using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/********************************************************************************
*Create By CG
*Function 
*********************************************************************************/
namespace ZXK.UTility
{
    public class CameraControl : MonoBehaviour
    {
        #region 相机状态
        /// <summary>
        /// 相机状态
        /// </summary>
        class CameraState
        {
            public float yaw;
            public float pitch;
            public float roll;
            public float x;
            public float y;
            public float z;

            public void SetFromTransform(Transform t)
            {
                pitch = t.eulerAngles.x;
                yaw = t.eulerAngles.y;
                roll = t.eulerAngles.z;
                x = t.position.x;
                y = t.position.y;
                z = t.position.z;
            }

            public void LerpTowards(CameraState target, float positionLerpPct, float rotationLerpPct)
            {
                yaw = Mathf.Lerp(yaw, target.yaw, rotationLerpPct);
                pitch = Mathf.Lerp(pitch, target.pitch, rotationLerpPct);
                roll = Mathf.Lerp(roll, target.roll, rotationLerpPct);

                x = Mathf.Lerp(x, target.x, positionLerpPct);
                y = Mathf.Lerp(y, target.y, positionLerpPct);
                z = Mathf.Lerp(z, target.z, positionLerpPct);
            }

            public void UpdateTransform(Transform t,Transform camera)
            {
                camera.eulerAngles = new Vector3(pitch, yaw, roll);
            }
        }
        #endregion

        CameraState m_TargetCameraState = new CameraState();
        CameraState m_InterpolatingCameraState = new CameraState();

        [Header("Movement Settings 移动设置")]
        [Tooltip("Exponential boost factor on translation, controllable by mouse wheel. 平移的指数增强因子，可通过鼠标滚轮控制。")]
        public float boost = 3.5f;

        [Tooltip("Time it takes to interpolate camera position 99% of the way to the target. 将相机位置插值到目标位置99%所需的时间。"), Range(0.001f, 1f)]
        public float positionLerpTime = 0.2f;

        [Header("Rotation Settings 旋转设定")]
        [Tooltip("X = Change in mouse position. 改变鼠标位置。\nY = Multiplicative factor for camera rotation. 相机旋转的乘性因子。")]
        public AnimationCurve mouseSensitivityCurve = new AnimationCurve(new Keyframe(0f, 0.5f, 0f, 5f), new Keyframe(1f, 2.5f, 0f, 0f));

        [Tooltip("Time it takes to interpolate camera rotation 99% of the way to the target. 插值相机旋转99%到目标所需的时间。"), Range(0.001f, 1f)]
        public float rotationLerpTime = 0.01f;

        [Tooltip("Whether or not to invert our Y axis for mouse input to rotation. 是否将鼠标输入的Y轴反转为旋转。")]
        public bool invertY = false;

        void OnEnable()
        {
            m_TargetCameraState.SetFromTransform(transform);
            m_InterpolatingCameraState.SetFromTransform(transform);
        }

        void Update()
        {
            // Rotation 旋转
            if (Input.GetMouseButton(1))
            {
                var mouseMovement = new Vector2(Input.GetAxis("Mouse X"), Input.GetAxis("Mouse Y") * (invertY ? 1 : -1));

                var mouseSensitivityFactor = mouseSensitivityCurve.Evaluate(mouseMovement.magnitude);

                m_TargetCameraState.yaw += mouseMovement.x * mouseSensitivityFactor;
                m_TargetCameraState.pitch += mouseMovement.y * mouseSensitivityFactor;
            }


            //// Speed up movement when shift key held 按住shift键时加速移动
            //if (Input.GetKey(KeyCode.LeftShift))
            //{
            //    //原速度*10为按下Shift后的速度
            //    translation *= 10.0f;
            //}


            // Framerate-independent interpolation 帧率无关插值
            // Calculate the lerp amount, such that we get 99% of the way to our target in the specified time 计算lerp的数量，这样我们就可以在指定的时间内到达目标的99%
            var positionLerpPct = 1f - Mathf.Exp((Mathf.Log(1f - 0.99f) / positionLerpTime) * Time.deltaTime);
            var rotationLerpPct = 1f - Mathf.Exp((Mathf.Log(1f - 0.99f) / rotationLerpTime) * Time.deltaTime);
            m_InterpolatingCameraState.LerpTowards(m_TargetCameraState, positionLerpPct, rotationLerpPct);

            m_InterpolatingCameraState.UpdateTransform(transform,transform.GetComponentInChildren<Camera>().transform);
        }
    }
}