# There're two ways to run this app:
#
# run the web
# $ export FLASK_APP=app.py
# $ flask run
#
# create or refresh the database
# $ python3 app.py

from flask import Flask, request, render_template, send_from_directory, abort, redirect, session, url_for, send_file, flash
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import func
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address

import ipfshttpclient
from mastodon import Mastodon

import pypinyin

from string import ascii_uppercase as AZ
from datetime import date, datetime
from functools import wraps
import hashlib
import shutil
import random
import os
import re
from config  import C

app = Flask(__name__)
app.config.from_object('config.C')
app.secret_key = C.session_key

limiter = Limiter(
    app,
    key_func=get_remote_address,
    default_limits=["50 / minute"],
)

db = SQLAlchemy(app)

ipfs_client = ipfshttpclient.connect()
ipfs_info = ipfs_client.id()

MAST_LOGIN_URL = Mastodon(api_base_url=C.mast_base_uri) \
                .auth_request_url(
                    client_id = C.mast_client_id,
                    redirect_uris = C.mast_redirect_uri,
                    scopes = ['read:accounts']
                )

class Paper(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    course = db.Column(db.String(30), index=True)
    teacher = db.Column(db.String(30), index=True)
    year = db.Column(db.Integer, index=True)
    author = db.Column(db.String(30), index=True)
    notes = db.Column(db.String(200))
    anon = db.Column(db.Boolean)
    create_date = db.Column(db.Date)
    like_num = db.Column(db.Integer, index=True, default=0)
    down_num = db.Column(db.Integer, index=True, default=0)
    file_hash = db.Column(db.String(64))

    # always increment 1 for the id of a new record
    __table_args__ = { 'sqlite_autoincrement': True }

    def is_downloaded(self):
        return bool(DownloadRelation.query.filter_by(paper_id=self.id, username=session.get('username')).count())

    def is_liked(self):
        return bool(LikeRelation.query.filter_by(paper_id=self.id, username=session.get('username')).count())

class DownloadRelation(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    paper_id = db.Column(db.Integer, index=True)
    username = db.Column(db.String(30), index=True)

class LikeRelation(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    paper_id = db.Column(db.Integer, index=True)
    username = db.Column(db.String(30), index=True)

if __name__ == "__main__":
    db.create_all()

@app.route('/pastExam/img/<path:path>')
def send_img(path):
    return send_from_directory('static/img', path)

def login_required(allow_guest=True):
    def login_required_instance(f):
        @wraps(f)
        def df(*args, **kwargs):
            username = session.get('username')
            if not username or (not allow_guest and username.startswith('guest<')):
                return redirect(url_for('login'))
            return f(*args, **kwargs, username=username)
        return df
    return login_required_instance

@app.route('/pastExam/login/')
def login():
    return app.send_static_file('login/index.html')

@app.route('/pastExam/login/count-info.html')
def login_count_info():
    return app.send_static_file('login/count-info.html')

@app.route('/pastExam/logout')
def logout():
    session.pop('username', None)
    return redirect('login')

@app.route('/pastExam/login/guest/')
def guest_login():
    return render_template('guest-login.html', vs=C.verify, allow_guest_upload=C.allow_guest_upload)

@app.route('/pastExam/login/guest/verify', methods=['POST'])
@limiter.limit("5 / hour")
def guest_login_verify():
    for name, ques, hint, ans in C.verify:
        if request.form.get(name) != ans:
            return '错误!', 401

    if 'uid' not in session:
        session['uid'] = random.randint(0, 10000000)

    session['username'] = 'guest<%s>' % session['uid']
    session.pop('avatar', None)
    session.permanent = True
    return {'r':0}

@app.route('/pastExam/login/mast/')
def mast_login():
    return redirect(MAST_LOGIN_URL)

@app.route('/pastExam/login/mast/auth')
def mast_login_auth():
    code = request.args.get('code')
    client = Mastodon(
            client_id=C.mast_client_id,
            client_secret=C.mast_client_sec,
            api_base_url=C.mast_base_uri
    )
    token = client.log_in(code=code, redirect_uri=C.mast_redirect_uri,scopes=['read:accounts'])
    info = client.account_verify_credentials()
    session['username'] = info.acct
    session['avatar'] = info.avatar
    session.permanent = True

    return redirect(url_for('list'))

def by_abc(l):
    d = {
            letter: [] for letter in AZ+'/'
    }
    for item in l:
        k = pypinyin.lazy_pinyin(item[0], style=pypinyin.Style.FIRST_LETTER, errors=lambda x:x[0])[0].upper()
        if k not in AZ:
            k = '/'
        d[k].append(item)

    return {k: v for k, v in d.items() if v}


@app.route('/pastExam/')
@login_required()
def list(username):
    avatar = session.get('avatar', C.guest_avatar)
    course = request.args.get('course')
    teacher = request.args.get('teacher')
    year = request.args.get('year')
    year = year and year.isdigit() and int(year)

