"""
A guild configuration setting available for editing via bot commands.
"""
from datetime import timedelta
from typing import Any, Optional, Type, Literal

from discord import Interaction, Permissions
from discord.app_commands import Range, Transform, describe
from discord.app_commands.commands import Command, Group, CommandCallback, rename
from discord.ext.commands import Bot

from config import CONFIG
from rocketbot.storage import Storage
from rocketbot.utils import bot_log, TimeDeltaTransformer, MOD_PERMISSIONS, dump_stacktrace, str_from_timedelta


class CogSetting:
	"""
	Describes a configuration setting for a guild that can be edited by the
	mods of those guilds. BaseCog can generate "/get" and "/set" commands (or
	"/enable" and "/disable" commands for boolean values) automatically, reducing
	the boilerplate of generating commands manually. Offers simple validation rules.
	"""

	permissions: Permissions = Permissions(Permissions.manage_messages.flag)

	def __init__(self,
			name: str,
			datatype: Optional[Type],
			default_value: Any,
			brief: Optional[str] = None,
			description: Optional[str] = None,
			min_value: Optional[Any] = None,
			max_value: Optional[Any] = None,
			enum_values: Optional[set[Any]] = None):
		"""
		Parameters
		----------
		name: str
			Setting identifier. Must follow variable naming conventions.
		datatype: Optional[Type]
		    Datatype of the setting. E.g. int, float, str
		default_value: Any
			Value to use if a guild has not yet configured one.
		brief: Optional[str]
			Description of the setting, starting with lower case.
			Will be inserted into phrases like "Sets <brief>" and
			"Gets <brief>".
		description: Optional[str]
		  	Long-form description. Min, max, and enum values will be
		    appended to the end, so does not need to include these.
		min_value: Optional[Any]
		    Smallest allowable value. Must be of the same datatype as
		    the value. None for no minimum.
		max_value: Optional[Any]
		    Largest allowable value. None for no maximum.
		enum_values: Optional[set[Any]]
		  	Set of allowed values. None if unconstrained.
		"""
		self.name: str = name
		self.datatype: Type = datatype
		self.default_value = default_value
		self.brief: Optional[str] = brief
		self.description: str = description or ''  # Can't be None
		self.min_value: Optional[Any] = min_value
		self.max_value: Optional[Any] = max_value
		self.enum_values: Optional[set[Any]] = enum_values
		if self.enum_values:
			value_list = '`' + ('`, `'.join(self.enum_values)) + '`'
			self.description += f' (Permitted values: {value_list})'
		elif self.min_value is not None and self.max_value is not None:
			self.description += f' (Value must be between `{self.min_value}` and `{self.max_value}`)'
		elif self.min_value is not None:
			self.description += f' (Minimum value: {self.min_value})'
		elif self.max_value is not None:
			self.description += f' (Maximum value: {self.max_value})'

	def validate_value(self, new_value: Any) -> None:
		"""
		Checks if a value is legal for this setting. Raises a ValueError if not.
		"""
		if self.min_value is not None and new_value < self.min_value:
			raise ValueError(f'`{self.name}` must be >= {self.min_value}')
		if self.max_value is not None and new_value > self.max_value:
			raise ValueError(f'`{self.name}` must be <= {self.max_value}')
		if self.enum_values is not None and new_value not in self.enum_values:
			allowed_values = '`' + ('`, `'.join(self.enum_values)) + '`'
			raise ValueError(f'`{self.name}` must be one of {allowed_values}')

	def set_up(self, cog: 'BaseCog') -> None:
		"""
		Sets up getter and setter commands for this setting. This should
		usually only be called by BaseCog.
		"""
		if self.name in ('enabled', 'is_enabled'):
			self.__enable_group.add_command(self.__make_enable_command(cog))
			self.__disable_group.add_command(self.__make_disable_command(cog))
		else:
			self.__get_group.add_command(self.__make_getter_command(cog))
			self.__set_group.add_command(self.__make_setter_command(cog))

	def to_stored_value(self, native_value: Any) -> Any:
		"""Converts a configuration value to a JSON-compatible datatype."""
		if self.datatype is timedelta:
			return native_value.total_seconds()
		return native_value

	def to_native_value(self, stored_value: Any) -> Any:
		"""Converts the stored JSON-compatible datatype to its actual value."""
		if self.datatype is timedelta and isinstance(stored_value, (int, float)):
			return timedelta(seconds=stored_value)
		return stored_value

