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

public class ClamBiteDetector : MonoBehaviour
{
    [Header("References")]
    [SerializeField] private ClamOpenClose clam;
    [SerializeField] private RaftHealth health;
    [SerializeField] private MemoryFragmentReset memoryFragment;

    [Header("Bite Damage")]
    [SerializeField] private int biteDamage = 20;

    [Header("Bite Zone")]
    [SerializeField] private Collider biteZoneCollider;

    [Tooltip("조개 미션이 시작되었을 때만 물림 판정을 합니다.")]
    [SerializeField] private bool missionActiveOnStart = false;

    [Tooltip("조개가 닫히는 동안 이미 한 번 물렸으면 추가 판정을 막습니다.")]
    [SerializeField] private bool biteOncePerClose = true;

    [Header("Target Detection")]
    [Tooltip("손 오브젝트에 붙일 태그입니다. 태그를 안 쓰면 XRHandMarker로도 판정합니다.")]
    [SerializeField] private string handTag = "PlayerHand";

    [Tooltip("기억의 조각 태그입니다. 단, 조각은 잡힌 상태일 때만 물림 대상으로 봅니다.")]
    [SerializeField] private string fragmentTag = "MemoryFragment";

    [Tooltip("기억의 조각은 플레이어가 잡고 있을 때만 물림 판정합니다.")]
    [SerializeField] private bool biteFragmentOnlyWhenGrabbed = true;

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

    private bool missionActive;
    private bool hasBittenThisClose;

    private readonly HashSet<Collider> collidersInside = new();

    private void Awake()
    {
        if (biteZoneCollider == null)
            biteZoneCollider = GetComponent<Collider>();

        if (biteZoneCollider != null)
        {
            biteZoneCollider.isTrigger = true;
            biteZoneCollider.enabled = false;
        }

        if (clam == null)
            clam = GetComponentInParent<ClamOpenClose>();

        if (health == null)
            health = FindFirstObjectByType<RaftHealth>();

        if (memoryFragment == null)
            memoryFragment = FindFirstObjectByType<MemoryFragmentReset>();

        missionActive = missionActiveOnStart;
    }

    private void OnEnable()
    {
        if (clam != null)
        {
            clam.onCloseStarted.AddListener(EnableBiteWindow);
            clam.onClosed.AddListener(DisableBiteWindow);
            clam.onOpened.AddListener(ResetBiteState);
        }
    }

    private void OnDisable()
    {
        if (clam != null)
        {
            clam.onCloseStarted.RemoveListener(EnableBiteWindow);
            clam.onClosed.RemoveListener(DisableBiteWindow);
            clam.onOpened.RemoveListener(ResetBiteState);
        }
    }

    private void OnTriggerEnter(Collider other)
    {
        collidersInside.Add(other);

        if (IsBiteWindowOpen())
            TryBite(other);
    }

    private void OnTriggerStay(Collider other)
    {
        collidersInside.Add(other);

        if (IsBiteWindowOpen())
            TryBite(other);
    }

    private void OnTriggerExit(Collider other)
    {
        collidersInside.Remove(other);
    }

    public void StartBiteMission()
    {
        missionActive = true;
        hasBittenThisClose = false;
        collidersInside.Clear();

        if (showDebugLog)
            Debug.Log("[ClamBiteDetector] 조개 미션 시작. 물림 판정 활성 준비.", this);
    }

    public void StopBiteMission()
    {
        missionActive = false;
        hasBittenThisClose = false;
        collidersInside.Clear();

        if (biteZoneCollider != null)
            biteZoneCollider.enabled = false;

        if (showDebugLog)
            Debug.Log("[ClamBiteDetector] 조개 미션 정지. 물림 판정 비활성.", this);
    }

    private void EnableBiteWindow()
    {
        if (!missionActive)
            return;

        hasBittenThisClose = false;

        if (biteZoneCollider != null)
            biteZoneCollider.enabled = true;

        if (showDebugLog)
            Debug.Log("[ClamBiteDetector] 조개 물림 판정 ON", this);

        foreach (Collider col in collidersInside)
        {
            if (col != null)
                TryBite(col);
        }
    }

    private void DisableBiteWindow()
    {
        if (biteZoneCollider != null)
            biteZoneCollider.enabled = false;

        collidersInside.Clear();

        if (showDebugLog && missionActive)
            Debug.Log("[ClamBiteDetector] 조개 물림 판정 OFF", this);
    }

    private void ResetBiteState()
    {
        hasBittenThisClose = false;
    }

    private bool IsBiteWindowOpen()
    {
        if (!missionActive)
            return false;

        if (biteZoneCollider == null)
            return false;

        return biteZoneCollider.enabled;
    }

    private void TryBite(Collider other)
    {
        if (other == null)
            return;

        if (!missionActive)
            return;

        if (biteOncePerClose && hasBittenThisClose)
            return;

        bool isHand = IsHandCollider(other);
        bool isGrabbedFragment = IsGrabbedMemoryFragment(other);

        if (!isHand && !isGrabbedFragment)
            return;

        hasBittenThisClose = true;

        if (health != null)
            health.TakeDamage(biteDamage);

        if (memoryFragment != null)
            memoryFragment.ResetFragment();

        if (showDebugLog)
        {
            Debug.Log($"[ClamBiteDetector] 조개에게 물림. 데미지 {biteDamage}, 기억의 조각 리셋", this);
        }
    }

    private bool IsHandCollider(Collider other)
    {
        if (other.CompareTag(handTag))
            return true;

        XRHandMarker marker = other.GetComponentInParent<XRHandMarker>();

        return marker != null;
    }

    private bool IsGrabbedMemoryFragment(Collider other)
    {
        MemoryFragmentReset fragment = other.GetComponentInParent<MemoryFragmentReset>();

        if (fragment == null)
        {
            if (!other.CompareTag(fragmentTag))
                return false;

            fragment = memoryFragment;
        }

        if (fragment == null)
            return false;

        XRGrabInteractable grab = fragment.GetComponent<XRGrabInteractable>();

        if (grab == null)
            return !biteFragmentOnlyWhenGrabbed;

        if (biteFragmentOnlyWhenGrabbed)
            return grab.isSelected;

        return true;
    }
}