using UnityEngine;
using TMPro;

//根据Unity动画曲线来变形
public class TMP_AnimationCurve : TMP_Curve
{
    public AnimationCurve animationCurveY = new AnimationCurve(new Keyframe(0, -1f), 
                                            new Keyframe(0.5f, 0f), 
                                            new Keyframe(1, -1f));
    public AnimationCurve animationCurveZ = new AnimationCurve(new Keyframe(0, 0), 
                                            new Keyframe(0.25f, .5f), 
                                            new Keyframe(0.5f, 1.0f), 
                                            new Keyframe(0.75f, .5f), 
                                            new Keyframe(1, 0f));
    public float curveScaleY = 1.0f;
    public float useForWidth = 10;

    private float cacheScaleY = 1.0f;
    private float cacheUseForWidth = 10f;
    
    public float curveScaleZ = 1.0f;
    public bool enableZ;

    protected override bool ParametersHaveChanged()
    {
        if (cacheScaleY != curveScaleY || cacheUseForWidth != useForWidth)
        {
            cacheScaleY = curveScaleY;
            cacheUseForWidth = useForWidth;
            return true;
        }
        return false;
    }

    protected override Matrix4x4 ComputeTransformationMatrix(Vector3 charMidBaselinePos, float zeroToOnePos, TMP_TextInfo textInfo,
        int charIdx, float totalLength)
    {
        animationCurveY.preWrapMode = WrapMode.Clamp;
        animationCurveY.postWrapMode = WrapMode.Clamp;
        animationCurveZ.preWrapMode = WrapMode.Clamp;
        animationCurveZ.postWrapMode = WrapMode.Clamp;
        
        float ty, ry, tz, rz;
        
        GetUpTR(charMidBaselinePos, zeroToOnePos, totalLength,out ty, out ry);
        GetForwardTR(charMidBaselinePos, zeroToOnePos, totalLength,out tz, out rz);
        return Matrix4x4.TRS(new Vector3(0, ty, -tz), Quaternion.Euler(0, rz, ry), Vector3.one);
    }

    private void GetUpTR(Vector3 charMidBaselinePos, float zeroToOnePos, float total, out float t, out float r)
    {
        //float boundsMinX = m_TextComponent.bounds.min.x;
        //float boundsMaxX = m_TextComponent.bounds.max.x;
        // Compute the angle of rotation for each character based on the animation curve

        float x0 = 0f;
        if (zeroToOnePos >= 0.5f)
        {
            x0 = (0.5f * useForWidth + (zeroToOnePos - 0.5f) * total) / useForWidth;
        }
        else if (zeroToOnePos < 0.5f)
        {
            x0 = ((useForWidth - total) *0.5f + zeroToOnePos * total) / useForWidth;
        }

        float x1 = x0 + 0.0001f;
        float y0 = animationCurveY.Evaluate(x0) * curveScaleY;
        float y1 = animationCurveY.Evaluate(x1) * curveScaleY;

        Vector3 horizontal = new Vector3(1, 0, 0);
        //Vector3 tangent = new Vector3(x1 * total, y1) - new Vector3(charMidBaselinePos.x, y0);
        Vector3 tangent = new Vector3(x1 * curveScaleY, y1) - new Vector3(x0 * curveScaleY, y0);

        float dot = Mathf.Acos(Vector3.Dot(horizontal, tangent.normalized)) * 57.2957795f;
        Vector3 cross = Vector3.Cross(horizontal, tangent);
        float angle = cross.z > 0 ? dot : 360 - dot;

        t = y0;
        r = angle;
    }

    private void GetForwardTR(Vector3 charMidBaselinePos, float zeroToOnePos, float total, out float t, out float r)
    {
        if (!enableZ)
        {
            t = r = 0;
            return;
        }

        float boundsMinX = m_TextComponent.bounds.min.x;
        float boundsMaxX = m_TextComponent.bounds.max.x;
        // Compute the angle of rotation for each character based on the animation curve
        float x0 = 0f;
        if (zeroToOnePos >= 0.5f)
        {
            x0 = (0.5f * useForWidth + (zeroToOnePos - 0.5f) * total) / useForWidth;
        }
        else if (zeroToOnePos < 0.5f)
        {
            x0 = ((useForWidth - total) *0.5f + zeroToOnePos * total) / useForWidth;
        }
        // Character's position relative to the bounds of the mesh.
        
        float x1 = x0 + 0.0001f;
        float z0 = animationCurveZ.Evaluate(x0) * curveScaleZ;
        float z1 = animationCurveZ.Evaluate(x1) * curveScaleZ;

        Vector3 horizontal = new Vector3(1, 0, 0);
        //Vector3 normal = new Vector3(-(y1 - y0), (x1 * (boundsMaxX - boundsMinX) + boundsMinX) - charMidBaselinePos.x, 0);
        Vector3 tangent = new Vector3(x1 * (boundsMaxX - boundsMinX) + boundsMinX, z1) - new Vector3(charMidBaselinePos.x, z0);

        float dot = Mathf.Acos(Vector3.Dot(horizontal, tangent.normalized)) * 57.2957795f;
        Vector3 cross = Vector3.Cross(horizontal, tangent);
        float angle = cross.z > 0 ? dot : 360 - dot;

        t = z0;
        r = angle;
    }
}