const http = require('http');
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const { URL } = require('url');

const PORT = Number(process.env.PORT || 3000);
const ROOT = __dirname;
const PUBLIC_DIR = path.join(ROOT, 'public');
const DATA_DIR = process.env.DATA_DIR || path.join(ROOT, 'data');
const SEED_DIR = path.join(ROOT, 'seed');
const SPONSORS_FILE = path.join(DATA_DIR, 'sponsors.json');
const CONFIG_FILE = path.join(DATA_DIR, 'config.json');
const ADMIN_PASSWORD = process.env.ADMIN_PASSWORD || 'changeme';
const IS_PROD = process.env.NODE_ENV === 'production';
const SESSION_TTL = 8 * 60 * 60 * 1000;
const sessions = new Map();

function ensureDataFile(name) {
  fs.mkdirSync(DATA_DIR, { recursive: true });
  const target = path.join(DATA_DIR, name);
  if (!fs.existsSync(target)) fs.copyFileSync(path.join(SEED_DIR, name), target);
}
ensureDataFile('sponsors.json');
ensureDataFile('config.json');

function readJson(file) { return JSON.parse(fs.readFileSync(file, 'utf8')); }
function writeJson(file, data) {
  const temp = `${file}.${crypto.randomUUID()}.tmp`;
  fs.writeFileSync(temp, JSON.stringify(data, null, 2));
  fs.renameSync(temp, file);
}
function getSponsors() { return readJson(SPONSORS_FILE).sort((a,b)=>(a.sortOrder||0)-(b.sortOrder||0)); }
function saveSponsors(s) { writeJson(SPONSORS_FILE, s); }
function getConfig() { return readJson(CONFIG_FILE); }
function activeSponsor(sponsors) { return sponsors.find(s=>s.status==='active') || sponsors.find(s=>s.status==='waiting') || null; }
function normalizeStatuses(sponsors, preferredActiveId=null) {
  const eligible=sponsors.filter(s=>s.status!=='qualified');
  let activeId=preferredActiveId;
  if(!activeId || !eligible.some(s=>s.id===activeId)){
    const existing=eligible.find(s=>s.status==='active');
    activeId=existing?existing.id:(eligible[0]?.id||null);
  }
  return sponsors.map(s=>s.status==='qualified'?s:{...s,status:s.id===activeId?'active':'waiting'});
}
function publicSponsorPayload(sponsor, config) {
  if(!sponsor)return null;
  return {id:sponsor.id,name:config.showSponsorName?sponsor.name:null,directs:sponsor.directs,goal:2,level:sponsor.level,referralUrl:`${config.dappReferralBaseUrl}${encodeURIComponent(sponsor.id)}`};
}
function securityHeaders(extra={}) {
  return {
    'X-Content-Type-Options':'nosniff','X-Frame-Options':'DENY','Referrer-Policy':'strict-origin-when-cross-origin',
    'Permissions-Policy':'camera=(), microphone=(), geolocation=()',
    'Content-Security-Policy':"default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; connect-src 'self'; font-src 'self' data:; form-action 'self'; frame-ancestors 'none'",
    ...extra
  };
}
function send(res,status,body,headers={}) { res.writeHead(status,securityHeaders(headers));res.end(body); }
function json(res,status,obj,headers={}) { send(res,status,JSON.stringify(obj),{'Content-Type':'application/json; charset=utf-8',...headers}); }
function parseCookies(req){const out={};for(const p of (req.headers.cookie||'').split(';')){const i=p.indexOf('=');if(i>0)out[p.slice(0,i).trim()]=decodeURIComponent(p.slice(i+1).trim())}return out}
function getSession(req){const token=parseCookies(req)['ctb.sid'];if(!token)return null;const s=sessions.get(token);if(!s)return null;if(s.expires<Date.now()){sessions.delete(token);return null}return {token,...s}}
function requireAdmin(req,res){if(!getSession(req)){json(res,401,{error:'Unauthorized'});return false}return true}
async function bodyJson(req){return await new Promise((resolve,reject)=>{let data='';req.on('data',c=>{data+=c;if(data.length>100000){reject(new Error('Payload too large'));req.destroy()}});req.on('end',()=>{if(!data)return resolve({});try{resolve(JSON.parse(data))}catch(e){reject(new Error('Invalid JSON'))}});req.on('error',reject)})}
function contentType(file){const ext=path.extname(file);return ({'.html':'text/html; charset=utf-8','.css':'text/css; charset=utf-8','.js':'application/javascript; charset=utf-8','.json':'application/json; charset=utf-8','.png':'image/png','.jpg':'image/jpeg','.jpeg':'image/jpeg','.svg':'image/svg+xml','.ico':'image/x-icon'}[ext]||'application/octet-stream')}
function staticFile(res,file,status=200){if(!fs.existsSync(file)||!fs.statSync(file).isFile())return false;send(res,status,fs.readFileSync(file),{'Content-Type':contentType(file),'Cache-Control':path.extname(file)==='.html'?'no-cache':'public, max-age=3600'});return true}

