{-
 *  Programmer:	Piotr Borek
 *  E-mail:     piotrborek@op.pl
 *  Copyright 2017 Piotr Borek
 *
 *  Distributed under the terms of the GPL (GNU Public License)
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}
{-# LANGUAGE TemplateHaskell #-}

module Mp.UI.MpData (
    MpData (..),
    mpColors,
    mpMusicDirectory,
    mpSongList,
    mpSongMap,
    mpSongInit,
    mpSongAdd,
    mpSongRemove,
    mpSongExists,

    module Mp.Configuration.AppColors
) where

import           Control.Lens
import           Control.Monad
import           Data.List
import qualified Data.Map.Strict            as Map
import           Simple.UI.All

import           Mp.Configuration.AppColors

data MpData = MpData
    { _mpColors         :: AppColors
    , _mpMusicDirectory :: String
    , _mpSongList       :: Attribute [String]
    , _mpSongMap        :: Attribute (Map.Map String Integer)
    }

makeLenses ''MpData

mpSongInit :: [String] -> UIApp MpData ()
mpSongInit songList = do
    mpData <- view appUserData
    writeAttr (mpData ^. mpSongList) songList
    let songList' = map (\x -> (x, 1)) songList
    writeAttr (mpData ^. mpSongMap) $ Map.fromList songList'

mpSongAdd :: String -> UIApp MpData ()
mpSongAdd _name = do
    mpData <- view appUserData
    modifyAttr (mpData ^. mpSongList) $ \xs -> xs ++ [_name]
    modifyAttr (mpData ^. mpSongMap) $ \m ->
        let v = Map.lookup _name m in
                case v of
                    Just x  -> Map.insert _name (succ x) m
                    Nothing -> Map.insert _name 1 m

mpSongRemove :: String -> UIApp MpData Int
mpSongRemove _name = do
    mpData <- view appUserData
    songList <- readAttr (mpData ^. mpSongList)
    let _indices = elemIndices _name songList

    when (null _indices) $ error "MpData.hs:79: indices == []"

    let _index = last _indices
    writeAttr (mpData ^. mpSongList) $ removeAt _index songList
    modifyAttr (mpData ^. mpSongMap) $ \songMap ->
        let v = Map.lookup _name songMap in
                case v of
                    Just 1  -> Map.delete _name songMap
                    Just _  -> Map.adjust pred _name songMap
                    Nothing -> songMap

    return _index

mpSongExists :: String -> UIApp MpData Bool
mpSongExists _name = do
    mpData <- view appUserData
    songMap <- readAttr (mpData ^. mpSongMap)
    case Map.lookup _name songMap of
        Just v  -> if v > 0 then return True else return False
        Nothing -> return False