{-
	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