#! /usr/bin/env python3

# Yandere Lewd Bot, an image posting bot for Pleroma
# Copyright (C) 2022 Anon <@Anon@yandere.cc>
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import os
from threading import Event
from mastodon import Mastodon, MastodonIllegalArgumentError, MastodonVersionError

def load_cfg(name):
	try:
		import importlib
		return importlib.import_module(name)
	except ImportError:
		raise FailedToLoadCfg("Invalid config file: {}".format(name))

class YandereBot:
	# YandereBot.__init__()
	# @param cfg            Name of configuration file
	# @param keyfile		Keyfile to decrypt settings_post
	# @param debug_mode     Should the bot run in debug mode (do not sign in or post to Pleroma)
	def __init__(self, cfg, keyfile=None, debug_mode=False):
		# From the threading library. Is responsible for putting the bot to sleep, and exiting when the user quits (Ctrl+C)
		self.eventSleep = Event()

		# The below settings are required from the configuration module
		self.settings = dict()

		# The configuration module
		self.cfg = load_cfg(cfg)
		self.load_settings(["settings_server", "settings_behavior", "settings_encrypt"])

		# Class variables
		self.mastodon_api = None
		self.failed_uploads = 0
		self.consecutive_failed_uploads = 0
		self.currentSessionCount = 0
		self.primed = False
		self.decrypted = False
		self.debug_mode = debug_mode or self.settings["settings_behavior"]["debug"]

		self.settings["settings_encrypt"]["keyfile"] = keyfile or self.settings["settings_encrypt"]["keyfile"]


	# Setup Exit Calls
	def exit(self):
		self.eventSleep.set()

	# Decryption settings
	# Used to set class attributes with the same name to the value specified in the config file.
	def load_settings(self, keys):
		try:
			for key in keys:
				self.settings[key] = getattr(self.cfg, key)

		except AttributeError as e:
			print(e)
			raise BadCfgFile
	
	def decrypt_settings(self):
		settings = self.settings
		settings_encrypt = settings["settings_encrypt"]
		settings_server = settings["settings_server"]
		if settings_encrypt["encrypt"] and not self.decrypted and not self.debug_mode:
			import FediBotEncryption
			try:
				self.settings["settings_server"] = FediBotEncryption.settings_server_decrypt(
						settings_server, settings_encrypt, settings_encrypt["keyfile"])
			except FediBotEncryption.EncryptionFail as e:
				raise BadCfgFile(str(e))
		self.decrypted = True

	# Login to Pleroma
	def login(self):
		skip_login = self.debug_mode or self.mastodon_api is not None
		if skip_login:
			return
		if not self.decrypted:
			self.decrypt_settings()
		try:
			settings = self.settings
			settings_server = settings["settings_server"]
			settings_behavior = settings["settings_behavior"]

			self.mastodon_api = Mastodon(
				client_id=settings_server["client_id"],
				client_secret=settings_server["client_secret"],
				access_token=settings_server["access_token"],
				api_base_url=settings_server["api_base_url"],
				feature_set=settings_behavior["feature_set"]   # <--- Necessary for Mastodon Version 1.5.1
			)
		except (MastodonIllegalArgumentError, MastodonVersionError) as e:
			print(e)
			raise FailedLogin
	
	def upload_media_list_validate(self, path_list):
		for path in path_list:
			if path is None or not os.path.isfile(path):
				raise FileNotFoundError("Could not upload: {}".format(path))


	# Returns a list of tuples that contain the media list path and media mastodon dictionary
	def upload_media_list(self, path_list):
		self.upload_media_list_validate(path_list)

		media_list = []
		for path in path_list:
			if not self.debug_mode:
				media = self.mastodon_api.media_post(path, description=os.path.basename(path))
				media_dict = {
						"path": path,
						"media": media
						}
				media_list.append(media_dict)
		return media_list

	def get_post_text(self, message, media_list):
		settings = self.settings
		settings_behavior = settings["settings_behavior"]

		content_type = settings_behavior["content_type"]
		content_newline = settings_behavior["content_newline"]
		static_message = content_newline.join(message)
		string_post = ""
		string_imglinks = []

		if media_list and settings_behavior["post_image_link"]:
			for media_dict in media_list:
				path = media_dict["path"]
				media = media_dict["media"]

				if path is None or media is None:
					continue
				elif content_type == "text/markdown" and not self.debug_mode:
					string_imglinks.append(
						"[{}]({})".format(os.path.basename(path), media["url"])
					)
				else:
					string_imglinks.append(media["url"])

		# Join non empty strings with a newline character
		string_imglinks_joined = content_newline.join(filter(None, string_imglinks))
		string_post = content_newline.join(filter(None, (static_message, string_imglinks_joined)))

		return string_post

	def _post(self, picked):
		settings = self.settings
		settings_behavior = settings["settings_behavior"]

		if not picked:
			raise InvalidPost("Picked cannot be None")
		if not picked["media_list"]:
			raise InvalidPost("Media list is empty")
		if self.debug_mode:
			return picked
		media_list = self.upload_media_list(picked["media_list"])
		message = self.get_post_text(picked["message"], media_list)
		self.mastodon_api.status_post(
			message,
			media_ids=[i["media"] for i in media_list],
			visibility=settings_behavior["visibility"],
			sensitive=picked["spoiler"],
			content_type=settings_behavior["content_type"]
			)
		return picked

	def pick(self):
		return None

	def after_post(self, picked):
		return picked

	def handle_post_exception(self):
		# An exception occurred
		self.failed_uploads += 1
		self.consecutive_failed_uploads += 1

	# The main post function
	# This funciton is responsible for picking, posting, and blacklisting an image in listPictures
	#
	# It is also responsible for removing the picked item from self.listPictures, which can be accomplished by simply
	# popping it at index 0. This should handle any error that might occur while posting.
	#
	# This function should return 'None' if a post failed, and the picked item from self.listPictures if it succeeded.
	def post(self, callback=None):
		# Post
		_picked = callback() if callable(callback) else self.pick()
		self._post(_picked)

		# After a successful post
		self.currentSessionCount += 1
		self.consecutive_failed_uploads = 0

		# The post was successful
		return _picked

	# [BEGIN THE PROGRAM]
	def prime_bot(self):
		if self.primed:
			return
		if not self.debug_mode:
			self.decrypt_settings()
			self.login()
		self.primed = True

	def start(self):
		self.prime_bot()

		# Begin posting
		self.main_loop()

		return 0

	# End Conditions:
	# 1. User presses Ctrl+C
	# 2. There is nothing left in the picture list to select from
	# 3. settings_behavior["uploads_per_post"] is less than uploads_per_post
	# 4. Consecutive failed uploads is less than max_errors
	def can_post(self):
		settings = self.settings["settings_behavior"]
		return (
				not self.eventSleep.is_set() and
				self.currentSessionCount < settings["uploads_per_post"] and
				self.consecutive_failed_uploads < settings["max_errors"]
				)

	def main_loop(self):
		sleep_seconds = self.settings["settings_behavior"]["retry_seconds"]
		while self.can_post():
			picked = self.post()
			self.after_post(picked)
			if self.can_post():
				self.eventSleep.wait(sleep_seconds)



# Custom Exceptions for YandereBot
class Debug(Exception):
	pass


class InvalidPost(Exception):
	pass


class FailedLogin(Exception):
	pass


class BadCfgFile(Exception):
	pass

class FailedToLoadCfg(Exception):
	pass