#[derive(Debug, Eq, PartialEq)]
pub struct Image {
    pub pixels: Vec<u32>, // 64 for SD, 256 for HD
}

impl From<String> for Image {
    #[inline]
    fn from(string: String) -> Image {
        let string = string.replace("\n", "");
        let pixels: Vec<&str> = string.split("").collect();
        // the above seems to add an extra "" at the start and end of the vec, so strip them below
        let pixels = &pixels[1..(pixels.len() - 1)];
        let pixels: Vec<u32> = pixels
            .iter()
            .map(|&pixel| pixel.parse::<u32>().unwrap())
            .collect();

        Image { pixels }
    }
}

impl ToString for Image {
    #[inline]
    fn to_string(&self) -> String {
        let mut string = String::new();

        let sqrt = (self.pixels.len() as f64).sqrt() as usize; // 8 for SD, 16 for HD
        for line in self.pixels.chunks(sqrt) {
            for pixel in line {
                string.push_str(&format!("{}", *pixel));
            }
            string.push('\n');
        }

        string.pop(); // remove trailing newline

        string
    }
}

#[cfg(test)]
mod test {
    use crate::image::Image;

    #[test]
    fn test_image_from_string() {
        let output = Image::from(include_str!("test-resources/image").to_string());

        let expected = Image {
            pixels: vec![
                1, 1, 1, 1, 1, 1, 1, 1,
                1, 1, 0, 0, 1, 1, 1, 1,
                1, 0, 1, 1, 1, 1, 1, 1,
                1, 1, 1, 1, 1, 1, 1, 1,
                1, 1, 1, 1, 1, 1, 1, 1,
                1, 1, 1, 1, 1, 1, 1, 1,
                1, 1, 1, 1, 1, 1, 1, 1,
                1, 1, 1, 1, 1, 1, 1, 1,
            ],
        };

        assert_eq!(output, expected);
    }

    #[test]
    fn test_image_to_string() {
        let output = crate::mock::image::chequers_1().to_string();
        let expected = include_str!("test-resources/image-chequers-1").to_string();
        assert_eq!(output, expected);
    }
}