const C='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',L=4,H={'Access-Control-Allow-Origin':'*'},r=_=>[...Array(L)].map(_=>C[Math.random()*C.length|0]).join(''),n=u=>{try{return new URL(u).href}catch(_){try{return new URL('https://'+u).href}catch(_){}}}

export async function onRequest({request,env,next}){
  if(request.method==='OPTIONS')return new Response(null,{headers:{...H,'Access-Control-Allow-Methods':'POST','Access-Control-Allow-Headers':'Content-Type'}})
  const u=new URL(request.url)
  if(u.pathname==='/api/create'&&request.method==='POST'){
    try{
      let{url:t,token:k}=await request.json()
      if(!k||!(await(await fetch('https://www.google.com/recaptcha/api/siteverify',{method:'POST',headers:{'Content-Type':'application/x-www-form-urlencoded'},body:`secret=${env.RECAPCHA_KEY}&response=${k}`})).json()).success)
        return new Response('CAPTCHA failed',{status:403,headers:H})
      t=n(t);if(!t)throw 0
      let s;do s=r();while(await env.EV.get(s))
      await env.EV.put(s,t)
      return new Response(JSON.stringify({slug:s,target:t,shortUrl:`${u.origin}/${s}`}),{headers:{'Content-Type':'application/json',...H}})
    }catch(_){return new Response('Invalid request',{status:400,headers:H})}
  }
  const p=u.pathname.slice(1)
  if(p){const t=await env.EV.get(p);if(t)return Response.redirect(t,302)}
  return next()
}