#[derive(Debug, Eq, PartialEq)]
pub struct Image {
    pub pixels: Vec<u8>, // 64 for SD, 256 for HD
}

impl From<String> for Image {
    #[inline]
    fn from(string: String) -> Image {
        let string = string.replace("NaN", "0");
        let string = string.trim();
        let lines: Vec<&str> = string.lines().collect();
        let dimension = lines.len();
        let mut pixels: Vec<u8> = Vec::new();

        for line in lines {
            let line = &line[..dimension];
            for char in line.chars().into_iter() {
                pixels.push(match char {'1' => 1, _ => 0});
            }
        }

        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
    }
}

#[inline]
pub(crate) fn animation_frames_from_string(string: String) -> Vec<Image> {
    let frames: Vec<&str> = string.split(">").collect();

    frames.iter().map(|&frame| Image::from(frame.to_string())).collect()
}

#[cfg(test)]
mod test {
    use crate::image::{Image, animation_frames_from_string};
    use crate::mock;

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

    #[test]
    fn test_animation_frames_from_string() {
        let output = animation_frames_from_string(
            include_str!("test-resources/animation_frames").to_string()
        );

        let expected = mock::image::animation_frames();

        assert_eq!(output, expected);
    }
}