ViaVersion/common/src/main/java/com/viaversion/viaversion/rewriter/ComponentRewriter.java

/*
 * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
 * Copyright (C) 2016-2023 ViaVersion and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.viaversion.viaversion.rewriter;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSyntaxException;
import com.viaversion.viaversion.api.Via;
import com.viaversion.viaversion.api.protocol.Protocol;
import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
import com.viaversion.viaversion.api.type.Type;

/**
 * Handles json chat components, containing methods to override certain parts of the handling.
 * Also contains methods to register a few of the packets using components.
 */
public class ComponentRewriter<C extends ClientboundPacketType> {
    protected final Protocol<C, ?, ?, ?> protocol;

    public ComponentRewriter(Protocol<C, ?, ?, ?> protocol) {
        this.protocol = protocol;
    }

    /**
     * Use empty constructor if no packet registering is needed.
     */
    public ComponentRewriter() {
        this.protocol = null;
    }

    /**
     * Processes components at the beginning of the packet.
     * Used for packets that have components as their very first value, so no special pre-reading is necessary.
     *
     * @param packetType clientbound packet type
     */
    public void registerComponentPacket(C packetType) {
        protocol.registerClientbound(packetType, new PacketHandlers() {
            @Override
            public void register() {
                handler(wrapper -> processText(wrapper.passthrough(Type.COMPONENT)));
            }
        });
    }

    @Deprecated/*(forRemoval = true)**/
    public void registerChatMessage(C packetType) {
        registerComponentPacket(packetType);
    }

    public void registerBossBar(C packetType) {
        protocol.registerClientbound(packetType, new PacketHandlers() {
            @Override
            public void register() {
                map(Type.UUID);
                map(Type.VAR_INT);
                handler(wrapper -> {
                    int action = wrapper.get(Type.VAR_INT, 0);
                    if (action == 0 || action == 3) {
                        processText(wrapper.passthrough(Type.COMPONENT));
                    }
                });
            }
        });
    }

    /**
     * Handles sub 1.17 combat event components.
     */
    public void registerCombatEvent(C packetType) {
        protocol.registerClientbound(packetType, new PacketHandlers() {
            @Override
            public void register() {
                handler(wrapper -> {
                    if (wrapper.passthrough(Type.VAR_INT) == 2) {
                        wrapper.passthrough(Type.VAR_INT);
                        wrapper.passthrough(Type.INT);
                        processText(wrapper.passthrough(Type.COMPONENT));
                    }
                });
            }
        });
    }

    /**
     * Handles sub 1.17 title components.
     */
    public void registerTitle(C packetType) {
        protocol.registerClientbound(packetType, new PacketHandlers() {
            @Override
            public void register() {
                handler(wrapper -> {
                    int action = wrapper.passthrough(Type.VAR_INT);
                    if (action >= 0 && action <= 2) {
                        processText(wrapper.passthrough(Type.COMPONENT));
                    }
                });
            }
        });
    }

    public JsonElement processText(String value) {
        try {
            JsonElement root = JsonParser.parseString(value);
            processText(root);
            return root;
        } catch (JsonSyntaxException e) {
            if (Via.getManager().isDebug()) {
                Via.getPlatform().getLogger().severe("Error when trying to parse json: " + value);
                throw e;
            }
            // Yay to malformed json being accepted
            return new JsonPrimitive(value);
        }
    }

    public void processText(JsonElement element) {
        if (element == null || element.isJsonNull()) return;
        if (element.isJsonArray()) {
            processAsArray(element);
            return;
        }
        if (element.isJsonPrimitive()) {
            handleText(element.getAsJsonPrimitive());
            return;
        }

        JsonObject object = element.getAsJsonObject();
        JsonPrimitive text = object.getAsJsonPrimitive("text");
        if (text != null) {
            handleText(text);
        }

        JsonElement translate = object.get("translate");
        if (translate != null) {
            handleTranslate(object, translate.getAsString());

            JsonElement with = object.get("with");
            if (with != null) {
                processAsArray(with);
            }
        }

        JsonElement extra = object.get("extra");
        if (extra != null) {
            processAsArray(extra);
        }

        JsonObject hoverEvent = object.getAsJsonObject("hoverEvent");
        if (hoverEvent != null) {
            handleHoverEvent(hoverEvent);
        }
    }

    protected void handleText(JsonPrimitive text) {
        // To override if needed
    }

    protected void handleTranslate(JsonObject object, String translate) {
        // To override if needed
    }

    // To override if needed (don't forget to call super if needed)
    protected void handleHoverEvent(JsonObject hoverEvent) {
        String action = hoverEvent.getAsJsonPrimitive("action").getAsString();
        if (action.equals("show_text")) {
            JsonElement value = hoverEvent.get("value");
            processText(value != null ? value : hoverEvent.get("contents"));
        } else if (action.equals("show_entity")) {
            JsonObject contents = hoverEvent.getAsJsonObject("contents");
            if (contents != null) {
                processText(contents.get("name"));
            }
        }
    }

    private void processAsArray(JsonElement element) {
        for (JsonElement jsonElement : element.getAsJsonArray()) {
            processText(jsonElement);
        }
    }

    public <T extends Protocol<C, ?, ?, ?>> T getProtocol() {
        return (T) protocol;
    }
}