using System;
using System.Collections.Generic;
using System.IO;
using Godot;
using NAudio.Wave;

namespace AudioEditor;

public partial class AudioFileAnalyzer : Node
{
    public static AudioFileAnalyzer Instance { get; private set; }

    public override void _Ready()
    {
        base._Ready();
        Instance = this;
    }

    public void AnalyzeFile(string path, out WaveformInfo waveformInfo)
    {
        waveformInfo = new();

        if (_waveformInfoCache.ContainsKey(path))
        {
            waveformInfo = _waveformInfoCache[path];
            return;
        }

        var ext = Path.GetExtension(path);

        switch (ext)
        {
            case ".wav":
                GD.Print("Analyzing a WAV file...");
                AnalyzeWav(path, out waveformInfo);
                break;
            default:
                GD.Print($"Format {ext} is not supported!");
                break;
        }

        _waveformInfoCache.Add(path, waveformInfo);
    }

    public bool TryGetFromCache(string path, out WaveformInfo waveformInfo)
    {
        return _waveformInfoCache.TryGetValue(path, out waveformInfo);
    }

    private void AnalyzeWav(string path, out WaveformInfo waveformInfo)
    {
        waveformInfo = new WaveformInfo();
        using (var reader = new WaveFileReader(path))
        {
            waveformInfo.Length = reader.TotalTime;
            waveformInfo.SampleRate = reader.WaveFormat.SampleRate;

            long sampleCount = reader.Length / reader.WaveFormat.BlockAlign;
            waveformInfo.Samples = new float[sampleCount];

            // Render the waveform
            byte[] buffer = new byte[reader.WaveFormat.BlockAlign];
            for (int i = 0; i < sampleCount; i++)
            {
                int sampleIndex = i * reader.WaveFormat.BlockAlign;
                while (reader.Position < reader.Length)
                {
                    // Read the raw bytes for the current sample
                    reader.Read(buffer, 0, buffer.Length);

                    // Convert the byte array to a 16-bit sample
                    short sample = BitConverter.ToInt16(buffer, 0);

                    waveformInfo.Samples[sampleIndex++] = (float)sample / short.MaxValue;
                }
            }
        }
    }

    private Dictionary<string, WaveformInfo> _waveformInfoCache = new();
}

public class WaveformInfo
{
    public int SampleRate { get; set; }
    public TimeSpan Length { get; set; }
    public float[] Samples { get; set; }
}