import sqlite3

from flask import current_app, g

import os
DB_FILE = os.environ.get('DB_FILE', './data/db.sqlite')

get_return = sqlite3.Connection


def get() -> get_return:
    if 'db' not in g:
        g.db = sqlite3.connect(
            DB_FILE,
            detect_types=sqlite3.PARSE_DECLTYPES,
        )
        g.db.row_factory = sqlite3.Row

    return g.db


def close(e=None):
    db = g.pop('db', None)

    if db:
        db.close()


def init():
    db = get()

    with current_app.open_resource('init.sql') as f:
        db.executescript(f.read().decode('utf8'))
        db.commit()


def init_app(app):
    app.teardown_appcontext(close)

    import os.path
    if not os.path.exists(DB_FILE):
        with app.app_context():
            init()