import sqlite3
from typing import IO
import click
from flask import Flask, current_app, g
from sqlalchemy import create_engine
from sqlalchemy.orm import Session


def get_database():
    if "db" not in g:
        g.db = sqlite3.connect(
            current_app.config["DATABASE"],
            detect_types=sqlite3.PARSE_DECLTYPES
        )
        g.db.row_factory = sqlite3.Row
    
    return g.db

def get_jiten_db():
    if "jiten_db" not in g:
        engine = create_engine(f"sqlite:///{current_app.config['JITEN_DB']}")
        g.jiten_db = Session(engine)
        print("Session is", g.jiten_db)

    return g.jiten_db

def initialize_database():
    db = get_database()

    with current_app.open_resource("schema.sql") as f:
        f: IO[bytes]
        db.executescript(f.read().decode())

def close_database(e=None):
    db = g.pop("db", None)

    if db is not None:
        db.close()

@click.command("init-db")
def init_db_command():
    """Wipe the existing database and create new tables."""
    if input("Are you sure you wish to overwrite any existing database? (y/n) ") == "y":
        initialize_database()
        click.echo("Initialized the database.")
    else:
        click.echo("Aborted.")

@click.command("prune-pfps")
def prune_pfps_command():
    """Removes excess profile pictures that aren't used in the database."""
    import os
    db = get_database()
    used_pfps = {row[0] for row in db.execute("SELECT pfp_filename FROM user_settings").fetchall()}
    stored_pfps = set(os.listdir(current_app.config["PFP_STORE"]))
    unused_pfps = stored_pfps - used_pfps
    for pfp in unused_pfps:
        os.remove(os.path.join(current_app.config["PFP_STORE"], pfp))

def initialize_app(app: Flask):
    app.teardown_appcontext(close_database)
    app.cli.add_command(init_db_command)
    app.cli.add_command(prune_pfps_command)