#!/usr/bin/env python3
import datetime
import json
import logging
import os
import pybikes
import sqlite3
import time

level = logging.WARNING
if os.environ.get('DEBUG', False):
    level = logging.DEBUG
logging.basicConfig(level=level)


def db_init(db_name=None):
    """
    Initialize a database connection, initialize the tables.

    Returns a new connection.
    """
    logging.info('Initialize DB...')
    now = datetime.datetime.now()
    if db_name is None:
        db_name = "week_%s.db" % now.strftime("%V")
    db_folder = os.path.join(
        'data',
        now.strftime('%Y')
    )
    if not os.path.isdir(db_folder):
        os.makedirs(db_folder)

    conn = sqlite3.connect(os.path.join(db_folder, db_name))
    c = conn.cursor()
    # Init tables
    c.execute("CREATE TABLE IF NOT EXISTS stations(" +
              "id INTEGER, " +
              "name TEXT, " +
              "address TEXT, " +
              "latitude REAL, " +
              "longitude REAL, " +
              "banking INTEGER, " +
              "bonus INTEGER, " +
              "bike_stands INTEGER)")
    c.execute("CREATE TABLE IF NOT EXISTS stationsstats(" +
              "station_id INTEGER, " +
              "available_bikes INTEGER, " +
              "available_ebikes INTEGER, " +
              "free_stands INTEGER, " +
              "status TEXT, " +
              "updated INTEGER, " +
              "FOREIGN KEY(station_id) REFERENCES stations(id) ON DELETE CASCADE)")
    c.execute("CREATE TABLE IF NOT EXISTS stationsevents(" +
              "station_id INTEGER, " +
              "timestamp INTEGER, " +
              "event TEXT, " +
              "FOREIGN KEY(station_id) REFERENCES stations(id) ON DELETE CASCADE)")
    c.execute("CREATE INDEX IF NOT EXISTS stationstats_station_id ON stationsstats (station_id)")
    c.execute("CREATE INDEX IF NOT EXISTS stationsstats_updated ON stationsstats (updated)")
    c.execute("CREATE INDEX IF NOT EXISTS stationsevents_station_id ON stationsevents (station_id)")
    c.execute("CREATE INDEX IF NOT EXISTS stationsevents_timestamp ON stationsevents (timestamp)")
    conn.commit()
    return conn


def update_stations(conn):
    """
    Update the stored station list.

    :param conn: Database connection.
    """
    logging.info('Get all stations from database...')
    c = conn.cursor()
    database_stations = {
        i[0]: i
        for i in c.execute(
            "SELECT id, name, address, latitude, longitude, banking, bonus, bike_stands FROM stations"
        ).fetchall()
    }

    logging.info('Get updated Velib stations from the API...')
    velib = pybikes.get("velib")
    velib.update()
    fetched_stations = {
        station.extra['uid']: station
        for station in velib.stations
        if 'uid' in station.extra
    }

    # List of SQL queries to perform for
    events = []  # events happening on stations (temporary closure etc)
    stations_update = []  # Update of stations (such as new stands number)
    new_stations = []  # New stations to add to the list
    stats = []  # Current stats of the station

    logging.info('Processing fetched stations...')
    for uid, station in fetched_stations.items():
        try:
            old_station = database_stations[uid]

            # Diff the two stations
            event = []
            if station.name != old_station[1]:
                event.append({"key": "name",
                              "old_value": old_station[1],
                              "new_value": station.name})
            if station.latitude != old_station[3]:
                event.append({"key": "latitude",
                              "old_value": old_station[3],
                              "new_value": station.latitude})
            if station.longitude != old_station[4]:
                event.append({"key": "longitude",
                              "old_value": old_station[4],
                              "new_value": station.longitude})
            if (
                "banking" in station.extra
                and station.extra["banking"] != old_station[5]
            ):
                event.append({"key": "banking",
                              "old_value": old_station[5],
                              "new_value": station.extra["banking"]})
            if (
                "slots" in station.extra
                and station.extra["slots"] != old_station[7]
            ):
                event.append({"key": "bike_stands",
                              "old_value": old_station[7],
                              "new_value": station.extra["slots"]})
            # If diff was found
            if len(event) > 0:
                stations_update.append(
                    (station.name,
                     station.latitude,
                     station.longitude,
                     station.extra["banking"],
                     station.extra["slots"],
                     uid)
                )
                events.append(
                    (uid, int(time.time()), json.dumps(event))
                )
        except KeyError:
            # Add the station to the database
            new_stations.append(
                (uid,
                 station.name,
                 "",  # Not available
                 station.latitude,
                 station.longitude,
                 station.extra["banking"],
                 False,  # Not available
                 station.extra["slots"])
            )
        stats.append(
            (uid,
             station.bikes - station.extra["ebikes"],
             station.extra["ebikes"],
             station.free,
             station.extra["status"],
             int(time.time()))  # Not available, using current timestamp
        )

    # Update stations
    logging.info('Updating stations in db...')
    c.executemany(
        "UPDATE stations SET name=?, latitude=?, longitude=?, " +
        "banking=?, bike_stands=? WHERE id=?",
        stations_update
    )
    # Insert events in the table
    logging.info('Storing stations events in db...')
    c.executemany(
        "INSERT INTO stationsevents(station_id, timestamp, event) " +
        "VALUES(?, ?, ?)",
        events
    )
    # Add the station to the database
    logging.info('Storing new stations in db...')
    c.executemany(
        "INSERT INTO " +
        "stations(id, name, address, latitude, longitude, banking, bonus, bike_stands) " +
        "VALUES(?, ?, ?, ?, ?, ?, ?, ?)",
        new_stations
    )

    # Insert the current state in the db
    logging.info('Storing current stations stats in db...')
    c.executemany(
        "INSERT INTO " +
        "stationsstats(station_id, available_bikes, available_ebikes, free_stands, status, updated) " +
        "VALUES(?, ?, ?, ?, ?, ?)",
        stats
    )
    conn.commit()


def main():
    """
    Handle main operations.
    """
    # Get updated list of stations for smovengo
    conn = db_init()
    update_stations(conn)


if __name__ == "__main__":
    main()