using System.Collections.Generic;
using GeometryTD.CustomEvent;
using GeometryTD.DataTable;
using GeometryTD.Definition;
using GeometryTD.Entity;
using GeometryTD.UI;
using UnityEngine;
using UnityGameFramework.Runtime;

namespace GeometryTD.CustomComponent
{
    public partial class CombatScheduler
    {
        private readonly List<DRLevelPhase> _phaseBuffer = new();
        private readonly Dictionary<int, IReadOnlyList<DRLevelSpawnEntry>> _spawnEntriesByPhaseId = new();
        private readonly EnemyManager _enemyManager = new();
        private readonly PhaseLoopRuntime _phaseLoopRuntime = new();
        private readonly CombatLoadSession _loadSession = new();
        private readonly CombatEventBridge _eventBridge = new();
        private readonly CombatInRunResourceManager _combatInRunResourceManager = new();
        private readonly EnemyDropResolver _enemyDropResolver = new();
        private readonly CombatSettlementFlowService _settlementFlowService = new();

        private EntityComponent _entity;
        private DRLevel _currentLevel;
        private CombatFinishFormUseCase _combatFinishFormUseCase;
        private RewardSelectFormUseCase _rewardSelectFormUseCase;
        private CombatStateBase _currentState;
        private bool _initialized;
        private bool _isFinishAsVictory = true;
        private bool _isCompleted;
        private bool _nodeEnterFired;
        private CombatSettlementContext _settlementContext;

        public bool IsRunning =>
            _currentState is CombatLoadingState or CombatRunningPhaseState or CombatWaitingForPhaseEndState;

        public bool IsCompleted => _isCompleted;
        public DRLevel CurrentLevel => _currentLevel;
        public DRLevelPhase CurrentPhase => _phaseLoopRuntime.CurrentPhase;
        public MapEntity CurrentMap => _loadSession.CurrentMap;
        public int DisplayPhaseIndex => _phaseLoopRuntime.DisplayPhaseIndex;
        public int PhaseCount => _phaseLoopRuntime.PhaseCount;
        public bool CanEndCombat => _phaseLoopRuntime.CanEndCombat;
        public int CurrentCoin => _combatInRunResourceManager.CurrentCoin;
        public int CurrentGold => _combatInRunResourceManager.CurrentGold;
        public int CurrentBaseHp => _combatInRunResourceManager.CurrentBaseHp;
        public int CurrentBuildTowerCount => _combatInRunResourceManager.CurrentBuildTowerCount;
        public int DefeatedEnemyCount => _enemyManager.DefeatedEnemyCount;
        public int GainedCoin => _combatInRunResourceManager.GainedCoin;
        public int GainedGold => _combatInRunResourceManager.GainedGold;

        public void OnInit()
        {
            if (!_initialized)
            {
                _entity = GameEntry.Entity;
                _eventBridge.Bind(
                    OnShowEntitySuccess,
                    OnShowEntityFailure,
                    OnHideEntityComplete,
                    OnOpenUIFormSuccess,
                    OnOpenUIFormFailure,
                    OnCloseUIFormComplete);
                _enemyManager.OnInit(this);
                _loadSession.OnInit(_entity);
                EnsureCombatFinishFormUseCaseBound();
                EnsureRewardSelectFormUseCaseBound();
                _initialized = true;
            }

            ResetRuntime();
        }

        public bool Start(
            DRLevel level,
            IReadOnlyList<DRLevelPhase> phases,
            IReadOnlyDictionary<int, IReadOnlyList<DRLevelSpawnEntry>> spawnEntriesByPhaseId)
        {
            if (!_initialized || _entity == null)
            {
                return HandleStartFailure("CombatScheduler start failed. Runtime is not initialized.");
            }

            if (level == null || phases == null || phases.Count <= 0)
            {
                return HandleStartFailure("CombatScheduler start failed. Invalid level or phase data.");
            }

