config/settings.yml
index 06cee2532..e63788ba2 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -48,6 +48,7 @@ defaults: &defaults
     report: true
     pending_account: true
     trending_tag: true
+    appeal: true
   interactions:
     must_be_follower: false
     must_be_following: false
diff --git a/db/migrate/20220124141035_create_appeals.rb b/db/migrate/20220124141035_create_appeals.rb
new file mode 100644
index 000000000..afb3efbd5
--- /dev/null
+++ b/db/migrate/20220124141035_create_appeals.rb
@@ -0,0 +1,14 @@
+class CreateAppeals < ActiveRecord::Migration[6.1]
+  def change
+    create_table :appeals do |t|
+      t.belongs_to :account, null: false, foreign_key: { on_delete: :cascade }
+      t.belongs_to :account_warning, null: false, foreign_key: { on_delete: :cascade }, index: { unique: true }
+      t.text :text, null: false, default: ''
+      t.datetime :approved_at
+      t.belongs_to :approved_by_account, foreign_key: { to_table: :accounts, on_delete: :nullify }
+      t.datetime :rejected_at
+      t.belongs_to :rejected_by_account, foreign_key: { to_table: :accounts, on_delete: :nullify }
+      t.timestamps
+    end
+  end
+end
diff --git a/db/migrate/20220210153119_add_overruled_at_to_account_warnings.rb b/db/migrate/20220210153119_add_overruled_at_to_account_warnings.rb
new file mode 100644
index 000000000..a082da774
--- /dev/null
+++ b/db/migrate/20220210153119_add_overruled_at_to_account_warnings.rb
@@ -0,0 +1,5 @@
+class AddOverruledAtToAccountWarnings < ActiveRecord::Migration[6.1]
+  def change
+    add_column :account_warnings, :overruled_at, :datetime
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index fd4633d69..8842dcd8c 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2022_01_18_183123) do
+ActiveRecord::Schema.define(version: 2022_02_10_153119) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -135,6 +135,7 @@ ActiveRecord::Schema.define(version: 2022_01_18_183123) do
     t.datetime "updated_at", null: false
     t.bigint "report_id"
     t.string "status_ids", array: true
+    t.datetime "overruled_at"
     t.index ["account_id"], name: "index_account_warnings_on_account_id"
     t.index ["target_account_id"], name: "index_account_warnings_on_target_account_id"
   end
@@ -243,6 +244,22 @@ ActiveRecord::Schema.define(version: 2022_01_18_183123) do
     t.bigint "status_ids", array: true
   end
 
+  create_table "appeals", force: :cascade do |t|
+    t.bigint "account_id", null: false
+    t.bigint "account_warning_id", null: false
+    t.text "text", default: "", null: false
+    t.datetime "approved_at"
+    t.bigint "approved_by_account_id"
+    t.datetime "rejected_at"
+    t.bigint "rejected_by_account_id"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["account_id"], name: "index_appeals_on_account_id"
+    t.index ["account_warning_id"], name: "index_appeals_on_account_warning_id", unique: true
+    t.index ["approved_by_account_id"], name: "index_appeals_on_approved_by_account_id"
+    t.index ["rejected_by_account_id"], name: "index_appeals_on_rejected_by_account_id"
+  end
+
   create_table "backups", force: :cascade do |t|
     t.bigint "user_id"
     t.string "dump_file_name"
@@ -1031,6 +1048,10 @@ ActiveRecord::Schema.define(version: 2022_01_18_183123) do
   add_foreign_key "announcement_reactions", "accounts", on_delete: :cascade
   add_foreign_key "announcement_reactions", "announcements", on_delete: :cascade
   add_foreign_key "announcement_reactions", "custom_emojis", on_delete: :cascade
+  add_foreign_key "appeals", "account_warnings", on_delete: :cascade
