using UnityEngine;
using UnityEditor;
using System.IO;

/// <summary>
/// 生成与 SpriteNoiseGlitch shader 三阶段对应的程序化音效。
/// 菜单: Tools > Generate Glitch Noise Audio
/// </summary>
public static class GlitchNoiseAudioGenerator
{
    private const int SampleRate = 44100;
    private const float Duration = 4f; // 每段音效时长（秒），便于循环使用
    private const string OutputFolder = "Assets/RawResources/Audio/GlitchNoise";

    [MenuItem("Tools/Generate Glitch Noise Audio")]
    public static void Generate()
    {
        string dir = Path.Combine(Application.dataPath, "RawResources", "Audio", "GlitchNoise");
        Directory.CreateDirectory(dir);

        GenerateStage1(dir);
        GenerateStage2(dir);
        GenerateStage3(dir);

        AssetDatabase.Refresh();
        Debug.Log($"[GlitchNoise] 已生成三阶段音效至 Assets/RawResources/Audio/GlitchNoise");
    }

    /// <summary>Stage 1: 轻微静态噪点 - 柔和白噪声</summary>
    private static void GenerateStage1(string dir)
    {
        int samples = (int)(SampleRate * Duration);
        float[] data = new float[samples];
        var rnd = new System.Random(12345);

        float gain = 0.12f;
        for (int i = 0; i < samples; i++)
        {
            data[i] = ((float)rnd.NextDouble() * 2f - 1f) * gain;
        }

        SaveWav(dir, "GlitchNoise_Stage1_Light.wav", data);
    }

    /// <summary>Stage 2: 中等 - 更多噪点 + 偶尔 glitch 爆音</summary>
    private static void GenerateStage2(string dir)
    {
        int samples = (int)(SampleRate * Duration);
        float[] data = new float[samples];
        var rnd = new System.Random(23456);

        float noiseGain = 0.22f;
        int glitchInterval = SampleRate / 4; // 约每 0.25 秒一次 glitch 爆音

        for (int i = 0; i < samples; i++)
        {
            float n = ((float)rnd.NextDouble() * 2f - 1f) * noiseGain;

            // 随机 glitch 爆音
            if (i > 0 && i % glitchInterval < 120)
            {
                float burst = ((float)rnd.NextDouble() * 2f - 1f) * 0.5f;
                n += burst * (1f - (i % glitchInterval) / 120f);
            }

            data[i] = Mathf.Clamp(n, -1f, 1f);
        }

        SaveWav(dir, "GlitchNoise_Stage2_Medium.wav", data);
    }

    /// <summary>Stage 3: 严重 - 强烈噪点 + 频繁 glitch + 数字故障感</summary>
    private static void GenerateStage3(string dir)
    {
        int samples = (int)(SampleRate * Duration);
        float[] data = new float[samples];
        var rnd = new System.Random(34567);

        float noiseGain = 0.4f;
        int blockSize = 2205; // 约 0.05 秒一块
        int glitchBlockEvery = 4;

        for (int i = 0; i < samples; i++)
        {
            int block = i / blockSize;
            float n = ((float)rnd.NextDouble() * 2f - 1f) * noiseGain;

            // 块状 glitch：整块随机反转/爆音
            if (block % glitchBlockEvery == 0)
            {
                int posInBlock = i % blockSize;
                float t = (float)posInBlock / blockSize;
                n += ((float)rnd.NextDouble() * 2f - 1f) * 0.6f * (1f - t);
            }

            // 随机“卡顿”短静音后爆音
            if (rnd.NextDouble() < 0.0003)
            {
                int silenceLen = 100 + rnd.Next(300);
                int end = Mathf.Min(i + silenceLen, samples);
                for (int j = i; j < end; j++)
                {
                    data[j] = j == end - 1 ? ((float)rnd.NextDouble() * 2f - 1f) * 0.8f : 0f;
                }
                i = end - 1;
            }
            else
            {
                data[i] = Mathf.Clamp(n, -1f, 1f);
            }
        }

        SaveWav(dir, "GlitchNoise_Stage3_Heavy.wav", data);
    }

    private static void SaveWav(string dir, string filename, float[] samples)
    {
        string path = Path.Combine(dir, filename);
        using (var fs = new FileStream(path, FileMode.Create))
        using (var bw = new BinaryWriter(fs))
        {
            // RIFF header
            bw.Write(new[] { 'R', 'I', 'F', 'F' });
            int dataSize = samples.Length * 2; // 16-bit
            bw.Write(36 + dataSize);
            bw.Write(new[] { 'W', 'A', 'V', 'E' });

            // fmt chunk
            bw.Write(new[] { 'f', 'm', 't', ' ' });
            bw.Write(16);           // chunk size
            bw.Write((short)1);     // PCM
            bw.Write((short)1);     // mono
            bw.Write(SampleRate);
            bw.Write(SampleRate * 2);
            bw.Write((short)2);
            bw.Write((short)16);

            // data chunk
            bw.Write(new[] { 'd', 'a', 't', 'a' });
            bw.Write(dataSize);

            foreach (float s in samples)
            {
                short sample = (short)Mathf.Clamp((int)(s * 32767), -32768, 32767);
                bw.Write(sample);
            }
        }
    }
}