beerpsi-x/patchers/_parser.ts

import vm from "node:vm";
import * as cheerio from "npm:cheerio";
import { BemaniPatch, BemaniPatcherArgs } from "./_types.ts";

export function bytesToHex(bytes: number[]) {
    return bytes.map((b) => b.toString(16).padStart(2, "0").toUpperCase()).join(
        "",
    );
}

export function parsePatcherHtml(filename: string, contents: string) {
    const $ = cheerio.load(contents);

    let script = "";

    for (const element of $("script").get()) {
        const code = $(element).html();

        if (!code?.includes("new Patcher")) {
            continue;
        }

        script += code;
        script += "\n";
    }

    if (script.length === 0) {
        console.warn(
            `Failed to find any BemaniPatcher patches in ${filename}.`,
        );
        return [];
    }

    const patchers: BemaniPatcherArgs[] = [];
    const context = {
        window: {
            addEventListener: (_type: string, listener: () => unknown) =>
                listener(),
        },
        Patcher: class {
            constructor(
                fname: string,
                description: string,
                patches: BemaniPatch[],
            ) {
                patchers.push({ fname, description, patches });
            }
        },
        PatchContainer: class {
            constructor(_patchers: unknown[]) {}
        },
    };

    vm.createContext(context);
    vm.runInContext(script, context);

    return patchers;
}