    is_my_upload = request.args.get('my_upload')
    is_my_fav = request.args.get('my_fav')

    has_course = course is not None
    has_teacher = teacher is not None
    has_year = year is not None
    ept = not (has_course or has_teacher or has_year) and is_my_fav is None and is_my_upload is None and 'page' not in request.args

    ps = Paper.query

    if course:
        ps = ps.filter_by(course=course)
    if teacher:
        ps = ps.filter_by(teacher=teacher)
    if year or year==0:
        ps = ps.filter_by(year=year)

    if is_my_upload:
        ps = ps.filter_by(author=username)
    if is_my_fav:
        ps = ps.join(LikeRelation, Paper.id==LikeRelation.paper_id).filter(LikeRelation.username==username)


    ps = ps.order_by(db.desc('like_num'), db.desc('down_num'), db.desc('id'))
    pagination = ps.paginate(max_per_page=100)
    curr_year = date.today().year
    all_courses  = db.session.query(Paper.course,  func.count()).group_by(Paper.course).all()
    all_courses_abc = by_abc(all_courses)
    all_teachers = db.session.query(Paper.teacher, func.count()).group_by(Paper.teacher).all()
    all_years    = db.session.query(Paper.year,    func.count()).group_by(Paper.year).all()
    ipfs_version = hashlib.sha256(C.ipfs_base_url.encode('utf-8')).hexdigest()
    ipfs_id = ipfs_info.get('ID')
    disable_upload = not C.allow_guest_upload and username.startswith('guest<')
    contributor_link = C.contributor_link
    return render_template('list.html', **locals())

def check_length(x, limit=30, allow_null=False):
    return (x and len(x) <= limit) or (allow_null and not x)

@app.route('/pastExam/upload', methods=['POST'])
@limiter.limit("10 / hour")
@login_required(allow_guest=C.allow_guest_upload)
def upload(username):
    name = request.form.get('name')
    teacher = request.form.get('teacher')
    year = request.form.get('year')
    year = year and year.isdigit() and int(year) or 0
    notes = request.form.get('notes', '')
    anon = request.form.get('anon') == 'on'

    if not (check_length(name) and check_length(teacher) and check_length(notes, 200, True)):
        abort(422)

    files = request.files.getlist('files[]')
    print(files)

    dir_name = username + str(datetime.now())
    base_path = os.path.join('/tmp', dir_name)
    os.mkdir(base_path)
    for f in files:
        filename = f.filename.replace('..','__')
        os.makedirs(os.path.dirname(os.path.join(base_path, filename)), exist_ok=True)
        f.save(os.path.join(base_path, filename))

    res = ipfs_client.add(base_path, recursive=True)
    file_hash = ''
    for r in res:
        if r.get('Name') == dir_name:
            file_hash = r.get('Hash')

    if not file_hash:
        abort(500)

    paper = Paper(
                course=name,
                teacher=teacher,
                year=year,
                notes=notes,
                anon=anon,
                author=username,
                create_date=date.today(),
                file_hash=file_hash
            )
    db.session.add(paper)
    db.session.commit()

    flash('上传成功')
    return redirect('.#part2')

@app.route('/pastExam/<pid>/download')
@limiter.limit("100 / hour")
@login_required()
def download(pid, username):
    p = Paper.query.get_or_404(pid)

    r = DownloadRelation.query.filter_by(paper_id=pid, username=username).count()

    if not r:
        r = DownloadRelation(paper_id=pid, username=username)
        db.session.add(r)
        p.down_num += 1
        db.session.commit()

    dformat = request.args.get('format')
    suff = {
            'zip': '.zip',
            'tar': '.tar',
            'gztar': '.tar.gz'
        }

    if dformat in suff:
        target_file = '/tmp/%s' % pid
        target_filename = target_file + suff[dformat]
        target_dir = os.path.join('/tmp', p.file_hash)

        if not os.path.exists(target_filename):
            if not os.path.exists(target_dir):
                ipfs_client.get(p.file_hash, target='/tmp')
            shutil.make_archive(target_file, dformat, target_dir)

        filename = re.sub('[^\w@_()（）-]', '_', '%s_%s_共享计划_%d' %(p.course, p.teacher, p.id)) + suff[dformat]
        return send_file(target_filename, as_attachment=True, attachment_filename=filename)

    return redirect(C.ipfs_base_url + p.file_hash, code=301) # 301减少不必要的请求

@app.route('/pastExam/<pid>/like', methods=['POST', 'DELETE'])
@limiter.limit("100 / hour")
@login_required()
def like(pid, username):
    p = Paper.query.get_or_404(pid)
    r = LikeRelation.query.filter_by(paper_id=pid, username=username).first()

    if request.method == 'POST':
        if not r:
            r = LikeRelation(paper_id=p.id, username=username)
            db.session.add(r)
            p.like_num += 1
            db.session.commit()
    else:
        if r:
            db.session.delete(r)
            p.like_num -= 1
            db.session.commit()

    return str(p.like_num)