use std::default::Default;

use mio::Token;
use strum_macros::{Display, EnumIter};

use crate::command::{CommandNew, CommandSet, Parse, ParserError};
use crate::database::Db;
use crate::queue::SendQueue;
use crate::result::RudeResult;
use crate::try_log;

/// Root level of command.
///
/// Every command must be implemented here, either directly or nested inside
/// a subcommand somewhere.
///
/// The parser matches against lowercase string representations of the enum
/// variants
#[derive(Clone, Debug, Display, EnumIter, Eq, Ord, PartialEq, PartialOrd)]
pub enum Command {
	N,
	S,
	E,
	W,
	U,
	D,
	North,
	South,
	East,
	West,
	Up,
	Down,
	Dig,
	Help,
	Look,
	New(CommandNew),
	Quit,
	Save,
	Say,
	Set(CommandSet),
	Default,
}

impl Default for Command {
	fn default() -> Self {
		Self::Default
	}
}

impl Parse for Command {
	fn help(&self) -> &str {
		match self {
			Self::N => "n :: Move one room to the north.",
			Self::S => "s :: Move one room to the south.",
			Self::E => "e :: Move one room to the east.",
			Self::W => "w :: Move one room to the west.",
			Self::U => "u :: Move one room up.",
			Self::D => "d :: Move one room down.",
			Self::North => "north :: Move one room to the north.",
			Self::South => "south :: Move one room to the south.",
			Self::East => "east :: Move one room to the east.",
			Self::West => "west :: Move one room to the west.",
			Self::Up => "up :: Move one room up.",
			Self::Down => "down :: Move one room down.",
			Self::Dig => "dig DIRECTION:: Dig a new path to a new room in the provided direction.",
			Self::Help => "help [COMMAND]:: Provide help on a specific command, or an overview.",
			Self::Look => "look :: Take a look around the current room.",
			Self::New(_) => "new :: Create new things.",
			Self::Quit => "quit :: Quit playing and disconnect from the game.",
			Self::Save => "save :: Write player information to disk.",
			Self::Say => "say MESSAGE:: Say something to the room.",
			Self::Set(_) => "set OPTIONS :: Set various parameters.",
			Self::Default => "",
		}
	}

	fn parse_subcommand(&self, s: String) -> RudeResult<(Self, String)> {
		match self {
			Self::New(_) => {
				let (command, args) =
					try_log!(CommandNew::parse(s), "Unable to parse new subcommand");
				Ok((Self::New(command), args))
			}
			Self::Set(_) => {
				let (command, args) =
					try_log!(CommandSet::parse(s), "Unable to parse set subcommand");
				Ok((Self::Set(command), args))
			}
			Self::Default => Err(ParserError::Default.into()),
			_ => Ok((self.clone(), s)),
		}
	}

	fn subcommand_help(&self) -> Option<String> {
		match self {
			Self::New(command_new) => Some(command_new.help_all()),
			Self::Set(command_set) => Some(command_set.help_all()),
			_ => None,
		}
	}

	fn dispatch_map_subcommand(&self, args: String, token: Token, db: &mut Db) -> SendQueue {
		match self {
			Self::New(command_new) => command_new.dispatch(command_new, args, token, db),
			Self::Set(command_set) => command_set.dispatch(command_set, args, token, db),
			_ => SendQueue::new(),
		}
	}

	fn dispatch_map(&self) -> fn(&Self, String, Token, &mut Db) -> SendQueue {
		match self {
			Self::N | Self::North => Self::dispatch_move_room,
			Self::S | Self::South => Self::dispatch_move_room,
			Self::E | Self::East => Self::dispatch_move_room,
			Self::W | Self::West => Self::dispatch_move_room,
			Self::U | Self::Up => Self::dispatch_move_room,
			Self::D | Self::Down => Self::dispatch_move_room,
			Self::Dig => Self::dispatch_dig,
			Self::Help => Self::dispatch_help,
			Self::New(_) => Self::dispatch_map_subcommand,
			Self::Look => Self::dispatch_look,
			Self::Quit => Self::dispatch_quit,
			Self::Save => Self::dispatch_save,
			Self::Say => Self::dispatch_say,
			Self::Set(_) => Self::dispatch_map_subcommand,
			Self::Default => Self::dispatch_default,
		}
	}
}