import assert from 'assert';
import crypto from 'crypto';
import { TextEncoder } from 'util';
import TCPClient from './structure/TCPClient';
import { SendVoteOptions } from './types/SendVoteOptions';

const encoder = new TextEncoder();

export function sendVote(host: string, port = 8192, options: SendVoteOptions): Promise<void> {
	host = host.trim();

	assert(typeof host === 'string', `Expected 'host' to be a 'string', got '${typeof host}'`);
	assert(host.length > 1, `Expected 'host' to have a length greater than 0, got ${host.length}`);
	assert(typeof port === 'number', `Expected 'port' to be a 'number', got '${typeof port}'`);
	assert(Number.isInteger(port), `Expected 'port' to be an integer, got '${port}'`);
	assert(port >= 0, `Expected 'port' to be greater than or equal to 0, got '${port}'`);
	assert(port <= 65535, `Expected 'port' to be less than or equal to 65535, got '${port}'`);
	assert(typeof options === 'object', `Expected 'options' to be an 'object', got '${typeof options}'`);
	assert(typeof options.username === 'string', `Expected 'options.username' to be an 'string', got '${typeof options.username}'`);
	assert(options.username.length > 1, `Expected 'options.username' to have a length greater than 0, got ${options.username.length}`);
	assert(typeof options.token === 'string', `Expected 'options.token' to be an 'string', got '${typeof options.token}'`);
	assert(options.token.length > 1, `Expected 'options.token' to have a length greater than 0, got ${options.token.length}`);

	return new Promise(async (resolve, reject) => {
		let socket: TCPClient | undefined = undefined;

		const timeout = setTimeout(() => {
			socket?.close();

			reject(new Error('Server is offline or unreachable'));
		}, options?.timeout ?? 1000 * 5);

		try {
			socket = new TCPClient();

			await socket.connect({ host, port, timeout: options?.timeout ?? 1000 * 5 });

			let challengeToken;

			// Handshake packet
			// https://github.com/NuVotifier/NuVotifier/wiki/Technical-QA#handshake
			{
				const version = await socket.readStringUntil(0x0A);
				const split = version.split(' ');

				if (split[0] !== 'VOTIFIER') throw new Error('Not connected to a Votifier server. Expected VOTIFIER in handshake, received: ' + version);
				if (split[1] !== '2') throw new Error('Unsupported Votifier version: ' + split[1]);

				challengeToken = split[2];
			}

			// Send vote packet
			// https://github.com/NuVotifier/NuVotifier/wiki/Technical-QA#protocol-v2
			{
				const payload: Record<string, string | number> = {
					serviceName: options.serviceName ?? 'minecraft-server-util (https://github.com/PassTheMayo/minecraft-server-util)',
					username: options.username,
					address: options.address ?? host + ':' + port,
					timestamp: options.timestamp ?? Date.now(),
					challenge: challengeToken
				};

				if (options.uuid) {
					payload.uuid = options.uuid;
				}

				const payloadSerialized = JSON.stringify(payload);

				const message = {
					payload: payloadSerialized,
					signature: crypto.createHmac('sha256', options.token).update(payloadSerialized).digest('base64')
				};

				const messageSerialized = JSON.stringify(message);
				const messageBytes = encoder.encode(messageSerialized);

				socket.writeInt16BE(0x733A);
				socket.writeInt16BE(messageBytes.byteLength);
				socket.writeBytes(messageBytes);
				await socket.flush(false);
			}

			// Response packet
			// https://github.com/NuVotifier/NuVotifier/wiki/Technical-QA#protocol-v2
			{
				const responseString = await socket.readStringUntil(0x0A);

				const response = JSON.parse(responseString);

				socket.close();

				clearTimeout(timeout);

				switch (response.status) {
					case 'ok': {
						resolve();

						break;
					}
					case 'error': {
						reject(new Error(response.cause + ': ' + response.error));

						break;
					}
					default: {
						reject(new Error('Server sent an unknown response: ' + responseString));

						break;
					}
				}
			}
		} catch (e) {
			clearTimeout(timeout);

			socket?.close();

			reject(e);
		}
	});
}