pub fn convert_bitmap_to_unicode(w: usize, h: usize, data: Vec<u8>) -> Vec<Vec<char>>
{

    const CHARS: [&str; 4] = [
        " ⠁⠂⠃⠄⠅⠆⠇⠈⠉⠊⠋⠌⠍⠎⠏⠐⠑⠒⠓⠔⠕⠖⠗⠘⠙⠚⠛⠜⠝⠞⠟⠠⠡⠢⠣⠤⠥⠦⠧⠨⠩⠪⠫⠬⠭⠮⠯⠰⠱⠲⠳⠴⠵⠶⠷⠸⠹⠺⠻⠼⠽⠾⠿",
        "⡀⡁⡂⡃⡄⡅⡆⡇⡈⡉⡊⡋⡌⡍⡎⡏⡐⡑⡒⡓⡔⡕⡖⡗⡘⡙⡚⡛⡜⡝⡞⡟⡠⡡⡢⡣⡤⡥⡦⡧⡨⡩⡪⡫⡬⡭⡮⡯⡰⡱⡲⡳⡴⡵⡶⡷⡸⡹⡺⡻⡼⡽⡾⡿",
        "⢀⢁⢂⢃⢄⢅⢆⢇⢈⢉⢊⢋⢌⢍⢎⢏⢐⢑⢒⢓⢔⢕⢖⢗⢘⢙⢚⢛⢜⢝⢞⢟⢠⢡⢢⢣⢤⢥⢦⢧⢨⢩⢪⢫⢬⢭⢮⢯⢰⢱⢲⢳⢴⢵⢶⢷⢸⢹⢺⢻⢼⢽⢾⢿",
        "⣀⣁⣂⣃⣄⣅⣆⣇⣈⣉⣊⣋⣌⣍⣎⣏⣐⣑⣒⣓⣔⣕⣖⣗⣘⣙⣚⣛⣜⣝⣞⣟⣠⣡⣢⣣⣤⣥⣦⣧⣨⣩⣪⣫⣬⣭⣮⣯⣰⣱⣲⣳⣴⣵⣶⣷⣸⣹⣺⣻⣼⣽⣾⣿",
    ];
    let bitchars = CHARS.iter().flat_map(|t| t.chars()).collect::<Vec<_>>();

    let px = |i: usize, j: usize| if i < w && j < h {data[j * w + i]} else {0};

    let mut output = vec![];

    for j in (0..h).step_by(4) 
    {
        let mut line = vec![];
        for i in (0..w).step_by(2)
        {
            let mut index = 0;
            index |= if px(i+0, j+0) < 128 {0} else {1 << 0};
            index |= if px(i+0, j+1) < 128 {0} else {1 << 1};
            index |= if px(i+0, j+2) < 128 {0} else {1 << 2};
            index |= if px(i+0, j+3) < 128 {0} else {1 << 3};
            index |= if px(i+1, j+0) < 128 {0} else {1 << 4};
            index |= if px(i+1, j+1) < 128 {0} else {1 << 5};
            index |= if px(i+1, j+2) < 128 {0} else {1 << 6};
            index |= if px(i+1, j+3) < 128 {0} else {1 << 7};

            line.push(bitchars[index]);
        }
        output.push(line);
    }
    
    output
}


fn read_jpeg_to_bitmap(file: &str) -> (usize, usize, Vec<u8>)
{
    use zune_jpeg::zune_core::{colorspace::ColorSpace, options::DecoderOptions, bytestream::ZCursor};
    let data = std::fs::read(file).unwrap();
    let options = DecoderOptions::default().jpeg_set_out_colorspace(ColorSpace::Luma);
    let mut decoder = zune_jpeg::JpegDecoder::new_with_options(ZCursor::new(&data), options);
    let pixels = decoder.decode().unwrap();
    let (w, h) = decoder.dimensions().unwrap();
    (w, h, pixels)
}


fn main() 
{
    match std::env::args().collect::<Vec<_>>().as_slice() {
        [_, bitmap_file, source_file, output_file] => 
        {
            let (w, h, pixels) = read_jpeg_to_bitmap(&bitmap_file);

            let char_bitmap = convert_bitmap_to_unicode(w, h, pixels);

            let source = std::fs::read_to_string(source_file).unwrap();

            let max_width = 120;

            let mut modified_lines = vec![];
            let mut buffer = Vec::with_capacity(1024);
            let mut row = 0;

            for line in source.lines() 
            {
                buffer.clear();
                buffer.extend(line.chars());
                if buffer.len() < max_width {
                    let needed = max_width - buffer.len();
                    buffer.extend(core::iter::repeat(' ').take(needed));
                }

                let mut i = 0;
                for j in 0..buffer.len() 
                {
                    if !buffer[j].is_whitespace() 
                    {
                        if j - i > 3 
                        {
                            let bmp_row = &char_bitmap[row];
                            for k in i..j {
                                buffer[k] = bmp_row[k % bmp_row.len()];
                            }
                            buffer[i  ] = '/';
                            buffer[i+1] = '*';
                            buffer[j-1] = '/';
                            buffer[j-2] = '*';
                        }

                        i = j + 1;
                    }
                }

                let j = buffer.len();
                if j - i > 3 
                {
                    let bmp_row = &char_bitmap[row];
                    for k in i..j {
                        buffer[k] = bmp_row[k % bmp_row.len()];
                    }
                    buffer[i  ] = '/';
                    buffer[i+1] = '*';
                    buffer[j-1] = '/';
                    buffer[j-2] = '*';
                }

                modified_lines.push(buffer.iter().collect::<String>());
                row += 1;
            }

            let new_source = modified_lines.join("\n");

            println!("{new_source}");

            std::fs::write(output_file, new_source).unwrap();
        }
        [path] =>
        {
            println!("usage: {path} art.jpg input_src output_src");
        }
        _ => 
        {
        }
    }

}