#!/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, bot.config)
	bot.register_callable(relevant_parts)


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
	del sys.modules[name]


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


def process_module(module, config):
	"""
	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, config)
				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")
	return any(hasattr(obj, attr) for attr in triggerable_attributes)


def process_callable(func, config):
	"""
	Sets various helper atributes about a given function.
	"""
	prefix = config.core.prefix
	doc = func.__doc__
	if doc:
		doc = doc.strip()
		doc = doc.replace("\t", "")
		doc = doc.replace("\n\n", "\x00")
		doc = doc.replace("\n", " ")
		doc = doc.replace("\x00", "\n")
	func._docs = {}

	func.example = getattr(func, "example", [(None, None)])
	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)

	if hasattr(func, 'commands'):
		if hasattr(func, 'example'):
			for n, example in enumerate(func.example):
				ex_input = example[0]
				if not ex_input:
					continue
				if ex_input[0] != prefix:
					ex_input = prefix + ex_input
				func.example[n] = (ex_input, example[1])
		if doc:
			for command in func.commands:
				func._docs[command] = (doc, func.example)