import RequestParser from '../Utils/RequestParser';
import BaseRouter from './BaseRouter';
import Logger from '../Utils/Logger';
import LayResponse from '../IO/LayResponse';

/**
 * Router class that extends BaseRouter.
 * @extends BaseRouter
 */
export default class Router extends BaseRouter {
	static allMethodKey = '$all';
	static methods = ['all', 'get', 'post', 'put', 'patch', 'head', 'options'];

	#domain = undefined;
	#server = undefined;
	#routes = new Map();
	#headerList = new Map();

	/**
	 * Constructor for the Router class.
	 * @param {Server} server - The server instance.
	 */
	constructor(server, options = {}) {
		super();
		this.#server = server;
		this.#domain = options.domain || undefined;
	}

	/**
	 * Get the server instance.
	 * @returns {Server} The server instance.
	 */
	getServer() {
		return this.#server;
	}

	/**
	 * Get the domain of the router
	 * @returns {String} The base domain for the router.
	 */
	getDomain() {
		return this.#domain;
	}

	/**
	 * Handle the incoming request.
	 * @param {RequestContext} reqContext - The request context.
	 * @returns {Promise<Response>} The response promise.
	 */
	async handle(reqContext) {
		let method = (reqContext.request.method || '').toString().toLowerCase();
		const methodKey = `$${method.toLowerCase()}`;
		let path;
		let url = reqContext.request.url;

		if (!(url instanceof URL) && typeof url == 'string') {
			url = new URL(url);
			path = url.pathname;
		}
		if (path.startsWith('/')) path = path.substring(1);
		if (path.endsWith('/')) path = path.substring(0, path.length - 1);

		let currentNode = this.#routes;
		let fallbackNode = currentNode.has('*') ? currentNode.get('*') : undefined;
		let paramsList = [];

		if (path != '') {
			let segments = path.split('/');
			for (let index = 0; index < segments.length; index++) {
				const segment = segments[index];
				if (currentNode.has('*')) {
					fallbackNode = currentNode.get('*');
				}

				if (currentNode.has(segment)) {
					currentNode = currentNode.get(segment);
					continue;
				}

				if (currentNode.has(':') || currentNode.has('?')) {
					paramsList.push(segment);
					currentNode = currentNode.get(':') ?? currentNode.get('?');
					continue;
				}

				currentNode = fallbackNode ?? null;
				break;
			}
		}

		if (
			!(currentNode instanceof Map) ||
			(['get', 'head'].indexOf(method) < 0 &&
				!currentNode.has(methodKey) &&
				!currentNode.has(Router.allMethodKey))
		) {LayResponse
			return new Response(`[${method}] Method Not Allowed`, {
				status: 405,
			});
		}

		if (
			!currentNode.has(methodKey) &&
			!currentNode.get(Router.allMethodKey)
		) {
			return new Response(`Not Implemented: [${method}, ${req.url}]`, {
				status: 501,
			});
		}

		let handle =
			currentNode.get(methodKey) || currentNode.get(Router.allMethodKey);

		if (typeof handle == 'object' && typeof handle.callback == 'function') {
			if (Array.isArray(handle.params)) {
				for (const name of handle.params) {
					let value = paramsList[reqContext.request.params.size];
					if (reqContext.request.params.has(name)) {
						let yet = reqContext.request.params.get(name);
						if (!Array.isArray(yet)) {
							yet = [yet];
						}
						yet.push(value);
						value = yet;
					}
					reqContext.request.params.set(name, value);
				}
			}
		}

		try {
			await reqContext.request.parseBody();
			let retVal = await this.executeMiddleware(
				handle.middleware,
				reqContext.request,
				reqContext.response,
				async () => {
					return await handle.callback(reqContext.request, reqContext.response);
				},
				5000 // Add a timeout of 5 seconds for middleware execution
			);

			await reqContext.request.parseBody();
			retVal = await handle.callback(
				reqContext.request,
				reqContext.response
			);
			if (typeof retVal != 'undefined') {
				if (retVal instanceof Promise) {
					retVal = await retVal;
				} else if (retVal instanceof LayResponse) {
					return await retVal.build();
				} else if (retVal instanceof Response) {
					return retVal;
				} else if (typeof retVal == 'string') {
					await reqContext.response.text(retVal);
				} else {
					reqContext.response.json(retVal);
				}
			}
		} catch (err) {
			console.error(err)
			Logger.error(err);
			return new Response('Something went wrong!', { status: 500 });
		}

		if (reqContext.response.redirect()) {
			return Response.redirect(
				reqContext.response.redirect,
				reqContext.response.status || 302
			);
		}

