const mm_client = (function() { "use strict";


class MattermostClient {
	constructor (endpoint, credentials_provider) {
		this.endpoint = endpoint;

		this.credentials = credentials_provider;
		const creds = this.credentials.get(this.endpoint);
		this.token = creds ? creds.token : null;
		console.info(`Created MattermostClient for ${this.endpoint}, ${this.token ? "found token" : "did not find token"}`);
	}

	async get(path, queryParams) {
		const headers = this.token ? {"Authorization": `Bearer ${this.token}`} : {};
		const response = await ajax.getJson(`${this.endpoint}${path}`, {headers, queryParams});
		if (!response.ok) {
			throw response;
		}
		return response.responseJson;
	}

	async post(path, data) {
		const headers = this.token ? {"Authorization": `Bearer ${this.token}`} : {};
		const response = await ajax.postJson(`${this.endpoint}${path}`, data, {headers});
		if (!response.ok) {
			throw response;
		}
		return response;
	}

	async paginatedGet(url, queryParams, perPage=200) {
		let data = [];

		let params = {page: 0, per_page: perPage};
		if (queryParams) {
			extend(params, queryParams);
		}

		let loadMore = true;
		while (loadMore) {
			if (params.page > 100) {
				throw new Error("Requesting more than 100 pages, something looks wrong or the response is massive (>20,000 items)");
			}

			const response = await this.get(url, params);
			data = data.concat(response);

			loadMore = response.length > 0;
			params.page++;
		}

		return data;
	}

	start() {
		assert(this.token);

		let _ = this.getUsers();
		return this.userMe().then(data => {
			this.me = data;
			this.websocket();
		});
	}

	async loggedIn() {
		if (!this.token) {
			return false;
		}
		try {
			const meResponse = await this.userMe();
			return true;
		} catch (e) {
			if (e instanceof ajax.NotOkError && e.xhr.status == 401) {
				return false;
			} else {
				throw e;
			}
		}
	}

	async logIn(login_id, password) {
		if (await this.loggedIn()) {
			throw Error("Already logged in on this server");
		}

		const response = await this.post("/users/login", {login_id, password});
		const token = response.getResponseHeader("Token");
		if (!token) {
			throw Error("No Token header in response to log in request");
		}
		this.credentials.store(this.endpoint, login_id, token);
		this.token = token;
		return response.responseJson;
	}

	async logOut() {
		console.log(this);
		console.log(this.token);
		assert(this.token, "logged in");
		try {
			const response = await this.post("/users/logout", this.token);
		} catch (e) {
			console.warn(e);
		}

		// Verify that the token is now invalidated
		if (await this.loggedIn()) {
			throw new Error("Failed to log out: token still works after trying to log out");
		}

		this.credentials.clear(this.endpoint);
		this.token = null;
		return response.responseJson;
	}

	user(user_id) {
		assertIsMattermostId(user_id);
		return this.get(`/users/${user_id}`);
	}
	userMe()            { return this.get("/users/me"); }
	myTeams()           { return this.get("/users/me/teams"); }

	myChannels(team_id) {
		assertIsMattermostId(team_id);
		return this.get(`/users/me/teams/${team_id}/channels`);
	}

	channelPosts(channel_id, beforePost=null, afterPost=null, since=null) {
		assertIsMattermostId(channel_id);
		assertIsNullOrMattermostId(beforePost);
		assertIsNullOrMattermostId(afterPost);
		return this.get(`/channels/${channel_id}/posts`, {
			before: beforePost, after: afterPost, since
		});
	}

	getUnread(team_id) {
		return this.get(`/users/me/teams/${team_id}/channels/members`);
	}

	markChannelRead(channel_id) {
		assertIsMattermostId(channel_id);
		return this.post(`/channels/members/me/view`, {
			channel_id: channel_id
		});
	}

	writePost(channel_id, message) {
		return this.post("/posts", {
			"channel_id": channel_id,
			"message": message
		});
	}

	executeSlashCommand(channel_id, command) {
		return this.post("/commands/execute", {channel_id, command});
	}

	getUsers() {
		if (!this.users) {
			this.users = this.paginatedGet("/users", {}).then(users => {
				const newUsers = Object.create(null);
				for (let user_data of users) {
					const user = user_data;
					newUsers[user.id] = user;
				}
				return newUsers;
			});
		}
		return this.users;
	}

	async filePublicLink(file_id) {
		const response = await this.get(`/files/${file_id}/link`, {});
		return response.link;
	}

	websocket() {
		assert(this.token, "logged in");

		const endpoint_destructuring = this.endpoint.match(/^([^:]+)(:\/\/.*)/);
		const protocol = endpoint_destructuring[1] === "https" ? "wss" : "ws";
		const endpoint = protocol + endpoint_destructuring[2] + "/websocket";

		const socket = new WebSocket(endpoint);

		socket.addEventListener("error", event => {
			 console.error("Websocket errored", event.data);
		});

		socket.addEventListener("close", event => {
			 console.info("Websocket closed", event.data);
		});

		socket.addEventListener("open", event => {
			console.log(`Opened websocket connection to ${endpoint}`);
			socket.send(`{"seq": 1, "action": "authentication_challenge", "data": {"token": "${this.token}"}}`);
		});

		socket.addEventListener("message", event => {
			console.log("Message from server ", event.data);
			const data = JSON.parse(event.data);

			if (data.event === "posted") {
				const post = JSON.parse(data.data.post);
				pubsub.publish("MESSAGES_NEW", {...post, endpoint: this.endpoint});

			} else if (data.event === "channel_viewed") {
				pubsub.publish("CHANNEL_READ", {endpoint: this.endpoint, channel_id: data.data.channel_id});
			}

		});

	}
}


let clients = Object.create(null);

function getOrCreate(endpoint) {
	if (!clients[endpoint]) {
		clients[endpoint] = new MattermostClient(endpoint, localstorage_credentials);
	}
	return clients[endpoint];
}

function getOrCreateMultiple(endpoints) {
	return endpoints.map(getOrCreate);
}

function drop(endpoint) {
	delete clients[endpoint];
}

return {getOrCreate, getOrCreateMultiple, drop};

})();