+  add_foreign_key "appeals", "accounts", column: "approved_by_account_id", on_delete: :nullify
+  add_foreign_key "appeals", "accounts", column: "rejected_by_account_id", on_delete: :nullify
+  add_foreign_key "appeals", "accounts", on_delete: :cascade
   add_foreign_key "backups", "users", on_delete: :nullify
   add_foreign_key "blocks", "accounts", column: "target_account_id", name: "fk_9571bfabc1", on_delete: :cascade
   add_foreign_key "blocks", "accounts", name: "fk_4269e03e65", on_delete: :cascade
diff --git a/spec/controllers/admin/disputes/appeals_controller_spec.rb b/spec/controllers/admin/disputes/appeals_controller_spec.rb
new file mode 100644
index 000000000..6a06f9406
--- /dev/null
+++ b/spec/controllers/admin/disputes/appeals_controller_spec.rb
@@ -0,0 +1,53 @@
+require 'rails_helper'
+
+RSpec.describe Admin::Disputes::AppealsController, type: :controller do
+  render_views
+
+  before { sign_in current_user, scope: :user }
+
+  let(:target_account) { Fabricate(:account) }
+  let(:strike) { Fabricate(:account_warning, target_account: target_account, action: :suspend) }
+  let(:appeal) { Fabricate(:appeal, strike: strike, account: target_account) }
+
+  before do
+    target_account.suspend!
+  end
+
+  describe 'POST #approve' do
+    let(:current_user) { Fabricate(:user, admin: true) }
+
+    before do
+      allow(UserMailer).to receive(:appeal_approved).and_return(double('email', deliver_later: nil))
+      post :approve, params: { id: appeal.id }
+    end
+
+    it 'unsuspends a suspended account' do
+      expect(target_account.reload.suspended?).to be false
+    end
+
+    it 'redirects back to the strike page' do
+      expect(response).to redirect_to(disputes_strike_path(appeal.strike))
+    end
+
+    it 'notifies target account about approved appeal' do
+      expect(UserMailer).to have_received(:appeal_approved).with(target_account.user, appeal)
+    end
+  end
+
+  describe 'POST #reject' do
+    let(:current_user) { Fabricate(:user, admin: true) }
+
+    before do
+      allow(UserMailer).to receive(:appeal_rejected).and_return(double('email', deliver_later: nil))
+      post :reject, params: { id: appeal.id }
+    end
+
+    it 'redirects back to the strike page' do
+      expect(response).to redirect_to(disputes_strike_path(appeal.strike))
+    end
+
+    it 'notifies target account about rejected appeal' do
+      expect(UserMailer).to have_received(:appeal_rejected).with(target_account.user, appeal)
+    end
+  end
+end
diff --git a/spec/controllers/disputes/appeals_controller_spec.rb b/spec/controllers/disputes/appeals_controller_spec.rb
new file mode 100644
index 000000000..faa571fc9
--- /dev/null
+++ b/spec/controllers/disputes/appeals_controller_spec.rb
@@ -0,0 +1,27 @@
+require 'rails_helper'
+
+RSpec.describe Disputes::AppealsController, type: :controller do
+  render_views
+
+  before { sign_in current_user, scope: :user }
+
+  let!(:admin) { Fabricate(:user, admin: true) }
+
+  describe '#create' do
+    let(:current_user) { Fabricate(:user) }
+    let(:strike) { Fabricate(:account_warning, target_account: current_user.account) }
+
+    before do
+      allow(AdminMailer).to receive(:new_appeal).and_return(double('email', deliver_later: nil))
+      post :create, params: { strike_id: strike.id, appeal: { text: 'Foo' } }
+    end
+
+    it 'notifies staff about new appeal' do
+      expect(AdminMailer).to have_received(:new_appeal).with(admin.account, Appeal.last)
+    end
+
+    it 'redirects back to the strike page' do
+      expect(response).to redirect_to(disputes_strike_path(strike.id))
+    end
+  end
+end
