from datetime import date
from datetime import datetime
from flask import Flask
from flask import render_template, make_response
from flask import request, redirect, g
from flask import url_for
from flask_sqlalchemy import SQLAlchemy
import uuid
import hashlib
import time
from functools import wraps
import os

app = Flask(__name__)
DATABASE = '/data/rollerverbrauch.db'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///'+DATABASE
sqldb = SQLAlchemy(app)

SECRET_KEY = 'development key'
app.config.from_object(__name__)


class User(sqldb.Model):
    id = sqldb.Column(sqldb.Integer, primary_key=True)
    username = sqldb.Column(sqldb.String(80), unique=True)
    email = sqldb.Column(sqldb.String(120), unique=True)
    salt = sqldb.Column(sqldb.String(8))
    password_hash = sqldb.Column(sqldb.String(64))

    def __init__(self, username, email, password):
        self.username = username
        self.email = email
        self.salt = uuid.uuid4().hex
        m = hashlib.sha256(password.encode('utf-8'))
        m = hashlib.sha256((m.hexdigest() + self.salt).encode('utf-8')).hexdigest()
        self.password_hash = m
        pass

    def __repr__(self):
        return '<User %r>' % self.username


class Pitstop(sqldb.Model):
    id = sqldb.Column(sqldb.Integer, primary_key=True)
    date = sqldb.Column(sqldb.Date)
    odometer = sqldb.Column(sqldb.Integer)
    litres = sqldb.Column(sqldb.Numeric(5,2))

    def __init__(self, odometer, litres, date):
        self.odometer = odometer
        self.litres = litres
        self.date = date

    def __repr__(self):
        return '<Pitstop %r km, %r l>' % (self.odometer, self.litres)

sqldb.create_all()
if User.query.filter_by(username='jlusiardi').first() is None:
    user1 = User('jlusiardi', 'joachim@lusiardi.de', 'pitstops')
    sqldb.session.add(user1)
    sqldb.session.commit()


def check_auth(username, password):
    user = User.query.filter_by(username=username).first()
    if user is None:
        return False
    salt = user.salt
    m = hashlib.sha256(password.encode('utf-8'))
    m = hashlib.sha256((m.hexdigest()+salt).encode('utf-8'))
    digest = m.hexdigest()
    ok = (User.query.filter_by(username=username, password_hash=digest).first() is not None)
    if not ok:
        app.logger.error("digest: " + digest)
    return ok


def authenticate():
    resp = make_response(render_template('login_required.html'), 401)
    resp.headers['WWW-Authenticate'] = 'Basic realm="Login Required"'
    return resp


def requires_auth(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        auth = request.authorization
        if not auth or not check_auth(auth.username, auth.password):
            return authenticate()
        return f(*args, **kwargs)
    return decorated


@app.before_request
def before_request():
    g.data = {}


@app.teardown_request
def teardown_request(exception):
    pass


@app.route('/')
@requires_auth
def index():
    return redirect(url_for('get_pit_stops'))


@app.route('/pitstops', methods=['POST'])
@requires_auth
def create_pit_stop():
    last_pitstop = Pitstop.query.order_by(Pitstop.date.desc()).first()
    if last_pitstop is None:
        last_pitstop = Pitstop(0, 0, None)
    error_msg = {}
    
    date_of_pitstop = request.form['date']
    try:
        date_of_pitstop = datetime.strptime(date_of_pitstop, '%Y-%m-%d').strftime('%Y-%m-%d')
    except ValueError:
        error_msg['date'] = 'invalid date, only YYYY-MM-DD is allowed'
        date_of_pitstop = request.form['date']
    
    odometer = request.form['odometer']
    try:
        odometer = int(odometer)
    except ValueError:
        error_msg['odometer'] = 'Illegal Value, only Integers allowed'
        odometer = None
    if odometer is not None and odometer <= last_pitstop.odometer:
        error_msg['odometer'] = 'Illegal Value, new Value must be bigger as given value'
        odometer = request.form['odometer']
    if odometer is None:
        odometer = request.form['odometer']
    
    litres = request.form['litres']
    try:
        litres = float(litres)
    except ValueError:
        error_msg['litres'] = 'Illegal Value, only floating point allowed'
        litres = None
    if litres is not None and litres <= 0:
        error_msg['litres'] = 'Litres must not be 0'
        litres = request.form['litres']
    if litres is None:
        litres = request.form['litres']
        
    # error checking here
    if len(error_msg) > 0:
        data = {'last': {'date': date_of_pitstop, 'odometer': odometer, 'litres': litres}, 'error': error_msg}
        return render_template('newPitStopForm.html', data=data)

    new_stop = Pitstop(odometer, litres, datetime.strptime(date_of_pitstop, '%Y-%m-%d'))
    sqldb.session.add(new_stop)
    sqldb.session.commit()
    
    return redirect(url_for('get_pit_stops'))


@app.route('/pitstops/createForm', methods=['GET'])
@requires_auth
def create_pit_stop_form():
    last_stop = Pitstop.query.order_by(Pitstop.date.desc()).first()
    if last_stop is None:
        last_stop = Pitstop(0, 0, date(1970, 1, 1))
    values = dict()
    values['odometer'] = last_stop.odometer
    values['litres'] = last_stop.litres
    values['date'] = time.strftime("%Y-%m-%d")
    g.data['last'] = values
    g.data['error'] = None
    return render_template('newPitStopForm.html', data=g.data)


@app.route('/pitstops', methods=['GET'])
@requires_auth
def get_pit_stops():
    data = prepare_pit_stops(Pitstop.query.all())
    g.data['pitstops'] = data
    return render_template('pitstops.html', data=g.data)


@app.route('/manual', methods=['GET'])
@requires_auth
def get_manual():
    return render_template('manual.html', data=g.data)


@app.route('/statistics', methods=['GET'])
@requires_auth
def get_statistics():
    pitstops = Pitstop.query.all()
    count = len(pitstops)
    distance = 0
    sum_litres = 0
    average_distance = 0
    average_litres_fuelled = 0
    average_litres_used = 0
    
    if count > 0:
        sum_litres = 0
        for pitstop in pitstops:
            sum_litres += pitstop.litres
        average_litres_fuelled = sum_litres/count
    if count > 1:
        distance = pitstops[-1].odometer - pitstops[0].odometer
        average_distance = distance/(count - 1)
        average_litres_used = 100 * (sum_litres-pitstops[0].litres)/distance
    g.data['distance'] = distance
    g.data['count'] = count
    g.data['litres'] = sum_litres
    g.data['averageDistance'] = average_distance
    g.data['averageListresFuelled'] = average_litres_fuelled
    g.data['averageListresUsed'] = average_litres_used
    return render_template('statistics.html', data=g.data)


def prepare_pit_stops(pss):
    pitstops = []
    for pitstop_index in range(0, len(pss)):
        p = dict()
        p['odometer'] = pss[pitstop_index].odometer
        p['litres'] = pss[pitstop_index].litres
        p['date'] = pss[pitstop_index].date
        pitstops.append(p)
    for pitstop_index in range(1, len(pitstops)):
        last = pitstops[pitstop_index - 1]
        curr = pitstops[pitstop_index]
        curr['distance'] = curr['odometer'] - last['odometer']
        curr['average'] = 100 * curr['litres']/curr['distance']
        last_date = last['date']
        curr_date = curr['date']
        curr['days'] = (curr_date - last_date).days
    pitstops.reverse()
    return pitstops

if __name__ == '__main__':
    DEBUG = 'DEBUG' in os.environ and os.environ['DEBUG'] != 'False'
    app.run(debug=DEBUG, host='0.0.0.0')