/*
  Copyright 2018 Google LLC

  Use of this source code is governed by an MIT-style
  license that can be found in the LICENSE file or at
  https://opensource.org/licenses/MIT.
*/

import {assert} from 'workbox-core/_private/assert.js';
import {getFriendlyURL} from 'workbox-core/_private/getFriendlyURL.js';
import {
  RouteHandler,
  RouteHandlerObject,
  RouteHandlerCallbackOptions,
  RouteMatchCallbackOptions,
} from 'workbox-core/types.js';
import {HTTPMethod, defaultMethod} from './utils/constants.js';
import {logger} from 'workbox-core/_private/logger.js';
import {normalizeHandler} from './utils/normalizeHandler.js';
import {Route} from './Route.js';
import {WorkboxError} from 'workbox-core/_private/WorkboxError.js';

import './_version.js';

type RequestArgs = string | [string, RequestInit?];

interface CacheURLsMessageData {
  type: string;
  payload: {
    urlsToCache: RequestArgs[];
  };
}

/**
 * The Router can be used to process a `FetchEvent` using one or more
 * {@link workbox-routing.Route}, responding with a `Response` if
 * a matching route exists.
 *
 * If no route matches a given a request, the Router will use a "default"
 * handler if one is defined.
 *
 * Should the matching Route throw an error, the Router will use a "catch"
 * handler if one is defined to gracefully deal with issues and respond with a
 * Request.
 *
 * If a request matches multiple routes, the **earliest** registered route will
 * be used to respond to the request.
 *
 * @memberof workbox-routing
 */
class Router {
  private readonly _routes: Map<HTTPMethod, Route[]>;
  private readonly _defaultHandlerMap: Map<HTTPMethod, RouteHandlerObject>;
  private _catchHandler?: RouteHandlerObject;

  /**
   * Initializes a new Router.
   */
  constructor() {
    this._routes = new Map();
    this._defaultHandlerMap = new Map();
  }

  /**
   * @return {Map<string, Array<workbox-routing.Route>>} routes A `Map` of HTTP
   * method name ('GET', etc.) to an array of all the corresponding `Route`
   * instances that are registered.
   */
  get routes(): Map<HTTPMethod, Route[]> {
    return this._routes;
  }

  /**
   * Adds a fetch event listener to respond to events when a route matches
   * the event's request.
   */
  addFetchListener(): void {
    // See https://github.com/Microsoft/TypeScript/issues/28357#issuecomment-436484705
    self.addEventListener('fetch', ((event: FetchEvent) => {
      const {request} = event;
      const responsePromise = this.handleRequest({request, event});
      if (responsePromise) {
        event.respondWith(responsePromise);
      }
    }) as EventListener);
  }

  /**
   * Adds a message event listener for URLs to cache from the window.
   * This is useful to cache resources loaded on the page prior to when the
   * service worker started controlling it.
   *
   * The format of the message data sent from the window should be as follows.
   * Where the `urlsToCache` array may consist of URL strings or an array of
   * URL string + `requestInit` object (the same as you'd pass to `fetch()`).
   *
   * ```
   * {
   *   type: 'CACHE_URLS',
   *   payload: {
   *     urlsToCache: [
   *       './script1.js',
   *       './script2.js',
   *       ['./script3.js', {mode: 'no-cors'}],
   *     ],
   *   },
   * }
   * ```
   */
  addCacheListener(): void {
    // See https://github.com/Microsoft/TypeScript/issues/28357#issuecomment-436484705
    self.addEventListener('message', ((event: ExtendableMessageEvent) => {
      // event.data is type 'any'
      // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
      if (event.data && event.data.type === 'CACHE_URLS') {
        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
        const {payload}: CacheURLsMessageData = event.data;

        if (process.env.NODE_ENV !== 'production') {
          logger.debug(`Caching URLs from the window`, payload.urlsToCache);
        }

        const requestPromises = Promise.all(
          payload.urlsToCache.map((entry: string | [string, RequestInit?]) => {
            if (typeof entry === 'string') {
              entry = [entry];
            }

            const request = new Request(...entry);
            return this.handleRequest({request, event});

            // TODO(philipwalton): TypeScript errors without this typecast for
            // some reason (probably a bug). The real type here should work but
            // doesn't: `Array<Promise<Response> | undefined>`.
          }) as any[],
        ); // TypeScript

        event.waitUntil(requestPromises);

        // If a MessageChannel was used, reply to the message on success.
        if (event.ports && event.ports[0]) {
          void requestPromises.then(() => event.ports[0].postMessage(true));
        }
      }
    }) as EventListener);
  }