            CleanupAllCombatEntities();
            CloseCombatFinishForm();
            CloseRewardSelectForm();
            _enemyManager.EndPhase();
            _enemyManager.ResetCombatStats();
            ResetRuntime();
            _isFinishAsVictory = true;

            _currentLevel = level;
            _combatInRunResourceManager.InitializeForCombat(level);
            for (int i = 0; i < phases.Count; i++)
            {
                DRLevelPhase phase = phases[i];
                if (phase != null)
                {
                    _phaseBuffer.Add(phase);
                }
            }

            if (spawnEntriesByPhaseId != null)
            {
                foreach (var pair in spawnEntriesByPhaseId)
                {
                    _spawnEntriesByPhaseId[pair.Key] = pair.Value;
                }
            }

            _phaseLoopRuntime.SetPhases(_phaseBuffer);
            if (_phaseLoopRuntime.PhaseCount <= 0)
            {
                return HandleStartFailure($"CombatScheduler start failed. Level '{level.Id}' has no phase data.");
            }

            ChangeState(new CombatLoadingState(this));
            Log.Info(
                "CombatScheduler started. Level={0}, PhaseCount={1}.",
                _currentLevel.Id,
                _phaseLoopRuntime.PhaseCount);
            return true;
        }

        public void OnUpdate(float elapseSeconds, float realElapseSeconds)
        {
            _currentState?.OnUpdate(elapseSeconds, realElapseSeconds);
        }

        public void OnDestroy()
        {
            if (!_initialized)
            {
                return;
            }

            _currentState?.OnExit();
            _currentState?.OnDestroy();
            _currentState = null;
            CleanupAllCombatEntities();
            CloseCombatFinishForm();
            CloseRewardSelectForm();
            _enemyManager.OnDestroy();
            ResetRuntime();
            _eventBridge.Unbind();
            _combatFinishFormUseCase = null;
            _rewardSelectFormUseCase = null;

            _entity = null;
            _initialized = false;
        }

        public bool TryEndCombatByPlayer()
        {
            if (_currentState is not CombatRunningPhaseState &&
                _currentState is not CombatWaitingForPhaseEndState)
            {
                return false;
            }

            return _phaseLoopRuntime.TryRequestEndCombat();
        }

        public void OnEnemyReachedBase(DREnemy enemy)
        {
            if (!IsRunning)
            {
                return;
            }

            int resolvedBaseDamage = enemy != null ? Mathf.Max(0, enemy.BaseDamage) : 0;
            if (resolvedBaseDamage <= 0)
            {
                return;
            }

            ApplyBaseDamage(resolvedBaseDamage);
        }

        public void OnEnemyDefeated(DREnemy enemy)
        {
            if (!IsRunning)
            {
                return;
            }

            EnemyDropResolveContext context = new(
                enemy,
                _phaseLoopRuntime.DisplayPhaseIndex,
                ResolveCurrentThemeType());
            EnemyDropResolveResult result = _enemyDropResolver.Resolve(context);
            _combatInRunResourceManager.AddEnemyDefeatedReward(result.Coin, result.Gold);

            if (!result.ShouldRollOutGameItem)
            {
                return;
            }

            _combatInRunResourceManager.TryRollOutGameItemDrop(
                context.DisplayPhaseIndex,
                context.ThemeType);
        }

        public bool OnCombatFinishReturnRequested()
        {
            if (_currentState is not CombatWaitingForReturnState waitingForReturnState)
            {
                return false;
            }

            waitingForReturnState.RequestReturn();
            return true;
        }

        public bool TryConsumeCoin(int coin)
        {
            return _combatInRunResourceManager.TryConsumeCoin(coin);
        }

        public void AddCoin(int coin)
        {
            _combatInRunResourceManager.AddCoin(coin);
        }

        public bool TryGetBuildTowerStats(int buildIndex, out TowerStatsData stats)
        {
            return _combatInRunResourceManager.TryGetBuildTowerStats(buildIndex, out stats);
        }

