using UnityEngine;
using System.Collections;
using System.Collections.Generic;

/// <summary>
/// Central manager for game state, death, and respawn logic
/// </summary>
public class GameManager : MonoBehaviour
{
    public static GameManager Instance { get; private set; }

    [Header("References")]
    public TeamCohesionManager cohesionManager;
    public CheckpointSystem checkpointSystem;
    public DeathScreenUI deathScreenUI;
    public GridMovement playerMovement;
    
    [Header("Death Settings")]
    public float deathDelay = 2f; // Time before showing death screen
    public float respawnFadeTime = 1f;
    public bool resetMonstersOnRespawn = false;
    
    [Header("Respawn Penalties (Optional)")]
    public bool applyGoldPenalty = false;
    public float goldPenaltyPercent = 0f; // 0 = no penalty
    
    private bool isPlayerDead = false;
    private CanvasGroup fadeCanvasGroup;

    private void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Destroy(gameObject);
            return;
        }
        Instance = this;
        
        // Create fade overlay if it doesn't exist
        CreateFadeOverlay();
    }

    private void Start()
    {
        if (cohesionManager == null)
            cohesionManager = FindFirstObjectByType<TeamCohesionManager>();
        
        if (checkpointSystem == null)
            checkpointSystem = FindFirstObjectByType<CheckpointSystem>();
            
        if (deathScreenUI == null)
            deathScreenUI = FindFirstObjectByType<DeathScreenUI>();
            
        if (playerMovement == null)
            playerMovement = FindFirstObjectByType<GridMovement>();
        
        // Verify setup
        ValidateSetup();
    }
    
    private void ValidateSetup()
    {
        Debug.Log("=== GameManager Setup Validation ===");
        Debug.Log($"Cohesion Manager: {(cohesionManager != null ? "✓ Assigned" : "✗ MISSING")}");
        Debug.Log($"Checkpoint System: {(checkpointSystem != null ? "✓ Assigned" : "✗ MISSING")}");
        Debug.Log($"Death Screen UI: {(deathScreenUI != null ? "✓ Assigned" : "✗ MISSING")}");
        Debug.Log($"Player Movement: {(playerMovement != null ? "✓ Assigned" : "✗ MISSING")}");
        
        if (cohesionManager == null || checkpointSystem == null || deathScreenUI == null || playerMovement == null)
        {
            Debug.LogError("[GameManager] Some references are missing! Respawn system may not work correctly.");
        }
        else
        {
            Debug.Log("[GameManager] All references validated successfully!");
        }
    }

    /// <summary>
    /// Called when all party members have died
    /// </summary>
    public void OnPartyWiped()
    {
        if (isPlayerDead) return; // Prevent multiple triggers
        
        isPlayerDead = true;
        Debug.Log("[GameManager] Party wiped! Initiating death sequence...");
        
        StartCoroutine(HandleDeathSequence());
    }

    private IEnumerator HandleDeathSequence()
    {
        // Disable player input
        if (playerMovement != null)
            playerMovement.enabled = false;
        
        // Stop all monster attacks
        StopAllMonsterAttacks();
        
        // Wait a moment for dramatic effect
        yield return new WaitForSeconds(deathDelay);
        
        // Fade to black
        yield return StartCoroutine(FadeToBlack(respawnFadeTime));
        
        // Show death screen
        if (deathScreenUI != null)
        {
            deathScreenUI.Show();
        }
        else
        {
            Debug.LogWarning("[GameManager] Death Screen UI not found, auto-respawning...");
            RespawnParty();
        }
    }

    /// <summary>
    /// Respawn the party at the last checkpoint
    /// </summary>
    public void RespawnParty()
    {
        Debug.Log("[GameManager] Respawning party...");
        StartCoroutine(RespawnSequence());
    }

    private IEnumerator RespawnSequence()
    {
        Debug.Log("[GameManager] RespawnSequence started");
        
        // Hide death screen if visible
        if (deathScreenUI != null)
        {
            deathScreenUI.Hide();
            Debug.Log("[GameManager] Death screen hidden");
        }
        
        // Small delay for UI to hide
        yield return new WaitForSeconds(0.2f);
        
        // Load checkpoint data
        if (checkpointSystem != null)
        {
            Debug.Log("[GameManager] Loading checkpoint...");
            checkpointSystem.LoadCheckpoint();
        }
        else
        {
            Debug.LogWarning("[GameManager] No CheckpointSystem found, performing basic respawn");
            BasicRespawn();
        }
        
        // Apply penalties if enabled
        if (applyGoldPenalty && goldPenaltyPercent > 0)
        {
            ApplyGoldPenalty();
        }
        
        // Reset monsters if enabled
        if (resetMonstersOnRespawn)
        {
            ResetMonsters();
        }
        