diff --git a/spec/controllers/disputes/strikes_controller_spec.rb b/spec/controllers/disputes/strikes_controller_spec.rb
new file mode 100644
index 000000000..157f9ec3c
--- /dev/null
+++ b/spec/controllers/disputes/strikes_controller_spec.rb
@@ -0,0 +1,30 @@
+require 'rails_helper'
+
+RSpec.describe Disputes::StrikesController, type: :controller do
+  render_views
+
+  before { sign_in current_user, scope: :user }
+
+  describe '#show' do
+    let(:current_user) { Fabricate(:user) }
+    let(:strike) { Fabricate(:account_warning, target_account: current_user.account) }
+
+    before do
+      get :show, params: { id: strike.id }
+    end
+
+    context 'when meant for the user' do
+      it 'returns http success' do
+        expect(response).to have_http_status(:success)
+      end
+    end
+
+    context 'when meant for a different user' do
+      let(:strike) { Fabricate(:account_warning) }
+
+      it 'returns http forbidden' do
+        expect(response).to have_http_status(:forbidden)
+      end
+    end
+  end
+end
diff --git a/spec/fabricators/account_warning_fabricator.rb b/spec/fabricators/account_warning_fabricator.rb
index db161d446..72fe835d9 100644
--- a/spec/fabricators/account_warning_fabricator.rb
+++ b/spec/fabricators/account_warning_fabricator.rb
@@ -1,5 +1,6 @@
 Fabricator(:account_warning) do
-  account        nil
-  target_account nil
-  text           "MyText"
+  account
+  target_account(fabricator: :account)
+  text { Faker::Lorem.paragraph }
+  action 'suspend'
 end
diff --git a/spec/fabricators/appeal_fabricator.rb b/spec/fabricators/appeal_fabricator.rb
new file mode 100644
index 000000000..339363822
--- /dev/null
+++ b/spec/fabricators/appeal_fabricator.rb
@@ -0,0 +1,5 @@
+Fabricator(:appeal) do
+  strike(fabricator: :account_warning)
+  account { |attrs| attrs[:strike].target_account }
+  text { Faker::Lorem.paragraph }
+end
diff --git a/spec/mailers/previews/admin_mailer_preview.rb b/spec/mailers/previews/admin_mailer_preview.rb
index 75ffbbf40..9c0372b47 100644
--- a/spec/mailers/previews/admin_mailer_preview.rb
+++ b/spec/mailers/previews/admin_mailer_preview.rb
@@ -15,4 +15,9 @@ class AdminMailerPreview < ActionMailer::Preview
   def new_trending_links
     AdminMailer.new_trending_links(Account.first, PreviewCard.limit(3))
   end
+
+  # Preview this email at http://localhost:3000/rails/mailers/admin_mailer/new_appeal
+  def new_appeal
+    AdminMailer.new_appeal(Account.first, Appeal.first)
+  end
 end
diff --git a/spec/mailers/previews/user_mailer_preview.rb b/spec/mailers/previews/user_mailer_preview.rb
index 69b9b971e..8de7d8669 100644
--- a/spec/mailers/previews/user_mailer_preview.rb
+++ b/spec/mailers/previews/user_mailer_preview.rb
@@ -82,6 +82,11 @@ class UserMailerPreview < ActionMailer::Preview
     UserMailer.warning(User.first, AccountWarning.last)
   end
 
+  # Preview this email at http://localhost:3000/rails/mailers/user_mailer/appeal_approved
+  def appeal_approved
+    UserMailer.appeal_approved(User.first, Appeal.last)
+  end
+
   # Preview this email at http://localhost:3000/rails/mailers/user_mailer/sign_in_token
   def sign_in_token
     UserMailer.sign_in_token(User.first.tap { |user| user.generate_sign_in_token }, '127.0.0.1', 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:75.0) Gecko/20100101 Firefox/75.0', Time.now.utc)
diff --git a/spec/models/appeal_spec.rb b/spec/models/appeal_spec.rb
new file mode 100644
index 000000000..14062dc4f
--- /dev/null
+++ b/spec/models/appeal_spec.rb
@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Appeal, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end