"""
Classes for crafting messages from the bot. Content can change as information
changes, and mods can perform actions on the message via emoji reactions.
"""
from datetime import datetime
from discord import Guild, Message, PartialEmoji, TextChannel

from config import CONFIG
from rocketbot.storage import ConfigKey, Storage
from rocketbot.utils import bot_log

class BotMessageReaction:
	"""
	A possible reaction to a bot message that will trigger an action. The list
	of available reactions will be listed at the end of a BotMessage. When a
	mod reacts to the message with the emote, something can happen.

	If the reaction is disabled, reactions will not register. The description
	will still show up in the message, but no emoji is shown. This can be used
	to explain why an action is no longer available.
	"""
	def __init__(self, emoji: str, is_enabled: bool, description: str):
		self.emoji = emoji
		self.is_enabled = is_enabled
		self.description = description

	def __eq__(self, other):
		return other is not None and \
			other.emoji == self.emoji and \
			other.is_enabled == self.is_enabled and \
			other.description == self.description

	@classmethod
	def standard_set(cls,
			did_delete: bool = None,
			message_count: int = 1,
			did_kick: bool = None,
			did_ban: bool = None,
			user_count: int = 1) -> list:
		"""
		Convenience factory for generating any of the three most common
		commands: delete message(s), kick user(s), and ban user(s). All
		arguments are optional. Resulting list can be passed directly to
		`BotMessage.set_reactions()`.

		Params
		- did_delete     Whether the message(s) have been deleted. Pass True or
		                 False if this applies, omit to leave out delete action.
		- message_count  How many messages there are. Used for pluralizing
		                 description. Defaults to 1. Omit if n/a.
		- did_kick       Whether the user(s) have been kicked. Pass True or
		                 False if this applies, omit to leave out kick action.
		- did_ban        Whether the user(s) have been banned. Pass True or
		                 False if this applies, omit to leave out ban action.
		- user_count     How many users there are. Used for pluralizing
		                 description. Defaults to 1. Omit if n/a.
		"""
		reactions = []
		if did_delete is not None:
			if did_delete:
				reactions.append(BotMessageReaction(
					CONFIG['trash_emoji'],
					False,
					'Message deleted' if message_count == 1 else 'Messages deleted'))
			else:
				reactions.append(BotMessageReaction(
					CONFIG['trash_emoji'],
					True,
					'Delete message' if message_count == 1 else 'Delete messages'))
		if did_kick is not None:
			if did_ban is not None and did_ban:
				# Don't show kick option at all if we also banned
				pass
			elif did_kick:
				reactions.append(BotMessageReaction(
					CONFIG['kick_emoji'],
					False,
					'User kicked' if user_count == 1 else 'Users kicked'))
			else:
				reactions.append(BotMessageReaction(
					CONFIG['kick_emoji'],
					True,
					'Kick user' if user_count == 1 else 'Kick users'))
		if did_ban is not None:
			if did_ban:
				reactions.append(BotMessageReaction(
					CONFIG['ban_emoji'],
					False,
					'User banned' if user_count == 1 else 'Users banned'))
			else:
				reactions.append(BotMessageReaction(
					CONFIG['ban_emoji'],
					True,
					'Ban user' if user_count == 1 else 'Ban users'))
		return reactions

class BotMessage:
	"""
	Holds state for a bot-generated message. A message is composed, sent via
	`BaseCog.post_message()`, and can later be updated.

	A message consists of a type (e.g. info, warning), text, optional quoted
	text (such as the content of a flagged message), and an optional list of
	actions that can be taken via a mod reacting to the message.
	"""

	TYPE_DEFAULT = 0
	TYPE_INFO = 1
	TYPE_MOD_WARNING = 2
	TYPE_SUCCESS = 3
	TYPE_FAILURE = 4

	def __init__(self,
			guild: Guild,
			text: str,
			type: int = TYPE_DEFAULT, # pylint: disable=redefined-builtin
			context = None,
			reply_to: Message = None):
		self.guild = guild
		self.text = text
		self.type = type
		self.context = context
		self.quote = None
		self.source_cog = None  # Set by `BaseCog.post_message()`
		self.__posted_text = None  # last text posted, to test for changes
		self.__posted_emoji = set()
		self.__message = None  # Message
		self.__reply_to = reply_to
		self.__reactions = []  # BotMessageReaction[]

	def is_sent(self) -> bool:
		"""
		Returns whether this message has been sent to the guild. This may
		continue returning False even after calling BaseCog.post_message if
		the guild has no configured warning channel.
		"""
		return self.__message is not None

	def message_id(self):
		'Returns the Message id or None if not sent.'
		return self.__message.id if self.__message else None

	def message_sent_at(self) -> datetime:
		'Returns when the message was sent or None if not sent.'
		return self.__message.created_at if self.__message else None

	def has_reactions(self) -> bool:
		'Whether this message has any reactions defined.'
		return len(self.__reactions) > 0

