using UnityEngine;

public class CameraController : MonoBehaviour
{
    [SerializeField] private float _dragSpeed;
    [SerializeField] private float _zoomSpeed;
    [SerializeField] private float _maxY;
    [SerializeField] private float _minY;

    private int _touchCount;
    private float _lastZoomDistance;
    private Vector2 _lastDragPosition;
    private bool _endedThisFrame;

    private void Update()
    {
        _touchCount = Input.touchCount;
        if (_touchCount != 1 && _touchCount != 2) return;

        ProcessTouch();

        if (_touchCount == 1)
            Drag();
        else
            Zoom();
    }

    private void ProcessTouch()
    {
        for (int i = 0; i < _touchCount; i++)
        {
            var touch = Input.GetTouch(i);
            if (touch.phase != TouchPhase.Began && touch.phase != TouchPhase.Ended) continue;

            _endedThisFrame = touch.phase == TouchPhase.Ended; // убрать дергание drag при поднятии второго пальца

            if (_touchCount == 2)
                _lastZoomDistance = Vector3.Distance(Input.GetTouch(0).position, Input.GetTouch(1).position);
            else
                _lastDragPosition = Input.GetTouch(0).position;
        }
    }

    private void Drag()
    {
        if (_endedThisFrame) return;
        var touchPos = Input.GetTouch(0).position;
        var dragDelta = touchPos - _lastDragPosition;
        var camFwd = Vector3.ProjectOnPlane(transform.forward, Vector3.up).normalized;
        var camRight = transform.right;
        var translation = camFwd * dragDelta.y + camRight * dragDelta.x;

        transform.Translate(translation * _dragSpeed * Time.deltaTime, Space.World);

        _lastDragPosition = touchPos;
    }

    private void Zoom()
    {
        var zoomDistance = Vector3.Distance(Input.GetTouch(0).position, Input.GetTouch(1).position);
        var zoomDelta = zoomDistance - _lastZoomDistance;
        _lastZoomDistance = zoomDistance;

        if (Mathf.Approximately(transform.position.y, _minY) && zoomDelta > 0 ||
            Mathf.Approximately(transform.position.y, _maxY) && zoomDelta < 0) return;

        transform.Translate(transform.forward * zoomDelta * _zoomSpeed * Time.deltaTime, Space.World);
        var pos = transform.position;
        pos.y = Mathf.Clamp(pos.y, _minY, _maxY);
        transform.position = pos;
    }
}