const app = require("express")();
app.use(require("cors")());

const fetch = require("node-fetch");
const jsdom = require("jsdom");

async function getResults(query) {
	return await fetch("https://www.bing.com/images/search?q=" + query)
		.then(response => response.text())
		.then(text => new jsdom.JSDOM(text).window.document)
		.then(document => {
			const imgNodes = document.getElementsByClassName("mimg");
			let results = [];
			for (let i = 0; i < imgNodes.length; i++) {
				const src = imgNodes[i].src;
				if (!src.startsWith("http")) {
					break;
				}
				results.push(src);
			}
			return results;
		});
}

app.get(["/random/:query*.jpg" /* legacy routing */, "/:query/random.jpg", "/:query/random"], (request, response) => {
	getResults(request.params.query).then(results => {
		response.redirect(results[Math.floor(Math.random() * results.length)]);
	});
});

app.get("/:query/list", (request, response) => {
	response.writeHead(200, { "Content-Type": "application/json" });
	getResults(request.params.query).then(results => {
		response.write(JSON.stringify(results));
		response.end();
	});
});

app.get(["/:query/:i.jpg", "/:query/:i"], (request, response) => {
	getResults(request.params.query).then(results => {
		response.redirect(results[request.params.i % results.length]);
	});
});

app.get(["/:query.jpg", "/:query"], (request, response) => {
	getResults(request.params.query).then(results => {
		response.redirect(results[0]);
	});
});

app.listen(process.argv[2] ? process.argv[2] : 3000);