leonitousconforti/tinyburg

import "frida-il2cpp-bridge";

import type { ISubscribeToMusicStatusAgent1Exports } from "./shared.js";
import { TinyTowerFridaAgent } from "../../src/agents/base-frida-agent.js";

/**
 * This agent showcases how to subscribe to information changes in the game. In
 * this case, it will alert if the music setting in the settings menu changes.
 *
 * While this could be achieved by polling the desired field very frequently,
 * there is a more elegant solution in my mind. Using frida MemoryAccessMonitor
 * we can watch regions of memory and be alerted when they are accessed or
 * modified. Then we can pass that alert through frida rpc channel to the
 * node.js side
 */
export class SubscribeToMusicStatusAgent1 extends TinyTowerFridaAgent<SubscribeToMusicStatusAgent1> {
    private readonly _notificationCallback: (status: boolean) => void;

    public constructor(
        onAccessCallback: (status: boolean) => void,
        oadDependenciesMaxRetries?: number,
        loadDependenciesWaitMs?: number
    ) {
        super(oadDependenciesMaxRetries, loadDependenciesWaitMs);
        this._notificationCallback = onAccessCallback;
    }

    public loadDependencies() {
        const csharpAssembly = Il2Cpp.domain.assembly("Assembly-CSharp");
        const VPlayerClass = csharpAssembly.image.class("VPlayer");
        const musicEnabledField = VPlayerClass.field<boolean>("musicEnabled");
        return { csharpAssembly, VPlayerClass, musicEnabledField };
    }

    public retrieveData() {
        const memoryRange = { base: this.dependencies.musicEnabledField.handle, size: 1 };
        const callbacks = {
            onAccess: (details: MemoryAccessDetails) => {
                send(details);
                this._notificationCallback(this.dependencies.musicEnabledField.value);
            },
        };
        MemoryAccessMonitor.enable(memoryRange, callbacks);
    }
}

/**
 * Defines the public interface of this agent, i.e what methods and properties
 * will be available over the frida rpc channel. In this case, only a main
 * function is exposed, which will create a new instance of the agent and starts
 * it. The start method takes care of everything from retrying dependency
 * loading to calling the retrieve data method.
 */
const rpcExports: ISubscribeToMusicStatusAgent1Exports = {
    main: async (notificationCallback) => {
        await new SubscribeToMusicStatusAgent1(notificationCallback).start();
    },
};
rpc.exports = rpcExports as unknown as RpcExports;