import logging
import re
import sys

from commands.echo import echo
from commands.hello_world import hello_world
from commands.links import links

pws_command_prefix = '/pws '
pws_command_regex = r'/pws (\S+)'
pws_command_with_args_regex = r'/pws \S+(.*)'

log_format = '%(asctime)s %(levelname)s\t%(filename)s %(message)s'
logging.basicConfig(stream=sys.stdout, level=logging.DEBUG, format=log_format)

async def handle_message(client, message):
    logging.info('Observed message: "' + str(message.content) + '" from user [' + str(message.author) + '].')

    #Ignore messages this bot has sent to avoid answering itself.
    if message.author == client.user:
        return

    #Respond only to messages starting with the PWS prefix.
    if message.content.startswith(pws_command_prefix):
        msg = [3]
        msg.append(pws_command_prefix)
        msg.append(re.match(pws_command_regex, message.content)[1])
        msg.append(re.match(pws_command_with_args_regex, message.content)[1])

        command = msg[2]
        args = msg[3]
        logging.info("Received Command: " + command + ", with Args: " + args)

        match command:
            case 'helloworld':
                await handle_command(command, hello_world, args, message, False)
            case 'echo': 
                await handle_command(command, echo, args, message, True)
            case 'links':
                await handle_command(command, links, args, message, False)
            case 'help' | 'commands':
                await handle_command(command, commands, args, message, False)
            case _:
                logging.warn('Invalid command ' + command + ' received.')
                await message.author.send('Invalid command `' + command + '`. Check list of commands for valid usage.')

commandsMessage = """# **Commands**
- /pws helloworld
- /pws echo
- /pws links
- /pws help
- /pws commands
"""

async def commands(message):
    await message.author.send(commandsMessage)

async def handle_command(command, func, args, message, should_have_args=True):
    await handle_command_with_args(command, func, args, message) if should_have_args else await handle_command_without_args(command, func, args, message)

async def handle_command_without_args(command, func, args, message):
    if args:
        logging.warn('Command ' + command + ' got unexpected arguments: ' + message.content + '.')
        await message.author.send('Unexpected arguments for command: `' + message.content + '`. Check list of commands (`/pws help`) for valid usage.')
    else:
        await func(message)

async def handle_command_with_args(command, func, args, message):
    if not args:
        logging.warn('Command ' + command + ' did not specify argument(s): ' + message.content + '.')
        await message.author.send('Did not specify argument(s) for command: `' + message.content + '`. Check list of commands (`/pws help`) for valid usage.')
    else:
        await func(message, args)