const EventEmitter = require("events");

module.exports.XSSBook = class XSSBook extends EventEmitter {
	constructor({ url, bridge_username, room }) {
		super();
		
		this.url = url;
		this.bridge_username = bridge_username;
		this.room = room;
		
		this.tokens = {};
		this.posts = {};
		
		this.pollLoop();
	}
	
	async api(url, method, data, token) {
		return await fetch(this.url + url, {
			method,
			headers: {
				"Cookie": token ? "auth=" + encodeURIComponent(token) : undefined,
				"Content-Type": data ? "application/json" : undefined,
			},
			body: data ? JSON.stringify(data) : undefined,
		});
	}
	
	async getUserToken(username) {
		if(username in this.tokens) {
			return this.tokens[username];
		}
		
		let req = await this.api("/api/auth/register", "POST", {
			firstname: username,
			lastname: username === this.bridge_username ? "[bridge]" : "[matrix]",
			email: username,
			password: username,
			gender: username === this.bridge_username ? "matrix bridge" : "matrix user",
			day: 1,
			month: 1,
			year: 1970,
		});
		if(req.ok) {
			const token = decodeURIComponent(/auth=([^;]+);/.exec(req.headers.get("set-cookie"))[1]);
			return this.tokens[username] = token;
		}
		
		console.log("couldn't register " + username + ":", await req.text());
		
		req = await this.api("/api/auth/login", "POST", {
			email: username,
			password: username,
		});
		if(req.ok) {
			const token = decodeURIComponent(/auth=([^;]+);/.exec(req.headers.get("set-cookie"))[1]);
			return this.tokens[username] = token;
		}
		
		console.log("couldn't login " + username + ":", await req.text());
		
		throw new Error("Couldn't get token for " + username);
	}
	
	async apiUser(url, method, data, username) {
		const token = await this.getUserToken(username);
		return await this.api(url, method, data, token);
	}
	
	async getUsers(ids) {
		const req = await this.apiUser("/api/users/load", "POST", {
			ids,
		}, this.bridge_username);
		
		return await req.json();
	}
	
	async post(username, content) {
		const res = await this.apiUser("/api/posts/create", "POST", {
			content,
		}, username);
		return (await res.json()).post_id;
	}
	
	async pollLoop() {
		let latest_post_id = 0, first = true;
		while(true) {
			await new Promise(r => setTimeout(r, 5000));
			const req = await this.apiUser("/api/posts/page", "POST", {
				page: 0,
			}, this.bridge_username);
			const posts = await req.json();
			
			if(!Array.isArray(posts) || !posts.length) {
				continue;
			}
			
			const new_posts = posts.filter(n => n.post_id > latest_post_id);
			if(!new_posts.length) {
				continue;
			}
			
			latest_post_id = Math.max(latest_post_id, ...new_posts.map(n => n.post_id));
			
			if(first) { // ignore posts from the first sync
				first = false;
				continue;
			}
			
			const users_list = await this.getUsers(new_posts.map(n => n.user_id));
			const users = {};
			users_list.forEach(user => {
				users[user.user_id] = user;
			});
			
			new_posts.forEach(post => {
				const user = users[post.user_id];
				
				this.emit("post", post, user);
			});
		}
	}
}