use rand::Rng;
use std::fmt;

#[derive(Clone, Copy)]
struct Cell {
    neighbors: u8,
    revealed: bool,
    flagged: bool,
    mine: bool,
}

impl fmt::Display for Cell {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.flagged {
            write!(f, "F")?;
        }

        if !self.revealed {
            write!(f, "+")?;
            return Ok(());
        }

        if self.mine {
            write!(f, "M")?;
            return Ok(());
        }

        if self.neighbors > 0 {
            write!(f, "{}", self.neighbors)?;
        } else {
            write!(f, "_")?;
        }

        Ok(())
    }
}

#[derive(Clone)]
struct Grid(Vec<Vec<Cell>>);

impl fmt::Display for Grid {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for row in self.0.iter() {
            for cell in row.iter() {
                write!(f, " {} ", cell)?;
            }
            write!(f, "\n")?;
        }
        Ok(())
    }
}

fn mark_neighbors(grid: &mut Grid, x: usize, y: usize) {
    for row in y.saturating_sub(1)..=y.saturating_add(1) {
        for col in x.saturating_sub(1)..=x.saturating_add(1) {
            if x == col && y == row {
                continue;
            }

            let Some(cell) = grid.0.get_mut(row).and_then(|row| row.get_mut(col)) else {
                continue;
            };

            cell.neighbors += 1;
        }
    }
}

fn plant_mines(grid: &mut Grid, mines: u8) {
    let mut rng = rand::thread_rng();

    let mut mines_left = mines;
    while mines_left > 0 {
        let row = rng.gen_range(0..grid.0.len());
        let col = rng.gen_range(0..grid.0[0].len());
        let cell: &mut Cell = &mut grid.0[row][col];

        if !cell.mine {
            mines_left -= 1;
            cell.mine = true;

            mark_neighbors(grid, col, row);
        }
    }
}

fn main() {
    let mut grid = Grid(vec![
        vec![
            Cell {
                neighbors: 0,
                flagged: false,
                mine: false,
                revealed: false,
            };
            9
        ];
        9
    ]);

    plant_mines(&mut grid, 10);

    println!("{}", grid);
}