// Eryn Wells <eryn@erynwells.me>

use crate::{Position, Square};
use std::fmt;
use std::fmt::Write;

pub struct DiagramFormatter<'a>(&'a Position);

impl<'a> fmt::Display for DiagramFormatter<'a> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut output = String::new();

        output.push_str("  +-----------------+\n");

        for rank in (0..8).rev() {
            write!(output, "{} | ", rank + 1)?;

            for file in 0..8 {
                let square = Square::from_rank_file(rank, file).unwrap();
                match self.0.piece_on_square(square) {
                    Some(placed_piece) => write!(output, "{} ", placed_piece.piece)?,
                    None => output.push_str(". "),
                }
            }

            output.push_str("|\n");
        }

        output.push_str("  +-----------------+\n");
        output.push_str("    a b c d e f g h\n");

        write!(f, "{}", output)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::piece::{Color, Piece};
    use crate::Position;

    #[test]
    fn empty() {
        let pos = Position::empty();
        let diagram = DiagramFormatter(&pos);
        println!("{}", diagram);
    }

    #[test]
    fn one_king() {
        let mut pos = Position::empty();
        pos.place_piece(
            &Piece::king(Color::Black),
            &Square::from_algebraic_str("h3").expect("h3"),
        )
        .expect("Unable to place piece");

        let diagram = DiagramFormatter(&pos);
        println!("{}", diagram);
    }
}