using Godot;
using System;

namespace AudioEditor;

public partial class Waveform : Control
{
    private WaveformInfo _waveform;

    public void SetWaveformInfo(WaveformInfo waveform)
    {
        _waveform = waveform;
        QueueRedraw();
    }

    public override void _Draw()
    {
        if (_waveform == null) return;
        base._Draw();

        int width = (int)Size.X;
        int height = (int)Size.Y;

        // Downsample the waveform to get a reasonable number of peaks to draw
        float[] averagePeaks = DownsampleToAveragePeaks(_waveform.Samples, width, _waveform.SampleRate);

        // Begin drawing the waveform
        for (int i = 0; i < width; i++)
        {
            float averagePeak = averagePeaks[i];

            // Normalize the average peak to fit within the height of the control
            int y = (int)(averagePeak * height / 2);

            // Drawing the line in the positive and negative direction from the center
            DrawLine(new Vector2(i, height / 2 - y), new Vector2(i, height / 2 + y), new Color(1, 1, 1, 0.7f));  // White with transparency
        }
    }

    private float[] DownsampleToAveragePeaks(float[] samples, int targetWidth, int sampleRate)
    {
        int totalSamples = samples.Length;
        float durationInSeconds = totalSamples / (float)sampleRate;  // Calculate the total duration in seconds
        int stepSize = totalSamples / targetWidth;  // Larger chunks for downsampling

        // If stepSize is 0 (due to rounding), default to 1 to prevent division by zero
        if (stepSize == 0) stepSize = 1;

        float[] averagePeaks = new float[targetWidth];

        for (int i = 0; i < targetWidth; i++)
        {
            int startIndex = i * stepSize;
            int endIndex = Math.Min(startIndex + stepSize, totalSamples);

            // Calculate the average or peak for this window (you can use GetPeak if needed)
            averagePeaks[i] = GetAverage(samples, startIndex, endIndex);
        }

        return averagePeaks;
    }

    // Get the average value of samples in the current window
    private float GetAverage(float[] samples, int startIndex, int endIndex)
    {
        float sum = 0f;
        int count = 0;
        for (int i = startIndex; i < endIndex; i++)
        {
            sum += Math.Abs(samples[i]);  // Use absolute values for consistency
            count++;
        }
        return count > 0 ? sum / count : 0f;
    }

    // Optional: You could use this method if you prefer showing the peak values
    private float GetPeak(float[] samples, int startIndex, int endIndex)
    {
        float maxPeak = 0f;
        for (int i = startIndex; i < endIndex; i++)
        {
            maxPeak = Math.Max(maxPeak, Math.Abs(samples[i]));
        }
        return maxPeak;
    }

    // This can be an alternative to GetAverage if you want to show average peak
    private float GetAveragePeak(float[] samples, int startIndex, int endIndex)
    {
        float sum = 0f;
        int count = 0;

        for (int i = startIndex; i < endIndex; i++)
        {
            sum += Math.Abs(samples[i]);  // Use absolute value for a more stable peak
            count++;
        }

        return count > 0 ? sum / count : 0f;  // Return the average
    }
}