using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.InputSystem;
using UnityEngine.InputSystem.Controls;
using UnityEngine.InputSystem.EnhancedTouch;
using UnityEngine.InputSystem.Layouts;
using UnityEngine.InputSystem.OnScreen;
using UnityEngine.Serialization;

[AddComponentMenu("Input/虚拟摇杆 - 新输入系统(InputSystem)")]
public class JoyStick_InputSystem : OnScreenControl, IPointerDownHandler
{
    enum JoyStickType
    {
        [InspectorName("固定在默认位置")]
        FixedInDefaultPosition = 0,

        [InspectorName("固定在触摸位置")]
        FixedInClickPosition = 1,

        [InspectorName("跟随触摸移动")]
        Flexible = 2
    }

    [Header("基础设置")]
    [Tooltip("摇杆背景")]
    [SerializeField]
    private RectTransform joyStickBackGround;

    [Tooltip("摇杆按钮")]
    [SerializeField]
    private RectTransform joyStickButton;

    [Tooltip("摇杆按钮移动范围(半径)")]
    [FormerlySerializedAs("movementRange")]
    [SerializeField]
    private float movementRange = 50;

    [Tooltip("控制设备路径")]
    [InputControl(layout = "Vector2")]
    [SerializeField]
    private new string controlPath;

    [Header("类型设置")]
    [Tooltip("摇杆类型")]
    [SerializeField]
    private JoyStickType joyStickType;

    [Tooltip("摇杆是否默认隐藏")]
    [SerializeField]
    private bool isHideWithoutTouch;

    //触摸屏(设备)
    private Touchscreen currentTouchScreen;

    //控制摇杆的触点对象
    private TouchControl joyStickTouch;

    //摇杆初始位置
    private Vector2 joyStickStartPos;

    //与屏幕相关的相机(主要用于将屏幕上的位置转换为某UI矩形内的相对位置)
    private Camera screenCamera;

    //模拟(鼠标或者笔)输入
    private TouchSimulation touchSimulation;

    //画布渲染模式
    private RenderMode renderMode;

    //点击区域UI的RectTransform
    private RectTransform rectTransform;

    protected override string controlPathInternal
    {
        get => controlPath;
        set => controlPath = value;
    }

    private void Awake()
    {
#if UNITY_EDITOR
        if (!gameObject.TryGetComponent(out touchSimulation))
        {
            touchSimulation = gameObject.AddComponent<TouchSimulation>();
        }
#endif
    }

    private void Start()
    {
        currentTouchScreen = Touchscreen.current;
        //记录摇杆初始位置
        joyStickStartPos = joyStickBackGround.anchoredPosition;
        if (isHideWithoutTouch)
        {
            joyStickBackGround.gameObject.SetActive(false);
        }
        //获取画布的渲染模式
        var canvas = transform.GetComponentInParent<Canvas>();
        renderMode = canvas != null ? canvas.renderMode : RenderMode.ScreenSpaceOverlay;
        //获取点击区域UI的RectTransform
        rectTransform = transform.GetComponent<RectTransform>();
    }

    private void Update()
    {
        UpdateJoyStickUIPos();
    }

    private void OnDestroy()
    {
#if UNITY_EDITOR
        touchSimulation = null;
#endif
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        //获取与屏幕相关的相机
        if (renderMode != RenderMode.ScreenSpaceOverlay)
        {
            screenCamera = eventData.pressEventCamera;
        }
        //摇杆没有被控制时分配控制权
        if (joyStickTouch == null)
        {
            for (int i = 0; i < currentTouchScreen.touches.Count; i++)
            {
                var touch = currentTouchScreen.touches[i];
                if (touch.phase.ReadValue() == UnityEngine.InputSystem.TouchPhase.Began)
                {
                    if (
                        RectTransformUtility.RectangleContainsScreenPoint(
                            rectTransform,
                            touch.position.ReadValue(),
                            screenCamera
                        )
                    )
                    {
                        joyStickTouch = touch;
                        RectTransformUtility.ScreenPointToLocalPointInRectangle(
                            rectTransform,
                            joyStickTouch.position.ReadValue(),
                            screenCamera,
                            out var joyStickBgPos
                        );
                        SetJoyStickUI(joyStickBgPos, Vector2.zero, true);
                    }
                }
            }
        }
    }

    private void UpdateJoyStickUIPos()
    {
        if (joyStickTouch == null)
            return;
        bool isActive = true;
        Vector2 joyStickBgPos = Vector2.zero;
        Vector2 joyStickBtnPos = Vector2.zero;
        Vector2 sendToControlValue = Vector2.zero;
        switch (joyStickTouch.phase.ReadValue())
        {
            case UnityEngine.InputSystem.TouchPhase.None:
                break;
            case UnityEngine.InputSystem.TouchPhase.Began:
            case UnityEngine.InputSystem.TouchPhase.Moved:
                //更新摇杆位置数据
                RectTransformUtility.ScreenPointToLocalPointInRectangle(
                    rectTransform,
                    joyStickTouch.position.ReadValue(),
                    screenCamera,
                    out var touchInRectPos
                );
                Vector2 delta = touchInRectPos - joyStickBackGround.anchoredPosition;
                joyStickBgPos = joyStickBackGround.anchoredPosition;
                if (joyStickType == JoyStickType.Flexible)
                {
                    if (delta.magnitude > movementRange)
                    {
                        joyStickBgPos += delta.normalized * (delta.magnitude - movementRange);
                    }
                }
                joyStickBtnPos = Vector2.ClampMagnitude(delta, movementRange);
                isActive = true;
                sendToControlValue = delta / movementRange;
                break;
            case UnityEngine.InputSystem.TouchPhase.Ended:
            case UnityEngine.InputSystem.TouchPhase.Canceled:
                //收回Touch对摇杆的控制权
                joyStickTouch = null;
                joyStickBgPos = joyStickStartPos;
                isActive = false;
                break;
            case UnityEngine.InputSystem.TouchPhase.Stationary:
                break;
        }
        //设置摇杆位置
        SetJoyStickUI(joyStickBgPos, joyStickBtnPos, isActive);
        //给控制器发送新位置
        SendValueToControl(sendToControlValue);
    }

    private void SetJoyStickUI(Vector2 joyStickBgPos, Vector2 joyStickBtnPos, bool isActive)
    {
        //设置joyStickBackGround位置
        switch (joyStickType)
        {
            case JoyStickType.FixedInDefaultPosition:
                break;
            case JoyStickType.FixedInClickPosition:
            case JoyStickType.Flexible:
                joyStickBackGround.anchoredPosition = joyStickBgPos;
                break;
        }
        //设置joyStickButton位置
        joyStickButton.anchoredPosition = joyStickBtnPos;
        //设置
        if (isHideWithoutTouch && joyStickBackGround.gameObject.activeSelf != isActive)
        {
            joyStickBackGround.gameObject.SetActive(isActive);
        }
    }
}