/**
 * 检查文章页代码块在窄屏下的滚动行为。
 *
 * 期望：代码块自身横向滚动（overflow-x: auto），
 * 而不是把整个页面撑出横向滚动条。
 *
 * 用法：CDP_WS=<ws地址> node scripts/check-code-blocks.mjs <url> <width>
 */

const [, , targetUrl, widthArg = "390"] = process.argv;
const width = Number(widthArg);

const wsUrl = process.env.CDP_WS;
if (!wsUrl) {
	console.error("缺少 CDP_WS 环境变量");
	process.exit(1);
}

const socket = new WebSocket(wsUrl);
let messageId = 0;
const pending = new Map();

function send(method, params = {}) {
	const id = ++messageId;
	socket.send(JSON.stringify({ id, method, params }));
	return new Promise((resolve, reject) => {
		pending.set(id, { resolve, reject });
		setTimeout(() => {
			if (pending.has(id)) {
				pending.delete(id);
				reject(new Error(`CDP 超时: ${method}`));
			}
		}, 30000);
	});
}

socket.addEventListener("message", (event) => {
	const message = JSON.parse(event.data);
	if (message.id && pending.has(message.id)) {
		const { resolve } = pending.get(message.id);
		pending.delete(message.id);
		resolve(message.result);
	}
});

socket.addEventListener("open", async () => {
	await send("Page.enable");
	await send("Runtime.enable");
	await send("Emulation.setDeviceMetricsOverride", {
		width,
		height: 900,
		deviceScaleFactor: 1,
		mobile: true,
	});
	await send("Page.navigate", { url: targetUrl });
	await new Promise((resolve) => setTimeout(resolve, 4000));

	const result = await send("Runtime.evaluate", {
		expression: `(() => {
			const pres = [...document.querySelectorAll('.prose-blog pre')];
			const doc = document.documentElement;

			return {
				documentOverflow: doc.scrollWidth - doc.clientWidth,
				preCount: pres.length,
				blocks: pres.map((pre, index) => {
					const figure = pre.closest('figure');
					return {
						index,
						overflowX: getComputedStyle(pre).overflowX,
						scrollable: pre.scrollWidth > pre.clientWidth,
						scrollWidth: pre.scrollWidth,
						clientWidth: pre.clientWidth,
						figureOverflow: figure ? getComputedStyle(figure).overflow : null,
					};
				}),
			};
		})()`,
		returnByValue: true,
	});

	console.log(JSON.stringify(result.result.value, null, 2));
	socket.close();
	process.exit(0);
});