        private void ResetRuntime()
        {
            _currentState = null;
            _phaseBuffer.Clear();
            _spawnEntriesByPhaseId.Clear();
            _phaseLoopRuntime.Reset();
            _loadSession.Reset();
            _combatInRunResourceManager.Reset();
            _settlementContext = null;
            _currentLevel = null;
            _isFinishAsVictory = true;
            _isCompleted = false;
            _nodeEnterFired = false;
        }

        private void CleanupAllCombatEntities()
        {
            _loadSession.Cleanup();
            _enemyManager.CleanupTrackedEnemies();
        }

        private void EnsureCombatFinishFormUseCaseBound()
        {
            _combatFinishFormUseCase ??= new CombatFinishFormUseCase(this);
            GameEntry.UIRouter.BindUIUseCase(UIFormType.CombatFinishForm, _combatFinishFormUseCase);
        }

        private void EnsureRewardSelectFormUseCaseBound()
        {
            _rewardSelectFormUseCase ??= new RewardSelectFormUseCase();
            GameEntry.UIRouter.BindUIUseCase(UIFormType.RewardSelectForm, _rewardSelectFormUseCase);
        }

        private void ChangeState(CombatStateBase nextState)
        {
            if (ReferenceEquals(_currentState, nextState))
            {
                return;
            }

            _currentState?.OnExit();
            _currentState?.OnDestroy();
            _currentState = nextState;
            _currentState?.OnInit();
            _currentState?.OnEnter();
        }

        private bool TryBeginNextPhase()
        {
            if (!_phaseLoopRuntime.TryEnterNextPhase(out DRLevelPhase nextPhase))
            {
                ChangeState(new CombatSettlementState(this, "Combat ended after loop completion.", true));
                return false;
            }

            _spawnEntriesByPhaseId.TryGetValue(nextPhase.Id, out IReadOnlyList<DRLevelSpawnEntry> spawnEntries);
            ChangeState(new CombatRunningPhaseState(this, nextPhase, spawnEntries));
            return true;
        }

        private void EnterWaitingForPhaseEnd()
        {
            ChangeState(new CombatWaitingForPhaseEndState(this));
        }

        private void CompleteCurrentPhase()
        {
            _enemyManager.EndPhase();
            Log.Info(
                "CombatScheduler phase completed. Level={0}, Phase={1}, Elapsed={2:F2}s.",
                _currentLevel != null ? _currentLevel.Id : 0,
                _phaseLoopRuntime.CurrentPhase != null ? _phaseLoopRuntime.CurrentPhase.Id : 0,
                _phaseLoopRuntime.CurrentPhaseElapsed);

            TryBeginNextPhase();
        }

        private bool ShouldEnterSettlementFromActiveState(out string reason, out bool isVictory)
        {
            if (GetCurrentBaseHp() <= 0)
            {
                reason = "Combat ended because base HP reached zero.";
                isVictory = false;
                return true;
            }

            if (_phaseLoopRuntime.IsEndCombatRequested)
            {
                reason = "Combat ended by player.";
                isVictory = true;
                return true;
            }

            reason = null;
            isVictory = true;
            return false;
        }

        private void OnFullBaseHpRewardSelected(RewardSelectItemRawData selectedReward)
        {
            if (_currentState is not CombatRewardSelectionState || _settlementContext == null)
            {
                return;
            }

            _settlementFlowService.ApplySelectedReward(_settlementContext, selectedReward);
            ChangeState(new CombatFinishFormState(this));
        }

        private void OnFullBaseHpRewardGiveUp()
        {
            if (_currentState is not CombatRewardSelectionState || _settlementContext == null)
            {
                return;
            }

