#!/usr/bin/env python3
"""
A module for interacting with Juice's database.
"""
import sqlite3
import threading


DB_LOCK = threading.Lock()


def init_db():
	"""
	Checks to see if the database is initialized yet or not. If not,
	the appropriate tables are created.
	"""
	con = sqlite3.connect('juice.db')
	cur = con.cursor()
	try:
		cur.execute("SELECT * FROM user LIMIT 1").fetchone()
		cur.execute("SELECT * FROM credential LIMIT 1").fetchone()
	except sqlite3.OperationalError:
		cur.execute("CREATE TABLE user("
			"id INTEGER PRIMARY KEY AUTOINCREMENT, "
			"name TEXT UNIQUE, "
			"token_hash TEXT"
			")"
		)
		cur.execute("CREATE TABLE credential("
			"id INTEGER PRIMARY KEY AUTOINCREMENT, "
			"user_id INTEGER REFERENCES user(id) ON UPDATE CASCADE, "
			"credential BLOB"
			")"
		)
		con.commit()
	con.close()
init_db()


def db_execute(*args, **kwargs):
	"""
	Opens a connection to the app's database and executes the SQL
	statements passed to this function.
	"""
	with sqlite3.connect('juice.db') as con:
		DB_LOCK.acquire()
		cur = con.cursor()
		res = cur.execute(*args, **kwargs)
		DB_LOCK.release()
		return res


def set_user(username):
	"""
	Adds a new user.
	"""
	db_execute(
		"INSERT INTO user(name) VALUES (?)",
		(username,)
	)
	return True


def set_user_token(username, token_hash):
	"""
	Sets a user's token hash.
	"""
	db_execute(
		"UPDATE user SET token_hash = ? WHERE name = ?",
		(token_hash, username)
	)
	return True


def get_user(username):
	"""
	Returns a user entry.
	"""
	data = db_execute(
		"SELECT * FROM user WHERE name = ?",
		(username,)
	).fetchone()
	return data


def set_credential(user_id, credential):
	"""
	Adds a credential to the database.
	"""
	db_execute(
		"INSERT INTO credential(user_id, credential) VALUES (?, ?)",
		(user_id, credential)
	)
	return True


def get_credentials(user_id):
	"""
	Returns all credentials registered to a user.
	"""
	data = db_execute(
		"SELECT * FROM credential WHERE user_id = ?",
		(user_id,)
	).fetchall()
	return data