import sqlite3
import os
import time
from datetime import datetime
from sqlite3 import Error
from threading import Thread, Lock

from modules import app_car, app_account, app_gps

# Resolve db/sql/ relative to the repo root regardless of the process's cwd
# (previously a relative "../db/sql/" path, which broke depending on how/from
# where app.py was launched).
_BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
_SQL_DIR = os.path.join(_BASE_DIR, "db", "sql")

account = app_account.Account()
car = app_car.Car()
sCarModel = ''.join(letter for letter in car.model if letter.isalnum())
sql_file = account.name + "_" + sCarModel + ".db"
sql_path = os.path.join(_SQL_DIR, sql_file)

LOG_INTERVAL = 5  # seconds between trip-tracking snapshots

_conn = None
_conn_lock = Lock()
_log_thread = None

SQL_CREATE_TRACKING_TABLE = """CREATE TABLE IF NOT EXISTS tracking (
                                id integer PRIMARY KEY,
                                VN text NOT NULL,
                                NAME text NOT NULL,
                                DATETIME datetime,
                                GPSX float,
                                GPSY float,
                                SPEED float,
                                ODOMETER float
                            );"""

SQL_CREATE_DTC_TABLE = """CREATE TABLE IF NOT EXISTS dtc (
                                id integer PRIMARY KEY,
                                NAME text NOT NULL,
                                STATUS text,
                                DTC_ID text
                            );"""


def create_conn(db_file):
    """Open a SQLite connection to db_file, creating its parent folder if needed.

    Returns the open connection (or None on failure) - previously this closed
    the connection immediately in a `finally` block and returned nothing,
    so every caller always got a dead `None` connection.
    """
    os.makedirs(os.path.dirname(db_file), exist_ok=True)
    conn = None
    try:
        conn = sqlite3.connect(db_file, check_same_thread=False)
        print("SQLite library version:", sqlite3.sqlite_version)
    except Error as e:
        print(e)
    return conn


def create_table(conn, create_table_sql):
    """ create a table from the create_table_sql statement
    :param conn: Connection object
    :param create_table_sql: a CREATE TABLE statement
    :return:
    """
    try:
        c = conn.cursor()
        c.execute(create_table_sql)
    except Error as e:
        print(e)


def get_conn():
    """Return the shared SQLite connection, opening + initializing tables on first use."""
    global _conn
    if _conn is None:
        _conn = create_conn(sql_path)
        if _conn is not None:
            create_table(_conn, SQL_CREATE_TRACKING_TABLE)
            create_table(_conn, SQL_CREATE_DTC_TABLE)
        else:
            print("Error! cannot create the database connection.")
    return _conn


def insert_tracking(gps_x, gps_y, speed, odometer=None):
    """Insert a single trip-tracking snapshot row (GPS position + speed)."""
    conn = get_conn()
    if conn is None:
        return

    sql = """INSERT INTO tracking (VN, NAME, DATETIME, GPSX, GPSY, SPEED, ODOMETER)
             VALUES (?, ?, ?, ?, ?, ?, ?)"""
    with _conn_lock:
        try:
            conn.execute(sql, (car.model, account.name, datetime.now(), gps_x, gps_y, speed, odometer))
            conn.commit()
        except Error as e:
            print("Failed to insert tracking row:", e)


def _log_loop():
    # Deferred import to avoid a circular import at module load time
    # (app_obd.py imports app_sql, and app_sql needs app_obd.speed here).
    from modules import app_obd

    while True:
        gps_x = app_gps.LocationX
        gps_y = app_gps.LocationY
        speed = app_obd.speed

        if gps_x is not None and gps_y is not None:
            insert_tracking(gps_x, gps_y, speed)

        time.sleep(LOG_INTERVAL)


def start_logging():
    """Start the background thread that periodically snapshots GPS+speed into SQLite."""
    global _log_thread
    if _log_thread is None or not _log_thread.is_alive():
        get_conn()  # make sure the db file/tables exist before the first insert
        _log_thread = Thread(target=_log_loop)
        _log_thread.daemon = True
        _log_thread.start()
        print(f"SQL tracking-logger thread started, alive: {_log_thread.is_alive()}")
    else:
        print(f"SQL tracking-logger thread already running, alive: {_log_thread.is_alive()}")


if __name__ == '__main__':
    get_conn()