ncw-convert 0.1.2

use std::{
    error::Error,
    fs::File,
    io::Seek,
    io::{Read, Write},
};

use hound::{WavSpec, WavWriter};
use ncw::NcwReader;

pub fn main() -> Result<(), Box<dyn Error>> {
    let args: Vec<String> = std::env::args().collect();
    if args.len() < 3 {
        println!("usage: ncw-convert <INPUT> <OUTPUT>");
        return Ok(());
    }

    let input = File::open(&args[1])?;
    let mut output = File::create(&args[2])?;

    write_wav(&mut NcwReader::read(&input)?, &mut output)?;

    Ok(())
}

pub fn write_wav<R: Read + Seek, W: Write + Seek>(
    reader: &mut NcwReader<R>,
    writer: &mut W,
) -> Result<(), Box<dyn Error>> {
    let spec = WavSpec {
        channels: reader.header.channels,
        sample_rate: reader.header.sample_rate,
        bits_per_sample: reader.header.bits_per_sample,
        sample_format: hound::SampleFormat::Int,
    };

    let mut writer = WavWriter::new(writer, spec)?;

    let samples = reader.decode_samples()?;

    for sample in samples {
        match reader.header.bits_per_sample {
            32 | 24 => {
                writer.write_sample(sample)?;
            }
            16 => {
                writer.write_sample(sample as i16)?;
            }
            8 => {
                writer.write_sample(sample as i8)?;
            }
            _ => panic!("Unknown output sample format"),
        }
    }
    writer.finalize()?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::{fs::File, io::Cursor};

    #[test]
    fn test_read_16bit_mono() -> Result<(), Box<dyn Error>> {
        let file = File::open("test-data/NCW/16-bit.ncw")?;
        let mut ncw = NcwReader::read(file)?;
        let mut buffer = Cursor::new(Vec::new());
        write_wav(&mut ncw, &mut buffer)?;
        Ok(())
    }

    #[test]
    fn test_read_24bit_stereo() -> Result<(), Box<dyn Error>> {
        let file = File::open("test-data/NCW/24-bit.ncw")?;
        let mut ncw = NcwReader::read(file)?;
        let mut buffer = Cursor::new(Vec::new());
        write_wav(&mut ncw, &mut buffer)?;
        Ok(())
    }
}