	async def set_text(self, new_text: str) -> None:
		"""
		Replaces the text of this message. If the message has been sent, it will
		be updated.
		"""
		self.text = new_text
		await self.update_if_sent()

	async def set_reactions(self, reactions: list) -> None:
		"""
		Replaces all BotMessageReactions with a new list. If the message has
		been sent, it will be updated.
		"""
		if reactions == self.__reactions:
			# No change
			return
		self.__reactions = reactions.copy() if reactions is not None else []
		await self.update_if_sent()

	async def add_reaction(self, reaction: BotMessageReaction) -> None:
		"""
		Adds one BotMessageReaction to this message. If a reaction already
		exists for the given emoji it is replaced with the new one. If the
		message has been sent, it will be updated.
		"""
		# Alias for update. Makes for clearer intent.
		await self.update_reaction(reaction)

	async def update_reaction(self, reaction: BotMessageReaction) -> None:
		"""
		Updates or adds a BotMessageReaction. If the message has been sent, it
		will be updated.
		"""
		found = False
		for i, existing in enumerate(self.__reactions):
			if existing.emoji == reaction.emoji:
				if reaction == self.__reactions[i]:
					# No change
					return
				self.__reactions[i] = reaction
				found = True
				break
		if not found:
			self.__reactions.append(reaction)
		await self.update_if_sent()

	async def remove_reaction(self, reaction_or_emoji) -> None:
		"""
		Removes a reaction. Can pass either a BotMessageReaction or just the
		emoji string. If the message has been sent, it will be updated.
		"""
		for i, existing in enumerate(self.__reactions):
			if (isinstance(reaction_or_emoji, str) and existing.emoji == reaction_or_emoji) or \
				(isinstance(reaction_or_emoji, BotMessageReaction) and \
					existing.emoji == reaction_or_emoji.emoji):
				self.__reactions.pop(i)
				await self.update_if_sent()
				return

	def reaction_for_emoji(self, emoji) -> BotMessageReaction:
		"""
		Finds the BotMessageReaction for the given emoji or None if not found.
		Accepts either a PartialEmoji or str.
		"""
		for reaction in self.__reactions:
			if isinstance(emoji, PartialEmoji) and reaction.emoji == emoji.name:
				return reaction
			if isinstance(emoji, str) and reaction.emoji == emoji:
				return reaction
		return None

	async def update_if_sent(self) -> None:
		"""
		Updates the text and/or reactions on a message if it was sent to
		the guild, otherwise does nothing. Does not need to be called by
		BaseCog subclasses.
		"""
		if self.__message:
			await self.update()

	async def update(self) -> None:
		"""
		Sends or updates an already sent message based on BotMessage state.
		Does not need to be called by BaseCog subclasses.
		"""
		content: str = self.__formatted_message()
		if self.__message:
			if content != self.__posted_text:
				await self.__message.edit(content=content)
				self.__posted_text = content
		else:
			if self.__reply_to:
				self.__message = await self.__reply_to.reply(content=content, mention_author=False)
				self.__posted_text = content
			else:
				channel_id = Storage.get_config_value(self.guild, ConfigKey.WARNING_CHANNEL_ID)
				if channel_id is None:
					bot_log(self.guild, None, '\u0007No warning channel set! No warning issued.')
					return
				channel: TextChannel = self.guild.get_channel(channel_id)
				if channel is None:
					bot_log(self.guild, None, '\u0007Configured warning channel does not exist!')
					return
				self.__message = await channel.send(content=content)
				self.__posted_text = content
		emoji_to_remove = self.__posted_emoji.copy()
		for reaction in self.__reactions:
			if reaction.is_enabled:
				if reaction.emoji not in self.__posted_emoji:
					await self.__message.add_reaction(reaction.emoji)
					self.__posted_emoji.add(reaction.emoji)
				if reaction.emoji in emoji_to_remove:
					emoji_to_remove.remove(reaction.emoji)
		for emoji in emoji_to_remove:
			await self.__message.clear_reaction(emoji)
			if emoji in self.__posted_emoji:
				self.__posted_emoji.remove(emoji)

	def __formatted_message(self) -> str:
		s: str = ''

		if self.type == self.TYPE_INFO:
			s += CONFIG['info_emoji'] + ' '
		elif self.type == self.TYPE_MOD_WARNING:
			mention: str = Storage.get_config_value(self.guild, ConfigKey.WARNING_MENTION)
			if mention:
				s += mention + ' '
			s += CONFIG['warning_emoji'] + ' '
		elif self.type == self.TYPE_SUCCESS:
			s += CONFIG['success_emoji'] + ' '
		elif self.type == self.TYPE_FAILURE:
			s += CONFIG['failure_emoji'] + ' '

		s += self.text

		if self.quote:
			s += f'\n\n> {self.quote}'

		if len(self.__reactions) > 0:
			s += '\n\nAvailable actions:'
			for reaction in self.__reactions:
				if reaction.is_enabled:
					s += f'\n     {reaction.emoji} {reaction.description}'
				else:
					s += f'\n     {reaction.description}'

		return s