#!/usr/bin/env python3
"""
Methods for loading modules.
"""
import os
import sys
import importlib

def load_module(bot, path):
	"""
	Loads a module from the provided path, cleans it up and registers
	it with the bot's internal callable list.
	"""
	module = importlib.import_module(path)
	if hasattr(module, 'setup'):
		module.setup(bot)
	relevant_parts = process_module(module)
	for part in relevant_parts:
		bot.register_callable(part)


def unload_module(bot, name):
	"""
	Unloads a module and deletes references to it from the bot's memory.
	"""
	old_module = sys.modules[name]

	# delete references to the module functions from the bot's memory
	for obj_name, obj in vars(old_module).items():
		bot.unregister_callable(obj)

	del old_module
	delattr(sys.modules['modules'], name.rpartition('.')[2])
	del sys.modules[name]


def find_modules():
	"""
	Searches through 'modules/' for python files and returns a dictionary
	with the module name as the key and the path as the value.
	"""
	modules = {}
	for file in os.listdir('modules'):
		if not file.endswith(".py"):
			continue
		name = file.replace(".py", "")
		modules[name] = "modules" + "." + name
	return modules


def process_module(module):
	"""
	Takes a module object and extracts relevant data objects out of it.
	Returns all callables(read: functions) and shutdowns(?).
	"""
	callables = []
	for key, obj in dict.items(vars(module)):
		if callable(obj):
			if is_triggerable(obj):
				process_callable(obj)
				callables.append(obj)
	return callables


def is_triggerable(obj):
	"""
	Checks if the given function object is triggerable by Fulvia, eg. has
	any of a few particular attributes or declarators defined.
	"""
	triggerable_attributes = ("commands", "hook", "url_callback", "user_joined")
	return any(hasattr(obj, attr) for attr in triggerable_attributes)


def process_callable(func):
	"""
	Sets various helper atributes about a given function.
	"""
	func.thread = getattr(func, "thread", True)
	func.hook = getattr(func, "hook", False)
	func.rate = getattr(func, "rate", 0)
	func.channel_rate = getattr(func, "channel_rate", 0)
	func.global_rate = getattr(func, "global_rate", 0)
	func.user_joined = getattr(func, "user_joined", False)