Add part placement preview, render all part boxes on hover (#349)

src/api/java/appeng/api/parts/IFacadeContainer.java

@@ -41,6 +41,13 @@ import appeng.api.util.AEPartLocation;
 public interface IFacadeContainer
 {
 
+	/**
+	 * Checks if the {@link IFacadePart} can be added to the given side.
+	 *
+	 * @return true if the facade can be successfully added
+	 */
+	boolean canAddFacade( IFacadePart a );
+
 	/**
 	 * Attempts to add the {@link IFacadePart} to the given side.
 	 *

src/api/java/appeng/api/parts/IPartHelper.java

@@ -24,6 +24,7 @@
 package appeng.api.parts;
 
 
+import appeng.api.util.AEPartLocation;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumActionResult;
@@ -32,6 +33,8 @@ import net.minecraft.util.EnumHand;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
 
+import javax.annotation.Nullable;
+
 
 public interface IPartHelper
 {
@@ -53,4 +56,51 @@ public interface IPartHelper
 	 * @return the render mode
 	 */
 	CableRenderMode getCableRenderMode();
+
+	/**
+	 * Try to get a part at a specific place in the world.
+	 *
+	 * @param w    world the part is in
+	 * @param pos  pos of the part host
+	 * @param side side to test for a part on.
+	 *
+	 * @return the part if it exists, null otherwise
+	 */
+	@Nullable
+	IPart getPart( World w, BlockPos pos, AEPartLocation side );
+
+	/**
+	 * Try to get a part host at a specific place in the world.
+	 *
+	 * @param w   world the part host is in
+	 * @param pos pos of the part host
+	 *
+	 * @return the part host if it exists, null otherwise
+	 */
+	@Nullable
+	IPartHost getPartHost( World w, BlockPos pos );
+
+	/**
+	 * Get a part host if it exists, or place one if it doesn't.
+	 *
+	 * @param w     world the part host is in
+	 * @param pos   pos to get or place the part host
+	 * @param force whether to skip permission and existing block checks and forcibly place the part host here.
+	 * @param p     the placing player, or null if none
+	 *
+	 * @return the existing or created part host, or null if it didn't already exist and part host is unable to be placed.
+	 */
+	@Nullable
+	IPartHost getOrPlacePartHost( World w, BlockPos pos, boolean force, @Nullable EntityPlayer p );
+
+	/**
+	 * Test if a part host can be successfully placed at a given position by the provided player.
+	 *
+	 * @param w   world the part host is in
+	 * @param pos pos to test for part host placement
+	 * @param p   the placing player, or null if none
+	 *
+	 * @return if the part can be placed at the provided world and position
+	 */
+	boolean canPlacePartHost( World w, BlockPos pos, @Nullable EntityPlayer p );
 }

src/api/java/appeng/api/parts/IPartHost.java

@@ -145,6 +145,17 @@ public interface IPartHost extends ICustomCableConnection
 	 */
 	SelectedPart selectPart( Vec3d pos );
 
+	/**
+	 * Same as {@link #selectPart(Vec3d)}, but with global instead of local coordinates.
+	 */
+	default SelectedPart selectPartGlobal( Vec3d pos ) {
+		DimensionalCoord globalPos = getLocation();
+		return selectPart(pos.subtract(
+				globalPos.getPos().getX(),
+				globalPos.getPos().getY(),
+				globalPos.getPos().getZ()));
+	}
+
 	/**
 	 * can be used by parts to trigger the tile or part to save.
 	 */