from datetime import datetime

from flask import Flask, redirect, request, render_template, flash
from flask_login import LoginManager, login_user, logout_user, login_required

from pos.config import Config
from pos.logging import init_logging, get_logger
from pos.database import Database, User, Product, Event, Transaction, Order


config = Config()
debug = config.core['GENERAL'].getboolean('Debug', False)
conf_db = config.core['DATABASE']
conf_flask = config.core['FLASK']

init_logging(config.logging)
log = get_logger('web')

app = Flask(__name__)
app.config.update(
    debug=debug,
    SECRET_KEY=conf_flask['SECRET_KEY']
)

login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = 'login'
login_manager.login_message_category = 'error'

db = Database(**conf_db)


@login_manager.user_loader
def load_user(uid):
    user = None
    with db.get_session() as session:
        user = session.query(User).get(uid)
    return user


@app.route('/')
def home():
    return redirect('/sell')


@app.route('/login', methods=['GET'])
def login_page():
    return render_template('login.html', title='Login')


@app.route('/login', methods=['POST'])
def login():
    username = request.form['username']
    password = request.form['password']

    if not all([username, password]):
        flash("Fill all fields.", 'error')
        return login_page(), 400

    with db.get_session() as session:
        user = session.query(User)\
                      .filter(User.username == username)\
                      .filter(User.is_active == 1)\
                      .one_or_none()

        if user is None:
            flash("User not found.", 'error')
            return login_page(), 400

        if user.password == password:
            login_user(user)
            session.add(user)
            user.is_authenticated = True
            flash("Succesfully logged in.", 'success')
            return redirect('/')
        else:
            flash("Wrong password.", 'error')
            return login_page(), 400


@app.route('/logout')
def logout():
    logout_user()
    return redirect('/')


def get_products(session):
    return session.query(Product)\
                  .filter(Product.is_active == 1)\
                  .order_by(Product.sort.asc())\
                  .all()


def get_event(session):
    return session.query(Event)\
                  .filter(Event.starts_at < datetime.now())\
                  .filter((Event.ends_at.is_(None))
                          | (Event.ends_at > datetime.now()))\
                  .one_or_none()


@app.route('/sell', methods=['GET'])
@login_required
def sell_page():
    with db.get_session() as session:
        products = get_products(session)
        event = get_event(session)

    return render_template('sell.html',
                           title='Sell', event=event, products=products)


@app.route('/sell', methods=['POST'])
@login_required
def sell():
    with db.get_session() as session:
        event = get_event(session)

    if event is None:
        flash("Can't perform order without an ongoing event!", 'error')
        return sell_page()

    quantities = request.form.values()
    if not any(int(qty) > 0 for qty in quantities):
        flash("Can't perform empty order!", 'error')
        return sell_page()

    with db.get_session() as session:
        items = request.form.items()
        orders = [
            Order(product_uid=uid, quantity=qty)
            for uid, qty in items
            if int(qty) > 0
        ]

        transaction = Transaction(event_uid=event.uid, orders=orders)
        session.add(transaction)

    flash("Success!", 'success')
    return sell_page()


if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8080, debug=debug)