  /**
   * Apply the routing rules to a FetchEvent object to get a Response from an
   * appropriate Route's handler.
   *
   * @param {Object} options
   * @param {Request} options.request The request to handle.
   * @param {ExtendableEvent} options.event The event that triggered the
   *     request.
   * @return {Promise<Response>|undefined} A promise is returned if a
   *     registered route can handle the request. If there is no matching
   *     route and there's no `defaultHandler`, `undefined` is returned.
   */
  handleRequest({
    request,
    event,
  }: {
    request: Request;
    event: ExtendableEvent;
  }): Promise<Response> | undefined {
    if (process.env.NODE_ENV !== 'production') {
      assert!.isInstance(request, Request, {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'handleRequest',
        paramName: 'options.request',
      });
    }

    const url = new URL(request.url, location.href);
    if (!url.protocol.startsWith('http')) {
      if (process.env.NODE_ENV !== 'production') {
        logger.debug(
          `Workbox Router only supports URLs that start with 'http'.`,
        );
      }
      return;
    }

    const sameOrigin = url.origin === location.origin;
    const {params, route} = this.findMatchingRoute({
      event,
      request,
      sameOrigin,
      url,
    });
    let handler = route && route.handler;

    const debugMessages = [];
    if (process.env.NODE_ENV !== 'production') {
      if (handler) {
        debugMessages.push([`Found a route to handle this request:`, route]);

        if (params) {
          debugMessages.push([
            `Passing the following params to the route's handler:`,
            params,
          ]);
        }
      }
    }

    // If we don't have a handler because there was no matching route, then
    // fall back to defaultHandler if that's defined.
    const method = request.method as HTTPMethod;
    if (!handler && this._defaultHandlerMap.has(method)) {
      if (process.env.NODE_ENV !== 'production') {
        debugMessages.push(
          `Failed to find a matching route. Falling ` +
            `back to the default handler for ${method}.`,
        );
      }
      handler = this._defaultHandlerMap.get(method);
    }

    if (!handler) {
      if (process.env.NODE_ENV !== 'production') {
        // No handler so Workbox will do nothing. If logs is set of debug
        // i.e. verbose, we should print out this information.
        logger.debug(`No route found for: ${getFriendlyURL(url)}`);
      }
      return;
    }

    if (process.env.NODE_ENV !== 'production') {
      // We have a handler, meaning Workbox is going to handle the route.
      // print the routing details to the console.
      logger.groupCollapsed(`Router is responding to: ${getFriendlyURL(url)}`);

      debugMessages.forEach((msg) => {
        if (Array.isArray(msg)) {
          logger.log(...msg);
        } else {
          logger.log(msg);
        }
      });

      logger.groupEnd();
    }

    // Wrap in try and catch in case the handle method throws a synchronous
    // error. It should still callback to the catch handler.
    let responsePromise;
    try {
      responsePromise = handler.handle({url, request, event, params});
    } catch (err) {
      responsePromise = Promise.reject(err);
    }

    // Get route's catch handler, if it exists
    const catchHandler = route && route.catchHandler;

    if (
      responsePromise instanceof Promise &&
      (this._catchHandler || catchHandler)
    ) {
      responsePromise = responsePromise.catch(async (err) => {
        // If there's a route catch handler, process that first
        if (catchHandler) {
          if (process.env.NODE_ENV !== 'production') {
            // Still include URL here as it will be async from the console group
            // and may not make sense without the URL
            logger.groupCollapsed(
              `Error thrown when responding to: ` +
                ` ${getFriendlyURL(
                  url,
                )}. Falling back to route's Catch Handler.`,
            );
            logger.error(`Error thrown by:`, route);
            logger.error(err);
            logger.groupEnd();
          }

          try {
            return await catchHandler.handle({url, request, event, params});
          } catch (catchErr) {
            if (catchErr instanceof Error) {
              err = catchErr;
            }
          }
        }

        if (this._catchHandler) {
          if (process.env.NODE_ENV !== 'production') {
            // Still include URL here as it will be async from the console group
            // and may not make sense without the URL
            logger.groupCollapsed(
              `Error thrown when responding to: ` +
                ` ${getFriendlyURL(
                  url,
                )}. Falling back to global Catch Handler.`,
            );
            logger.error(`Error thrown by:`, route);
            logger.error(err);
            logger.groupEnd();
          }
          return this._catchHandler.handle({url, request, event});
        }