	@staticmethod
	def native_value_to_str(native_value: Any) -> str:
		"""Formats a native configuration value to a user-presentable string."""
		if native_value is None:
			return '<no value>'
		if isinstance(native_value, timedelta):
			return str_from_timedelta(native_value)
		if isinstance(native_value, bool):
			return 'true' if native_value else 'false'
		return f'{native_value}'

	def __make_getter_command(self, cog: 'BaseCog') -> Command:
		setting: CogSetting = self
		setting_name = setting.name
		if cog.config_prefix is not None:
			setting_name = f'{cog.config_prefix}_{setting_name}'
		async def getter(interaction: Interaction) -> None:
			key = f'{cog.__class__.__name__}.{setting.name}'
			value = setting.to_native_value(Storage.get_config_value(interaction.guild, key))
			if value is None:
				value = setting.to_native_value(cog.get_cog_default(setting.name))
				await interaction.response.send_message(
					f'{CONFIG["info_emoji"]} `{setting_name}` is using default of `{CogSetting.native_value_to_str(value)}`',
					ephemeral=True
				)
			else:
				await interaction.response.send_message(
					f'{CONFIG["info_emoji"]} `{setting_name}` is set to `{CogSetting.native_value_to_str(value)}`',
					ephemeral=True
				)

		bot_log(None, cog.__class__, f"Creating /get {setting_name}")
		command = Command(
			name=setting_name,
			description=f'Shows {self.brief}.',
			callback=getter,
			parent=CogSetting.__get_group,
			extras={
				'cog': cog,
				'setting': setting,
				'long_description': setting.description,
			},
		)
		return command

	def __make_setter_command(self, cog: 'BaseCog') -> Command:
		setting: CogSetting = self
		setting_name = setting.name
		if cog.config_prefix is not None:
			setting_name = f'{cog.config_prefix}_{setting_name}'
		async def setter_general(interaction: Interaction, new_value) -> None:
			try:
				setting.validate_value(new_value)
			except ValueError as ve:
				await interaction.response.send_message(
					f'{CONFIG["failure_emoji"]} {ve}',
					ephemeral=True
				)
				return
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(interaction.guild, key, setting.to_stored_value(new_value))
			await interaction.response.send_message(
				f'{CONFIG["success_emoji"]} `{setting_name}` is now set to `{setting.to_native_value(new_value)}`',
				ephemeral=True
			)
			await cog.on_setting_updated(interaction.guild, setting)
			cog.log(interaction.guild, f'{interaction.user.name} set {key} to {new_value}')

		setter: CommandCallback = setter_general
		if self.datatype == int:
			if self.min_value is not None or self.max_value is not None:
				r_min = self.min_value
				r_max = self.max_value
				@rename(new_value=self.name)
				@describe(new_value=self.brief)
				async def setter_range(interaction: Interaction, new_value: Range[int, r_min, r_max]) -> None:
					await setter_general(interaction, new_value)
				setter = setter_range
			else:
				@rename(new_value=self.name)
				@describe(new_value=self.brief)
				async def setter_int(interaction: Interaction, new_value: int) -> None:
					await setter_general(interaction, new_value)
				setter = setter_int
		elif self.datatype == float:
			@rename(new_value=self.name)
			@describe(new_value=self.brief)
			async def setter_float(interaction: Interaction, new_value: float) -> None:
				await setter_general(interaction, new_value)
			setter = setter_float
		elif self.datatype == timedelta:
			@rename(new_value=self.name)
			@describe(new_value=f'{self.brief} (e.g. 30s, 5m, 1h30s, or 7d)')
			async def setter_timedelta(interaction: Interaction, new_value: Transform[timedelta, TimeDeltaTransformer]) -> None:
				await setter_general(interaction, new_value)
			setter = setter_timedelta
		elif getattr(self.datatype, '__origin__', None) == Literal:
			dt = self.datatype
			@rename(new_value=self.name)
			@describe(new_value=self.brief)
			async def setter_enum(interaction: Interaction, new_value: dt) -> None:
				await setter_general(interaction, new_value)
			setter = setter_enum
		elif self.datatype == str:
			if self.enum_values is not None:
				raise ValueError('Type for a setting with enum values should be typing.Literal')
			else:
				@rename(new_value=self.name)
				@describe(new_value=self.brief)
				async def setter_str(interaction: Interaction, new_value: str) -> None:
					await setter_general(interaction, new_value)
				setter = setter_str
		elif self.datatype == bool:
			@rename(new_value=self.name)
			@describe(new_value=self.brief)
			async def setter_bool(interaction: Interaction, new_value: bool) -> None:
				await setter_general(interaction, new_value)
			setter = setter_bool
		elif self.datatype is not None:
			raise ValueError(f'Invalid type {self.datatype}')

		bot_log(None, cog.__class__, f"Creating /set {setting_name} {self.datatype}")
		command = Command(
			name=setting_name,
			description=f'Sets {self.brief}.',
			callback=setter,
			parent=CogSetting.__set_group,
			extras={
				'cog': cog,
				'setting': setting,
				'long_description': setting.description,
			},
		)
		return command

	def __make_enable_command(self, cog: 'BaseCog') -> Command:
		setting: CogSetting = self
		async def enabler(interaction: Interaction) -> None:
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(interaction.guild, key, True)
			await interaction.response.send_message(
				f'{CONFIG["success_emoji"]} {setting.brief.capitalize()} enabled.',
				ephemeral=True
			)
			await cog.on_setting_updated(interaction.guild, setting)
			cog.log(interaction.guild, f'{interaction.user.name} enabled {cog.__class__.__name__}')

		bot_log(None, cog.__class__, f"Creating /enable {cog.config_prefix}")
		command = Command(
			name=cog.config_prefix,
			description=f'Enables {cog.qualified_name} functionality.',
			callback=enabler,
			parent=CogSetting.__enable_group,
			extras={
				'cog': cog,
				'setting': setting,
				'long_description': setting.description,
			},
		)
		return command

