import re
import json
import pytz
import random
import string
import hashlib
import datetime
import functools
from urllib.parse import urlparse
from flask import Flask, request, session, render_template, url_for, \
                  redirect, Blueprint
from flask import g as flask_g
from peewee import CharField, DateTimeField, ForeignKeyField, DoesNotExist
from playhouse.flask_utils import FlaskDB
from passlib.hash import pbkdf2_sha256


journalmarks = Blueprint('journalmarks', __name__, template_folder='templates',
                         static_folder='static')
db_wrapper = FlaskDB()


class User(db_wrapper.Model):
    username = CharField(unique=True)
    password = CharField()


class AccessToken(db_wrapper.Model):
    token = CharField()
    redeemed = DateTimeField(null=True, default=None)


class Journalmark(db_wrapper.Model):
    user = ForeignKeyField(User, backref='journalmarks')
    created = DateTimeField(default=datetime.datetime.utcnow)
    tag = CharField(unique=True)
    content = CharField()


def login_required(f):
    @functools.wraps(f)
    def decorated_function(*args, **kwargs):
        if 'username' not in session:
            return redirect(url_for('journalmarks.login', next=request.path))
        try:
            u = User.select().where(User.username == session['username']).get()
        except DoesNotExist:
            return ('user not found', 400, None)
        flask_g.user = u
        return f(*args, **kwargs)
    return decorated_function


@journalmarks.route('/register', methods=['GET'])
def register():
    return render_template('register.html')

@journalmarks.route('/register', methods=['POST'])
def process_registration():
    print(request.json)
    if len(request.json) != 3:
        return ('wrong number of fields', 400, None)
    try:
        token = request.json['token']
        username = request.json['username']
        password_hash = request.json['password_hash']
    except ValueError:
        return ('invalid field names', 400, None)
    if not re.match('^[a-zA-Z0-9]*$', token):
        return ('invalid token', 400, None)
    if not re.match('^[a-zA-Z0-9._]*$', username):
        return ('invalid username', 400, None)
    if not re.match('^[a-f0-9]{64}$', password_hash):
        return ('invalid password hash', 400, None)
    password_hash = pbkdf2_sha256.encrypt(password_hash)

    try:
        at = AccessToken.select().where(AccessToken.token == token).get()
    except DoesNotExist:
        return ('token does not exist', 400, None)

    if at.redeemed is not None:
        return ('token already used', 400, None)

    if User.select().where(User.username == username).count() > 0:
        return ('user already exists', 400, None)

    with db_wrapper.database.atomic():
        u = User(username=username, password=password_hash)
        at.redeemed = datetime.datetime.utcnow()
        u.save()
        at.save()
    return json.dumps('ok')


@journalmarks.route('/login', methods=['GET'])
def show_login():
    if 'next' in request.args and urlparse(request.args['next']).netloc == '':
        next = request.args['next']
    else:
        next = url_for('journalmarks.index')
    return render_template('login.html', next=next)


@journalmarks.route('/login', methods=['POST'])
def login():
    print(request.json)
    if len(request.json) != 2:
        return ('wrong number of fields', 400, None)
    try:
        username = request.json['username']
        password_hash = request.json['password_hash']
    except ValueError:
        return ('invalid field names', 400, None)
    if not re.match('^[a-zA-Z0-9._]*$', username):
        return ('invalid username', 400, None)
    if not re.match('^[a-f0-9]{64}$', password_hash):
        return ('invalid password hash', 400, None)

    try:
        u = User.select().where(User.username == username).get()
    except DoesNotExist:
        return ('invalid credentials', 400, None)
    if not pbkdf2_sha256.verify(password_hash, u.password):
        return ('invalid credentials', 400, None)

    session['username'] = u.username
    session.permanent = True
    return json.dumps('ok')


@journalmarks.route('/logout')
def logout():
    if 'username' in session:
        del session['username']
    return render_template('logout.html')


@journalmarks.route('/')
@login_required
def index():
    return render_template('index.html')


@journalmarks.route('/create', methods=['POST'])
@login_required
def create():
    if len(request.json) != 1 or 'content' not in request.json:
        return ('invalid fields', 400, None)
    content = request.json['content']

    tag = None
    while tag is None:
        tag = ''.join([ random.choice(string.ascii_lowercase + string.digits) \
                        for i in range(4) ])
        if Journalmark.select().where(Journalmark.tag == tag).count() > 0:
            tag = None
    j = Journalmark(user=flask_g.user, tag=tag, content=json.dumps(content))
    j.save()
    return json.dumps(tag)


@journalmarks.route('/delete', methods=['POST'])
@login_required
def delete():
    if len(request.json) != 1 or 'tag' not in request.json:
        return ('invalid fields', 400, None)
    tag = request.json['tag']
    try:
        j = Journalmark.select().where(
                (Journalmark.tag == tag) & (Journalmark.user == flask_g.user)
            ).get()
        j.delete_instance()
    except DoesNotExist:
        return ('tag not found', 404, None)
    return json.dumps('ok')


@journalmarks.route('/update', methods=['POST'])
@login_required
def update():
    if request.json.keys() != {'tag', 'content'}:
        return ('invalid fields', 400, None)
    tag, content = request.json['tag'], request.json['content']
    try:
        j = Journalmark.select().where(
                (Journalmark.tag == tag) & (Journalmark.user == flask_g.user)
            ).get()
    except DoesNotExist:
        return ('tag not found', 404, None)
    j.content = json.dumps(content)
    j.save()
    return json.dumps('ok')


@journalmarks.route('/overview', methods=['GET'])
@login_required
def overview():
    return render_template('overview.html')


@journalmarks.route('/overview', methods=['POST'])
@login_required
def overview_get_journalmarks():
    jms = Journalmark.select().where(Journalmark.user == flask_g.user) \
        .order_by(Journalmark.created.desc())
    ret = []
    for j in jms:
        try:
            content = json.loads(j.content)
        except ValueError:
            content = None
        ret.append({
            'created': pytz.utc.localize(j.created).isoformat(),
            'tag': j.tag,
            'content': content
        })
    return json.dumps(ret)


@journalmarks.route('/<tag>')
@login_required
def get_journalmark(tag):
    print(tag)
    try:
        j = Journalmark.select().where(
                (Journalmark.tag == tag) & (Journalmark.user == flask_g.user)
            ).get()
    except DoesNotExist:
        return render_template('not_found.html')
    return render_template('get_journalmark.html', j=j)


def create_app(config_filename):
    app = Flask(__name__)
    app.register_blueprint(journalmarks)
    app.config.from_pyfile(config_filename)
    app.secret_key = app.config['SECRET_KEY']
    db_wrapper.init_app(app)
    return app