        throw err;
      });
    }

    return responsePromise;
  }

  /**
   * Checks a request and URL (and optionally an event) against the list of
   * registered routes, and if there's a match, returns the corresponding
   * route along with any params generated by the match.
   *
   * @param {Object} options
   * @param {URL} options.url
   * @param {boolean} options.sameOrigin The result of comparing `url.origin`
   *     against the current origin.
   * @param {Request} options.request The request to match.
   * @param {Event} options.event The corresponding event.
   * @return {Object} An object with `route` and `params` properties.
   *     They are populated if a matching route was found or `undefined`
   *     otherwise.
   */
  findMatchingRoute({
    url,
    sameOrigin,
    request,
    event,
  }: RouteMatchCallbackOptions): {
    route?: Route;
    params?: RouteHandlerCallbackOptions['params'];
  } {
    const routes = this._routes.get(request.method as HTTPMethod) || [];
    for (const route of routes) {
      let params: Promise<any> | undefined;
      // route.match returns type any, not possible to change right now.
      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
      const matchResult = route.match({url, sameOrigin, request, event});
      if (matchResult) {
        if (process.env.NODE_ENV !== 'production') {
          // Warn developers that using an async matchCallback is almost always
          // not the right thing to do.
          if (matchResult instanceof Promise) {
            logger.warn(
              `While routing ${getFriendlyURL(url)}, an async ` +
                `matchCallback function was used. Please convert the ` +
                `following route to use a synchronous matchCallback function:`,
              route,
            );
          }
        }

        // See https://github.com/GoogleChrome/workbox/issues/2079
        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
        params = matchResult;
        if (Array.isArray(params) && params.length === 0) {
          // Instead of passing an empty array in as params, use undefined.
          params = undefined;
        } else if (
          matchResult.constructor === Object && // eslint-disable-line
          Object.keys(matchResult).length === 0
        ) {
          // Instead of passing an empty object in as params, use undefined.
          params = undefined;
        } else if (typeof matchResult === 'boolean') {
          // For the boolean value true (rather than just something truth-y),
          // don't set params.
          // See https://github.com/GoogleChrome/workbox/pull/2134#issuecomment-513924353
          params = undefined;
        }

        // Return early if have a match.
        return {route, params};
      }
    }
    // If no match was found above, return and empty object.
    return {};
  }

  /**
   * Define a default `handler` that's called when no routes explicitly
   * match the incoming request.
   *
   * Each HTTP method ('GET', 'POST', etc.) gets its own default handler.
   *
   * Without a default handler, unmatched requests will go against the
   * network as if there were no service worker present.
   *
   * @param {workbox-routing~handlerCallback} handler A callback
   * function that returns a Promise resulting in a Response.
   * @param {string} [method='GET'] The HTTP method to associate with this
   * default handler. Each method has its own default.
   */
  setDefaultHandler(
    handler: RouteHandler,
    method: HTTPMethod = defaultMethod,
  ): void {
    this._defaultHandlerMap.set(method, normalizeHandler(handler));
  }

  /**
   * If a Route throws an error while handling a request, this `handler`
   * will be called and given a chance to provide a response.
   *
   * @param {workbox-routing~handlerCallback} handler A callback
   * function that returns a Promise resulting in a Response.
   */
  setCatchHandler(handler: RouteHandler): void {
    this._catchHandler = normalizeHandler(handler);
  }

  /**
   * Registers a route with the router.
   *
   * @param {workbox-routing.Route} route The route to register.
   */
  registerRoute(route: Route): void {
    if (process.env.NODE_ENV !== 'production') {
      assert!.isType(route, 'object', {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'registerRoute',
        paramName: 'route',
      });

      assert!.hasMethod(route, 'match', {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'registerRoute',
        paramName: 'route',
      });

      assert!.isType(route.handler, 'object', {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'registerRoute',
        paramName: 'route',
      });

      assert!.hasMethod(route.handler, 'handle', {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'registerRoute',
        paramName: 'route.handler',
      });

      assert!.isType(route.method, 'string', {
        moduleName: 'workbox-routing',
        className: 'Router',
        funcName: 'registerRoute',
        paramName: 'route.method',
      });
    }

    if (!this._routes.has(route.method)) {
      this._routes.set(route.method, []);
    }

    // Give precedence to all of the earlier routes by adding this additional
    // route to the end of the array.
    this._routes.get(route.method)!.push(route);
  }

  /**
   * Unregisters a route with the router.
   *
   * @param {workbox-routing.Route} route The route to unregister.
   */
  unregisterRoute(route: Route): void {
    if (!this._routes.has(route.method)) {
      throw new WorkboxError('unregister-route-but-not-found-with-method', {
        method: route.method,
      });
    }

    const routeIndex = this._routes.get(route.method)!.indexOf(route);
    if (routeIndex > -1) {
      this._routes.get(route.method)!.splice(routeIndex, 1);
    } else {
      throw new WorkboxError('unregister-route-route-not-registered');
    }
  }
}

export {Router};