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// Copyright 2019 Yusuke Sakurai. All rights reserved. MIT license.import { listenAndServe, ServeOptions, ServerRequest } from "./server.ts";import { encode } from "https://deno.land/std@v0.7.0/strings/encode.ts";
export type RoutedServerRequest = ServerRequest & {  match?: RegExpMatchArray;};
/** basic handler for http request */export type HttpHandler = (req: RoutedServerRequest) => unknown;
/** * Find the match that appeared in the nearest position to the beginning of word. * If positions are same, the longest one will be picked. * Return -1 and null if no match found. * */export function findLongestAndNearestMatch(  pathname: string,  patterns: (string | RegExp)[]): { index: number; match: RegExpMatchArray } {  let lastMatchIndex = pathname.length;  let lastMatchLength = 0;  let match: RegExpMatchArray = null;  let index = -1;  for (let i = 0; i < patterns.length; i++) {    const pattern = patterns[i];    const m = pathname.match(pattern);    if (!m) continue;    if (      m.index < lastMatchIndex ||      (m.index === lastMatchIndex && m[0].length > lastMatchLength)    ) {      index = i;      match = m;      lastMatchIndex = m.index;      lastMatchLength = m[0].length;    }  }  return { index, match };}
export interface HttpRouter {  handle(pattern: string | RegExp, handlers: HttpHandler);
  listen(addr: string, opts?: ServeOptions): void;}
/** create HttpRouter object */export function createRouter(): HttpRouter {  const routes: { pattern: string | RegExp; handlers: HttpHandler[] }[] = [];  return {    handle(pattern: string | RegExp, ...handlers: HttpHandler[]) {      routes.push({ pattern, handlers });    },    listen(addr: string, opts?: ServeOptions) {      listenAndServe(        addr,        async req => {          let { pathname } = new URL(req.url, addr);          const { index, match } = findLongestAndNearestMatch(            pathname,            routes.map(v => v.pattern)          );          if (index > -1) {            const { handlers } = routes[index];            for (const handler of handlers) {              await handler(Object.assign(req, { match }));              if (req.isResponded()) {                break;              }            }            if (!req.isResponded()) {              await req.respond({                status: 500,                headers: new Headers(),                body: encode("Not Responded")              });            }          } else {            await req.respond({              status: 404,              headers: new Headers(),              body: encode("Not Found")            });          }        },        opts      );    }  };}