{-
	Copyright (C) 2018 Dr. Alistair Ward

	This file is part of BishBosh.

	BishBosh 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.

	BishBosh 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 BishBosh.  If not, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]	Defines the fields a user can mutate.
-}

module BishBosh.UI.SetObject (
-- * Types
-- ** Data-types
	SetObject(..),
-- * Functions
	autoComplete,
-- ** Constructors
	mkSearchDepth
 ) where

import qualified	BishBosh.Data.Exception		as Data.Exception
import qualified	BishBosh.Input.SearchOptions	as Input.SearchOptions
import qualified	Control.Arrow
import qualified	Control.DeepSeq
import qualified	Control.Exception
import qualified	Data.Char
import qualified	Data.List
import qualified	Data.List.Extra

-- | The fields a user can mutate; currently there's only one.
newtype SetObject	= SearchDepth Input.SearchOptions.SearchDepth	deriving Eq

instance Control.DeepSeq.NFData SetObject where
	rnf (SearchDepth searchDepth)		= Control.DeepSeq.rnf searchDepth

instance Show SetObject where
	showsPrec _ (SearchDepth searchDepth)	= showString Input.SearchOptions.searchDepthTag . showChar ' ' . shows searchDepth

instance Read SetObject where
	readsPrec _ s	= case Control.Arrow.first Data.List.Extra.lower `map` lex s of
		[("searchdepth", s')]		-> Control.Arrow.first mkSearchDepth `map` reads s'
		_				-> []	-- No parse.

-- | Smart constructor.
mkSearchDepth :: Input.SearchOptions.SearchDepth -> SetObject
mkSearchDepth searchDepth
	| searchDepth < Input.SearchOptions.minimumSearchDepth	= Control.Exception.throw . Data.Exception.mkOutOfBounds . showString "BishBosh.UI.SetObject.mkSearchDepth:\t" $ shows Input.SearchOptions.searchDepthTag " must be positive."
	| otherwise						= SearchDepth searchDepth

-- | Replace the first word of the specified string with the name of a command of which it is an unambiguous case-insensitive prefix.
autoComplete :: ShowS
autoComplete	= uncurry (++) . Control.Arrow.first (
	\word -> case [
		tag |
			tag	<- [Input.SearchOptions.searchDepthTag],
			Data.List.Extra.lower word `Data.List.isPrefixOf` Data.List.Extra.lower tag
	] of
		[tag]	-> tag
		_	-> word
 ) . break Data.Char.isSpace . Data.List.Extra.trimStart