'use strict';
const https=require('node:https');
const {verifyInnerAuthority}=require('./tls-authority.cjs');
const {gateRequest,GateError}=require('./http-request-gate.cjs');
const {validateResponse}=require('./http-response-gate.cjs');
const {createWorkAdmission}=require('./work-admission.cjs');
const {recordLifecycle}=require('./bounded-audit.cjs');

/** Isolated decrypted HTTPS leg for one caller-authenticated CONNECT binding.
 * Trusted caller supplies certificate, authorization and HTTPS forwarder.
 * This is NOT a CONNECT proxy, certificate issuer or OS network boundary.
 */
function createInspectionServer({key,cert,binding,authority,current,inspect,forward,maxBytes=1048576,maxResponseBytes=1048576,deadlineMs=5000,maxClients=8,workAdmission,lifecycle,auditAdmission,connectionContext}) {
  if(typeof authority!=='string'||!authority||!Number.isSafeInteger(deadlineMs)||deadlineMs<1||deadlineMs>60000||!Number.isSafeInteger(maxBytes)||maxBytes<0||maxBytes>16777216||!Number.isSafeInteger(maxResponseBytes)||maxResponseBytes<0||maxResponseBytes>16777216||!Number.isSafeInteger(maxClients)||maxClients<1||maxClients>64||typeof current!=='function'||typeof inspect!=='function'||typeof forward!=='function')throw new GateError('invalid-configuration');
  const sockets=new Set();
  const admission=workAdmission||createWorkAdmission({maxJobs:maxClients});
  const controlAdmission=auditAdmission||createWorkAdmission({maxJobs:maxClients});
  const rejectAudit=(context,code,facts,scope='request')=>recordLifecycle({admission:controlAdmission,deadlineMs,context,code,facts,scope});
  let server;
  try {
    server=https.createServer({key,cert,minVersion:'TLSv1.2',handshakeTimeout:deadlineMs},async(req,res)=>{
      const controller=new AbortController();let phase='request',totalExpired=false,authorized=false;const expires=performance.now()+deadlineMs;
      const totalTimer=setTimeout(()=>{totalExpired=true;controller.abort();},deadlineMs);
      const auditContext=lifecycle?.begin(connectionContext?.requestId);
      let receivedBytes=0;
      const received=chunk=>{receivedBytes=Math.min(20*1024*1024,receivedBytes+chunk.length);};
      req.on('data',received);
      const abort=()=>controller.abort();
      res.once('close',abort);
      try {
        verifyInnerAuthority(binding,{rawHeaders:req.rawHeaders,url:req.url,servername:req.socket.servername||undefined});
        const target=req.url.startsWith('/')?`https://${binding.authority}${req.url}`:req.url;
        const parsed=new URL(target);
        const rawHeaders=req.rawHeaders.slice();
        for(let index=0;index<rawHeaders.length;index+=2)if(rawHeaders[index].toLowerCase()==='host')rawHeaders[index+1]=binding.authority;
        // Stream methods remain bound to the actual IncomingMessage. Only
        // immutable routing metadata is adapted for the reusable HTTP gate.
