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

package net.minecraft.server;

import java.util.Random;
// CraftBukkit start
import org.bukkit.BlockChangeDelegate;
import org.bukkit.Bukkit;
import org.bukkit.block.BlockState;
import org.bukkit.craftbukkit.CraftWorld;
import org.bukkit.event.world.StructureGrowEvent;
import org.bukkit.material.MaterialData;
// CraftBukkit end

public class WorldGenHugeMushroom extends WorldGenerator implements BlockSapling.TreeGenerator { // CraftBukkit - add interface

    private int a = -1;

    public WorldGenHugeMushroom(int i) {
        super(true);
        this.a = i;
    }

    public WorldGenHugeMushroom() {
        super(false);
    }

    // CraftBukkit start - delegate to generate() and use BlockChangeDelegate
    public boolean a(World world, Random random, int i, int j, int k) {
        return grow((BlockChangeDelegate) world, random, i, j, k, null, null, null);
    }

    public boolean generate(BlockChangeDelegate world, Random random, int i, int j, int k) {
        return grow(world, random, i, j, k, null, null, null);
    }

    public boolean grow(BlockChangeDelegate world, Random random, int i, int j, int k, StructureGrowEvent event, ItemStack itemstack, CraftWorld bukkitWorld) {
        // CraftBukkit end
        int l = random.nextInt(2);

        if (this.a >= 0) {
            l = this.a;
        }

        int i1 = random.nextInt(3) + 4;
        boolean flag = true;

        if (j >= 1 && j + i1 + 1 < 256) {
            int j1;
            int k1;
            int l1;
            int i2;

            for (j1 = j; j1 <= j + 1 + i1; ++j1) {
                byte b0 = 3;

                if (j1 == j) {
                    b0 = 0;
                }

                for (k1 = i - b0; k1 <= i + b0 && flag; ++k1) {
                    for (l1 = k - b0; l1 <= k + b0 && flag; ++l1) {
                        if (j1 >= 0 && j1 < 256) {
                            i2 = world.getTypeId(k1, j1, l1);
                            if (i2 != 0 && i2 != Block.LEAVES.id) {
                                flag = false;
                            }
                        } else {
                            flag = false;
                        }
                    }
                }
            }

            if (!flag) {
                return false;
            } else {
                j1 = world.getTypeId(i, j - 1, k);
                if (j1 != Block.DIRT.id && j1 != Block.GRASS.id && j1 != Block.MYCEL.id) {
                    return false;
                // CraftBukkit - Adjust canPlace check to handle non-World BlockChangeDelegates (orig check was: !Block.BROWN_MUSHROOM.canPlace(world, i, j, k))
                } else if ((world.getTypeId(i, j, k) != 0 && !Block.byId[world.getTypeId(i, j, k)].material.isReplacable()) || (world instanceof World && !Block.BROWN_MUSHROOM.canPlace((World) world, i, j, k))) {
                    return false;
                } else {
                    // CraftBukkit start
                    if (event == null) {
                        this.setTypeAndData(world, i, j - 1, k, Block.DIRT.id, 0);
                    } else {
                        BlockState dirtState = bukkitWorld.getBlockAt(i, j - 1, k).getState();
                        dirtState.setTypeId(Block.DIRT.id);
                        event.getBlocks().add(dirtState);
                    }
                    // CraftBukkit end
                    int j2 = j + i1;

                    if (l == 1) {
                        j2 = j + i1 - 3;
                    }

                    for (k1 = j2; k1 <= j + i1; ++k1) {
                        l1 = 1;
                        if (k1 < j + i1) {
                            ++l1;
                        }

                        if (l == 0) {
                            l1 = 3;
                        }

                        for (i2 = i - l1; i2 <= i + l1; ++i2) {
                            for (int k2 = k - l1; k2 <= k + l1; ++k2) {
                                int l2 = 5;

                                if (i2 == i - l1) {
                                    --l2;
                                }

                                if (i2 == i + l1) {
                                    ++l2;
                                }

                                if (k2 == k - l1) {
                                    l2 -= 3;
                                }

                                if (k2 == k + l1) {
                                    l2 += 3;
                                }

                                if (l == 0 || k1 < j + i1) {
                                    if ((i2 == i - l1 || i2 == i + l1) && (k2 == k - l1 || k2 == k + l1)) {
                                        continue;
                                    }

                                    if (i2 == i - (l1 - 1) && k2 == k - l1) {
                                        l2 = 1;
                                    }

                                    if (i2 == i - l1 && k2 == k - (l1 - 1)) {
                                        l2 = 1;
                                    }

                                    if (i2 == i + (l1 - 1) && k2 == k - l1) {
                                        l2 = 3;
                                    }

                                    if (i2 == i + l1 && k2 == k - (l1 - 1)) {
                                        l2 = 3;
                                    }

                                    if (i2 == i - (l1 - 1) && k2 == k + l1) {
                                        l2 = 7;
                                    }

                                    if (i2 == i - l1 && k2 == k + (l1 - 1)) {
                                        l2 = 7;
                                    }

                                    if (i2 == i + (l1 - 1) && k2 == k + l1) {
                                        l2 = 9;
                                    }

                                    if (i2 == i + l1 && k2 == k + (l1 - 1)) {
                                        l2 = 9;
                                    }
                                }

                                if (l2 == 5 && k1 < j + i1) {
                                    l2 = 0;
                                }

                                if ((l2 != 0 || j >= j + i1 - 1) && !Block.n[world.getTypeId(i2, k1, k2)]) {
                                    // CraftBukkit start
                                    if (event == null) {
                                       this.setTypeAndData(world, i2, k1, k2, Block.BIG_MUSHROOM_1.id + l, l2);
                                    } else {
                                        BlockState state = bukkitWorld.getBlockAt(i2, k1, k2).getState();
                                        state.setTypeId(Block.BIG_MUSHROOM_1.id + l);
                                        state.setData(new MaterialData(Block.BIG_MUSHROOM_1.id + l, (byte) l2));
                                        event.getBlocks().add(state);
                                    }
                                    // CraftBukkit end
                                }
                            }
                        }
                    }

                    for (k1 = 0; k1 < i1; ++k1) {
                        l1 = world.getTypeId(i, j + k1, k);
                        if (!Block.n[l1]) {
                            // CraftBukkit start
                            if (event == null) {
                                this.setTypeAndData(world, i, j + k1, k, Block.BIG_MUSHROOM_1.id + l, 10);
                            } else {
                                BlockState state = bukkitWorld.getBlockAt(i, j + k1, k).getState();
                                state.setTypeId(Block.BIG_MUSHROOM_1.id + l);
                                state.setData(new MaterialData(Block.BIG_MUSHROOM_1.id + l, (byte) 10));
                                event.getBlocks().add(state);
                            }
                            // CraftBukkit end
                        }
                    }
                    // CraftBukkit start
                    if (event != null) {
                        Bukkit.getPluginManager().callEvent(event);
                        if (!event.isCancelled()) {
                            for (BlockState state : event.getBlocks()) {
                                state.update(true);
                            }
                        }
                    }
                    // CraftBukkit end

                    return true;
                }
            }
        } else {
            return false;
        }
    }
}