import sqlite3
from datetime import datetime
from flask import Flask
from flask import render_template
from flask import url_for
from flask import request, redirect, g
from contextlib import closing
import os, os.path

app = Flask(__name__)
DATABASE = '/data/rollerverbrauch.db'
DEBUG = True
SECRET_KEY = 'development key'
USERNAME = 'admin'
PASSWORD = 'default'
app.config.from_object(__name__)

def connect_db():
    result = sqlite3.connect(app.config['DATABASE'])
    return result

def init_db():
    with closing(connect_db()) as db:
        with app.open_resource('schema.sql', mode='r') as f:
            sql_commands = f.read()
            print(sql_commands)
            db.cursor().executescript(sql_commands)
        db.commit()

@app.before_request
def before_request():
    g.db = connect_db()

@app.teardown_request
def teardown_request(exception):
    db = getattr(g, 'db', None)
    if db is not None:
        db.close()

@app.route('/')
def index():
    #data = {'pitstopsUrl': url_for('getPitStops')}
    #return render_template('index.html', data=data)
    return redirect(url_for('getPitStops'))

@app.route('/pitstops', methods=['POST'])
def createPitStop():
    last_pitstop = getLastPitStop()
    errorMsg = {}
    
    date = request.form['date']
    try:
        date = datetime.strptime(date, '%Y-%m-%d').strftime('%Y-%m-%d')
    except ValueError:
        errorMsg['date'] = 'invalid date, only YYYY-MM-DD is allowed'
        date = request.form['date']
    
    odometer = request.form['odometer']
    try:
        odometer = int(odometer)
    except ValueError:
        errorMsg['odometer'] = 'Illegal Value, only Integers allowed'
        odometer = None
    if odometer is not None and odometer <= last_pitstop['odometer']:
        errorMsg['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:
        errorMsg['litres'] = 'Illegal Value, only floating point allowed'
        litres = None
    if litres is not None and litres <= 0:
        errorMsg['litres'] = 'Litres must not be 0'
        litres = request.form['litres']
    if litres is None:
        litres = request.form['litres']
        
    # error checking here
    if len(errorMsg) > 0:
        data = {'last': {'date': date, 'odometer': odometer, 'litres': litres}, 'error': errorMsg}
        return render_template('newPitStopForm.html', data=data)

    addPitStop(date, odometer, litres)

    return redirect(url_for('getPitStops'))

@app.route('/pitstops/createForm', methods=['GET'])
def createPitStopForm():
    data = {'last':getLastPitStop(), 'error': None}
    return render_template('newPitStopForm.html', data=data)

@app.route('/pitstops', methods=['GET'])
def getPitStops():
    data = {'pitstops': preparePitStops(getAllPitStops())}
    return render_template('pitstops.html', data=data)

@app.route('/statistics', methods=['GET'])
def getStatistics():
    pitstops = getAllPitStops()
    count = len(pitstops)
    distance = 0
    sumLitres = 0
    averageDistance = 0
    averageLitresFuelled = 0
    averageLitresUsed = 0
    
    if count > 0:
        sumLitres = 0
        for pitstop in pitstops:
            sumLitres += pitstop['litres']
        averageLitresFuelled = round(sumLitres/count, 2)
    if count > 1:
        distance = pitstops[-1]['odometer'] - pitstops[0]['odometer']
        averageDistance = round(distance/(count - 1), 2)
        averageLitresUsed = round(100 * (sumLitres-pitstops[0]['litres'])/distance, 2)
    data = {
            'distance':distance,
            'count': count,
            'litres': round(sumLitres, 2),
            'averageDistance': averageDistance,
            'averageListresFuelled': averageLitresFuelled,
            'averageListresUsed': averageLitresUsed}
    return render_template('statistics.html', data=data)

def preparePitStops(pitstops):
    for index in range(1, len(pitstops)):
        last = pitstops[index - 1]
        curr = pitstops[index]
        curr['distance'] = curr['odometer'] - last['odometer']
        curr['average'] = round(100 * curr['litres']/curr['distance'], 2)
        last_date = datetime.strptime(last['date'], '%Y-%m-%d')
        curr_date = datetime.strptime(curr['date'], '%Y-%m-%d')
        curr['days'] = (curr_date - last_date).days
    return pitstops

def getLastPitStop():
    cur = g.db.execute('select date, odometer, litres from pitstops order by date desc limit 1')
    pitstops = [dict(date=row[0], odometer=row[1], litres=row[2]) for row in cur.fetchall()]
    if len(pitstops) == 0:
        return {'date': datetime.strftime(datetime.now(), '%Y-%m-%d'), 'odometer': 0, 'litres': 0}
    return pitstops[0]

def getAllPitStops():
    cur = g.db.execute('select date, odometer, litres from pitstops order by id asc')
    pitstops = [dict(date=row[0], odometer=row[1], litres=row[2]) for row in cur.fetchall()]
    return pitstops

def addPitStop(date, odometer, litres):
    g.db.execute('insert into pitstops (date, odometer, litres) values (?, ?, ?)', [date, odometer, litres])
    g.db.commit()



if __name__ == '__main__':
    if not os.path.isfile(DATABASE) or os.stat(DATABASE).st_size == 0:
        init_db()
    app.run(debug=True, host='0.0.0.0')