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


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

	get id() {
		return this._endpoint;
	}

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

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


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

	async authenticatedGet(url, queryParams) {
		assert(this.token, "logged in");
		const response = await this.api.get(url, this.token, queryParams);
		return response.responseJson;
	}

	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 (this.token && await this.tokenWorks()) {
			throw Error("Already logged in on this server");
		}

		const response = await this.api.post("/users/login", undefined, {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.api.id, login_id, token);
		this.token = token;
		return response.responseJson;
	}

	async logOut() {
		assert(this.token, "logged in");
		const response = await this.api.post("/users/logout", this.token);

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

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

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

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

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

return {MattermostApi, MattermostClient};

})();