use mino::matrix::{COLUMNS, EMPTY_ROW, FULL_ROW};
use mino::Mat;

mod downstacking;

pub use downstacking::mystery_mdse;

pub fn evaluate(mat: &Mat, pcnt: usize) -> i32 {
    // TODO: public interface for weights etc.

    struct Weights {
        height: i32,
        i_deps: i32,
        mdse: i32,
        pcnt: i32,
    }

    const W: Weights = Weights {
        height: 5,
        i_deps: 10,
        mdse: 10,
        pcnt: 10,
    };

    let mut rating = 0;
    rating += max_height(mat) * W.height;
    rating += i_deps(mat) * W.i_deps;
    rating += mystery_mdse(mat) * W.mdse;
    rating += (pcnt as i32) * W.pcnt;
    rating
}

pub fn max_height(matrix: &Mat) -> i32 {
    matrix.rows() as i32
}

pub fn i_deps(matrix: &Mat) -> i32 {
    let mut depth = [0u8; COLUMNS as usize];
    let mut count = 0;
    for y in 0..matrix.rows() {
        // 012345689xxxx
        //         ↑
        // _______xxx___
        let mut mask = 0b111 << (COLUMNS - 2);
        // _______x.x___
        let mut test = 0b101 << (COLUMNS - 2);
        for x in (0..COLUMNS).rev() {
            if matrix.test_row(y, mask, test) {
                depth[x as usize] += 1;
                depth[x as usize] %= 4;
                if depth[x as usize] == 3 {
                    count += 1;
                }
            } else {
                depth[x as usize] = 0;
            }
            mask >>= 1;
            test >>= 1;
        }
    }
    count
}

pub fn row_trans(matrix: &Mat) -> i32 {
    let mut prev_row = FULL_ROW;
    let mut count = 0;
    for &curr_row in &matrix[..] {
        count += (curr_row ^ prev_row).count_ones();
        prev_row = curr_row;
    }
    count += (prev_row ^ EMPTY_ROW).count_ones();
    count as i32
}

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

    #[test]
    fn test_i_deps() {
        assert_eq!(i_deps(Mat::EMPTY), 0);
        assert_eq!(
            i_deps(mat! {
                "xxxxx...xx";
                "xxxxx..xxx";
                "xxxxx.xx.x";
                "xxxxx.xxxx";
            }),
            0
        );
        assert_eq!(
            i_deps(mat! {
                "xxx.....xx";
                "xxxx..xxxx";
                "xxxxx.xxxx";
                "x.xxx.xxxx";
            }),
            0
        );
        assert_eq!(
            i_deps(mat! {
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            1
        );
        assert_eq!(
            i_deps(mat! {
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            1
        );
        assert_eq!(
            i_deps(mat! {
                "xxxxxxxx.x";
                "xxxxxxxx.x";
                "xxxxxxxx.x";
                "xxxxxxxx.x";
                "x.xxxxxxxx";
                "x.xxxxxxxx";
                "x.xxxxxxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            3,
        );
        assert_eq!(
            i_deps(mat! {
                // 6 rows
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            1
        );
        assert_eq!(
            i_deps(mat! {
                // 7 rows
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            2
        );
        assert_eq!(
            i_deps(mat! {
                "x.x......x";
                "x.xxx.xxxx";
                "x.xxx.xxxx";
                "x.xxx.xxxx";
            }),
            2
        );
    }

    #[test]
    fn test_row_trans() {
        assert_eq!(row_trans(Mat::EMPTY), 10);
        assert_eq!(
            row_trans(mat! {
                "x.........";
                "xx........";
                "xxx.......";
                "xxxx......";
                "xxxxx.....";
                "xxxxxx....";
                "xxxxxxx...";
                "xxxxxxxx..";
                "xxxxxxxxx.";
                "xxxxxxxxxx";
            }),
            10,
        );
        assert_eq!(
            row_trans(mat! {
                "xxxxx.xxxx";
            }),
            9 + 1,
        );
        assert_eq!(
            row_trans(mat! {
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
                "xxxxx.xxxx";
            }),
            9 + 1,
        );
        assert_eq!(
            row_trans(mat! {
                "xxxxx.xxxx";
                "xxxx.Xxxxx";
            }),
            9 + 2 + 1
        );
        assert_eq!(
            row_trans(mat! {
                "xxxxx.xxx.";
                "xx....xxxx";
            }),
            8 + 4 + 4
        );
        assert_eq!(
            row_trans(mat! {
                "xxxx..xxxx";
                "xxxx...xxx";
                "xxxxx.xxxx";
            }),
            8 + 1 + 2 + 1,
        );
    }
}