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

/// <summary>
/// Simple IMGUI-based enemy selection UI for attack targeting
/// Alternative to direct mouse targeting
/// </summary>
public class EnemySelectionUI : MonoBehaviour
{
    [Header("Settings")]
    public KeyCode toggleKey = KeyCode.Tab;
    public bool useEnemyListMode = false; // Can be toggled in inspector

    [Header("UI Settings")]
    public float windowWidth = 300f;
    public float windowHeight = 400f;
    public float buttonHeight = 40f;

    private bool isVisible = false;
    private Character currentAttacker;
    private List<Character> availableEnemies = new List<Character>();
    private Character selectedEnemy;
    private Vector2 scrollPosition;

    // Events
    public event System.Action<Character> OnEnemySelected;
    public event System.Action OnSelectionCancelled;

    private GUIStyle windowStyle;
    private GUIStyle buttonStyle;
    private GUIStyle selectedButtonStyle;
    private GUIStyle labelStyle;
    private bool stylesInitialized = false;

    void Update()
    {
        // Toggle enemy list mode with Tab key
        if (Input.GetKeyDown(toggleKey))
        {
            useEnemyListMode = !useEnemyListMode;
            Debug.Log($"🎯 Enemy selection mode: {(useEnemyListMode ? "List UI" : "Direct Targeting")}");
        }

        // Close UI with Escape
        if (isVisible && Input.GetKeyDown(KeyCode.Escape))
        {
            HideEnemySelection();
            OnSelectionCancelled?.Invoke();
        }
    }

    void OnGUI()
    {
        if (!isVisible) return;

        InitializeStyles();
        DrawEnemySelectionWindow();
    }

    private void InitializeStyles()
    {
        if (stylesInitialized) return;

        windowStyle = new GUIStyle(GUI.skin.window);
        windowStyle.fontSize = 16;
        windowStyle.fontStyle = FontStyle.Bold;

        buttonStyle = new GUIStyle(GUI.skin.button);
        buttonStyle.fontSize = 14;
        buttonStyle.alignment = TextAnchor.MiddleLeft;
        buttonStyle.padding = new RectOffset(10, 10, 10, 10);

        selectedButtonStyle = new GUIStyle(buttonStyle);
        selectedButtonStyle.normal.background = buttonStyle.active.background;
        selectedButtonStyle.normal.textColor = Color.yellow;
        selectedButtonStyle.fontStyle = FontStyle.Bold;

        labelStyle = new GUIStyle(GUI.skin.label);
        labelStyle.fontSize = 14;
        labelStyle.fontStyle = FontStyle.Bold;
        labelStyle.alignment = TextAnchor.MiddleCenter;

        stylesInitialized = true;
    }

    private void DrawEnemySelectionWindow()
    {
        Rect windowRect = new Rect(
            Screen.width - windowWidth - 20,
            (Screen.height - windowHeight) / 2,
            windowWidth,
            windowHeight
        );

        GUI.Window(0, windowRect, DrawWindowContent,
            $"Select Target for {(currentAttacker ? currentAttacker.CharacterName : "Character")}",
            windowStyle);
    }

    private void DrawWindowContent(int windowID)
    {
        GUILayout.BeginVertical();

        // Instructions
        GUILayout.Label("Choose an enemy to attack:", labelStyle);
        GUILayout.Space(10);

        // Scroll area for enemy list
        scrollPosition = GUILayout.BeginScrollView(scrollPosition,
            GUILayout.ExpandHeight(true));

        foreach (Character enemy in availableEnemies)
        {
            if (enemy == null) continue;

            bool isSelected = (selectedEnemy == enemy);
            GUIStyle currentStyle = isSelected ? selectedButtonStyle : buttonStyle;

            // Create button content with enemy info
            string buttonText = $"{enemy.CharacterName}";
            if (enemy.TryGetComponent<Character>(out var character))
            {
                buttonText += $" (HP: {character.CurrentHealth}/{character.MaxHealth})";
            }

            if (GUILayout.Button(buttonText, currentStyle, GUILayout.Height(buttonHeight)))
            {
                SelectEnemy(enemy);
            }