        const adapted=new Proxy(req,{get(object,name){if(name==='url')return `http://${binding.authority}${parsed.pathname}${parsed.search}`;if(name==='rawHeaders')return rawHeaders;const value=Reflect.get(object,name);return typeof value==='function'?value.bind(object):value;}});
        const secureSnapshot=value=>Object.freeze({...value,auditContext,markStage:value=>{if(value==='scan'||value==='forward')phase=value;},request:Object.freeze({...value.request,url:target})});
        const response=await gateRequest(adapted,{authority,current,maxBytes,deadlineMs:Math.max(1,Math.ceil(expires-performance.now())),signal:controller.signal,inspect:value=>{phase='scan';return admission.run(()=>inspect(secureSnapshot(value)),{payload:value.body});},forward:async value=>{
          phase='forward';authorized=true;
          let cancelled;
          let forwardExpired=false;
          const forwardTimer=setTimeout(()=>{forwardExpired=true;controller.abort();},Math.max(1,Math.ceil(expires-performance.now())));
          try {
            const cancellation=new Promise((_,reject)=>{cancelled=()=>reject(new GateError('upstream-failed'));controller.signal.addEventListener('abort',cancelled,{once:true});if(controller.signal.aborted)cancelled();});
            const result=await Promise.race([admission.run(()=>forward(Object.freeze({...secureSnapshot(value),signal:controller.signal,maxResponseBytes})),{payload:value.body}),cancellation]);
            return validateResponse(result,maxResponseBytes);
          } catch(error) {throw new GateError(totalExpired?(phase==='scan'?'inspection-deadline':'forward-deadline'):forwardExpired?'forward-deadline':controller.signal.aborted?'aborted':['invalid-upstream-response','unsupported-upstream-encoding','authority-expired','audit-unavailable','audit-persistence-failed'].includes(error?.code)?error.code:'upstream-failed');}
          finally {clearTimeout(forwardTimer);controller.signal.removeEventListener('abort',cancelled);}
        }});
        if(controller.signal.aborted||res.destroyed)return;
        res.writeHead(response.statusCode,response.headers);res.end(response.body);
      } catch(error) {
        const code=totalExpired?(phase==='scan'?'inspection-deadline':phase==='forward'?'forward-deadline':'deadline'):error instanceof GateError||error?.name==='AuthorityError'?error.code:'inspection-failed';
        try {await rejectAudit(auditContext,code,{bytes:receivedBytes,detectedType:'unknown',host:binding.hostname});}catch{}
        const upstream=code==='inspection-deadline'?authorized:['upstream-failed','forward-deadline','invalid-upstream-response','unsupported-upstream-encoding'].includes(code);
        if(!res.destroyed&&!res.headersSent){res.writeHead(upstream?502:403,{'connection':'close','content-type':'text/plain'});res.end(upstream?'upstream-failed':code);}
      } finally {clearTimeout(totalTimer);res.removeListener('close',abort);req.removeListener('data',received);}
    });
  } catch {throw new GateError('invalid-tls-configuration');}
  server.maxConnections=maxClients;
  server.headersTimeout=deadlineMs;
  server.requestTimeout=deadlineMs;
  server.keepAliveTimeout=1;
  // Idle fallback leaves room for a complete inspection phase followed by
  // its separately bounded forward phase. Neither wall clock is renewable.
  server.on('connection',socket=>{sockets.add(socket);socket.setTimeout(deadlineMs*3,()=>socket.destroy());socket.once('close',()=>sockets.delete(socket));});
  const malformedContexts=new WeakMap();
  server.on('clientError',(_error,socket)=>{if(!malformedContexts.has(socket))malformedContexts.set(socket,lifecycle?.begin(connectionContext?.requestId));const context=malformedContexts.get(socket);void rejectAudit(context,'invalid-headers',{bytes:0,detectedType:'unknown',host:binding.hostname}).catch(()=>{}).finally(()=>socket.destroy());});
  server.on('tlsClientError',(_error,socket)=>{void rejectAudit(connectionContext,'connect-denied',{bytes:0,detectedType:'unknown',host:binding.hostname},'connect').catch(()=>{}).finally(()=>socket.destroy());});
  return Object.freeze({
    // Trusted authenticated CONNECT acceptor only; no public IPC exposure.
    // HTTPS Server owns TLS negotiation on this accepted raw TCP socket.
    acceptAuthenticatedSocket(socket){server.emit('connection',socket);},
    async listen(){await new Promise((resolve,reject)=>{server.once('error',reject);server.listen(0,'127.0.0.1',()=>{server.removeListener('error',reject);resolve();});});return server.address().port;},
    async close(){if(!workAdmission)admission.close();if(!auditAdmission)controlAdmission.close();for(const socket of sockets)socket.destroy();await new Promise(resolve=>server.close(resolve));}
  });
}
module.exports={createInspectionServer};