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

package net.minecraft.server;

public class ItemWorldMap extends ItemWorldMapBase {

    protected ItemWorldMap(int i) {
        super(i);
        this.c(1);
    }

    public WorldMap a(ItemStack itemstack, World world) {

        WorldMap worldmap = (WorldMap) world.a(WorldMap.class, "map_" + itemstack.getData());

        if (worldmap == null) {
            itemstack.b(world.b("map"));
            String s = "map_" + itemstack.getData();

            worldmap = new WorldMap(s);
            worldmap.b = world.q().c();
            worldmap.c = world.q().e();
            worldmap.e = 3;
            worldmap.map = (byte) world.worldProvider.dimension;
            worldmap.a();
            world.a(s, (WorldMapBase) worldmap);
        }

        return worldmap;
    }

    public void a(World world, Entity entity, WorldMap worldmap) {
        if (((WorldServer) world).dimension == worldmap.map) { // CraftBukkit
            short short1 = 128;
            short short2 = 128;
            int i = 1 << worldmap.e;
            int j = worldmap.b;
            int k = worldmap.c;
            int l = MathHelper.floor(entity.locX - (double) j) / i + short1 / 2;
            int i1 = MathHelper.floor(entity.locZ - (double) k) / i + short2 / 2;
            int j1 = 128 / i;

            if (world.worldProvider.e) {
                j1 /= 2;
            }

            ++worldmap.g;

            for (int k1 = l - j1 + 1; k1 < l + j1; ++k1) {
                if ((k1 & 15) == (worldmap.g & 15)) {
                    int l1 = 255;
                    int i2 = 0;
                    double d0 = 0.0D;

                    for (int j2 = i1 - j1 - 1; j2 < i1 + j1; ++j2) {
                        if (k1 >= 0 && j2 >= -1 && k1 < short1 && j2 < short2) {
                            int k2 = k1 - l;
                            int l2 = j2 - i1;
                            boolean flag = k2 * k2 + l2 * l2 > (j1 - 2) * (j1 - 2);
                            int i3 = (j / i + k1 - short1 / 2) * i;
                            int j3 = (k / i + j2 - short2 / 2) * i;
                            byte b0 = 0;
                            byte b1 = 0;
                            byte b2 = 0;
                            int[] aint = new int[256];
                            Chunk chunk = world.getChunkAtWorldCoords(i3, j3);
                            int k3 = i3 & 15;
                            int l3 = j3 & 15;
                            int i4 = 0;
                            double d1 = 0.0D;
                            int j4;
                            int k4;
                            int l4;
                            int i5;

                            if (world.worldProvider.e) {
                                l4 = i3 + j3 * 231871;
                                l4 = l4 * l4 * 31287121 + l4 * 11;
                                if ((l4 >> 20 & 1) == 0) {
                                    aint[Block.DIRT.id] += 10;
                                } else {
                                    aint[Block.STONE.id] += 10;
                                }

                                d1 = 100.0D;
                            } else {
                                for (l4 = 0; l4 < i; ++l4) {
                                    for (j4 = 0; j4 < i; ++j4) {
                                        k4 = chunk.b(l4 + k3, j4 + l3) + 1;
                                        int j5 = 0;

                                        if (k4 > 1) {
                                            boolean flag1 = false;

                                            do {
                                                flag1 = true;
                                                j5 = chunk.getTypeId(l4 + k3, k4 - 1, j4 + l3);
                                                if (j5 == 0) {
                                                    flag1 = false;
                                                } else if (k4 > 0 && j5 > 0 && Block.byId[j5].material.C == MaterialMapColor.b) {
                                                    flag1 = false;
                                                }

                                                if (!flag1) {
                                                    --k4;
                                                    if (k4 <= 0) break; // CraftBukkit
                                                    j5 = chunk.getTypeId(l4 + k3, k4 - 1, j4 + l3);
                                                }
                                            } while (!flag1);

