/**
 * Request.js
 *
 * Request class contains server only options
 *
 * All spec algorithm step numbers are based on https://fetch.spec.whatwg.org/commit-snapshots/ae716822cb3a61843226cd090eefc6589446c1d2/.
 */

import {format as formatUrl} from 'url';
import Headers from './headers.js';
import Body, {clone, extractContentType, getTotalBytes} from './body.js';
import {isAbortSignal} from './utils/is.js';
import {getSearch} from './utils/get-search.js';

const INTERNALS = Symbol('Request internals');

/**
 * Check if `obj` is an instance of Request.
 *
 * @param  {*} obj
 * @return {boolean}
 */
const isRequest = object => {
	return (
		typeof object === 'object' &&
		typeof object[INTERNALS] === 'object'
	);
};

/**
 * Request class
 *
 * Ref: https://fetch.spec.whatwg.org/#request-class
 *
 * @param   Mixed   input  Url or Request instance
 * @param   Object  init   Custom options
 * @return  Void
 */
export default class Request extends Body {
	constructor(input, init = {}) {
		let parsedURL;

		// Normalize input and force URL to be encoded as UTF-8 (https://github.com/node-fetch/node-fetch/issues/245)
		if (isRequest(input)) {
			parsedURL = new URL(input.url);
		} else {
			parsedURL = new URL(input);
			input = {};
		}

		let method = init.method || input.method || 'GET';
		method = method.toUpperCase();

		// eslint-disable-next-line no-eq-null, eqeqeq
		if (((init.body != null || isRequest(input)) && input.body !== null) &&
			(method === 'GET' || method === 'HEAD')) {
			throw new TypeError('Request with GET/HEAD method cannot have body');
		}

		const inputBody = init.body ?
			init.body :
			(isRequest(input) && input.body !== null ?
				clone(input) :
				null);

		super(inputBody, {
			size: init.size || input.size || 0
		});

		const headers = new Headers(init.headers || input.headers || {});

		if (inputBody !== null && !headers.has('Content-Type')) {
			const contentType = extractContentType(inputBody, this);
			if (contentType) {
				headers.append('Content-Type', contentType);
			}
		}

		let signal = isRequest(input) ?
			input.signal :
			null;
		if ('signal' in init) {
			signal = init.signal;
		}

		// eslint-disable-next-line no-eq-null, eqeqeq
		if (signal != null && !isAbortSignal(signal)) {
			throw new TypeError('Expected signal to be an instanceof AbortSignal or EventTarget');
		}

		this[INTERNALS] = {
			method,
			redirect: init.redirect || input.redirect || 'follow',
			headers,
			parsedURL,
			signal
		};

		// Node-fetch-only options
		this.follow = init.follow === undefined ? (input.follow === undefined ? 20 : input.follow) : init.follow;
		this.compress = init.compress === undefined ? (input.compress === undefined ? true : input.compress) : init.compress;
		this.counter = init.counter || input.counter || 0;
		this.agent = init.agent || input.agent;
		this.highWaterMark = init.highWaterMark || input.highWaterMark || 16384;
		this.insecureHTTPParser = init.insecureHTTPParser || input.insecureHTTPParser || false;
	}

	get method() {
		return this[INTERNALS].method;
	}

	get url() {
		return formatUrl(this[INTERNALS].parsedURL);
	}

	get headers() {
		return this[INTERNALS].headers;
	}

	get redirect() {
		return this[INTERNALS].redirect;
	}

	get signal() {
		return this[INTERNALS].signal;
	}

	/**
	 * Clone this request
	 *
	 * @return  Request
	 */
	clone() {
		return new Request(this);
	}

	get [Symbol.toStringTag]() {
		return 'Request';
	}
}

Object.defineProperties(Request.prototype, {
	method: {enumerable: true},
	url: {enumerable: true},
	headers: {enumerable: true},
	redirect: {enumerable: true},
	clone: {enumerable: true},
	signal: {enumerable: true}
});

/**
 * Convert a Request to Node.js http request options.
 *
 * @param   Request  A Request instance
 * @return  Object   The options object to be passed to http.request
 */
export const getNodeRequestOptions = request => {
	const {parsedURL} = request[INTERNALS];
	const headers = new Headers(request[INTERNALS].headers);

	// Fetch step 1.3
	if (!headers.has('Accept')) {
		headers.set('Accept', '*/*');
	}

	// HTTP-network-or-cache fetch steps 2.4-2.7
	let contentLengthValue = null;
	if (request.body === null && /^(post|put)$/i.test(request.method)) {
		contentLengthValue = '0';
	}

	if (request.body !== null) {
		const totalBytes = getTotalBytes(request);
		// Set Content-Length if totalBytes is a number (that is not NaN)
		if (typeof totalBytes === 'number' && !Number.isNaN(totalBytes)) {
			contentLengthValue = String(totalBytes);
		}
	}

	if (contentLengthValue) {
		headers.set('Content-Length', contentLengthValue);
	}

	// HTTP-network-or-cache fetch step 2.11
	if (!headers.has('User-Agent')) {
		headers.set('User-Agent', 'node-fetch');
	}

	// HTTP-network-or-cache fetch step 2.15
	if (request.compress && !headers.has('Accept-Encoding')) {
		headers.set('Accept-Encoding', 'gzip,deflate,br');
	}

	let {agent} = request;
	if (typeof agent === 'function') {
		agent = agent(parsedURL);
	}

	if (!headers.has('Connection') && !agent) {
		headers.set('Connection', 'close');
	}

	// HTTP-network fetch step 4.2
	// chunked encoding is handled by Node.js

	const search = getSearch(parsedURL);

	// Manually spread the URL object instead of spread syntax
	const requestOptions = {
		path: parsedURL.pathname + search,
		pathname: parsedURL.pathname,
		hostname: parsedURL.hostname,
		protocol: parsedURL.protocol,
		port: parsedURL.port,
		hash: parsedURL.hash,
		search: parsedURL.search,
		query: parsedURL.query,
		href: parsedURL.href,
		method: request.method,
		headers: headers[Symbol.for('nodejs.util.inspect.custom')](),
		insecureHTTPParser: request.insecureHTTPParser,
		agent
	};

	return requestOptions;
};