import sqlite3
import os
from datetime import date

def connect_db():
    """
    Connects to the SQLite database file and returns the connection object.
    If the file does not exist, it prints an error message.
    """
    db_file = 'time_tracker.db'
    if not os.path.exists(db_file):
        print(f"Error: Database file '{db_file}' not found. Please run the database creation script first.")
        return None
    
    return sqlite3.connect(db_file)

def add_time_entry():
    """
    Prompts the user for details and adds a new time entry to the database.
    """
    conn = connect_db()
    if not conn:
        return

    try:
        cursor = conn.cursor()

        # Display all active clients for selection
        cursor.execute('SELECT client_id, client_name FROM clients WHERE active = 1 ORDER BY client_name')
        active_clients = cursor.fetchall()
        
        if not active_clients:
            print("No active clients found. Please add an active client first.")
            return

        print("\n--- Select a Client ---")
        for client_id, client_name in active_clients:
            print(f"{client_id}: {client_name}")
        print("0: Exit")  # Added exit option
        print("----------------------")

        while True:
            try:
                choice = int(input("Enter the ID of the client (or 0 to exit): "))
            except ValueError:
                print("Invalid input. Please enter a number.")
                continue

            if choice == 0:
                print("Exiting time entry.")
                return  # Exit the function if the user chooses 0

            # Check if the entered ID is in the list of active clients
            if any(c[0] == choice for c in active_clients):
                client_id = choice
                break
            else:
                print("Invalid client ID. Please enter a valid ID from the list.")

        print(f"\n--- Add New Time Entry for Client ID {client_id} ---")
        project = input("Enter project name: ")
        description = input("Enter a brief description: ")

        # Get the hours and validate it's a number
        while True:
            try:
                hours = float(input("Enter number of hours (e.g., 1.5): "))
                if hours <= 0:
                    print("Hours must be a positive number.")
                else:
                    break
            except ValueError:
                print("Invalid input. Please enter a number for hours.")
        
        # Get the date, defaulting to today's date
        entry_date = input(f"Enter the date (YYYY-MM-DD, default is today: {date.today()}): ")
        if not entry_date:
            entry_date = str(date.today())

        # The 'invoiced' field defaults to 0 (false)
        invoiced = 0

        # Insert the new time entry into the database
        cursor.execute('''
            INSERT INTO time_tracking (project, description, invoiced, date, hours, client_id)
            VALUES (?, ?, ?, ?, ?, ?)
        ''', (project, description, invoiced, entry_date, hours, client_id))
        
        conn.commit()
        print("\nTime entry added successfully!")
        
        # Fetch and display the newly created entry
        last_id = cursor.lastrowid
        cursor.execute('SELECT * FROM time_tracking WHERE entry_id = ?', (last_id,))
        new_entry = cursor.fetchone()
        
        print("\n--- New Time Entry Details ---")
        print(f"ID: {new_entry[0]}")
        print(f"Project: {new_entry[1]}")
        print(f"Description: {new_entry[2]}")
        print(f"Invoiced: {'Yes' if new_entry[3] else 'No'}")
        print(f"Date: {new_entry[4]}")
        print(f"Hours: {new_entry[5]:.2f}")
        print(f"Client ID: {new_entry[6]}")
        print("------------------------------\n")

    except sqlite3.Error as e:
        print(f"An error occurred: {e}")
    finally:
        if conn:
            conn.close()

if __name__ == "__main__":
    add_time_entry()