use image::{DynamicImage, GrayImage, ImageFormat};
use imageproc::template_matching::MatchTemplateMethod;

const REFERENCE_PNGS: [&[u8]; 10] = [
    include_bytes!("../data/0.png"),
    include_bytes!("../data/1.png"),
    include_bytes!("../data/2.png"),
    include_bytes!("../data/3.png"),
    include_bytes!("../data/4.png"),
    include_bytes!("../data/5.png"),
    include_bytes!("../data/6.png"),
    include_bytes!("../data/7.png"),
    include_bytes!("../data/8.png"),
    include_bytes!("../data/9.png"),
];

fn x_matches(image: &GrayImage, template: &GrayImage) -> Vec<u32> {
    let match_values = imageproc::template_matching::match_template(
        image,
        template,
        MatchTemplateMethod::CrossCorrelationNormalized,
    );
    match_values
        .enumerate_pixels()
        .filter(|(_x, _y, pix)| pix.0[0] > 0.9)
        .map(|(x, _y, _pix)| x)
        .collect()
}

pub fn ocr(image: DynamicImage) -> u32 {
    let grayscale_image = image::imageops::grayscale(&image);
    let mut digit_x_positions: Vec<(u8, u32)> = (0..10)
        .flat_map(|i| {
            let png_i =
                image::load_from_memory_with_format(REFERENCE_PNGS[i as usize], ImageFormat::Png)
                    .unwrap();
            let grey_png_i = image::imageops::grayscale(&png_i);
            x_matches(&grayscale_image, &grey_png_i)
                .into_iter()
                .map(move |x| (i, x))
        })
        .collect();
    digit_x_positions.sort_by_key(|&(_i, x)| x);
    let digits: String = digit_x_positions
        .into_iter()
        .map(|(i, _x)| format!("{}", i))
        .collect();
    dbg!(&digits);
    digits.parse().unwrap()
}