using UnityEngine;
using Shapes;
using System.Collections.Generic;

[ExecuteAlways]
public class LakeVisualizer : ImmediateModeShapeDrawer
{
    [Header("网格设置")]
    public float fieldSize = 20f;
    public int pointCount = 30;
    public float pointSize = 0.15f;
    public float lineWidth = 0.03f;

    [Header("波动参数")]
    public float noiseScale = 0.3f;
    public float waveHeight = 1.5f;
    public float waveSpeed = 1f;
    public float timeScale = 1f;

    [Header("涟漪参数")]
    public float rippleStrength = 2f;
    public float rippleDuration = 1.5f;
    public float rippleSpreadSpeed = 6f;
    public float rippleSharpness = 2f;

    [Header("目标设置")]
    public Vector2 targetPosition = Vector2.zero;
    public float shapeChangeRadius = 4f; // 控制形状混合的范围

    private Vector3[] points;
    private float time;

    private struct Ripple
    {
        public Vector2 position;
        public float startTime;
    }

    private List<Ripple> ripples = new List<Ripple>();

    private void Update()
    {
        time = Application.isPlaying ? Time.time * timeScale : 0f;

        if (Application.isPlaying && Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, out RaycastHit hit))
            {
                ripples.Add(new Ripple
                {
                    position = new Vector2(hit.point.x, hit.point.z),
                    startTime = Time.time
                });
            }
        }

        ripples.RemoveAll(r => Time.time - r.startTime > rippleDuration);
    }

    private float GetNoiseHeight(float x, float z, float currentTime)
    {
        float noise = 0f;
        float amp = 1f;
        float freq = 1f;

        for (int i = 0; i < 3; i++)
        {
            float nx = x * freq * noiseScale;
            float nz = z * freq * noiseScale;
            float nt = currentTime * waveSpeed * freq;
            noise += Mathf.PerlinNoise(nx + nt, nz + nt) * amp;
            amp *= 0.5f;
            freq *= 2f;
        }

        return noise * waveHeight;
    }

    public override void DrawShapes(Camera cam)
    {
        using (Draw.Command(cam))
        {
            Draw.ResetAllDrawStates();
            Draw.LineGeometry = LineGeometry.Volumetric3D;
            Draw.Thickness = lineWidth;

            float step = fieldSize / (pointCount - 1);
            float halfSize = fieldSize * 0.5f;

            if (points == null || points.Length != pointCount * pointCount)
                points = new Vector3[pointCount * pointCount];

            for (int i = 0; i < pointCount; i++)
            {
                for (int j = 0; j < pointCount; j++)
                {
                    float x = -halfSize + j * step;
                    float z = -halfSize + i * step;
                    Vector2 pos2D = new Vector2(x, z);

                    float baseY = GetNoiseHeight(x, z, time);
                    float rippleY = 0f;
                    float brightness = 0f;
                    float shapeBlend = 0f;

                    foreach (var ripple in ripples)
                    {
                        float elapsed = Time.time - ripple.startTime;
                        float spread = elapsed * rippleSpreadSpeed;
                        float dist = Vector2.Distance(pos2D, ripple.position);

                        float ease = Mathf.Sin(Mathf.Clamp01(elapsed / rippleDuration) * Mathf.PI);
                        float spike = Mathf.Exp(-Mathf.Pow(dist - spread, 2f) * rippleSharpness);
                        float bright = Mathf.Exp(-Mathf.Pow((dist - spread) * 0.5f, 2f));

                        rippleY += spike * rippleStrength * ease;
                        brightness += bright * ease;

                        // 目标点接近程度影响形状混合程度
                        float targetDist = Vector2.Distance(ripple.position, targetPosition);
                        float shapeFactor = Mathf.Clamp01(1f - targetDist / shapeChangeRadius);
                        shapeBlend = Mathf.Max(shapeBlend, shapeFactor * ease);
                    }

                    float finalY = baseY + rippleY;
                    Vector3 worldPos = new Vector3(x, finalY, z);
                    points[i * pointCount + j] = worldPos;

                    float depth = (finalY + waveHeight) / (waveHeight * 2f);
                    float brightnessScale = Mathf.Clamp01(1f + brightness);
                    Color pointColor = Color.Lerp(new Color(0.5f, 1f, 1f), new Color(0f, 0.5f, 1f), depth);
                    pointColor *= brightnessScale;

                    float scale = pointSize * (1f - depth * 0.5f);

                    // 形状混合逻辑（近似插值）
                    if (shapeBlend < 0.1f)
                    {
                        Draw.Sphere(worldPos, scale, pointColor);
                    }
                    else if (shapeBlend < 0.3f)
                    {
                        Draw.Torus(worldPos, scale * 0.6f, scale * 0.2f, pointColor); // 环形
                    }
                    else if (shapeBlend < 0.6f)
                    {
                        Draw.Cube(worldPos, scale * 1.4f, pointColor); // 立方体
                    }
                    else if (shapeBlend < 0.9f)
                    {
                        Draw.Cone(worldPos, scale * 1.6f, scale * 0.5f, pointColor); // 锥体
                    }
                    else
                    {
                        Vector3 a = worldPos + Vector3.up * scale;
                        Vector3 b = worldPos + new Vector3(scale, -scale, 0);
                        Vector3 c = worldPos + new Vector3(-scale, -scale, 0);
                        Draw.Triangle(a, b, c, pointColor); // 三角形
                    }
                }
            }

            // 连接线条（可选）
            for (int i = 0; i < pointCount; i++)
            {
                for (int j = 0; j < pointCount; j++)
                {
                    int index = i * pointCount + j;
                    Vector3 current = points[index];

                    if (j < pointCount - 1)
                    {
                        Vector3 next = points[index + 1];
                        DrawLine(current, next);
                    }

                    if (i < pointCount - 1)
                    {
                        Vector3 next = points[index + pointCount];
                        DrawLine(current, next);
                    }
                }
            }
        }
    }

    void DrawLine(Vector3 a, Vector3 b)
    {
        float avgY = (a.y + b.y) * 0.5f;
        float lineDepth = (avgY + waveHeight) / (waveHeight * 2f);
        Color lineColor = Color.Lerp(Color.cyan, new Color(0, 0.5f, 1f, 0.3f), lineDepth);
        Draw.Line(a, b, lineWidth * (1f - lineDepth * 0.5f), lineColor);
    }
}