use std::collections::HashMap;

fn extract_color_distribution(image_data: &[u8]) -> HashMap<u32, f32> {
    let mut color_distribution: HashMap<u32, f32> = HashMap::new();
    let total_pixels = image_data.len() as f32 / 4.0;//für 4 Werte

    for pixel in image_data.chunks_exact(4) {
        let r = pixel[0] as u32;
        let g = pixel[1] as u32;
        let b = pixel[2] as u32;
        let a = pixel[3] as u32;
        let rgba = (r << 24) | (g << 16) | (b << 8) | a;

        *color_distribution.entry(rgba).or_insert(0.0) += 1.0;
    }

    for (_, count) in &mut color_distribution {
        *count /= total_pixels;
    }

    color_distribution
}

fn extract_average_brightness(image: &[u8]) -> u8 {
    let mut sum: u32 = 0;
    let mut count: u32 = 0;

    for i in (0..image.len()).step_by(4) {
        let r = image[i] as u32;
        let g = image[i + 1] as u32;
        let b = image[i + 2] as u32;

        // (0.299 * R) + (0.587 * G) + (0.114 * B)
        let brightness = ((0.299 * r as f32) + (0.587 * g as f32) + (0.114 * b as f32)).round() as u32;

        sum += brightness;
        count += 1;
    }
    let average_brightness = (sum / count) as u8;
        average_brightness
}


fn main() {

test2();

}

fn test2(){

    let image_data: Vec<(u8, u8, u8, u8)> = vec![
        (255, 0, 0, 255),   // Red
        (0, 255, 0, 255),   // Green
        (0, 0, 255, 255),   // Blue
    ];
    //convert image data to useable &u8 slice
    let byte_slice: &[u8] = unsafe {
        std::slice::from_raw_parts(
            image_data.as_ptr() as *const u8,
            image_data.len() * 4,
        )
    };
    let color_distribution = extract_color_distribution(&byte_slice);
    let color_distribution_vec: Vec<f32> = color_distribution.values().cloned().collect();
    let average_brightness = extract_average_brightness(&byte_slice);
    println!("{:?}", average_brightness);
    println!("{:?}", color_distribution_vec);
}