using System;
using UnityEngine;

namespace GeometryTD.UI
{
    public class CombatSelectFormUseCase : IUIUseCase
    {
        private const int BuildOptionCount = 4;

        private readonly Option[] _buildOptions = new Option[BuildOptionCount];
        private readonly Option _upgradeOption = new Option(CombatSelectActionType.UpgradeTower, 0, true);
        private readonly Option _destroyOption = new Option(CombatSelectActionType.DestroyTower, 0, false);

        private Func<int> _coinProvider;
        private bool _isVisible;
        private CombatSelectDisplayMode _displayMode = CombatSelectDisplayMode.Hidden;
        private Vector2 _contentPosition;

        public CombatSelectFormUseCase()
        {
            _coinProvider = DefaultCoinProvider;

            for (int i = 0; i < BuildOptionCount; i++)
            {
                _buildOptions[i] = new Option(CombatSelectActionType.BuildTower, i, true);
            }
        }

        public CombatSelectFormRawData CreateInitialModel()
        {
            return BuildModel();
        }

        public CombatSelectFormRawData TryRefresh()
        {
            return BuildModel();
        }

        public void SetCoinProvider(Func<int> coinProvider)
        {
            _coinProvider = coinProvider ?? DefaultCoinProvider;
        }

        public void SetBuildAction(int buildIndex, Func<bool> buildAction, int cost, Sprite icon = null)
        {
            if (buildIndex < 0 || buildIndex >= _buildOptions.Length)
            {
                return;
            }

            Option option = _buildOptions[buildIndex];
            option.Action = buildAction;
            option.Price = Mathf.Max(0, cost);
            option.Icon = icon;
            option.IsGain = false;
            option.IsVisible = true;
        }

        public void SetBuildAction(int buildIndex, Action buildAction, int cost, Sprite icon = null)
        {
            if (buildAction == null)
            {
                SetBuildAction(buildIndex, (Func<bool>)null, cost, icon);
                return;
            }

            SetBuildAction(
                buildIndex,
                () =>
                {
                    buildAction.Invoke();
                    return true;
                },
                cost,
                icon);
        }

        public void SetUpgradeAction(Func<bool> upgradeAction, int cost, Sprite icon = null)
        {
            _upgradeOption.Action = upgradeAction;
            _upgradeOption.Price = Mathf.Max(0, cost);
            _upgradeOption.Icon = icon;
            _upgradeOption.IsGain = false;
            _upgradeOption.IsVisible = true;
        }

        public void SetUpgradeAction(Action upgradeAction, int cost, Sprite icon = null)
        {
            if (upgradeAction == null)
            {
                SetUpgradeAction((Func<bool>)null, cost, icon);
                return;
            }

            SetUpgradeAction(
                () =>
                {
                    upgradeAction.Invoke();
                    return true;
                },
                cost,
                icon);
        }

        public void SetDestroyAction(Func<bool> destroyAction, int gain, Sprite icon = null)
        {
            _destroyOption.Action = destroyAction;
            _destroyOption.Price = Mathf.Max(0, gain);
            _destroyOption.Icon = icon;
            _destroyOption.IsGain = true;
            _destroyOption.IsVisible = true;
        }

        public void SetDestroyAction(Action destroyAction, int gain, Sprite icon = null)
        {
            if (destroyAction == null)
            {
                SetDestroyAction((Func<bool>)null, gain, icon);
                return;
            }

