using System.Collections;
using UnityEngine;
using UnityEngine.XR.Interaction.Toolkit;
using UnityEngine.XR.Interaction.Toolkit.Interactables;

public class SteeringKeyGrabMusic : MonoBehaviour
{
    [Header("References")]
    [SerializeField] private XRGrabInteractable grabInteractable;
    [SerializeField] private AudioSource audioSource;

    [Header("Playback")]
    [SerializeField] private bool playOnGrab = true;
    [SerializeField] private bool stopOnRelease = true;

    [Tooltip("키를 잡았을 때 음악을 처음부터 다시 재생할지 여부입니다.")]
    [SerializeField] private bool restartFromBeginningOnGrab = false;

    [Header("Fade")]
    [SerializeField] private bool useFade = true;
    [SerializeField] private float fadeInDuration = 0.4f;
    [SerializeField] private float fadeOutDuration = 0.5f;

    [Range(0f, 1f)]
    [SerializeField] private float targetVolume = 1f;

    [Header("Debug")]
    [SerializeField] private bool showDebugLog = true;

    private Coroutine fadeRoutine;
    private bool isGrabbed;

    private void Awake()
    {
        if (grabInteractable == null)
            grabInteractable = GetComponentInChildren<XRGrabInteractable>(true);

        if (audioSource == null)
            audioSource = GetComponent<AudioSource>();

        if (audioSource != null)
        {
            audioSource.playOnAwake = false;
            audioSource.loop = true;

            if (useFade)
                audioSource.volume = 0f;
            else
                audioSource.volume = targetVolume;
        }
    }

    private void OnEnable()
    {
        if (grabInteractable != null)
        {
            grabInteractable.selectEntered.AddListener(OnKeyGrabbed);
            grabInteractable.selectExited.AddListener(OnKeyReleased);
        }
    }

    private void OnDisable()
    {
        if (grabInteractable != null)
        {
            grabInteractable.selectEntered.RemoveListener(OnKeyGrabbed);
            grabInteractable.selectExited.RemoveListener(OnKeyReleased);
        }
    }

    private void OnKeyGrabbed(SelectEnterEventArgs args)
    {
        isGrabbed = true;

        if (!playOnGrab)
            return;

        if (audioSource == null)
        {
            if (showDebugLog)
                Debug.LogWarning("[SteeringKeyGrabMusic] AudioSource가 연결되지 않았습니다.", this);

            return;
        }

        if (restartFromBeginningOnGrab)
            audioSource.time = 0f;

        if (!audioSource.isPlaying)
            audioSource.Play();

        if (useFade)
            StartFade(targetVolume, fadeInDuration);
        else
            audioSource.volume = targetVolume;

        if (showDebugLog)
            Debug.Log("[SteeringKeyGrabMusic] 키 잡음. 음악 재생.", this);
    }

    private void OnKeyReleased(SelectExitEventArgs args)
    {
        isGrabbed = false;

        if (!stopOnRelease)
            return;

        if (audioSource == null)
            return;

        if (useFade)
            StartFade(0f, fadeOutDuration, stopAfterFade: true);
        else
            audioSource.Stop();

        if (showDebugLog)
            Debug.Log("[SteeringKeyGrabMusic] 키 놓음. 음악 정지.", this);
    }

    private void StartFade(float target, float duration, bool stopAfterFade = false)
    {
        if (fadeRoutine != null)
            StopCoroutine(fadeRoutine);

        fadeRoutine = StartCoroutine(FadeRoutine(target, duration, stopAfterFade));
    }

    private IEnumerator FadeRoutine(float target, float duration, bool stopAfterFade)
    {
        if (audioSource == null)
            yield break;

        float startVolume = audioSource.volume;
        float timer = 0f;
        float safeDuration = Mathf.Max(0.01f, duration);

        while (timer < safeDuration)
        {
            timer += Time.deltaTime;

            float t = Mathf.Clamp01(timer / safeDuration);
            float smoothT = t * t * (3f - 2f * t);

            audioSource.volume = Mathf.Lerp(startVolume, target, smoothT);

            yield return null;
        }

        audioSource.volume = target;

        if (stopAfterFade && !isGrabbed)
        {
            audioSource.Stop();
        }

        fadeRoutine = null;
    }
}