		return await reqContext.response.build();
	}

	/**
	 * Add a route to the router.
	 * @param {string} route - The route path.
	 * @param {function} callback - The route callback function.
	 * @param {Object} options - The route options.
	 * @param {function[]} [middleware] - The middleware functions.
	 */
	add(route, callback) {
		let options = arguments[2];
		let middleware = arguments[3];

		if (typeof callback !== 'function')
			throw new TypeError('`callback` must be a function');
		if (typeof route !== 'string')
			throw new TypeError('`route` must be a string');
		if (Router.methods.indexOf(options.method) < 0)
			throw new Error(
				`invalid \`method\` (${options.method}) given`,
				Router.methods
			);

		if (!Array.isArray(middleware)) {
			middleware = typeof middleware == 'function' ? [middleware] : null;
		}

		const methodKey = `$${options.method.toLowerCase()}`;
		if (route.startsWith('/')) route = route.substring(1);
		if (route.endsWith('/')) route = route.substring(0, route.length - 1);

		let params = [];
		let segments = route.split('/');
		let currentNode = this.#routes;

		if (route == '') {
			if (currentNode.get(methodKey)) {
				if (!this.#server.option('allowRouteOverwrite')) {
					Logger(
						`overwriting of routes is prohibited: [${options.method}] \`${route}\``
					);
					return;
				}

				Logger(`overwriting route for \`${route}\``);
			}
			currentNode.set(methodKey, { callback, middleware, params: [] });
			return;
		}

		// add method to the segments to store the callback with
		//   and to allow different methods for the same route
		for (let index = 0; index < segments.length; index++) {
			let segment = segments[index];
			let varName = null;

			if (segment.startsWith(':')) {
				let newSegment = ':';
				varName = segment.substring(1);
				if (segment.endsWith('?')) {
					// optional param
					newSegment = '?';
					varName = varName.substring(0, -1);
				}
				segment = newSegment;
				params.push(varName);
			}

			if (!currentNode.has(segment)) currentNode.set(segment, new Map());

			currentNode = currentNode.get(segment);
		}

		if (currentNode.has(methodKey)) {
			if (!this.#server.option('allowRouteOverwrite')) {
				Logger(
					`overwriting of routes is prohibited: [${method}] \`${route}\``
				);
				return;
			}

			Logger(`overwriting route for \`${route}\``);
		}

		currentNode.set(methodKey, { callback, middleware, params });
	}

	/**
	 * Remove a route from the router.
	 * @param {string} route - The route path.
	 * @param {string} method - The HTTP method.
	 * @param {function} [cb=null] - The callback function to remove.
	 * @returns {boolean} True if the route was removed, false otherwise.
	 */
	remove(route, method, cb = null) {
		const methodKey = `$${method.toLowerCase()}`;
		if (route.startsWith('/')) route = route.substring(1);
		if (route.endsWith('/')) route = route.substring(0, route.length - 1);

		let currentNode = this.#routes;

		if (route != '') {
			let segments = route.toString().split('/');

			for (let index = 0; index < segments.length; index++) {
				const segment = segments[index];

				if (currentNode.has(segment)) {
					currentNode = currentNode.get(segment);
					continue;
				}

				if (currentNode.has(':') || currentNode.has('?')) {
					currentNode = currentNode.get(':') ?? currentNode.get('?');
					continue;
				}

				currentNode = null;
				break;
			}
		}

		if (
			!(currentNode instanceof Map) ||
			!currentNode.has(methodKey) ||
			(typeof cb == 'function' && currentNode.get(methodKey) != cb)
		) {
			return false;
		}

		return currentNode.delete(methodKey);
	}

	/**
	 * Execute the middleware chain.
	 * @param {function[]} middleware - The middleware functions.
	 * @param {Request} req - The request object.
	 * @param {Response} res - The response object.
	 * @param {function} next - The next function to call.
	 * @returns {Promise<void>} A promise that resolves when the middleware chain is completed.
	 */
	async executeMiddleware(middleware, req, res, next) {
		if (!Array.isArray(middleware) || middleware.length === 0) {
			return await next();
		}

		const executeNext = async (index) => {
			if (index >= middleware.length) {
				return await next();
			}

			const currentMiddleware = middleware[index];

			const timeoutPromise = new Promise((_, reject) => {
				setTimeout(() => {
					reject(new Error('Middleware execution timed out'));
				}, timeout);
			});

			try {
				await Promise.race([
					currentMiddleware(req, res, async () => {
						return await executeNext(index + 1);
					}),
					timeoutPromise,
				]);
			} catch (err) {
				throw err;
			}
		};

		return await executeNext(0);
	}
}