import sqlite3

class DatabaseHelper:
    def __init__(self, db=None):
        print("Initializing database")
        self.conn = None
        self.cursor = None

        if db:
            self.open(db)

    def __enter__(self):
        return self
    
    def __exit__(self):
        self.close()

    def open(self, db):
        try:
            self.conn = sqlite3.connect(db)
            self.cursor = self.conn.cursor()
        except:
            pass

    def commit(self):
        if self.conn:
            self.conn.commit()

    def query(self, sql, values=None):
        if values == None:
            self.cursor.execute(sql)
            self.commit()
        else:
            self.cursor.execute(sql, values)
            self.commit()

    def close(self):
        if self.conn:
            self.conn.commit()
            self.conn.close()
            self.cursor.close()

    # Query functions 
    def loginUser(self, username, password):
        if not self.conn:
            return None
        try:
            self.cursor.execute("SELECT * FROM `users` WHERE (`username` = ? AND `password` = ?)", (username, password,))
            return self.cursor.fetchone()
        except sqlite3.Error as error:
            print(error)
            return None

    def createUser(self, private_key, public_key, username, password):
        if not self.conn:
            return None
        try:
            self.cursor.execute("INSERT INTO `users` (private_key, public_key, username, password) VALUES (?, ?, ?, ?)", (private_key, public_key, username, password,))
            self.commit()
            return True
        except sqlite3.Error as error:
            print(error)
            return False

    def changePassword(self, user_privatekey, old_password, password):
        if not self.conn:
            return None

        try:
            self.cursor.execute("UPDATE `users` SET `password` = ? WHERE (`private_key` = ? AND `password` = ?)", (password, user_privatekey, old_password,))
            self.commit()

            return True

        except sqlite3.Error as error:
            print(error)
            return None
        
    def changeUsername(self, user_privatekey, username):
        if not self.conn:
            return None

        # Execute the query
        try:
            self.cursor.execute("UPDATE `users` SET username = ? WHERE `private_key` = ?", (username, user_privatekey,))
            self.commit()

            return True

        except sqlite3.Error as error:
            print(error)
            return None

    def deleteUser(self, user_privatekey):
        # Check if the database is open
        if not self.conn:
            return None

        # Execute the query
        try:
            self.cursor.execute("DELETE FROM `users` WHERE `private_key` = ?", (user_privatekey, ))
            self.commit()

            return True

        except sqlite3.Error as error:
            print(error)
            return None
        
    def fetchUserByUsername(self, username):
        if not self.conn:
            return None

        try:
            self.cursor.execute("SELECT * FROM `users` WHERE `username` = ?", (username,))

            return self.cursor.fetchone()

        except sqlite3.Error as error:
            print(error)
            return None

    def checkMigrations(self):
        self.query("CREATE TABLE IF NOT EXISTS `users` ( `private_key` BLOB NOT NULL , `public_key` BLOB NOT NULL , `username` VARCHAR(255) NOT NULL , `password` VARCHAR(255) NOT NULL )")