using UnityEngine;
using TMPro;

public class SelectionManager : MonoBehaviour
{
    public static SelectionManager Instance { get; private set; }

    [Header("Nameplate")]
    public Canvas worldSpaceCanvas;                 // a World Space Canvas in scene
    public GameObject nameplatePrefab;              // prefab containing TextMeshProUGUI
    public Vector3 nameplateOffset = new Vector3(0, 2.2f, 0);

    [Header("Colors")]
    public Color friendlyColor = Color.green;
    public Color neutralColor = Color.cyan;
    public Color enemyColor = Color.red;

    Selectable current;
    GameObject activeNameplate;
    NameplateController nameplateController;

    void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Debug.LogWarning("Multiple SelectionManager instances detected. Destroying duplicate.", gameObject);
            Destroy(gameObject);
            return;
        }
        Instance = this;
    }

    void OnDestroy()
    {
        if (Instance == this) Instance = null;
    }

    public void Select(Selectable s)
    {
        if (s == null)
        {
            ClearSelection();
            return;
        }

        if (current == s) return;

        ClearSelection();

        current = s;
        current.OnSelected();

        CreateNameplate(s.displayName, GetColorForAttitude(s.attitude));
    }

    public void Select(Building b)
    {
        if (b == null)
        {
            ClearSelection();
            return;
        }

        ClearSelection();
        b.OnSelected();

        CreateNameplate(b.displayName, GetColorForAttitude(b.attitude));
    }

    void CreateNameplate(string displayName, Color color)
    {
        if (nameplatePrefab == null || worldSpaceCanvas == null) return;

        activeNameplate = Instantiate(nameplatePrefab, worldSpaceCanvas.transform, false);
        nameplateController = activeNameplate.GetComponent<NameplateController>();
        
        if (nameplateController == null)
        {
            Debug.LogError("NameplateController not found on nameplate prefab!", nameplatePrefab);
            DestroyNameplate();
            return;
        }

        if (current != null)
        {
            nameplateController.Initialize(current, color, nameplateOffset);
        }
        else
        {
            // For buildings, we'll update in LateUpdate with the last known target
            nameplateController.SetDisplayName(displayName);
            nameplateController.ApplyColor(color);
        }
    }

    public void ClearSelection()
    {
        if (current != null)
        {
            current.OnDeselected();
            current = null;
        }

        DestroyNameplate();
    }

    void DestroyNameplate()
    {
        if (activeNameplate != null) Destroy(activeNameplate);
        activeNameplate = null;
        nameplateController = null;
    }

    Color GetColorForAttitude(Attitude a)
    {
        return a switch
        {
            Attitude.Friendly => friendlyColor,
            Attitude.Neutral => neutralColor,
            Attitude.Enemy => enemyColor,
            _ => neutralColor
        };
    }

    void LateUpdate()
    {
        // Update nameplate position if it exists and has a target
        if (nameplateController != null && current != null)
        {
            nameplateController.FollowTarget(current.transform, nameplateOffset);
        }

        // Clean up orphaned nameplates if current object was destroyed
        if (current == null && activeNameplate != null)
        {
            DestroyNameplate();
        }
    }
}