use rand::Rng;

#[derive(PartialEq, Clone, Copy, Debug)]
pub enum TileType {
    Wall,
    Floor,
}

impl TileType {
    pub fn glyph(&self) -> carpet::CP437 {
        match self {
            TileType::Wall => carpet::CP437::from_char('#'),
            TileType::Floor => carpet::CP437::from_u8(0),
        }
    }
}

pub struct Map {
    pub tiles: carpet::Board<TileType>,
    pub rooms: Vec<carpet::Rect>,
}

impl Map {
    pub fn new() -> Map {
        let mut rng = rand::thread_rng();
        let mut map = Map {
            tiles: carpet::Board::new_with_default(80, 50, TileType::Wall),
            rooms: Vec::new(),
        };

        const MAX_ROOMS: usize = 30;
        const MIN_SIZE: usize = 6;
        const MAX_SIZE: usize = 10;

        for _ in 0..MAX_ROOMS {
            let w = rng.gen_range(MIN_SIZE, MAX_SIZE);
            let h = rng.gen_range(MIN_SIZE, MAX_SIZE);
            let x = rng.gen_range(1, 80 - w);
            let y = rng.gen_range(1, 50 - h);
            let room = carpet::Rect::new([x, y], [w, h]);
            if map.rooms.iter().any(|r| r.overlaps(room)) {
                continue;
            }
            map.carve(room);
            if let Some(prev) = map.rooms.first() {
                let c1 = room.center();
                let c2 = prev.center();
                let join = if rng.gen() {
                    carpet::Coord { x: c1.x, y: c2.y }
                } else {
                    carpet::Coord { x: c2.x, y: c1.y }
                };
                map.carve(carpet::Rect::from_points(c1, join));
                map.carve(carpet::Rect::from_points(join, c2));
            }

            map.rooms.push(room);
        }

        map
    }

    fn carve(&mut self, rect: carpet::Rect) {
        let iter = self
            .tiles
            .window_iter_mut(rect)
            .expect(&format!("Rect {:?} of map bounds", rect));
        for (_, _, t) in iter {
            *t = TileType::Floor;
        }
    }

    pub fn passable(&self, (x, y): (usize, usize)) -> bool {
        Some(&TileType::Floor) == self.tiles.get(x, y)
    }
}