#!/usr/bin/env node
/**
 * cdp_script_source.js —— 用 CDP Debugger 取某个标签页里**已解析脚本**的原文。
 *
 * 为什么需要它（而不是再 fetch 一次）:
 *   `tdc.js?app_data=..&t=..` **每次请求返回不同构建**, 所以"再抓一次"拿不到当前会话
 *   正在跑的那一份。只有 Debugger.scriptParsed + Debugger.getScriptSource 能拿到**运行时
 *   真正执行的那份源码**（缓存命中也不影响）。
 *
 * 零依赖 (Node >= 22 内置 WebSocket/fetch)。
 *
 * 用法:
 *   node tools/cdp_script_source.js --match drag_ele --url-substr tdc.js --out /tmp/build.js
 *   node tools/cdp_script_source.js --match drag_ele --list
 */
const fs = require('fs');

function arg(name, def) {
    const i = process.argv.indexOf('--' + name);
    if (i < 0) return def;
    const v = process.argv[i + 1];
    return (v === undefined || v.startsWith('--')) ? true : v;
}

class Cdp {
    constructor(ws) { this.ws = ws; this.id = 0; this.waits = new Map(); this.handlers = []; }
    static async connect(url) {
        const ws = new WebSocket(url);
        await new Promise((res, rej) => { ws.onopen = res; ws.onerror = rej; });
        const c = new Cdp(ws);
        ws.onmessage = ev => {
            const m = JSON.parse(ev.data);
            if (m.id && c.waits.has(m.id)) {
                const { res, rej } = c.waits.get(m.id);
                c.waits.delete(m.id);
                m.error ? rej(new Error(JSON.stringify(m.error))) : res(m.result);
            } else if (m.method) {
                for (const h of c.handlers) h(m);
            }
        };
        return c;
    }
    send(method, params = {}) {
        const id = ++this.id;
        this.ws.send(JSON.stringify({ id, method, params }));
        return new Promise((res, rej) => this.waits.set(id, { res, rej }));
    }
    on(fn) { this.handlers.push(fn); }
    close() { try { this.ws.close(); } catch (e) {} }
}
const sleep = ms => new Promise(r => setTimeout(r, ms));

(async () => {
    const port = parseInt(arg('port', '9222'), 10);
    const match = arg('match', null);
    const substr = arg('url-substr', null);
    const wait = parseInt(arg('wait', '1500'), 10);

    const targets = (await (await fetch(`http://127.0.0.1:${port}/json/list`)).json())
        .filter(t => t.type === 'page' || t.type === 'iframe');
    let target = match ? targets.find(t => (t.url || '').includes(match)) : targets[0];
    if (!target) throw new Error('没有可用标签页');

    const cdp = await Cdp.connect(target.webSocketDebuggerUrl);
    const scripts = [];
    cdp.on(m => { if (m.method === 'Debugger.scriptParsed') scripts.push(m.params); });
    await cdp.send('Debugger.enable');
    await sleep(wait);                       // 等已经跑过的脚本被重新上报
    await cdp.send('Runtime.enable');
    await cdp.send('Runtime.evaluate', { expression: '1' });   // 触发一次上下文

    if (arg('list', false)) {
        for (const s of scripts) console.log(`${String(s.url || '').slice(0, 120)}\t${s.length}B`);
        cdp.close();
        return;
    }
    const hits = scripts.filter(s => substr ? String(s.url || '').includes(substr) : true);
    if (!hits.length) throw new Error(`没找到匹配 ${substr} 的已解析脚本 (共 ${scripts.length} 个)`);
    const pick = hits[hits.length - 1];
    const r = await cdp.send('Debugger.getScriptSource', { scriptId: pick.scriptId });
    const out = arg('out', '/tmp/cdp_script.js');
    fs.writeFileSync(out, r.scriptSource, 'utf8');
    console.log(JSON.stringify({ ok: true, url: pick.url, length: r.scriptSource.length, out,
                                 candidates: hits.map(h => String(h.url).slice(0, 90)) }, null, 1));
    cdp.close();
})().catch(e => { console.error('CDP_ERROR: ' + e.message); process.exit(1); });