//
// Language support for Dockerfiles and Compose files, backed by
// docker-language-server (github.com/docker/docker-language-server).
//
// The binary is a single ~40 MB executable, which is too large to ship inside
// the extension, so the managed mode downloads the pinned release into the
// extension's global storage the first time it is needed.
//

const { exec } = require("../Utilities/Process");
const notify = require("../Utilities/Notify");

const RELEASE_URL = "https://github.com/docker/docker-language-server/releases/download";
// docker-language-server decides what a document is from the languageId the
// editor sends, and Nova sends the syntax name. Compose support only switches
// on for "dockercompose", which is why the Compose syntax carries that name.
const SYNTAXES = ["dockerfile", "dockercompose"];

class DockerLanguageClient {
	constructor() {
		this.client = null;
		this.disposables = new CompositeDisposable();

		for (let key of ["apple_container.lsp.mode", "apple_container.lsp.path", "apple_container.lsp.version"]) {
			this.disposables.add(nova.config.onDidChange(key, () => this.restart()));
		}
	}

	get mode() {
		return nova.config.get("apple_container.lsp.mode", "string") || "Managed Binary";
	}

	get version() {
		return (nova.config.get("apple_container.lsp.version", "string") || "").trim() || "v0.20.1";
	}

	async start() {
		if (this.mode === "Disabled") {
			return;
		}

		let path = null;

		try {
			path = this.mode === "Custom Path" ? this.customPath() : await this.managedPath();
		} catch (error) {
			notify.configFailure("Docker Language Server unavailable", error, "apple-container-lsp");
			return;
		}

		if (!path) {
			return;
		}

		this.stop();

		try {
			this.client = new LanguageClient(
				"unsupervised.AppleContainer.dls",
				"Docker Language Server",
				{
					path: path,
					args: ["start", "--stdio"],
					type: "stdio"
				},
				{
					syntaxes: SYNTAXES
				}
			);

			this.client.onDidStop((error) => {
				if (error) {
					notify.failure(
						"Docker Language Server stopped",
						error,
						"apple-container-lsp-stopped"
					);
				}
			});

			this.client.start();
			nova.subscriptions.add(this.client);
		} catch (error) {
			notify.failure("Docker Language Server failed to launch", error, "apple-container-lsp");
			this.client = null;
		}
	}

	stop() {
		if (!this.client) {
			return;
		}

		this.client.stop();
		nova.subscriptions.remove(this.client);
		this.client = null;
	}

	async restart() {
		this.stop();
		await this.start();
	}

	dispose() {
		this.stop();
		this.disposables.dispose();
	}

	customPath() {
		let path = (nova.config.get("apple_container.lsp.path", "string") || "").trim();

		if (!path) {
			throw new Error("Set the path to docker-language-server in the extension's preferences.");
		}

		if (!nova.fs.access(path, nova.fs.X_OK)) {
			throw new Error(`${path} is not an executable file.`);
		}

		return path;
	}

	// Returns the managed binary, downloading it when it is missing.
	async managedPath() {
		let architecture = await this.architecture();
		let name = `docker-language-server-darwin-${architecture}-${this.version}`;
		let directory = nova.extension.globalStoragePath;
		let path = nova.path.join(directory, name);

		if (nova.fs.access(path, nova.fs.X_OK)) {
			return path;
		}

		if (!nova.fs.access(directory, nova.fs.F_OK)) {
			nova.fs.mkdir(directory);
		}

		await this.download(`${RELEASE_URL}/${this.version}/${name}`, path);

		return path;
	}

	async architecture() {
		let result = await exec("/usr/bin/uname", ["-m"]);
		return result.stdout.trim() === "x86_64" ? "amd64" : "arm64";
	}

	async download(url, destination) {
		notify.info(
			"Downloading Docker Language Server",
			`${this.version} for Dockerfile and Compose support. This happens once.`,
			"apple-container-lsp-download"
		);

		// A partial file would look like a working binary on the next launch,
		// so download beside the target and move it into place at the end.
		let temporary = `${destination}.download`;

		try {
			await exec("/usr/bin/curl", [
				"--fail",
				"--location",
				"--silent",
				"--show-error",
				"--output",
				temporary,
				url
			]);
			await exec("/bin/chmod", ["+x", temporary]);
			nova.fs.move(temporary, destination);
		} catch (error) {
			try {
				nova.fs.remove(temporary);
			} catch (cleanupError) {
				// Nothing to clean up.
			}

			throw new Error(`Could not download ${url}: ${error.message}`);
		}
	}
}

module.exports = { DockerLanguageClient };