	def __make_disable_command(self, cog: 'BaseCog') -> Command:
		setting: CogSetting = self
		async def disabler(interaction: Interaction) -> None:
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(interaction.guild, key, False)
			await interaction.response.send_message(
				f'{CONFIG["success_emoji"]} {setting.brief.capitalize()} disabled.',
				ephemeral=True
			)
			await cog.on_setting_updated(interaction.guild, setting)
			cog.log(interaction.guild, f'{interaction.user.name} disabled {cog.__class__.__name__}')

		bot_log(None, cog.__class__, f"Creating /disable {cog.config_prefix}")
		command = Command(
			name=cog.config_prefix,
			description=f'Disables {cog.config_prefix} functionality',
			callback=disabler,
			parent=CogSetting.__disable_group,
			extras={
				'cog': cog,
				'setting': setting,
				'long_description': setting.description,
			},
		)
		return command

	__set_group: Group
	__get_group: Group
	__enable_group: Group
	__disable_group: Group

	@classmethod
	def set_up_all(cls, cog: 'BaseCog', bot: Bot, settings: list['CogSetting']) -> None:
		"""
		Sets up editing commands for a list of CogSettings and adds them to a
		cog. If the cog has a command Group, commands will be added to it.
		Otherwise, they will be added at the top level.
		"""
		cls.__set_up_base_commands(bot)
		if len(settings) == 0:
			return
		bot_log(None, cog.__class__, f"Setting up slash commands for {cog.__class__.__name__}")
		for setting in settings:
			setting.set_up(cog)
		bot_log(None, cog.__class__, f"Done setting up slash commands for {cog.__class__.__name__}")

	@classmethod
	def __set_up_base_commands(cls, bot: Bot) -> None:
		if getattr(cls, f'_CogSetting__set_group', None) is not None:
			return
		cls.__set_group = Group(
			name='set',
			description='Sets a configuration value for this guild.',
			default_permissions=MOD_PERMISSIONS,
			extras={
				'long_description': 'Settings are guild-specific. If no value is set, a default is used. Use `/get` to '
									'see the current value for this guild.',
			},
		)
		cls.__get_group = Group(
			name='get',
			description='Shows a configuration value for this guild.',
			default_permissions=MOD_PERMISSIONS,
			extras={
				'long_description': 'Settings are guild-specific. Shows the configured value or default value for a '
									'variable for this guild. Use `/set` to change the value.',
			},
		)
		cls.__enable_group = Group(
			name='enable',
			description='Enables a module for this guild',
			default_permissions=MOD_PERMISSIONS,
			extras={
				'long_description': 'Modules are enabled on a per-guild basis and are off by default. Use `/disable` '
									'to disable an enabled module.',
			},
		)
		cls.__disable_group = Group(
			name='disable',
			description='Disables a module for this guild.',
			default_permissions=MOD_PERMISSIONS,
			extras={
				'long_description': 'Modules are enabled on a per-guild basis and are off by default. Use `/enable` '
					                're-enable a disabled module.',
			},
		)
		bot.tree.add_command(cls.__set_group)
		bot.tree.add_command(cls.__get_group)
		bot.tree.add_command(cls.__enable_group)
		bot.tree.add_command(cls.__disable_group)

		from rocketbot.cogs.basecog import BaseCog
		async def show_all(interaction: Interaction) -> None:
			try:
				guild = interaction.guild
				if guild is None:
					await interaction.response.send_message(
						f'{CONFIG["error_emoji"]} No guild.',
						ephemeral=True,
						delete_after=10,
					)
					return
				text = '## :information_source: Configuration'
				for cog_name, cog in sorted(bot.cogs.items()):
					if not isinstance(cog, BaseCog):
						continue
					bcog: BaseCog = cog
					if len(bcog.settings) == 0:
						continue
					text += f'\n### {bcog.qualified_name} Module'
					for setting in sorted(bcog.settings, key=lambda s: (s.name != 'enabled', s.name)):
						key = f'{bcog.__class__.__name__}.{setting.name}'
						value = setting.to_native_value(Storage.get_config_value(guild, key))
						deflt = setting.to_native_value(bcog.get_cog_default(setting.name))
						if setting.name == 'enabled':
							text += f'\n- Module is '
							if value is not None:
								text += '**' + ('enabled' if value else 'disabled') + '**'
							else:
								text += ('enabled' if deflt else 'disabled') + ' _(default)_'
						else:
							if value is not None:
								text += f'\n- `{bcog.config_prefix}_{setting.name}` = **{CogSetting.native_value_to_str(value)}**'
							else:
								text += f'\n- `{bcog.config_prefix}_{setting.name}` = {CogSetting.native_value_to_str(deflt)} _(using default)_'
				await interaction.response.send_message(
					text,
					ephemeral=True,
				)
			except BaseException as e:
				dump_stacktrace(e)
		show_all_command = Command(
			name='all',
			description='Shows all configuration for this guild.',
			callback=show_all,
		)
		cls.__get_group.add_command(show_all_command)