use image::{DynamicImage, GenericImageView, Pixel, Rgb, RgbImage, ImageBuffer};
use std::env;
mod xkcd_colours;
mod x11_colours;
mod css_colours;
//use xkcd_colours as colours;
//use x11_colours as colours;
use css_colours as colours;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() == 2 {
        process_image_file(&args[1]);
    }
    replace_colours_with_nearest();
}

fn replace_colours_with_nearest() {
    let img = image::open("resources/pexels-scott-webb-137594.jpg").unwrap();
    let (width, height) = img.dimensions();
    let mut out: RgbImage = ImageBuffer::new(width, height);
    for x in 0..width {
        for y in 0..height {
            let pixel = img.get_pixel(x, y).to_rgb();
            out.put_pixel(x, y, Rgb(get_nearest_colour(pixel).to_rgb()));
        }
    }
    out.save("out.jpg").unwrap();
}

fn get_all_nearest_colours(img: DynamicImage) -> Vec<(colours::Colour, u32)> {
    let mut colours: Vec<(colours::Colour, u32)> = Vec::with_capacity(colours::NUM_COLOURS);
    for c in colours::Colour::iterator() {
        colours.push((c.clone(), 0));
    }
    for pixel in img.pixels() {
        let pixel_colour = get_nearest_colour(pixel.2.to_rgb());
        colours[pixel_colour as usize].1 = colours[pixel_colour as usize].1 + 1;
    }
    colours.retain(|(_c, n)| *n != 0 as u32);
    colours.sort_by(|a, b| b.1.cmp(&a.1));
    colours
}

fn get_nearest_colour(p: Rgb<u8>) -> colours::Colour {
    let mut lowest_distance = f64::MAX;
    let mut closest_colour = colours::Colour::Black;
    for col in colours::Colour::iterator() {
        let c = col.to_rgb();
        let d = (p.0[0] as i32 - c[0] as i32).pow(2) + (p.0[1] as i32 - c[1] as i32).pow(2) as i32 + (p.0[2] as i32 - c[2] as i32).pow(2);
        let d = (d as f64).sqrt();
        if d < lowest_distance {
            closest_colour = col.clone();
            lowest_distance = d;
        }
    }
    closest_colour
}

fn process_image_file(file: &str) -> Vec<(colours::Colour, u32)> {
    let img = image::open(file).unwrap();
    let colours = get_all_nearest_colours(img);
    colours
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_rusty_pic() {
        let colours = process_image_file("resources/pexels-scott-webb-137594.jpg");
        println!("{:?}", colours);
    }

    #[test]
    fn test_birdy_pic() {
        let colours = process_image_file("resources/pexels-erik-karits-3761421.jpg");
        println!("{:?}", colours);
    }

    #[test]
    fn test_painty_pic() {
        let colours = process_image_file("resources/pexels-steve-johnson-1070536.jpg");
        println!("{:?}", colours);
    }   
}