'use strict';

function routeKey(method,pathname){return `${String(method||'GET').toUpperCase()} ${pathname}`}

function createHttpRouter({notFound}={}){
  const routes=new Map();
  const add=(method,pathname,handler)=>{
    if(typeof handler!=='function')throw new TypeError('Route handler must be a function');
    const key=routeKey(method,pathname);
    if(routes.has(key))throw new Error(`Duplicate route: ${key}`);
    routes.set(key,handler);return api;
  };
  const dispatch=async(req,res,url)=>{
    const handler=routes.get(routeKey(req.method,url.pathname));
    if(handler)return handler(req,res,url);
    if(typeof notFound==='function')return notFound(req,res,url);
    return false;
  };
  const api=Object.freeze({add,dispatch,has:(method,pathname)=>routes.has(routeKey(method,pathname)),routes:()=>Object.freeze([...routes.keys()])});
  return api;
}

module.exports=Object.freeze({routeKey,createHttpRouter});