extern crate hound;
extern crate samplerate_rs;

use hound::{SampleFormat, WavSpec, WavWriter};
use samplerate_rs::{ConverterType, Samplerate};

fn main() {
    // Generate a 880Hz sine wave for 1 second in 44100Hz with one channel.
    let freq_left = std::f32::consts::PI * 880f32 / 44100f32;
    let freq_right = std::f32::consts::PI * 1200f32 / 44100f32;
    let input_left = (0..44100 * 10).map(|i| (freq_left * i as f32).sin());
    let input_right = (0..44100 * 10).map(|i| (freq_right * i as f32).sin());
    let input: Vec<f32> = input_left
        .zip(input_right)
        .map(|(l, r)| vec![l, r])
        .flatten()
        .collect();

    // Create a new converter.
    let converter = Samplerate::new(ConverterType::SincBestQuality, 44100, 48000, 2).unwrap();

    // Create a writer for writing the resampled data to disk.
    let mut writer_48000 = WavWriter::create(
        "sine-48000.wav",
        WavSpec {
            channels: 2,
            sample_rate: 48000,
            bits_per_sample: 32,
            sample_format: SampleFormat::Float,
        },
    )
    .unwrap();

    // Write the audio to the converter a loop, or if you may, as a stream.
    let chunk_size = 4410; // 100ms
    for i in 0..input.len() / chunk_size {
        let resampled = converter
            .process(&input[i * chunk_size..(i + 1) * chunk_size])
            .unwrap();
        resampled
            .iter()
            .for_each(|i| writer_48000.write_sample(*i).unwrap());
    }
}