bazaarflux/src/main/java/me/lethunderhawk/dungeon/placement/SchematicRoomPlacer.java

package me.lethunderhawk.dungeon.placement;

import com.google.gson.Gson;
import com.google.gson.JsonParseException;
import com.sk89q.worldedit.EditSession;
import com.sk89q.worldedit.WorldEdit;
import com.sk89q.worldedit.extent.clipboard.Clipboard;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormat;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardFormats;
import com.sk89q.worldedit.extent.clipboard.io.ClipboardReader;
import com.sk89q.worldedit.function.operation.Operation;
import com.sk89q.worldedit.function.operation.Operations;
import com.sk89q.worldedit.math.BlockVector3;
import com.sk89q.worldedit.session.ClipboardHolder;
import com.sk89q.worldedit.bukkit.BukkitAdapter;
import me.lethunderhawk.world.util.schematic.Rotation;
import me.lethunderhawk.world.util.schematic.Vector3i;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.util.BoundingBox;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public final class SchematicRoomPlacer {

    private static final Gson GSON = new Gson();

    private SchematicRoomPlacer() {}

    /**
     * Places a room schematic at a given anchor.
     *
     * @param schematicFile .schem file
     * @param world Bukkit world
     * @param anchor anchor location (world-space origin)
     * @param rotation rotation (NONE, CLOCKWISE_90, CLOCKWISE_180, CLOCKWISE_270)
     * @return true if successfully validated and placed
     */
    public static boolean placeRoom(
            File schematicFile,
            World world,
            Location anchor,
            Rotation rotation
    ) {
        if(schematicFile == null) return false;
        if (!schematicFile.exists()) return false;

        RoomMetadata meta = loadMetadata(schematicFile);
        if (meta == null) return false;

        Clipboard clipboard = loadClipboard(schematicFile);
        if (clipboard == null) return false;

        BoundingBox box = meta.boundingBox.rotated(rotation).shift(anchor.toVector());
        //if (!isAreaClear(world, box)) return false;

        return pasteClipboard(clipboard, world, anchor, meta.anchor, rotation);
    }

    // ---------- Internal ----------

    private static Clipboard loadClipboard(File file) {
        ClipboardFormat format = ClipboardFormats.findByPath(file.getAbsoluteFile().toPath());
        if (format == null) return null;

        try (ClipboardReader reader = format.getReader(new java.io.FileInputStream(file))) {
            return reader.read();
        } catch (IOException e) {
            return null;
        }
    }

    private static RoomMetadata loadMetadata(File schematic) {
        File metaFile = new File(schematic.getParent(), schematic.getName().replace(".schem", ".json"));
        if (!metaFile.exists()) return null;

        try (FileReader reader = new FileReader(metaFile)) {
            return GSON.fromJson(reader, RoomMetadata.class);
        } catch (IOException | JsonParseException e) {
            return null;
        }
    }

    private static boolean isAreaClear(World world, BoundingBox box) {
        int minX = (int) box.getMinX();
        int minY = (int) box.getMinY();
        int minZ = (int) box.getMinZ();
        int maxX = (int) box.getMaxX();
        int maxY = (int) box.getMaxY();
        int maxZ = (int) box.getMaxZ();

        for (int x = minX; x <= maxX; x++) {
            for (int y = minY; y <= maxY; y++) {
                for (int z = minZ; z <= maxZ; z++) {

                    if (!world.getBlockAt(x, y, z).isEmpty()) {
                        return false;
                    }
                }
            }
        }
        return true;
    }

    private static boolean pasteClipboard(
            Clipboard clipboard,
            World world,
            Location anchor,
            Vector3i schematicAnchor,
            Rotation rotation
    ) {
        com.sk89q.worldedit.world.World weWorld = BukkitAdapter.adapt(world);

        BlockVector3 pastePos = BlockVector3.at(
                anchor.getBlockX() - schematicAnchor.x(),
                anchor.getBlockY() - schematicAnchor.y(),
                anchor.getBlockZ() - schematicAnchor.z()
        );

        try (EditSession session = WorldEdit.getInstance()
                .newEditSessionBuilder()
                .world(weWorld)
                .build()) {

            ClipboardHolder holder = new ClipboardHolder(clipboard);
            holder.setTransform(holder.getTransform().combine(rotation.toTransform()));

            Operation op = holder
                    .createPaste(session)
                    .to(pastePos)
                    .ignoreAirBlocks(true)
                    .build();

            Operations.complete(op);
            session.close();
            return true;

        } catch (Exception e) {
            return false;
        }
    }
}