async function handleApi(req,res,pathname){
  if(req.method==='GET'&&pathname==='/health') return json(res,200,{ok:true});
  if(req.method==='GET'&&pathname==='/api/public/config'){
    const c=getConfig();return json(res,200,{siteName:c.siteName,programName:c.programName,bridgeHeadline:c.bridgeHeadline,bridgeSubheadline:c.bridgeSubheadline,premiumEntryPol:c.premiumEntryPol,telegramUrl:c.telegramUrl,supportLabel:c.supportLabel,showQueueProgress:c.showQueueProgress});
  }
  if(req.method==='GET'&&pathname==='/api/public/current-sponsor'){
    const sponsors=getSponsors(),c=getConfig(),a=activeSponsor(sponsors);if(!a)return json(res,404,{error:'No active sponsor is currently assigned.'});
    return json(res,200,{sponsor:publicSponsorPayload(a,c),waitingCount:sponsors.filter(s=>s.status==='waiting').length,message:'Always use the current sponsor shown on this page. Team placement rotates as members qualify.'});
  }
  if(req.method==='POST'&&pathname==='/api/public/join-click'){
    let sponsors=getSponsors();const a=activeSponsor(sponsors);if(a){sponsors=sponsors.map(s=>s.id===a.id?{...s,clicks:(s.clicks||0)+1}:s);saveSponsors(sponsors)}return json(res,200,{ok:true});
  }
  if(req.method==='POST'&&pathname==='/api/admin/login'){
    const b=await bodyJson(req).catch(e=>null);if(!b)return json(res,400,{error:'Invalid request'});if(typeof b.password!=='string'||b.password!==ADMIN_PASSWORD)return json(res,401,{error:'Invalid password'});
    const token=crypto.randomBytes(32).toString('hex');sessions.set(token,{expires:Date.now()+SESSION_TTL});const cookie=`ctb.sid=${encodeURIComponent(token)}; Path=/; HttpOnly; SameSite=Lax; Max-Age=${SESSION_TTL/1000}${IS_PROD?'; Secure':''}`;return json(res,200,{ok:true},{'Set-Cookie':cookie});
  }
  if(req.method==='POST'&&pathname==='/api/admin/logout'){
    const s=getSession(req);if(s)sessions.delete(s.token);return json(res,200,{ok:true},{'Set-Cookie':'ctb.sid=; Path=/; HttpOnly; SameSite=Lax; Max-Age=0'});
  }
  if(pathname.startsWith('/api/admin/')&&!requireAdmin(req,res))return;
  if(req.method==='GET'&&pathname==='/api/admin/state')return json(res,200,{sponsors:getSponsors(),config:getConfig()});
  if(req.method==='POST'&&pathname==='/api/admin/sponsors'){
    const b=await bodyJson(req);const {id,name,parentId='',level='Scintilla',notes=''}=b;if(!id||!name)return json(res,400,{error:'ID and name are required.'});let sponsors=getSponsors();if(sponsors.some(s=>String(s.id)===String(id)))return json(res,409,{error:'That sponsor ID already exists.'});
    const maxOrder=sponsors.reduce((m,s)=>Math.max(m,s.sortOrder||0),0);sponsors.push({id:String(id).trim(),name:String(name).trim(),parentId:String(parentId||'').trim(),directs:0,level,status:sponsors.some(s=>s.status==='active')?'waiting':'active',sortOrder:maxOrder+10,clicks:0,notes:String(notes||'').trim()});sponsors=normalizeStatuses(sponsors);saveSponsors(sponsors);return json(res,201,{sponsors});
  }
  if(req.method==='PATCH'&&pathname==='/api/admin/config'){
    const b=await bodyJson(req),cur=getConfig(),next={...cur};for(const k of ['siteName','programName','bridgeHeadline','bridgeSubheadline','premiumEntryPol','dappReferralBaseUrl','telegramUrl','supportLabel','showSponsorName','showQueueProgress'])if(Object.prototype.hasOwnProperty.call(b,k))next[k]=b[k];next.premiumEntryPol=Number(next.premiumEntryPol)||362;next.updatedAt=new Date().toISOString();writeJson(CONFIG_FILE,next);return json(res,200,{config:next});
  }
  const m=pathname.match(/^\/api\/admin\/sponsors\/([^/]+)(?:\/(increment|activate|qualify|reset|move))?$/);
  if(m){const id=decodeURIComponent(m[1]),action=m[2]||null;let sponsors=getSponsors(),idx=sponsors.findIndex(s=>s.id===id);if(idx<0)return json(res,404,{error:'Sponsor not found.'});
    if(req.method==='PATCH'&&!action){const b=await bodyJson(req);for(const k of ['name','parentId','directs','level','notes'])if(Object.prototype.hasOwnProperty.call(b,k))sponsors[idx][k]=b[k];sponsors[idx].directs=Math.max(0,Math.min(2,Number(sponsors[idx].directs)||0));saveSponsors(sponsors);return json(res,200,{sponsors});}
    if(req.method==='DELETE'&&!action){const wasActive=sponsors[idx].status==='active';sponsors.splice(idx,1);if(wasActive)sponsors=normalizeStatuses(sponsors);saveSponsors(sponsors);return json(res,200,{sponsors});}
    if(req.method==='POST'&&action==='increment'){sponsors[idx].directs=Math.min(2,(Number(sponsors[idx].directs)||0)+1);saveSponsors(sponsors);return json(res,200,{sponsors});}
    if(req.method==='POST'&&action==='activate'){if(sponsors[idx].status==='qualified')return json(res,400,{error:'Qualified sponsors cannot be activated until reset.'});sponsors=normalizeStatuses(sponsors,id);saveSponsors(sponsors);return json(res,200,{sponsors});}
    if(req.method==='POST'&&action==='qualify'){sponsors[idx]={...sponsors[idx],directs:2,status:'qualified'};sponsors=normalizeStatuses(sponsors);saveSponsors(sponsors);return json(res,200,{sponsors,active:activeSponsor(sponsors)});}
    if(req.method==='POST'&&action==='reset'){sponsors[idx]={...sponsors[idx],directs:0,status:'waiting'};sponsors=normalizeStatuses(sponsors);saveSponsors(sponsors);return json(res,200,{sponsors});}
    if(req.method==='POST'&&action==='move'){const b=await bodyJson(req);const swap=b.direction==='up'?idx-1:idx+1;if(swap>=0&&swap<sponsors.length){const t=sponsors[idx].sortOrder;sponsors[idx].sortOrder=sponsors[swap].sortOrder;sponsors[swap].sortOrder=t;saveSponsors(sponsors)}return json(res,200,{sponsors:getSponsors()});}
  }
  return json(res,404,{error:'API endpoint not found'});
}

