"use strict";

const LOCALSTORAGE_KEY_SERVERS = "mattermostServers";

function byId(id, nullOk=false) {
	const el = document.getElementById(id);
	if (!el && !nullOk) {
		console.error(`No element #${id}`);
	}
	return el;
}

function storeCredentials(endpoint, login_id, token) {
	let storedServers = JSON.parse(window.localStorage.getItem(LOCALSTORAGE_KEY_SERVERS) || "[]");
	if (!(endpoint in storedServers)) storedServers.push(endpoint);
	window.localStorage.setItem(LOCALSTORAGE_KEY_SERVERS, JSON.stringify(storedServers));

	window.localStorage.setItem(`${LOCALSTORAGE_KEY_SERVERS}_${endpoint}`, JSON.stringify({login_id, token}));
}

function getCredentials(endpoint) {
	return JSON.parse(window.localStorage.getItem(`${LOCALSTORAGE_KEY_SERVERS}_${endpoint}`) || "null");
}

class MattermostApi {
	constructor(endpoint) {
		this.endpoint = endpoint;
	}

	async validateToken(token) {
		const response = await ajax.getJson(`${this.endpoint}/users/me`, {
			headers: {
				"Authorization": `Bearer ${token}`
			}
		});
		if (!response.ok) {
			throw response;
		}
		return response;
	}

	logIn(login_id, password) {
		return ajax.postJson(`${this.endpoint}/users/login`, {login_id, password})
			.then(response => {
				let token = response.getHeader("Token");
				storeCredentials(this.endpoint, login_id, token);
				return response;
			})
			.then(response => {
				document.body.innerHTML = "";
				const pre = document.createElement("pre");
				pre.innerText = JSON.stringify(response.json, null, 2);
				document.body.appendChild(pre);

				return response;
			})
			.catch(error => {
				console.error(error);
				document.body.innerText = `An error occurred: ${error}`;
			});
	}
}

/**
 * Return an endpoint URL that has a protocol, domain and path
 */
function normalizedEndpoint(endpoint) {
	let matches = endpoint.match(/^(https?:\/\/)?([^\/]+)(\/.*)?$/i);
	if (!matches) throw Error("Invalid endpoint URL");

	let protocol = matches[1] || "https://";
	let domain = matches[2];
	let path = matches[3] || "/api/v4";

	return `${protocol}${domain}${path}`;
}

function logIn() {
	let endpoint = normalizedEndpoint(byId("server").value);

	let api = new MattermostApi(endpoint);
	api.logIn(byId("username").value, byId("password").value);
}

function validateToken() {
	let endpoint = normalizedEndpoint(byId("server").value);

	let cred = getCredentials(endpoint);
	if (!cred || !cred.token) {
		byId("validate").value = "No token, log in first";
		byId("validate").disabled = false;
	}

	let api = new MattermostApi(endpoint);
	api.validateToken(cred.token)
		.then(() => {
			byId("validate").value = "Validation succeeded";
			byId("validate").disabled = false;
		})
		.catch(() => {
			byId("validate").value = "Validation failed";
			byId("validate").disabled = false;
		});
}