#!/usr/bin/env python3

import uuid
import sqlite3
from datetime import datetime
from flask import Flask, request, render_template, current_app
from flask_uuid import FlaskUUID
from flask_qrcode import QRcode
from flask_socketio import SocketIO, emit
from werkzeug.middleware.proxy_fix import ProxyFix
import hashlib
import json

# WIP: use sockets to broadcast when a hit to the expected uuid has been
# received, so that connected clients (the Chromium public browser) can
# refresh the qr code and update the list of users
# https://flask-socketio.readthedocs.io

app = Flask(__name__)
FlaskUUID(app)
#QRcode(app)
qrcode = QRcode(app)
app.config['SECRET_KEY'] = '53a8373e7ae652cd38beba15454b1dc4'
#app = ProxyFix(app, x_for=1, x_host=1)
app.wsgi_app = ProxyFix(app.wsgi_app)
socketio = SocketIO(app, async_mode=None)

def get_db_connection():
    conn = sqlite3.connect('database.db')
    conn.row_factory = sqlite3.Row
    return conn

def hash_string(string):
    salt = 'xpwQDFQ7gvcQ--rgO7l9yA'
    return hashlib.md5(salt.encode() + string.encode()).hexdigest()

def check_hash(string, hashed_string):
    salt = 'xpwQDFQ7gvcQ--rgO7l9yA'
    return hashed_string == hashlib.md5(salt.encode() + string.encode()).hexdigest()

def generate_next_url():
    next_uuid = str(uuid.uuid1())
    url = request.url_root + str(next_uuid) + '/' + hash_string(next_uuid)
    return url

@app.route('/')
def show_qr_and_list():
    # TODO: reject direct connections to server; allow access only via proxy

    return render_template("template.html")

@app.route('/scan')
def show_qr_reader():
    return current_app.send_static_file('scan.html')

@app.route('/<uuid:id>/<hashed>')
def catch_uuids(id, hashed):
    user = request.headers.get('Remote-User')
    # TODO: Check directly with Authelia using https://auth.agofer.net/api/verify
    time = datetime.now().strftime("%A %Y-%m-%d %H:%M:%S")
    error = None
    data = []
    conn = get_db_connection()
    existing = conn.execute(
            'SELECT * FROM hits WHERE uuid = ?', (str(id),)).fetchone()
    if not user:
        error = 'NO_USERNAME'
    elif existing:
        error = 'ALREADY_USED'
    elif not check_hash(str(id), str(hashed)):
        error = 'DIFFERENT_NODE'
    else:
        conn.execute("INSERT INTO hits (uuid, user) VALUES (?, ?)", (str(id), user))
        conn.commit()
        #socketio.emit('qr_used', {'data': (time, user, str(id))})
        url = generate_next_url()
        qr = qrcode(url)
        socketio.emit('qr_used', {'data': (qr, url, user, time)})

        data = conn.execute(
                'SELECT * FROM hits WHERE user = ? ORDER BY id DESC LIMIT 10', (user,)
                ).fetchall()
    conn.close()

    return render_template('thanks.html', user=user, time=time, error=error, hits=data)

@socketio.on('message')
def handle_message(data):
    print('received message: ' + data)

@socketio.on('connection')
def handle_initial_connection(json_data):
    url = generate_next_url()
    qr = qrcode(url)
    conn = get_db_connection()
    last_entries = conn.execute('SELECT user, created FROM hits ORDER BY id DESC LIMIT 10')
    array_entries = []
    for entry in last_entries:
        array_entries.append((entry[0], entry[1]))
    conn.close()
    emit('initial_qr', {'data': (qr, url, array_entries)})
    #socketio.emit('initial_qr', {'data': (qr,)})
    print('received json: ' + str(json_data))

if __name__ == '__main__':
    #app.run(host='0.0.0.0')
    socketio.run(app, host='0.0.0.0')