                                            if (j5 != 0 && Block.byId[j5].material.isLiquid()) {
                                                i5 = k4 - 1;
                                                boolean flag2 = false;

                                                int k5;

                                                do {
                                                    k5 = chunk.getTypeId(l4 + k3, i5--, j4 + l3);
                                                    ++i4;
                                                } while (i5 > 0 && k5 != 0 && Block.byId[k5].material.isLiquid());
                                            }
                                        }

                                        d1 += (double) k4 / (double) (i * i);
                                        ++aint[j5];
                                    }
                                }
                            }

                            i4 /= i * i;
                            int l5 = b0 / (i * i);

                            l5 = b1 / (i * i);
                            l5 = b2 / (i * i);
                            l4 = 0;
                            j4 = 0;

                            for (k4 = 0; k4 < 256; ++k4) {
                                if (aint[k4] > l4) {
                                    j4 = k4;
                                    l4 = aint[k4];
                                }
                            }

                            double d2 = (d1 - d0) * 4.0D / (double) (i + 4) + ((double) (k1 + j2 & 1) - 0.5D) * 0.4D;
                            byte b3 = 1;

                            if (d2 > 0.6D) {
                                b3 = 2;
                            }

                            if (d2 < -0.6D) {
                                b3 = 0;
                            }

                            i5 = 0;
                            if (j4 > 0) {
                                MaterialMapColor materialmapcolor = Block.byId[j4].material.C;

                                if (materialmapcolor == MaterialMapColor.n) {
                                    d2 = (double) i4 * 0.1D + (double) (k1 + j2 & 1) * 0.2D;
                                    b3 = 1;
                                    if (d2 < 0.5D) {
                                        b3 = 2;
                                    }

                                    if (d2 > 0.9D) {
                                        b3 = 0;
                                    }
                                }

                                i5 = materialmapcolor.q;
                            }

                            d0 = d1;
                            if (j2 >= 0 && k2 * k2 + l2 * l2 < j1 * j1 && (!flag || (k1 + j2 & 1) != 0)) {
                                byte b4 = worldmap.f[k1 + j2 * short1];
                                byte b5 = (byte) (i5 * 4 + b3);

                                if (b4 != b5) {
                                    if (l1 > j2) {
                                        l1 = j2;
                                    }

                                    if (i2 < j2) {
                                        i2 = j2;
                                    }

                                    worldmap.f[k1 + j2 * short1] = b5;
                                }
                            }
                        }
                    }

                    if (l1 <= i2) {
                        worldmap.a(k1, l1, i2);
                    }
                }
            }
        }
    }

    public void a(ItemStack itemstack, World world, Entity entity, int i, boolean flag) {
        if (!world.isStatic) {
            WorldMap worldmap = this.a(itemstack, world);

            if (entity instanceof EntityHuman) {
                EntityHuman entityhuman = (EntityHuman) entity;

                worldmap.a(entityhuman, itemstack);
            }

            if (flag) {
                this.a(world, entity, worldmap);
            }
        }
    }

    public void c(ItemStack itemstack, World world, EntityHuman entityhuman) {
        itemstack.b(world.b("map"));
        String s = "map_" + itemstack.getData();
        WorldMap worldmap = new WorldMap(s);

        world.a(s, (WorldMapBase) worldmap);
        worldmap.b = MathHelper.floor(entityhuman.locX);
        worldmap.c = MathHelper.floor(entityhuman.locZ);
        worldmap.e = 3;
        worldmap.map = (byte) ((WorldServer) world).dimension; // CraftBukkit
        worldmap.a();
    }

    public Packet b(ItemStack itemstack, World world, EntityHuman entityhuman) {
        byte[] abyte = this.a(itemstack, world).a(itemstack, world, entityhuman);

        return abyte == null ? null : new Packet131((short) Item.MAP.id, (short) itemstack.getData(), abyte);
    }
}