            ChangeState(new CombatFinishFormState(this));
        }

        private LevelThemeType ResolveCurrentThemeType()
        {
            if (_currentLevel != null)
            {
                return _currentLevel.LevelThemeType;
            }

            if (GameEntry.CombatNode != null)
            {
                return GameEntry.CombatNode.CurrentThemeType;
            }

            return LevelThemeType.None;
        }

        private int ApplyBaseDamage(int damage)
        {
            return _combatInRunResourceManager.ApplyBaseDamage(damage);
        }

        private int GetCurrentBaseHp()
        {
            return Mathf.Max(0, _combatInRunResourceManager.CurrentBaseHp);
        }

        private void CloseCombatFinishForm()
        {
            GameEntry.UIRouter.CloseUI(UIFormType.CombatFinishForm);
        }

        private void CloseRewardSelectForm()
        {
            GameEntry.UIRouter.CloseUI(UIFormType.RewardSelectForm);
        }

        private void CompleteCombatAndNotify(bool succeeded)
        {
            _isCompleted = true;
            _currentState = null;
            _combatInRunResourceManager.MarkCombatEnded();
            GameEntry.CombatNode?.OnCombatEndedByScheduler(succeeded);
        }

        private bool HandleStartFailure(string errorMessage)
        {
            Log.Warning("{0}", errorMessage);
            _enemyManager.EndPhase();
            CleanupAllCombatEntities();
            CloseCombatFinishForm();
            CloseRewardSelectForm();
            ResetRuntime();
            return false;
        }

        private void EnterFailureFallback(string errorMessage)
        {
            if (_currentState is CombatFailedState || _isCompleted)
            {
                return;
            }

            ChangeState(new CombatFailedState(this, errorMessage, true));
        }

        private static int ResolveEnemyHpRateMultiplier(int displayPhaseIndex, int phaseCount)
        {
            if (displayPhaseIndex <= 0 || phaseCount <= 0)
            {
                return 1;
            }

            int completedLoopCount = Mathf.Max(0, (displayPhaseIndex - 1) / phaseCount);
            if (completedLoopCount >= 30)
            {
                return int.MaxValue;
            }

            return 1 << completedLoopCount;
        }

        #region Event Handlers

        private void OnShowEntitySuccess(ShowEntitySuccessEventArgs args)
        {
            var status = _loadSession.HandleShowEntitySuccess(args, out string errorMessage);
            if (status == CombatLoadSession.EventHandleStatus.Failed)
            {
                EnterFailureFallback(errorMessage);
                return;
            }

            if (status == CombatLoadSession.EventHandleStatus.Succeeded)
            {
                MapEntity map = _loadSession.CurrentMap;
                Log.Info(
                    "Map ready. LevelId={0}, PathCells={1}, FoundationCells={2}, Spawners={3}, House={4}.",
                    _currentLevel != null ? _currentLevel.Id : 0,
                    map.PathCells.Count,
                    map.FoundationCells.Count,
                    map.Spawners.Length,
                    map.House != null ? map.House.name : "None");
            }
        }

        private void OnShowEntityFailure(ShowEntityFailureEventArgs args)
        {
            var status = _loadSession.HandleShowEntityFailure(args, out string errorMessage);
            if (status == CombatLoadSession.EventHandleStatus.Failed)
            {
                EnterFailureFallback(errorMessage);
            }
        }

        private void OnHideEntityComplete(HideEntityCompleteEventArgs args)
        {
            _loadSession.HandleHideEntityComplete(args);
        }

        private void OnOpenUIFormSuccess(OpenUIFormSuccessEventArgs args)
        {
            var status = _loadSession.HandleOpenUIFormSuccess(args, out string errorMessage);
            if (status == CombatLoadSession.EventHandleStatus.Failed)
            {
                EnterFailureFallback(errorMessage);
            }
        }

        private void OnOpenUIFormFailure(OpenUIFormFailureEventArgs args)
        {
            var status = _loadSession.HandleOpenUIFormFailure(args, out string errorMessage);
            if (status == CombatLoadSession.EventHandleStatus.Failed)
            {
                EnterFailureFallback(errorMessage);
            }
        }

        private void OnCloseUIFormComplete(CloseUIFormCompleteEventArgs args)
        {
            _loadSession.HandleCloseUIFormComplete(args);
        }

        #endregion

        private void GameOverByFailure()
        {
            CompleteCombatAndNotify(false);
        }

    }
}