Add changers to ExprBookPages

src/main/java/ch/njol/skript/expressions/ExprBookPages.java

@@ -21,94 +21,162 @@
 import ch.njol.skript.Skript;
 import ch.njol.skript.aliases.Aliases;
 import ch.njol.skript.aliases.ItemType;
+import ch.njol.skript.classes.Changer.ChangeMode;
 import ch.njol.skript.doc.Description;
 import ch.njol.skript.doc.Examples;
 import ch.njol.skript.doc.Name;
 import ch.njol.skript.doc.Since;
+import ch.njol.skript.expressions.base.PropertyExpression;
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.ExpressionType;
 import ch.njol.skript.lang.SkriptParser;
 import ch.njol.skript.lang.util.SimpleExpression;
 import ch.njol.util.Kleenean;
+import ch.njol.util.coll.CollectionUtils;
 import org.bukkit.event.Event;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
+import org.bukkit.inventory.meta.ItemMeta;
 import org.eclipse.jdt.annotation.Nullable;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 @Name("Book Pages")
 @Description("The pages of a book.")
-@Examples({"on book sign:",
-			"\tmessage \"Book Pages: %pages of event-item%\"",
-			"\tmessage \"Book Page 1: %page 1 of event-item%\""})
-@Since("2.2-dev31")
-public class ExprBookPages extends SimpleExpression<String> {
-
+@Examples({
+	"on book sign:",
+	"\tmessage \"Book Pages: %pages of event-item%\"",
+	"\tmessage \"Book Page 1: %page 1 of event-item%\"",
+	"set page 1 of player's held item to \"Book writing\""
+})
+@Since("2.2-dev31, INSERT VERSION (changers)")
+public class ExprBookPages extends PropertyExpression<ItemType, String> {
+
 	static {
 		Skript.registerExpression(ExprBookPages.class, String.class, ExpressionType.PROPERTY,
-				"[all] [the] [book] (pages|content) of %itemtypes%",
-				"%itemtypes%'s [book] (pages|content)",
-				"[book] page %number% of %itemtypes%", 
-				"%itemtypes%'s [book] page %number%");
+			"[(all [[of] the]|the)] [book] (pages|content) of %itemtypes%",
+			"%itemtypes%'[s] [book] (pages|content)",
+			"[book] page %number% of %itemtypes%",
+			"%itemtypes%'[s] [book] page %number%");
 	}
-
-	private static final ItemType bookItem = Aliases.javaItemType("book with text");
-
-	@SuppressWarnings("null")
-	private Expression<ItemType> book;
+
 	@Nullable
 	private Expression<Number> page;
-	
+
 	@SuppressWarnings("null")
 	@Nullable
 	@Override
-	protected String[] get(Event e) {
-		ItemStack itemStack = book.getSingle(e).getRandom();
-		if (itemStack == null || !bookItem.isOfType(itemStack))
-			return null;
-		List<String> pages = ((BookMeta) itemStack.getItemMeta()).getPages();
-		if (page != null){
-			Number pageNumber = page.getSingle(e);
-			if (pageNumber == null){
-				return null;
+	protected String[] get(Event event, ItemType[] source) {
+		List<String> pages = new ArrayList<>();
+		for (ItemType itemType : source) {
+			ItemMeta meta = itemType.getItemMeta();
+			if (!(meta instanceof BookMeta))
+				continue;
+			BookMeta bookMeta = (BookMeta) meta;
+			if (page == null) {
+				pages.addAll(bookMeta.getPages());
+			} else {
+				Number pageNumber = page.getSingle(event);
+				if (pageNumber == null)
+					continue;
+				int page = pageNumber.intValue();
+				if (page <= 0 || page > bookMeta.getPageCount())
+					continue;
+				pages.add(bookMeta.getPage(page));
 			}
-			int page = pageNumber.intValue();
-			if ((page) > pages.size() || page < 1){
+		}
+		return pages.toArray(new String[0]);
+	}
+
+	@Nullable
+	@Override
+	public Class<?>[] acceptChange(ChangeMode mode) {
+		switch (mode) {
+			case SET:
+			case RESET:
+			case DELETE:
+				return CollectionUtils.array(page == null ? String[].class : String.class);
+			case ADD:
+				return page == null ? CollectionUtils.array(String[].class) : null;
+			default:
 				return null;
-			}
-			return new String[]{pages.get(page - 1)};
-		}else{
-			return pages.toArray(new String[pages.size()]);
 		}
 	}
-	
+
 	@Override
-	public boolean isSingle() {
-		return page != null;
+	public void change(Event event, @Nullable Object[] delta, ChangeMode mode) {
+		ItemType[] itemTypes = getExpr().getArray(event);
+		int page = this.page == null ? -1 : this.page.getOptionalSingle(event).orElse(-1).intValue();
+		String[] newPages = delta == null ? null : new String[delta.length];
+		if (newPages != null)
+			for (int i = 0; i < delta.length; i++)
+				newPages[i] = delta[i] + "";
+		for (ItemType itemType : itemTypes) {
+			if (itemType == null)
+				continue;
+			ItemMeta meta = itemType.getItemMeta();
+			if (!(meta instanceof BookMeta))
+				continue;
+			BookMeta bookMeta = (BookMeta) meta;
+			List<String> pages = new ArrayList<>(bookMeta.getPages());
+			int pageCount = bookMeta.getPageCount();
+			switch (mode) {
+				case DELETE:
+				case RESET:
+					if (this.page == null) {
+						pages = Arrays.asList("");
+					} else {
+						if (page <= 0 || page > pageCount)
+							continue;
+						pages.remove(page - 1);
+					}
+					break;
+				case SET:
+					if (newPages.length == 0)
+						continue;
+					if (this.page == null) {
+						pages = Arrays.asList(newPages);
+					} else {
+						if (page <= 0)
+							continue;
+						while (pages.size() < page) {
+							pages.add("");
+						}
+						pages.set(page - 1, newPages[0]);
+					}
+					break;
+				case ADD:
+					pages.addAll(Arrays.asList(newPages));
+					break;
+			}
+			bookMeta.setPages(pages);
+			itemType.setItemMeta(bookMeta);
+		}
 	}
-	
+
 	@Override
 	public Class<? extends String> getReturnType() {
 		return String.class;
 	}
-	
+
 	@Override
-	public String toString(@Nullable Event e, boolean debug) {
-		return "book pages of " + book.toString(e, debug);
+	public String toString(@Nullable Event event, boolean debug) {
+		return "book pages of " + getExpr().toString(event, debug);
 	}
-	
+
 	@SuppressWarnings({"unchecked", "null"})
 	@Override
 	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
-		if (matchedPattern == 0 || matchedPattern == 1){
-			book = (Expression<ItemType>) exprs[0];
-		}else{
-			if (matchedPattern == 2){
-				page =(Expression<Number>) exprs[0];
-				book = (Expression<ItemType>) exprs[1];
-			}else{
-				book = (Expression<ItemType>) exprs[0];
+		if (matchedPattern == 0 || matchedPattern == 1) {
+			setExpr((Expression<ItemType>) exprs[0]);
+		} else {
+			if (matchedPattern == 2) {
+				page = (Expression<Number>) exprs[0];
+				setExpr((Expression<ItemType>) exprs[1]);
+			} else {
+				setExpr((Expression<ItemType>) exprs[0]);
 				page = (Expression<Number>) exprs[1];
 			}
 		}