"""
Starting launcher of the game. This is where you host new games or join other ones.
"""
import tkinter as tk
import concurrent.futures
import pypong.networking.client as client

global running

# Don't allow any more than this number of threads when looking for games
# Can cripple a network at high numbers
MAX_SCAN_REQUESTS = 64

def main():
    """
    Runs the game launcher.
    """

    # Executor used for scanning local network for servers
    executor = concurrent.futures.ThreadPoolExecutor(max_workers=MAX_SCAN_REQUESTS)

    main_window = tk.Tk()
    main_window.title('PynPong Launcher')
    main_window.resizable(width=False, height=False)

    main_window.geometry('500x300')

    def quit_launcher():
        """
        Quits the main menu.
        """
        global running
        running = False
        # Stop executor from creating new scanning tasks
        executor.shutdown(wait=False, cancel_futures=True)

    def check_game(game_ip):
        """
        Checks to see if there is a game bein ghosted at a given IP

        :param game_ip: IP address to check for a host
        :return: Response from the server (or timeout if nothing found)
        """
        result = client.check_ip(game_ip)
        return result

    def get_games(network):
        """
        Refreshes the game list.

        :param network: The network to scan for games on
        """
        listbox.delete(0, tk.END)
        listbox.insert(0, ' Building IP range...')
        main_window.update()

        possible_ips = client.get_ips_from_network(network.get().split(' ')[0])

        listbox.delete(0, tk.END)
        listbox.insert(0, 'this might take some time...')
        listbox.insert(0, 'Refreshing server listing,')
        main_window.update()

        futures = []
        # Use the executor to create threads to search for games
        for ip in possible_ips:
            future = executor.submit(check_game, ip)
            futures.append(future)

        game_found = False

        for future in futures:
            result = future.result()

            if 'PYPONGRST;SVRINFO' in result:  # Check to make sure response has the right header and type
                raw_response = result.split(';')  # Split response by block (denoted by semicolons)
                response = []

                # Split up each block by chunks (<COMMAND>:<RESPONSE>)
                # e.g. the block 'NAME:Nicholas Dyer' -> ['NAME', 'Nicholas Dyer']
                for block in raw_response:
                    chunks = block.split(':')
                    for chunk in chunks:
                        response.append(chunk)

                # Make sure the response has the NAME command
                if 'NAME' in response:
                    # Session name is the next index after the command
                    session_name = response[response.index('NAME') + 1]
                    if not game_found:  # If this is the first game found, clear out the list
                        listbox.delete(0, tk.END)
                        game_found = True
                    listbox.insert(0, session_name)
            main_window.update()  # Update screen while finding games (laggy, but works)

        if not game_found:
            listbox.delete(0, tk.END)
            listbox.insert(0, 'No games found!')

    def get_addresses():
        """
        Get the current machine's local interfaces and their corresponding addresses in CIDR notation

        :return: Address in CIDR notation along with the interface

        Example:

        ['172.20.126.4/24 [eth0]', 192.168.2.43/16 [wlan0]']
        """
        interface_info = client.get_interface_info()
        shortened_info = []

        for interface in interface_info:
            shortened_info.append('{0} [{1}]'.format(interface.network, interface.interface_name))

        return shortened_info

    # Create the top title label
    title_label = tk.Label(text='PynPong Launcher', fg='white', bg='#000040', padx=1, pady=20)
    title_label.pack(side=tk.TOP, fill=tk.BOTH)

    # Create the list of games
    global listbox
    listbox = tk.Listbox(main_window)
    listbox.pack(side=tk.LEFT, expand=True, fill=tk.BOTH)
    # Add scrollbar
    scrollbar = tk.Scrollbar(main_window)
    scrollbar.pack(side=tk.LEFT, fill=tk.Y)
    # Link scrollbar to list of games
    listbox.config(yscrollcommand=scrollbar.set)
    scrollbar.config(command=listbox.yview)

    # Create buttons
    button_frame = tk.Frame(main_window)
    tk.Button(button_frame, text='Host a Game', height=3, width=30).pack()
    tk.Button(button_frame, text='Join Selected Game', height=3, width=30).pack()
    tk.Button(button_frame, text='Refresh Game List', height=2, width=20,
              command=lambda: get_games(selected_network)).pack()
    networks = get_addresses()
    selected_network = tk.StringVar()
    selected_network.set(networks[0])
    interface_menu = tk.OptionMenu(button_frame, selected_network, *networks)
    interface_menu.pack()
    button_frame.pack(side=tk.RIGHT)

    # Set it so that if the X is pressed the application quits
    main_window.protocol('WM_DELETE_WINDOW', quit_launcher)

    global running
    running = True

    while running:
        main_window.update()


if __name__ == '__main__':
    main()