"""
A guild configuration setting available for editing via bot commands.
"""
from types import coroutine
from typing import Any, Optional, Type

from discord.ext import commands
from discord.ext.commands import Bot, Cog, Command, Context, Group

from config import CONFIG
from rocketbot.storage import Storage
from rocketbot.utils import first_command_group

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.
	"""
	def __init__(self,
			name: str,
			datatype: Type,
			brief: Optional[str] = None,
			description: Optional[str] = None,
			usage: Optional[str] = None,
			min_value: Optional[Any] = None,
			max_value: Optional[Any] = None,
			enum_values: Optional[set[Any]] = None):
		"""
		Params:
		- name         Setting identifier. Must follow variable naming
		               conventions.
		- datatype     Datatype of the setting. E.g. int, float, str
		- brief        Description of the setting, starting with lower case.
		               Will be inserted into phrases like "Sets <brief>" and
					   "Gets <brief".
		- description  Long-form description. Min, max, and enum values will be
		               appended to the end, so does not need to include these.
		- usage        Description of the value argument in a set command, e.g.
		               "<maxcount:int>"
		- min_value    Smallest allowable value. Must be of the same datatype as
		               the value. None for no minimum.
		- max_value    Largest allowable value. None for no maximum.
		- enum_values  Set of allowed values. None if unconstrained.
		"""
		self.name: str = name
		self.datatype: Type = datatype
		self.brief: Optional[str] = brief
		self.description: str = description or ''  # Can't be None
		self.usage: Optional[str] = usage
		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 or self.min_value is not None or self.max_value is not None:
			self.description += '\n'
		if self.enum_values:
			allowed_values = '`' + ('`, `'.join(enum_values)) + '`'
			self.description += f'\nAllowed values: {allowed_values}'
		if self.min_value is not None:
			self.description += f'\nMin value: {self.min_value}'
		if self.max_value is not None:
			self.description += f'\nMax value: {self.max_value}'
		if self.usage is None:
			self.usage = f'<{self.name}>'

	def validate_value(self, new_value) -> 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: Cog, bot: Bot, group: Group) -> 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'):
			(group or bot).add_command(self.__make_enable_command(cog))
			(group or bot).add_command(self.__make_disable_command(cog))
		else:
			(group or bot).add_command(self.__make_getter_command(cog))
			(group or bot).add_command(self.__make_setter_command(cog))

	def __make_getter_command(self, cog: Cog) -> Command:
		setting: CogSetting = self
		async def getter(cog: Cog, context: Context) -> None:
			setting_name = setting.name
			if context.command.parent:
				setting_name = f'{context.command.parent.name}.{setting_name}'
			key = f'{cog.__class__.__name__}.{setting.name}'
			value = Storage.get_config_value(context.guild, key)
			if value is None:
				value = cog.get_cog_default(setting.name)
				await context.message.reply(
					f'{CONFIG["info_emoji"]} `{setting_name}` is using default of `{value}`',
					mention_author=False)
			else:
				await context.message.reply(
					f'{CONFIG["info_emoji"]} `{setting_name}` is set to `{value}`',
					mention_author=False)
		command = Command(
			getter,
			name=f'get{setting.name}',
			brief=f'Shows {setting.brief}',
			description=setting.description,
			checks=[
				commands.has_permissions(ban_members=True),
				commands.guild_only(),
			])
		command.cog = cog
		return command

	def __make_setter_command(self, cog: Cog) -> Command:
		setting: CogSetting = self
		async def setter_common(cog: Cog, context: Context, new_value) -> None:
			try:
				setting.validate_value(new_value)
			except ValueError as ve:
				await context.message.reply(
					f'{CONFIG["failure_emoji"]} {ve}',
					mention_author=False)
				return
			setting_name = setting.name
			if context.command.parent:
				setting_name = f'{context.command.parent.name}.{setting_name}'
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(context.guild, key, new_value)
			await context.message.reply(
				f'{CONFIG["success_emoji"]} `{setting_name}` is now set to `{new_value}`',
				mention_author=False)
			await cog.on_setting_updated(context.guild, setting)
			cog.log(context.guild, f'{context.author.name} set {key} to {new_value}')

		async def setter_int(cog, context, new_value: int):
			await setter_common(cog, context, new_value)
		async def setter_float(cog, context, new_value: float):
			await setter_common(cog, context, new_value)
		async def setter_str(cog, context, new_value: str):
			await setter_common(cog, context, new_value)
		async def setter_bool(cog, context, new_value: bool):
			await setter_common(cog, context, new_value)

		setter: coroutine = None
		if setting.datatype == int:
			setter = setter_int
		elif setting.datatype == float:
			setter = setter_float
		elif setting.datatype == str:
			setter = setter_str
		elif setting.datatype == bool:
			setter = setter_bool
		else:
			raise ValueError(f'Datatype {setting.datatype} unsupported')

		command = Command(
			setter,
			name=f'set{setting.name}',
			brief=f'Sets {setting.brief}',
			description=setting.description,
			usage=setting.usage,
			checks=[
				commands.has_permissions(ban_members=True),
				commands.guild_only(),
			])
		# Passing `cog` in init gets ignored and set to `None` so set after.
		# This ensures the callback is passed the cog as `self` argument.
		command.cog = cog
		return command

	def __make_enable_command(self, cog: Cog) -> Command:
		setting: CogSetting = self
		async def enabler(cog: Cog, context: Context) -> None:
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(context.guild, key, True)
			await context.message.reply(
				f'{CONFIG["success_emoji"]} {setting.brief.capitalize()} enabled.',
				mention_author=False)
			await cog.on_setting_updated(context.guild, setting)
			cog.log(context.guild, f'{context.author.name} enabled {cog.__class__.__name__}')

		command = Command(
			enabler,
			name='enable',
			brief=f'Enables {setting.brief}',
			description=setting.description,
			checks=[
				commands.has_permissions(ban_members=True),
				commands.guild_only(),
			])
		command.cog = cog
		return command

	def __make_disable_command(self, cog: Cog) -> Command:
		setting: CogSetting = self
		async def disabler(cog: Cog, context: Context) -> None:
			key = f'{cog.__class__.__name__}.{setting.name}'
			Storage.set_config_value(context.guild, key, False)
			await context.message.reply(
				f'{CONFIG["success_emoji"]} {setting.brief.capitalize()} disabled.',
				mention_author=False)
			await cog.on_setting_updated(context.guild, setting)
			cog.log(context.guild, f'{context.author.name} disabled {cog.__class__.__name__}')

		command = Command(
			disabler,
			name='disable',
			brief=f'Disables {setting.brief}',
			description=setting.description,
			checks=[
				commands.has_permissions(ban_members=True),
				commands.guild_only(),
			])
		command.cog = cog
		return command

	@classmethod
	def set_up_all(cls, cog: Cog, 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.
		"""
		group: Group = first_command_group(cog)
		for setting in settings:
			setting.set_up(cog, bot, group)