            // Highlight selected enemy in the scene
            if (isSelected)
            {
                HighlightEnemy(enemy);
            }
        }

        GUILayout.EndScrollView();

        GUILayout.Space(10);

        // Action buttons
        GUILayout.BeginHorizontal();

        GUI.enabled = selectedEnemy != null;
        if (GUILayout.Button("Attack Selected", GUILayout.Height(30)))
        {
            ConfirmSelection();
        }
        GUI.enabled = true;

        if (GUILayout.Button("Cancel", GUILayout.Height(30)))
        {
            CancelSelection();
        }

        GUILayout.EndHorizontal();

        GUILayout.Space(5);
        GUILayout.Label("Press TAB to toggle targeting mode", GUI.skin.box);
        GUILayout.Label("Press ESC to cancel", GUI.skin.box);

        GUILayout.EndVertical();
    }

    public void ShowEnemySelection(Character attacker)
    {
        if (!useEnemyListMode)
        {
            Debug.Log("🎯 Enemy list mode disabled - use direct targeting");
            return;
        }

        currentAttacker = attacker;
        selectedEnemy = null;

        // Find all enemy characters
        RefreshEnemyList();

        if (availableEnemies.Count == 0)
        {
            Debug.LogWarning("No enemies found for targeting!");
            return;
        }

        isVisible = true;
        Debug.Log($"🎯 Enemy selection UI shown for {attacker.CharacterName} - {availableEnemies.Count} enemies available");
    }

    public void HideEnemySelection()
    {
        isVisible = false;
        selectedEnemy = null;
        ClearEnemyHighlights();
        Debug.Log("🎯 Enemy selection UI hidden");
    }

    private void RefreshEnemyList()
    {
        availableEnemies.Clear();

        // Find all characters tagged as enemies
        Character[] allCharacters = FindObjectsByType<Character>(FindObjectsSortMode.None);

        foreach (Character character in allCharacters)
        {
            if (character.CompareTag("Enemy") && character.CurrentHealth > 0)
            {
                availableEnemies.Add(character);
            }
        }

        // Sort by distance to attacker for convenience
        if (currentAttacker != null)
        {
            availableEnemies = availableEnemies
                .OrderBy(enemy => Vector3.Distance(currentAttacker.transform.position, enemy.transform.position))
                .ToList();
        }

        Debug.Log($"🎯 Found {availableEnemies.Count} available enemies");
    }

    private void SelectEnemy(Character enemy)
    {
        // Clear previous selection highlight
        if (selectedEnemy != null)
        {
            ClearEnemyHighlight(selectedEnemy);
        }

        selectedEnemy = enemy;
        Debug.Log($"🎯 Selected enemy: {enemy.CharacterName}");
    }

    private void ConfirmSelection()
    {
        if (selectedEnemy != null)
        {
            Debug.Log($"✅ Attack target confirmed: {selectedEnemy.CharacterName}");
            OnEnemySelected?.Invoke(selectedEnemy);
            HideEnemySelection();
        }
    }

    private void CancelSelection()
    {
        Debug.Log("❌ Enemy selection cancelled");
        OnSelectionCancelled?.Invoke();
        HideEnemySelection();
    }

    private void HighlightEnemy(Character enemy)
    {
        // Add visual highlight to the enemy (simple outline or color change)
        if (enemy != null)
        {
            // Use the character's existing visual state system
            enemy.SetVisualState(ActionDecisionState.NoAction); // Temporary highlight
        }
    }

    private void ClearEnemyHighlight(Character enemy)
    {
        if (enemy != null)
        {
            enemy.SetVisualState(ActionDecisionState.NoAction); // Reset to normal
        }
    }

    private void ClearEnemyHighlights()
    {
        foreach (Character enemy in availableEnemies)
        {
            ClearEnemyHighlight(enemy);
        }
    }

    void OnDestroy()
    {
        OnEnemySelected = null;
        OnSelectionCancelled = null;
    }
}