using UnityEngine;
using TMPro;

/// <summary>
/// Place this component on a GameObject to create a checkpoint zone.
/// When the player enters, it will save the current game state.
/// </summary>
[RequireComponent(typeof(BoxCollider))]
public class CheckpointTrigger : MonoBehaviour
{
    [Header("Checkpoint Settings")]
    [Tooltip("Show a visual effect when checkpoint is activated")]
    public bool showVisualFeedback = true;

    [Tooltip("Only trigger once, or every time player enters")]
    public bool oneTimeUse = false;

    [Tooltip("Custom checkpoint message")]
    public string checkpointMessage = "Checkpoint Saved";

    [Header("Visual Feedback")]
    public GameObject checkpointVFX;
    public AudioClip checkpointSound;
    public TextMeshProUGUI checkpointText;
    public CanvasGroup textCanvasGroup;
    
    [Header("Fade Animation")]
    [Tooltip("Duration of fade in/out animation")]
    public float fadeDuration = 0.5f;
    [Tooltip("How long the message stays visible")]
    public float displayDuration = 2f;

    private bool hasBeenTriggered = false;
    private BoxCollider triggerCollider;
    private AudioSource audioSource;

    private void Awake()
    {
        // Ensure collider is trigger
        triggerCollider = GetComponent<BoxCollider>();
        if (triggerCollider != null)
        {
            triggerCollider.isTrigger = true;
        }

        // Setup audio source if sound is assigned
        if (checkpointSound != null)
        {
            audioSource = gameObject.AddComponent<AudioSource>();
            audioSource.clip = checkpointSound;
            audioSource.playOnAwake = false;
        }
    }

    private void OnTriggerEnter(Collider other)
    {
        // Check if player entered
        if (other.CompareTag("Player"))
        {
            // If one-time use and already triggered, ignore
            if (oneTimeUse && hasBeenTriggered)
                return;

            ActivateCheckpoint();
        }
    }

    /// <summary>
    /// Activate this checkpoint and save game state
    /// </summary>
    public void ActivateCheckpoint()
    {
        CheckpointSystem checkpointSystem = CheckpointSystem.Instance;

        if (checkpointSystem != null)
        {
            // Save checkpoint at this position
            checkpointSystem.SaveCheckpointAt(transform.position);

            Debug.Log($"[Checkpoint] {checkpointMessage} at {transform.position}");

            // Show feedback
            if (showVisualFeedback)
            {
                ShowFeedback();
            }

            hasBeenTriggered = true;
        }
        else
        {
            Debug.LogWarning("[Checkpoint] CheckpointSystem not found!");
        }
    }

    private void ShowFeedback()
    {
        // Play sound
        if (audioSource != null && checkpointSound != null)
        {
            audioSource.Play();
        }

        // Spawn VFX
        if (checkpointVFX != null)
        {
            checkpointVFX.SetActive(true);
            Destroy(checkpointVFX, fadeDuration * 2 + displayDuration);
        }
        
        // Show text with smooth fade animation
        if (checkpointText != null && textCanvasGroup != null)
        {
            checkpointText.text = checkpointMessage;
            checkpointText.gameObject.SetActive(true);
            StartCoroutine(FadeTextInOut());
        }

        Debug.Log($"[Checkpoint] ✓ {checkpointMessage}");
    }

    private System.Collections.IEnumerator FadeTextInOut()
    {
        // Fade in from 0 to 1
        float elapsed = 0f;
        while (elapsed < fadeDuration)
        {
            elapsed += Time.deltaTime;
            textCanvasGroup.alpha = Mathf.Lerp(0f, 1f, elapsed / fadeDuration);
            yield return null;
        }
        textCanvasGroup.alpha = 1f;

        // Display at full opacity
        yield return new WaitForSeconds(displayDuration);

        // Fade out from 1 to 0
        elapsed = 0f;
        while (elapsed < fadeDuration)
        {
            elapsed += Time.deltaTime;
            textCanvasGroup.alpha = Mathf.Lerp(1f, 0f, elapsed / fadeDuration);
            yield return null;
        }
        textCanvasGroup.alpha = 0f;
        
        // Deactivate text object
        checkpointText.gameObject.SetActive(false);
    }

    /// <summary>
    /// Reset this checkpoint so it can be triggered again
    /// </summary>
    public void ResetCheckpoint()
    {
        hasBeenTriggered = false;
    }

    // Visualize checkpoint in editor
    private void OnDrawGizmos()
    {
        Gizmos.color = hasBeenTriggered ? Color.green : Color.yellow;
        Gizmos.DrawWireCube(transform.position, Vector3.one * 2f);

        Gizmos.color = Color.cyan;
        Gizmos.DrawLine(transform.position, transform.position + Vector3.up * 3f);
    }
}