alex/beta-minecraft-rust

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//! `BlockBed` metadata and the standing spots around a bed.

use super::shape::BlockView;

/// `BlockBed.headBlockToFootBlockMap`: from the foot half to the head half, per direction.
pub const HEAD_OFFSETS: [[i32; 2]; 4] = [[0, 1], [-1, 0], [0, -1], [1, 0]];

/// `ModelBed.footInvisibleFaceRemap`, which redstone wire also uses to find repeater inputs.
pub const FOOT_INVISIBLE_FACES: [i32; 4] = [2, 3, 0, 1];

/// `ModelBed.bedDirection`: the bed's face texture for each direction and side.
pub const BED_DIRECTION: [[u8; 6]; 4] = [
    [1, 0, 3, 2, 5, 4],
    [1, 0, 5, 4, 2, 3],
    [1, 0, 2, 3, 4, 5],
    [1, 0, 4, 5, 3, 2],
];

pub fn direction(metadata: u8) -> usize {
    usize::from(metadata & 3)
}

/// `BlockBed.isBlockFootOfBed`, which despite its name marks the pillow half.
pub fn is_head(metadata: u8) -> bool {
    metadata & 8 != 0
}

pub fn is_occupied(metadata: u8) -> bool {
    metadata & 4 != 0
}

/// `BlockBed.getNearestEmptyChunkCoordinates`: the `skip`th free spot around the bed at `bed`.
pub fn standing_spot(
    world: &impl BlockView,
    [x, y, z]: [i32; 3],
    mut skip: u32,
) -> Option<[i32; 3]> {
    let [dx, dz] = HEAD_OFFSETS[direction(world.metadata(x, y, z))];
    for step in 0..=1 {
        let (x0, z0) = (x - dx * step - 1, z - dz * step - 1);
        for sx in x0..=x0 + 2 {
            for sz in z0..=z0 + 2 {
                if world.block(sx, y - 1, sz).is_normal_cube()
                    && world.block(sx, y, sz).is_air()
                    && world.block(sx, y + 1, sz).is_air()
                {
                    if skip == 0 {
                        return Some([sx, y, sz]);
                    }
                    skip -= 1;
                }
            }
        }
    }
    None
}