using UnityEngine;
using UnityEngine.Events;

public class TouchToCloseOrDragCamera : MonoBehaviour
{
    [Header("Targets")]
    public Camera cam;
    public Transform orbitTarget;            // 기준점(없으면 월드원점)

    [Header("Tap Settings")]
    public float tapMaxTime = 0.25f;         // 이 시간 이내면 탭
    public float tapMaxMovePixels = 10f;     // 이 픽셀 이내면 탭

    [Header("Orbit Settings")]
    public float orbitSpeedX = 0.2f;         // 좌우 회전 감도
    public float orbitSpeedY = 0.2f;         // 상하 회전 감도
    public float minPitch = -80f;
    public float maxPitch = 80f;
    public float distance = 6f;              // 타깃까지 거리

    [Header("On Tap Action")]
    public UnityEvent OnSingleTap;           // 탭 시 실행. 기본으로 현재 화면 비활성화하도록 세팅

    // 내부 상태
    int activePointerId = -1;
    Vector2 downPos;
    float downTime;
    bool dragging;
    float yaw, pitch;

    void Reset()
    {
        cam = Camera.main;
    }

    void Awake()
    {
        if (cam == null) cam = Camera.main;
        if (orbitTarget == null) { var t = new GameObject("OrbitTarget").transform; t.position = Vector3.zero; orbitTarget = t; }
        // 기본 탭 동작: 이 스크립트가 달린 루트 오브젝트 비활성화(화면 종료 역할)
        if (OnSingleTap == null) OnSingleTap = new UnityEvent();
        if (OnSingleTap.GetPersistentEventCount() == 0)
            OnSingleTap.AddListener(() => gameObject.SetActive(false));

        // 초기 카메라 각도 계산
        var toCam = (cam.transform.position - orbitTarget.position).normalized;
        yaw = Mathf.Atan2(toCam.x, toCam.z) * Mathf.Rad2Deg;
        pitch = Mathf.Asin(toCam.y) * Mathf.Rad2Deg;
    }

    void Update()
    {
#if UNITY_EDITOR || UNITY_STANDALONE
        HandleMouse();
#else
        HandleTouch();
#endif
        // 오빗 카메라 적용
        ApplyOrbit();
    }

    void HandleMouse()
    {
        if (Input.GetMouseButtonDown(0))
        {
            activePointerId = 0;
            downPos = Input.mousePosition;
            downTime = Time.unscaledTime;
            dragging = false;
        }
        else if (Input.GetMouseButton(0) && activePointerId == 0)
        {
            Vector2 cur = Input.mousePosition;
            if (!dragging && Vector2.Distance(cur, downPos) > tapMaxMovePixels) dragging = true;
            if (dragging)
            {
                Vector2 delta = (Vector2)Input.mousePosition - downPos;
                OrbitByDelta(delta);
                downPos = cur; // 연속 드래그
            }
        }
        else if (Input.GetMouseButtonUp(0) && activePointerId == 0)
        {
            Vector2 upPos = Input.mousePosition;
            float dt = Time.unscaledTime - downTime;
            float dist = Vector2.Distance(upPos, downPos);

            if (!dragging && dt <= tapMaxTime && dist <= tapMaxMovePixels)
            {
                // 단일 탭
                OnSingleTap?.Invoke();
            }
            activePointerId = -1;
            dragging = false;
        }
    }

    void HandleTouch()
    {
        if (Input.touchCount == 0) return;

        // 이미 추적 중인 손가락이 있으면 그걸 우선
        int idx = -1;
        if (activePointerId != -1)
        {
            for (int i = 0; i < Input.touchCount; i++)
                if (Input.touches[i].fingerId == activePointerId) { idx = i; break; }
        }

        // 없으면 첫 터치로 시작
        if (idx == -1) { var t0 = Input.touches[0]; idx = 0; activePointerId = t0.fingerId; }

        var t = Input.touches[idx];

        switch (t.phase)
        {
            case TouchPhase.Began:
                downPos = t.position;
                downTime = Time.unscaledTime;
                dragging = false;
                break;

            case TouchPhase.Moved:
            case TouchPhase.Stationary:
                if (!dragging && Vector2.Distance(t.position, downPos) > tapMaxMovePixels) dragging = true;
                if (dragging && t.phase == TouchPhase.Moved)
                {
                    OrbitByDelta(t.deltaPosition);
                }
                break;

            case TouchPhase.Ended:
            case TouchPhase.Canceled:
                float dt = Time.unscaledTime - downTime;
                float dist = Vector2.Distance(t.position, downPos);
                if (!dragging && dt <= tapMaxTime && dist <= tapMaxMovePixels)
                {
                    OnSingleTap?.Invoke();
                }
                activePointerId = -1;
                dragging = false;
                break;
        }
    }

    void OrbitByDelta(Vector2 delta)
    {
        yaw += delta.x * orbitSpeedX;
        pitch -= delta.y * orbitSpeedY;
        pitch = Mathf.Clamp(pitch, minPitch, maxPitch);
    }

    void ApplyOrbit()
    {
        Quaternion rot = Quaternion.Euler(pitch, yaw, 0f);
        Vector3 pos = orbitTarget.position + rot * (Vector3.back * distance);
        cam.transform.SetPositionAndRotation(pos, rot);
    }
}