'use strict';
const {URL, URLSearchParams} = require('url'); // TODO: Use the `URL` global when targeting Node.js 10
const urlLib = require('url');
const is = require('@sindresorhus/is');
const urlParseLax = require('url-parse-lax');
const lowercaseKeys = require('lowercase-keys');
const urlToOptions = require('./utils/url-to-options');
const isFormData = require('./utils/is-form-data');
const merge = require('./merge');
const knownHookEvents = require('./known-hook-events');

const retryAfterStatusCodes = new Set([413, 429, 503]);

// `preNormalize` handles static options (e.g. headers).
// For example, when you create a custom instance and make a request
// with no static changes, they won't be normalized again.
//
// `normalize` operates on dynamic options - they cannot be saved.
// For example, `body` is everytime different per request.
// When it's done normalizing the new options, it performs merge()
// on the prenormalized options and the normalized ones.

const preNormalize = (options, defaults) => {
	if (is.nullOrUndefined(options.headers)) {
		options.headers = {};
	} else {
		options.headers = lowercaseKeys(options.headers);
	}

	if (options.baseUrl && !options.baseUrl.toString().endsWith('/')) {
		options.baseUrl += '/';
	}

	if (options.stream) {
		options.json = false;
	}

	if (is.nullOrUndefined(options.hooks)) {
		options.hooks = {};
	} else if (!is.object(options.hooks)) {
		throw new TypeError(`Parameter \`hooks\` must be an object, not ${is(options.hooks)}`);
	}

	for (const event of knownHookEvents) {
		if (is.nullOrUndefined(options.hooks[event])) {
			if (defaults) {
				options.hooks[event] = [...defaults.hooks[event]];
			} else {
				options.hooks[event] = [];
			}
		}
	}

	if (is.number(options.timeout)) {
		options.gotTimeout = {request: options.timeout};
	} else if (is.object(options.timeout)) {
		options.gotTimeout = options.timeout;
	}

	delete options.timeout;

	const {retry} = options;
	options.retry = {
		retries: 0,
		methods: [],
		statusCodes: [],
		errorCodes: []
	};

	if (is.nonEmptyObject(defaults) && retry !== false) {
		options.retry = {...defaults.retry};
	}

	if (retry !== false) {
		if (is.number(retry)) {
			options.retry.retries = retry;
		} else {
			options.retry = {...options.retry, ...retry};
		}
	}

	if (options.gotTimeout) {
		options.retry.maxRetryAfter = Math.min(...[options.gotTimeout.request, options.gotTimeout.connection].filter(n => !is.nullOrUndefined(n)));
	}

	if (is.array(options.retry.methods)) {
		options.retry.methods = new Set(options.retry.methods.map(method => method.toUpperCase()));
	}

	if (is.array(options.retry.statusCodes)) {
		options.retry.statusCodes = new Set(options.retry.statusCodes);
	}

	if (is.array(options.retry.errorCodes)) {
		options.retry.errorCodes = new Set(options.retry.errorCodes);
	}

	return options;
};

const normalize = (url, options, defaults) => {
	if (is.plainObject(url)) {
		options = {...url, ...options};
		url = options.url || {};
		delete options.url;
	}

	if (defaults) {
		options = merge({}, defaults.options, options ? preNormalize(options, defaults.options) : {});
	} else {
		options = merge({}, preNormalize(options));
	}

	if (!is.string(url) && !is.object(url)) {
		throw new TypeError(`Parameter \`url\` must be a string or object, not ${is(url)}`);
	}

	if (is.string(url)) {
		if (options.baseUrl) {
			if (url.toString().startsWith('/')) {
				url = url.toString().slice(1);
			}

			url = urlToOptions(new URL(url, options.baseUrl));
		} else {
			url = url.replace(/^unix:/, 'http://$&');
			url = urlParseLax(url);
		}
	} else if (is(url) === 'URL') {
		url = urlToOptions(url);
	}

