using UnityEngine;

[ExecuteInEditMode]
[RequireComponent(typeof(LineRenderer))]
public class SynthWaveform : MonoBehaviour
{
    [System.Serializable]
    public class SynthVoice
    {
        public bool enabled = true;        // 是否启用该波形
        [Range(0f, 1f)]
        public float waveMorph = 0f;       // 0~1 控制波形从三角到脉冲环形渐变
        public float frequency = 1f;       // 基础频率
        public int octave = 0;             // 八度调整（+/-）
        [Range(0f, 1f)]
        public float amplitude = 1f;       // 振幅
        [Range(0.1f, 0.9f)]
        public float pulseWidth = 0.5f;    // 脉冲宽度，仅在Pulse阶段有效
    }

    public SynthVoice[] voices = new SynthVoice[3];

    [Header("绘图设置")]
    public int resolution = 300;
    public float waveWidth = 10f;
    public float waveHeight = 1f;
    public float speed = 2f;

    [Header("周期设置")]
    [Range(1, 20)]
    public int cycles = 4; // 在waveWidth内显示几个波周期

    [Header("跳动点")]
    public Transform glowPointInstance; // 小球跳动点物体

    private LineRenderer lineRenderer;
    private Vector3[] points;
    private float phaseOffset = 0f;

    void OnEnable()
    {
        lineRenderer = GetComponent<LineRenderer>();
        lineRenderer.positionCount = resolution;
        points = new Vector3[resolution];
    }

    void Update()
    {
        phaseOffset += Time.deltaTime * speed;
        UpdateWave();
        UpdateGlowPoint();
    }

    void UpdateWave()
    {
        Vector3 origin = transform.position;
        Quaternion rotation = transform.rotation;

        for (int i = 0; i < resolution; i++)
        {
            float x = ((float)i / (resolution - 1)) * waveWidth;
            float time = (x / waveWidth) * cycles + phaseOffset;

            float sample = 0f;
            foreach (var voice in voices)
            {
                if (!voice.enabled) continue;

                float freq = voice.frequency * Mathf.Pow(2, voice.octave);
                float wavePos = (time * freq) % 1f;

                float morphValue = voice.waveMorph * 20f; // 0~20两圈循环
                float val = MorphWaveCircular(morphValue, wavePos, voice.pulseWidth);

                sample += val * voice.amplitude;
            }

            sample = Mathf.Clamp(sample, -1f, 1f);
            Vector3 localPos = new Vector3(x, sample * waveHeight, 0f);
            points[i] = origin + rotation * localPos;
        }

        lineRenderer.SetPositions(points);
    }

    void UpdateGlowPoint()
    {
        if (glowPointInstance == null || points == null || points.Length == 0) return;

        // phaseOffset在0~1之间循环，映射points索引
        float t = phaseOffset % 1f;
        int idx = Mathf.RoundToInt(t * (resolution - 1));
        idx = Mathf.Clamp(idx, 0, resolution - 1);

        // 小球X固定为最右端点X
        float fixedX = points[resolution - 1].x;
        // 小球Y跟随索引对应的波形Y
        float y = points[idx].y;

        glowPointInstance.position = new Vector3(fixedX, y, points[idx].z);
    }

    // 环形渐变波形 morphValue 0~20，循环两圈
    float MorphWaveCircular(float morphValue, float time, float pulseWidth)
    {
        float val = morphValue % 20f;

        float[] keyPoints = { 0f, 4f, 7f, 10f, 14f, 17f, 20f };
        int[] waveIDs = { 0, 1, 2, 3, 3, 0, 1 };

        int idx = 0;
        for (int i = 0; i < keyPoints.Length - 1; i++)
        {
            if (val >= keyPoints[i] && val < keyPoints[i + 1])
            {
                idx = i;
                break;
            }
        }

        float t = (val - keyPoints[idx]) / (keyPoints[idx + 1] - keyPoints[idx]);
        float waveA = GetWaveByID(waveIDs[idx], time, pulseWidth);
        float waveB = GetWaveByID(waveIDs[idx + 1], time, pulseWidth);
        return Mathf.Lerp(waveA, waveB, t);
    }

    float GetWaveByID(int id, float t, float pulseWidth)
    {
        switch (id)
        {
            case 0: return Triangle(t);
            case 1: return Sawtooth(t);
            case 2: return Square(t);
            case 3: return Pulse(t, pulseWidth);
            default: return 0f;
        }
    }

    float Sawtooth(float t)
    {
        return 2f * t - 1f;
    }

    float Triangle(float t)
    {
        return 1f - 4f * Mathf.Abs(Mathf.Round(t - 0.25f) - (t - 0.25f));
    }

    float Square(float t)
    {
        return t < 0.5f ? 1f : -1f;
    }

    float Pulse(float t, float pulseWidth)
    {
        return t < pulseWidth ? 1f : -1f;
    }
}