Paper/src/main/java/net/minecraft/server/BlockSign.java

package net.minecraft.server;

import java.util.Random;

import org.bukkit.event.block.BlockRedstoneEvent; // CraftBukkit

public class BlockSign extends BlockContainer {

    private Class a;
    private boolean b;

    protected BlockSign(Class oclass, boolean flag) {
        super(Material.WOOD);
        this.b = flag;
        this.a = oclass;
        float f = 0.25F;
        float f1 = 1.0F;

        this.a(0.5F - f, 0.0F, 0.5F - f, 0.5F + f, f1, 0.5F + f);
    }

    public AxisAlignedBB a(World world, int i, int j, int k) {
        return null;
    }

    public void updateShape(IBlockAccess iblockaccess, int i, int j, int k) {
        if (!this.b) {
            int l = iblockaccess.getData(i, j, k);
            float f = 0.28125F;
            float f1 = 0.78125F;
            float f2 = 0.0F;
            float f3 = 1.0F;
            float f4 = 0.125F;

            this.a(0.0F, 0.0F, 0.0F, 1.0F, 1.0F, 1.0F);
            if (l == 2) {
                this.a(f2, f, 1.0F - f4, f3, f1, 1.0F);
            }

            if (l == 3) {
                this.a(f2, f, 0.0F, f3, f1, f4);
            }

            if (l == 4) {
                this.a(1.0F - f4, f, f2, 1.0F, f1, f3);
            }

            if (l == 5) {
                this.a(0.0F, f, f2, f4, f1, f3);
            }
        }
    }

    public int b() {
        return -1;
    }

    public boolean d() {
        return false;
    }

    public boolean b(IBlockAccess iblockaccess, int i, int j, int k) {
        return true;
    }

    public boolean c() {
        return false;
    }

    public TileEntity a(World world, int i) {
        try {
            return (TileEntity) this.a.newInstance();
        } catch (Exception exception) {
            throw new RuntimeException(exception);
        }
    }

    public Item getDropType(int i, Random random, int j) {
        return Items.SIGN;
    }

    public void doPhysics(World world, int i, int j, int k, Block block) {
        boolean flag = false;

        if (this.b) {
            if (!world.getType(i, j - 1, k).getMaterial().isBuildable()) {
                flag = true;
            }
        } else {
            int l = world.getData(i, j, k);

            flag = true;
            if (l == 2 && world.getType(i, j, k + 1).getMaterial().isBuildable()) {
                flag = false;
            }

            if (l == 3 && world.getType(i, j, k - 1).getMaterial().isBuildable()) {
                flag = false;
            }

            if (l == 4 && world.getType(i + 1, j, k).getMaterial().isBuildable()) {
                flag = false;
            }

            if (l == 5 && world.getType(i - 1, j, k).getMaterial().isBuildable()) {
                flag = false;
            }
        }

        if (flag) {
            this.b(world, i, j, k, world.getData(i, j, k), 0);
            world.setAir(i, j, k);
        }

        super.doPhysics(world, i, j, k, block);

        // CraftBukkit start
        if (block != null && block.isPowerSource()) {
            org.bukkit.block.Block bukkitBlock = world.getWorld().getBlockAt(i, j, k);
            int power = bukkitBlock.getBlockPower();

            BlockRedstoneEvent eventRedstone = new BlockRedstoneEvent(bukkitBlock, power, power);
            world.getServer().getPluginManager().callEvent(eventRedstone);
        }
        // CraftBukkit end
    }
}