        // Small delay before fade in
        yield return new WaitForSeconds(0.3f);
        
        Debug.Log("[GameManager] Starting fade from black...");
        
        // Fade back from black
        yield return StartCoroutine(FadeFromBlack(respawnFadeTime));
        
        Debug.Log("[GameManager] Fade complete, re-enabling player controls");
        
        // Re-enable player input
        if (playerMovement != null)
            playerMovement.enabled = true;
        
        isPlayerDead = false;
        
        Debug.Log("[GameManager] Respawn complete!");
    }

    /// <summary>
    /// Basic respawn without checkpoint system - restores party to full health
    /// </summary>
    private void BasicRespawn()
    {
        if (cohesionManager == null || cohesionManager.groupMembers == null)
        {
            Debug.LogError("[GameManager] Cannot respawn: CohesionManager or group members not found");
            return;
        }
        
        foreach (var character in cohesionManager.groupMembers)
        {
            character.currentHP = character.maxHP;
            character.currentFatigue = character.maxFatigue;
            character.currentMana = character.maxMana;
            
            // Update UI
            UIUpdater.Instance?.UpdateCharacterHP(character);
            UIUpdater.Instance?.UpdateCharacterFatigue(character);
        }
    }


    private void ApplyGoldPenalty()
    {
        // TODO: Implement gold system penalty if you have a gold/currency system
        Debug.Log($"[GameManager] Gold penalty applied: {goldPenaltyPercent}%");
    }

    private void StopAllMonsterAttacks()
    {
        // Find all monster formation groups and stop their attacks
        MonsterFormationGroup[] monsterGroups = FindObjectsByType<MonsterFormationGroup>(FindObjectsSortMode.None);
        
        foreach (var group in monsterGroups)
        {
            // Stop their current behavior immediately
            group.StopAllCoroutines();
            group.isChasing = false;
            group.hasDetectedPlayer = false;
            
            // Stop individual monster animations
            foreach (var monster in group.frontRow)
            {
                if (monster != null)
                    monster.StopMove();
            }
            foreach (var monster in group.backRow)
            {
                if (monster != null)
                    monster.StopMove();
            }
            
            Debug.Log($"[GameManager] Stopped attacks from monster group: {group.gameObject.name}");
        }
    }
    
    private void ResetMonsters()
    {
        // Find all monster formation groups and reset them
        MonsterFormationGroup[] monsterGroups = FindObjectsByType<MonsterFormationGroup>(FindObjectsSortMode.None);
        
        foreach (var group in monsterGroups)
        {
            // Stop their current behavior
            group.StopAllCoroutines();
            group.isChasing = false;
            group.hasDetectedPlayer = false;
            
            Debug.Log($"[GameManager] Reset monster group: {group.gameObject.name}");
        }
    }

    #region Fade Effects
    
    private void CreateFadeOverlay()
    {
        // Create a full-screen black overlay for fade effects
        GameObject fadeObj = new GameObject("FadeOverlay");
        fadeObj.transform.SetParent(transform);
        
        Canvas canvas = fadeObj.AddComponent<Canvas>();
        canvas.renderMode = RenderMode.ScreenSpaceOverlay;
        canvas.sortingOrder = 100; // Below death screen UI (which should be 200+)
        
        fadeCanvasGroup = fadeObj.AddComponent<CanvasGroup>();
        fadeCanvasGroup.alpha = 0f;
        fadeCanvasGroup.interactable = false;
        fadeCanvasGroup.blocksRaycasts = false;
        
        // Add black panel
        GameObject panel = new GameObject("BlackPanel");
        panel.transform.SetParent(fadeObj.transform, false);
        
        UnityEngine.UI.Image image = panel.AddComponent<UnityEngine.UI.Image>();
        image.color = Color.black;
        
        RectTransform rect = panel.GetComponent<RectTransform>();
        rect.anchorMin = Vector2.zero;
        rect.anchorMax = Vector2.one;
        rect.sizeDelta = Vector2.zero;
    }

    private IEnumerator FadeToBlack(float duration)
    {
        float elapsed = 0f;
        while (elapsed < duration)
        {
            elapsed += Time.deltaTime;
            fadeCanvasGroup.alpha = Mathf.Lerp(0f, 1f, elapsed / duration);
            yield return null;
        }
        fadeCanvasGroup.alpha = 1f;
    }

    private IEnumerator FadeFromBlack(float duration)
    {
        float elapsed = 0f;
        while (elapsed < duration)
        {
            elapsed += Time.deltaTime;
            fadeCanvasGroup.alpha = Mathf.Lerp(1f, 0f, elapsed / duration);
            yield return null;
        }
        fadeCanvasGroup.alpha = 0f;
    }
    
    #endregion

    public bool IsPlayerDead() => isPlayerDead;
}