import {join} from "jsr:@std/path";
var decoder = new TextDecoder("utf8");

var infojsoncache = new Map();
async function getInfoJson(ytid) {
	if (infojsoncache.has(ytid)) return infojsoncache.get(ytid);
	try {
		var text = await Deno.readTextFile(join(process.env.MEDIA_DIR, ytid, "info.json"));
		var json = JSON.parse(text);
		infojsoncache.set(ytid, json);
		setTimeout(() => {
			infojsoncache.delete(ytid);
		}, 600000);
		return json;
	} catch (e) {
		infojsoncache.set(ytid, null);
		setTimeout(() => {
			infojsoncache.delete(ytid);
		}, 5000);
		return null;
	}
}

export async function ytdl_if_not_already(ytid) {
	var info = await getInfoJson(ytid);
	if (info) return info;
	return await run_ytdlp_deduplicated(ytid);
}

var running_ytdl = new Map();
export async function run_ytdlp_deduplicated(ytid) {
	var run = running_ytdl.get(ytid);
	if (!run) {
		run = run_ytdlp(ytid);
		run.finally(() => {
			running_ytdl.delete(ytid);
		}).catch(()=>{});
		running_ytdl.set(ytid, run);
	}
	return await run;
}

export async function run_ytdlp(ytid) {
	var cwd = await Deno.makeTempDir();
	console.debug("tmpdir", cwd);

	var command = new Deno.Command("yt-dlp", {
		args: [
			"-f", "bestvideo*[vcodec!^=av01]+bestaudio/best",
			"--no-mtime", "--no-playlist", "-J", "--no-simulate", ytid,
		],
		cwd,
		stdout: "piped",
		stderr: "piped",
		stdin: "null"
	});

	var result = {ts: new Date()};
	var output = await command.output();
	if (!output.success) {
		result.error = decoder.decode(output.stderr).trim();
	}

	else {
		var stdout_text = decoder.decode(output.stdout).trim();
		var jsons = stdout_text.split("\n");
		if (jsons.length > 1) console.warn("more than one jsons outputted");
		var json = JSON.parse(jsons[0]);
		await Deno.writeTextFile(join(cwd, "more.json"), JSON.stringify(json));

		result.title = json.title;
		result.description = json.description;
		result.thumbnail = json.thumbnail;
		result.channel = json.channel;
		result.duration = json.duration;
		result.duration_string = json.duration_string;
		result.view_count = json.view_count;
		result.upload_date = json.upload_date;
		result.filename = json.requested_downloads[0].filename;

		if (!result.filename) {
			var files = await Array.fromAsync(Deno.readDir(cwd));
			files = files.map(file => file.name);
			result.filename = files.find(name => /\.(?:webm|mp4|mkv)$/i.test(name));
		}

		let stat = await Deno.stat(join(cwd, result.filename));
		result.size = stat.size;
	}

	await Deno.writeTextFile(join(cwd, "info.json"), JSON.stringify(result));
	
	var newpath = join(process.env.MEDIA_DIR, ytid);
	try {
		await Deno.rename(cwd, newpath);
	} catch (error) {
		if (error.code === "ENOTEMPTY") {
			await Deno.remove(newpath, {recursive: true});
			await Deno.rename(cwd, newpath);
		}
		else {
			throw error;
		}
	}

	return result;
}