            SetDestroyAction(
                () =>
                {
                    destroyAction.Invoke();
                    return true;
                },
                gain,
                icon);
        }

        public void SetUpgradePrice(int cost)
        {
            _upgradeOption.Price = Mathf.Max(0, cost);
        }

        public void SetUpgradeVisible(bool visible)
        {
            _upgradeOption.IsVisible = visible;
        }

        public void SetDestroyGain(int gain)
        {
            _destroyOption.Price = Mathf.Max(0, gain);
            _destroyOption.IsGain = true;
        }

        public void ShowForFoundation(Vector2 contentPosition)
        {
            _contentPosition = contentPosition;
            _displayMode = CombatSelectDisplayMode.Build;
            _isVisible = true;
        }

        public void ShowForTower(Vector2 contentPosition)
        {
            _contentPosition = contentPosition;
            _displayMode = CombatSelectDisplayMode.Func;
            _isVisible = true;
        }

        public void Hide()
        {
            _isVisible = false;
            _displayMode = CombatSelectDisplayMode.Hidden;
        }

        public bool TryExecuteAction(CombatSelectActionType actionType, int actionIndex)
        {
            if (!_isVisible)
            {
                return false;
            }

            Option option = GetOption(actionType, actionIndex);
            if (option == null || !option.IsVisible)
            {
                return false;
            }

            int currentCoin = Mathf.Max(0, _coinProvider != null ? _coinProvider.Invoke() : 0);
            if (!CanExecute(option, currentCoin))
            {
                return false;
            }

            if (option.Action == null)
            {
                return false;
            }

            bool result = option.Action.Invoke();
            if (result)
            {
                Hide();
            }

            return result;
        }

        private CombatSelectFormRawData BuildModel()
        {
            int currentCoin = Mathf.Max(0, _coinProvider != null ? _coinProvider.Invoke() : 0);
            TowerSelectItemRawData[] buildItems = new TowerSelectItemRawData[_buildOptions.Length];
            for (int i = 0; i < _buildOptions.Length; i++)
            {
                buildItems[i] = BuildOptionRawData(_buildOptions[i], currentCoin);
            }

            return new CombatSelectFormRawData
            {
                IsVisible = _isVisible,
                ContentPosition = _contentPosition,
                DisplayMode = _displayMode,
                BuildItems = buildItems,
                UpgradeItem = BuildOptionRawData(_upgradeOption, currentCoin),
                DestroyItem = BuildOptionRawData(_destroyOption, currentCoin)
            };
        }

        private Option GetOption(CombatSelectActionType actionType, int actionIndex)
        {
            switch (actionType)
            {
                case CombatSelectActionType.BuildTower:
                    if (actionIndex < 0 || actionIndex >= _buildOptions.Length)
                    {
                        return null;
                    }

                    return _buildOptions[actionIndex];
                case CombatSelectActionType.UpgradeTower:
                    return _upgradeOption;
                case CombatSelectActionType.DestroyTower:
                    return _destroyOption;
                default:
                    return null;
            }
        }

        private static int DefaultCoinProvider()
        {
            if (GameEntry.CombatNode == null)
            {
                return 0;
            }

            return Mathf.Max(0, GameEntry.CombatNode.CurrentCoin);
        }

        private static bool CanExecute(Option option, int currentCoin)
        {
            if (option == null)
            {
                return false;
            }

            if (option.RequiresAffordable && currentCoin < option.Price)
            {
                return false;
            }

            return true;
        }

        private static TowerSelectItemRawData BuildOptionRawData(Option option, int currentCoin)
        {
            if (option == null)
            {
                return null;
            }

            return new TowerSelectItemRawData
            {
                Icon = option.Icon,
                Price = option.Price,
                IsGain = option.IsGain,
                IsVisible = option.IsVisible,
                IsInteractable = option.Action != null && CanExecute(option, currentCoin),
                ActionType = option.ActionType,
                ActionIndex = option.ActionIndex
            };
        }

        private sealed class Option
        {
            public readonly CombatSelectActionType ActionType;
            public readonly int ActionIndex;
            public readonly bool RequiresAffordable;

            public int Price;
            public bool IsGain;
            public bool IsVisible = true;
            public Sprite Icon;
            public Func<bool> Action;

            public Option(CombatSelectActionType actionType, int actionIndex, bool requiresAffordable)
            {
                ActionType = actionType;
                ActionIndex = actionIndex;
                RequiresAffordable = requiresAffordable;
            }
        }
    }
}