import sqlite3

def create_database():
    """
    Connects to the SQLite database and creates the 'clients' and 'time_tracking' tables
    if they do not already exist.
    """
    db_file = 'time_tracker.db'  # Define the database file name
    conn = None  # Initialize the connection variable to None

    try:
        # Connect to the database. This will create the file if it doesn't exist.
        conn = sqlite3.connect(db_file)
        cursor = conn.cursor()

        # Create the 'clients' table. The 'address' field has been split into
        # separate fields for better data organization.
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS clients (
                client_id INTEGER PRIMARY KEY,
                client_name TEXT NOT NULL UNIQUE,
                street_address_1 TEXT,
                street_address_2 TEXT,
                city TEXT,
                state TEXT,
                zip_code TEXT,
                billing_rate REAL,
                balance REAL,
                active INTEGER NOT NULL DEFAULT 1
            );
        ''')
        
        # Create the 'time_tracking' table with new fields for date and hours.
        # The 'invoiced' field is an INTEGER where 0 is false and 1 is true.
        # The 'client_id' is a foreign key that references the 'clients' table.
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS time_tracking (
                entry_id INTEGER PRIMARY KEY,
                project TEXT NOT NULL,
                description TEXT,
                invoiced INTEGER NOT NULL DEFAULT 0 CHECK(invoiced IN (0, 1)),
                date TEXT NOT NULL,
                hours REAL NOT NULL,
                client_id INTEGER,
                FOREIGN KEY (client_id) REFERENCES clients (client_id)
            );
        ''')

        # Commit the changes to the database.
        conn.commit()
        print(f"Successfully created tables 'clients' and 'time_tracking' in '{db_file}'")

    except sqlite3.Error as e:
        # Print an error message if something goes wrong.
        print(f"An error occurred: {e}")

    finally:
        # Ensure the database connection is always closed, even if an error occurs.
        if conn:
            conn.close()
            print("Database connection closed.")

if __name__ == "__main__":
    # Call the function to create the database when the script is run directly.
    create_database()