const server=http.createServer(async(req,res)=>{
  try{
    const u=new URL(req.url,`http://${req.headers.host||'localhost'}`),pathname=decodeURIComponent(u.pathname);
    if(pathname==='/health'||pathname.startsWith('/api/'))return await handleApi(req,res,pathname);
    if(req.method!=='GET'&&req.method!=='HEAD')return send(res,405,'Method Not Allowed',{'Content-Type':'text/plain; charset=utf-8'});
    let file;
    if(pathname==='/')file=path.join(PUBLIC_DIR,'index.html');else if(pathname==='/start'||pathname==='/start/')file=path.join(PUBLIC_DIR,'start.html');else if(pathname==='/admin'||pathname==='/admin/')file=path.join(PUBLIC_DIR,'admin.html');else{
      const safe=path.normalize(pathname).replace(/^([.][.][/\\])+/, '').replace(/^[/\\]+/,'');file=path.join(PUBLIC_DIR,safe);if(!file.startsWith(PUBLIC_DIR))file='';
    }
    if(file&&staticFile(res,file))return;return staticFile(res,path.join(PUBLIC_DIR,'404.html'),404);
  }catch(e){console.error(e);json(res,500,{error:'Internal server error'});}
});
server.listen(PORT,()=>{console.log(`Crypto Team Build sponsor router running on http://localhost:${PORT}`);if(ADMIN_PASSWORD==='changeme')console.warn('WARNING: Set ADMIN_PASSWORD before production deployment.');});