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;
            }
        }

        internal async Task Add(ExpenseModel expenseModel)
        {
            if (ExpenseModel != null)
            {
                if (!expenseModel.Equals(ExpenseModel))
                {
                    expenseModels.Add(new GameStateHandlerItem<ExpenseModel>(_gameStateId, expenseModel));
                }
            } 
            else 
            { 
                expenseModels.Add(new GameStateHandlerItem<ExpenseModel>(_gameStateId, expenseModel));
            }
        }

        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);

            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();
        }

        internal async Task Add(GameState newState)
        {
            if (!newState.Equals(GameState))
            {
                _gameStateId = newState.Id;
                var item = new GameStateHandlerItem<GameState>(_gameStateId, newState with { Counter = gameStates.Count + 1 });
                gameStates.Add(item);
            }
        }
        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.AddRange(existingGameStates.Select(_ => new GameStateHandlerItem<GameState>(_.Id,_)));

            _gameStateId = gameStates.Last().GameStateId;

            return existingGameStates.Last();
        }

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