	// Override both null/undefined with default protocol
	options = merge({path: ''}, url, {protocol: url.protocol || 'https:'}, options);

	for (const hook of options.hooks.init) {
		const called = hook(options);

		if (is.promise(called)) {
			throw new TypeError('The `init` hook must be a synchronous function');
		}
	}

	const {baseUrl} = options;
	Object.defineProperty(options, 'baseUrl', {
		set: () => {
			throw new Error('Failed to set baseUrl. Options are normalized already.');
		},
		get: () => baseUrl
	});

	const {query} = options;
	if (is.nonEmptyString(query) || is.nonEmptyObject(query) || query instanceof URLSearchParams) {
		if (!is.string(query)) {
			options.query = (new URLSearchParams(query)).toString();
		}

		options.path = `${options.path.split('?')[0]}?${options.query}`;
		delete options.query;
	}

	if (options.hostname === 'unix') {
		const matches = /(.+?):(.+)/.exec(options.path);

		if (matches) {
			const [, socketPath, path] = matches;
			options = {
				...options,
				socketPath,
				path,
				host: null
			};
		}
	}

	const {headers} = options;
	for (const [key, value] of Object.entries(headers)) {
		if (is.nullOrUndefined(value)) {
			delete headers[key];
		}
	}

	if (options.json && is.undefined(headers.accept)) {
		headers.accept = 'application/json';
	}

	if (options.decompress && is.undefined(headers['accept-encoding'])) {
		headers['accept-encoding'] = 'gzip, deflate';
	}

	const {body} = options;
	if (is.nullOrUndefined(body)) {
		options.method = options.method ? options.method.toUpperCase() : 'GET';
	} else {
		const isObject = is.object(body) && !is.buffer(body) && !is.nodeStream(body);
		if (!is.nodeStream(body) && !is.string(body) && !is.buffer(body) && !(options.form || options.json)) {
			throw new TypeError('The `body` option must be a stream.Readable, string or Buffer');
		}

		if (options.json && !(isObject || is.array(body))) {
			throw new TypeError('The `body` option must be an Object or Array when the `json` option is used');
		}

		if (options.form && !isObject) {
			throw new TypeError('The `body` option must be an Object when the `form` option is used');
		}

		if (isFormData(body)) {
			// Special case for https://github.com/form-data/form-data
			headers['content-type'] = headers['content-type'] || `multipart/form-data; boundary=${body.getBoundary()}`;
		} else if (options.form) {
			headers['content-type'] = headers['content-type'] || 'application/x-www-form-urlencoded';
			options.body = (new URLSearchParams(body)).toString();
		} else if (options.json) {
			headers['content-type'] = headers['content-type'] || 'application/json';
			options.body = JSON.stringify(body);
		}

		options.method = options.method ? options.method.toUpperCase() : 'POST';
	}

	if (!is.function(options.retry.retries)) {
		const {retries} = options.retry;

		options.retry.retries = (iteration, error) => {
			if (iteration > retries) {
				return 0;
			}

			if ((!error || !options.retry.errorCodes.has(error.code)) && (!options.retry.methods.has(error.method) || !options.retry.statusCodes.has(error.statusCode))) {
				return 0;
			}

			if (Reflect.has(error, 'headers') && Reflect.has(error.headers, 'retry-after') && retryAfterStatusCodes.has(error.statusCode)) {
				let after = Number(error.headers['retry-after']);
				if (is.nan(after)) {
					after = Date.parse(error.headers['retry-after']) - Date.now();
				} else {
					after *= 1000;
				}

				if (after > options.retry.maxRetryAfter) {
					return 0;
				}

				return after;
			}

			if (error.statusCode === 413) {
				return 0;
			}

			const noise = Math.random() * 100;
			return ((2 ** (iteration - 1)) * 1000) + noise;
		};
	}

	return options;
};

const reNormalize = options => normalize(urlLib.format(options), options);

module.exports = normalize;
module.exports.preNormalize = preNormalize;
module.exports.reNormalize = reNormalize;