using GameModel;
using GameModel.Contract;
using GameModel.Contracts;
using Microsoft.VisualBasic.FileIO;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GameHandler
{
    class GameStateHandlerItem<T>
    {
        internal Guid GameStateId;
        internal bool Saved;
        internal T Data;
        public GameStateHandlerItem(Guid gameStateId, T data)
        {
            GameStateId = gameStateId;
            Data = data;
        }
    }

    public class GameStateHandler
    {
        private Guid _gameStateId;

        private List<GameStateHandlerItem<GameState>> gameStates = new List<GameStateHandlerItem<GameState>>();
        //private List<GameStateHandlerItem<ExpenseModel>> expenseModels = new List<GameStateHandlerItem<ExpenseModel>>();
        private List<GameStateHandlerItem<PlayerExpense>> memberExpenses = new List<GameStateHandlerItem<PlayerExpense>>();

        private List<GameStateHandlerItem<GameState>> redoableGameStates = new List<GameStateHandlerItem<GameState>>();
        //private List<GameStateHandlerItem<ExpenseModel>> redoableExpenseModels = new List<GameStateHandlerItem<ExpenseModel>>();
        private List<GameStateHandlerItem<PlayerExpense>> redoableMeberExpenses = new List<GameStateHandlerItem<PlayerExpense>>();

        private IGameRepository _gameRepository;
        private IExpenseRepository _expenseRepository;

        public GameStateHandler(IGameRepository gameRepository, IExpenseRepository expenseRepository) 
        {
            _gameRepository = gameRepository;
            _expenseRepository = expenseRepository;
        }

        //public ExpenseModel ExpenseModel
        //{
        //    get
        //    {
        //        var res = expenseModels.LastOrDefault();
        //        if (res != null)
        //        {
        //            return res.Data;
        //        }
        //        return null;
        //    }
        //}

        public GameState GameState 
        { 
            get
            {
                var res = gameStates.LastOrDefault();
                if (res != null)
                {
                    return res.Data;
                }
                return null;
            }
        }

        public Guid NextGameStateId
        {
            get
            {
                if (_gameStateId == Guid.Empty)
                {
                    _gameStateId = Guid.NewGuid();
                }
                return _gameStateId;
            }
        }

        public Guid StartNewState()
        {
            _gameStateId = Guid.NewGuid();        
            return _gameStateId;
        }

        internal void Add(IEnumerable<PlayerExpense> playerExpenses)
        {
            foreach (var playerExpense in playerExpenses)
            {
                Add(playerExpense);
            }
        }

        internal void Add(PlayerExpense playerExpense)
        {
            var model = playerExpense with { GamestateId = _gameStateId };
            memberExpenses.Add(new GameStateHandlerItem<PlayerExpense>(_gameStateId, model));            
        }

        internal void Add(GameState newState)
        {
            if (newState.Id != Guid.Empty && newState.Id != NextGameStateId)
            {
                throw new InvalidDataException("GameState is not new");
            }
            var model = newState with { Id = _gameStateId, Counter = gameStates.Count + 1 };
            
            var item = new GameStateHandlerItem<GameState>(_gameStateId, model);
            gameStates.Add(item);           
        }

        public async Task Save()
        {
            await DeleteRedoableStates(); // first delete undone items - otherwise ID is not unique in DB

            var gameState = gameStates.FirstOrDefault(_ => _.GameStateId == _gameStateId);
            await Save(gameState);

            foreach (var memberExpense in memberExpenses.Where(_ => _.GameStateId == _gameStateId))
            {
                await Save(memberExpense);
            }

            //var expenseModelItem = expenseModels.FirstOrDefault(_ => _.GameStateId == _gameStateId);
            //if (expenseModelItem != null)
            //{
            //    var expenseModel = expenseModelItem.Data;
            //    foreach (var memberExpense in expenseModel.MemberExpenses.Where(_ => _.GamestateId == _gameStateId))
            //    {
            //        var item = new GameStateHandlerItem<PlayerExpense>(memberExpense.GamestateId, memberExpense);
            //        memberExpenses.Add(item);
            //        await Save(item);
            //    }
            //}
        }


        private async Task DeleteRedoableStates()
        {
            if (redoableGameStates.Count > 0)
            {
                await _gameRepository.Delete(redoableGameStates.Select(_ => _.Data));
                redoableGameStates.Clear();
            }

            if (redoableMeberExpenses.Count > 0)
            {
                // wird über fremdschlüssel gelöscht
                //await _expenseRepository.Delete(redoableMeberExpenses.Select(_ => _.Data));
                redoableMeberExpenses.Clear();
            }

            //redoableExpenseModels.Clear();
        }



        private async Task Save(GameStateHandlerItem<PlayerExpense> item)
        {
            await _expenseRepository.Save(item.Data);
        }

        private async Task Save(GameStateHandlerItem<GameState> item)
        {
            await _gameRepository.Save(item.Data);
        }

        public GameState Redo()
        {
            if (gameStates.Count == 0)
            {
                return null;
            }

            if (redoableGameStates.Count > 0)
            {
                var redoId = redoableGameStates.Last().GameStateId;

                gameStates.AddRange(redoableGameStates.Where(_ => _.GameStateId == redoId));
                //expenseModels.AddRange(redoableExpenseModels.Where(_ => _.GameStateId == redoId));
                memberExpenses.AddRange(redoableMeberExpenses.Where(_ => _.GameStateId == redoId));

                redoableGameStates.RemoveAll(_ => _.GameStateId == redoId);
                //redoableExpenseModels.RemoveAll(_ => _.GameStateId == redoId);
                redoableMeberExpenses.RemoveAll(_ => _.GameStateId == redoId);
            }

            _gameStateId = gameStates.Last().GameStateId;
            return GameState;
        }

        public GameState Undo()
        {
            if (gameStates.Count <= 1)
            {
                return null;
            }

            redoableGameStates.AddRange(gameStates.Where(_ => _.GameStateId == _gameStateId));
            //redoableExpenseModels.AddRange(expenseModels.Where(_ => _.GameStateId == _gameStateId));
            redoableMeberExpenses.AddRange(memberExpenses.Where(_ => _.GameStateId == _gameStateId));

            gameStates.RemoveAll(_ => _.GameStateId == _gameStateId);
            //expenseModels.RemoveAll(_ => _.GameStateId == _gameStateId);
            memberExpenses.RemoveAll(_ => _.GameStateId == _gameStateId);

            _gameStateId = gameStates.Last().GameStateId;

            return GameState;
        }

        internal async Task<Game> CreateNewGame(string gameName)
        {
            return await _gameRepository.Create(gameName);
        }

        internal async Task<GameState> LoadState(Guid gameId)
        {
            var existingGameStates = await _gameRepository.LoadStates(gameId);
            gameStates.Clear();
            gameStates.AddRange(existingGameStates.Select(_ => new GameStateHandlerItem<GameState>(_.Id,_)));

            _gameStateId = gameStates.Last().GameStateId;

            memberExpenses.Clear();
            //_expenseRepository.GetMemberExpenses();

            return existingGameStates.Last();
        }

        internal async Task<Game?> LoadGame(Guid gameId)
        {
            return await _gameRepository.LoadGame(gameId);
        }
    }
}