// Eryn Wells <eryn@erynwells.me>

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

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

impl<'a, PosC> DiagramFormatter<'a, PosC> {
    pub fn new(position: &'a Position<PosC>) -> DiagramFormatter<PosC> {
        DiagramFormatter(position)
    }
}

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

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

        for rank in Rank::ALL.iter().rev() {
            write!(output, "{} | ", rank)?;

            for file in File::ALL.iter() {
                let square = Square::from_file_rank(*file, *rank);
                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);
    }

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