package net.rustnotmc.protocol;

/**
 * The block ids a world is made of.
 *
 * These live in the protocol rather than in the server because they are the
 * vocabulary of the wire: a chunk that arrives at the client is a byte per
 * block, and both ends have to agree on what each byte means. A server that
 * invented its own ids would leave the client guessing.
 *
 * Kept as plain constants rather than an enum so that a chunk can store them in
 * a byte array. A world holding an enum per block costs sixteen bytes a block
 * and a garbage collector problem for every chunk that moves.
 *
 * The ids do not have to match anything right now. What matters is that they are
 * stable, because they go into save files and onto the wire, and that air is
 * zero, because every "is this chunk generated" shortcut in the code assumes it.
 */
public final class Blocks {

    public static final byte AIR = 0;
    public static final byte STONE = 1;
    public static final byte DIRT = 2;
    public static final byte GRASS = 3;
    public static final byte SAND = 4;
    public static final byte WATER = 5;
    public static final byte WOOD = 6;
    public static final byte LEAVES = 7;

    /** Lowest and highest legal block id. */
    public static final byte MIN = AIR;
    public static final byte MAX = LEAVES;

    private Blocks() {
    }

    public static String name(byte id) {
        switch (id) {
            case AIR: return "air";
            case STONE: return "stone";
            case DIRT: return "dirt";
            case GRASS: return "grass";
            case SAND: return "sand";
            case WATER: return "water";
            case WOOD: return "wood";
            case LEAVES: return "leaves";
            default: return "unknown(" + id + ")";
        }
    }

    /** True when a player can walk through it. */
    public static boolean isPassable(byte id) {
        return id == AIR || id == WATER;
    }

    /** True when light passes through it. */
    public static boolean isTransparent(byte id) {
        return id == AIR || id == WATER;
    }

    public static boolean isValid(byte id) {
        return id >= MIN && id <= MAX;
    }
}