use super::{InitialMapBuilder, BuilderMap, Rect, TileType, draw_corridor};
use rltk::RandomNumberGenerator;

const MIN_ROOM_SIZE : i32 = 8;

pub struct BspInteriorBuilder {
    rects: Vec<Rect>
}

impl InitialMapBuilder for BspInteriorBuilder {
    #[allow(dead_code)]
    fn build_map(&mut self, rng: &mut rltk::RandomNumberGenerator, build_data : &mut BuilderMap) {
        self.build(rng, build_data);
    }
}

impl BspInteriorBuilder {
    #[allow(dead_code)]
    pub fn new() -> Box<BspInteriorBuilder> {
        Box::new(BspInteriorBuilder{
            rects: Vec::new()
        })
    }

    fn build(&mut self, rng : &mut RandomNumberGenerator, build_data : &mut BuilderMap) {
        let mut rooms : Vec<Rect> = Vec::new();
        self.rects.clear();
        self.rects.push( Rect::new(1, 1, build_data.map.width-2, build_data.map.height-2) ); // Start with a single map-sized rectangle
        let first_room = self.rects[0];
        self.add_subrects(first_room, rng); // Divide the first room

        let rooms_copy = self.rects.clone();
        for r in rooms_copy.iter() {
            let room = *r;
            //room.x2 -= 1;
            //room.y2 -= 1;
            rooms.push(room);
            for y in room.y1 .. room.y2 {
                for x in room.x1 .. room.x2 {
                    let idx = build_data.map.xy_idx(x, y);
                    if idx > 0 && idx < ((build_data.map.width * build_data.map.height)-1) as usize {
                        build_data.map.tiles[idx] = TileType::Floor;
                    }
                }
            }
            build_data.take_snapshot();
        }

        // Now we want corridors
        for i in 0..rooms.len()-1 {
            let room = rooms[i];
            let next_room = rooms[i+1];
            let start_x = room.x1 + (rng.roll_dice(1, i32::abs(room.x1 - room.x2))-1);
            let start_y = room.y1 + (rng.roll_dice(1, i32::abs(room.y1 - room.y2))-1);
            let end_x = next_room.x1 + (rng.roll_dice(1, i32::abs(next_room.x1 - next_room.x2))-1);
            let end_y = next_room.y1 + (rng.roll_dice(1, i32::abs(next_room.y1 - next_room.y2))-1);
            draw_corridor(&mut build_data.map, start_x, start_y, end_x, end_y);
            build_data.take_snapshot();
        }
        build_data.rooms = Some(rooms);
    }

    fn add_subrects(&mut self, rect : Rect, rng : &mut RandomNumberGenerator) {
        // Remove the last rect from the list
        if !self.rects.is_empty() {
            self.rects.remove(self.rects.len() - 1);
        }

        // Calculate boundaries
        let width  = rect.x2 - rect.x1;
        let height = rect.y2 - rect.y1;
        let half_width = width / 2;
        let half_height = height / 2;

        let split = rng.roll_dice(1, 4);

        if split <= 2 {
            // Horizontal split
            let h1 = Rect::new( rect.x1, rect.y1, half_width-1, height );
            self.rects.push( h1 );
            if half_width > MIN_ROOM_SIZE { self.add_subrects(h1, rng); }
            let h2 = Rect::new( rect.x1 + half_width, rect.y1, half_width, height );
            self.rects.push( h2 );
            if half_width > MIN_ROOM_SIZE { self.add_subrects(h2, rng); }
        } else {
            // Vertical split
            let v1 = Rect::new( rect.x1, rect.y1, width, half_height-1 );
            self.rects.push(v1);
            if half_height > MIN_ROOM_SIZE { self.add_subrects(v1, rng); }
            let v2 = Rect::new( rect.x1, rect.y1 + half_height, width, half_height );
            self.rects.push(v2);
            if half_height > MIN_ROOM_SIZE { self.add_subrects(v2, rng); }
        }
    }
}
