// app.js
(() => {
  const WS_URI = "wss://promptly-az40.onrender.com/ws";
  const statusEl = document.getElementById("status");
  const connectBtn = document.getElementById("connectBtn");
  const disconnectBtn = document.getElementById("disconnectBtn");
  const modeText = document.getElementById("modeText");
  const messagesEl = document.getElementById("messages");
  const inputEl = document.getElementById("input");
  const sendBtn = document.getElementById("sendBtn");
  const fileBtn = document.getElementById("fileBtn");
  const filePicker = document.getElementById("filePicker");
  const loginOverlay = document.getElementById("loginOverlay");
  const loginForm = document.getElementById("loginForm");
  const loginUsername = document.getElementById("loginUsername");
  const loginPassword = document.getElementById("loginPassword");
  const loginGuest = document.getElementById("loginGuest");
  const themeToggle = document.getElementById("themeToggle");
  const root = document.getElementById("root");
  const onlineCountEl = document.getElementById("onlineCount");

  let ws = null;
  let handshakeStep = 0;
  let awaiting = null;
  let lastUsername = "";
  let connected = false;
  let pendingLogin = null; // {username,password}

  // Utility
  function stripAnsi(str){ return String(str).replace(/\x1b\[[0-9;]*m/g,''); }
  function setStatus(connectedNow){
    connected = !!connectedNow;
    if(connected){
      statusEl.classList.remove("disconnected");
      statusEl.classList.add("connected");
      statusEl.textContent = "Connected";
      disconnectBtn.disabled = false;
      connectBtn.disabled = true;
    }else{
      statusEl.classList.remove("connected");
      statusEl.classList.add("disconnected");
      statusEl.textContent = "Disconnected";
      disconnectBtn.disabled = true;
      connectBtn.disabled = false;
    }
  }

  function appendMessage(content, cls='system'){
    const el = document.createElement('div');
    el.className = 'msg ' + (cls === 'me' ? 'me' : (cls === 'file' ? 'file' : 'system'));
    if(typeof content === 'string'){
      el.textContent = content;
    } else if(content.type === 'file'){
      // content: {filename, blob, isImage}
      const meta = document.createElement('div');
      meta.className = 'meta';
      meta.textContent = `📥 Received ${content.filename}`;
      el.appendChild(meta);
      if(content.isImage){
        const wrap = document.createElement('a');
        wrap.href = URL.createObjectURL(content.blob);
        wrap.download = content.filename;
        wrap.className = 'img-wrap';
        const img = document.createElement('img');
        img.src = wrap.href;
        img.alt = content.filename;
        wrap.appendChild(img);
        el.appendChild(wrap);
        // download link below
        const dl = document.createElement('a');
        dl.href = wrap.href;
        dl.download = content.filename;
        dl.className = 'download-link muted';
        dl.textContent = `Download ${content.filename}`;
        el.appendChild(dl);
        // revoke after a bit when user navigates away
        setTimeout(()=>URL.revokeObjectURL(wrap.href), 60000);
      } else {
        const dl = document.createElement('a');
        dl.href = URL.createObjectURL(content.blob);
        dl.download = content.filename;
        dl.className = 'download-link muted';
        dl.textContent = `Download ${content.filename}`;
        el.appendChild(dl);
        setTimeout(()=>URL.revokeObjectURL(dl.href), 60000);
      }
    } else {
      el.textContent = JSON.stringify(content);
    }
    messagesEl.appendChild(el);
    messagesEl.scrollTo({top: messagesEl.scrollHeight, behavior: 'smooth'});
  }

  function connect(){
    if(ws) try{ ws.close() }catch(e){}
    ws = new WebSocket(WS_URI);
    ws.binaryType = 'arraybuffer';
    ws.addEventListener('open', ()=>{
      setStatus(true);
      appendMessage('🟢 Connected to ' + WS_URI);
      handshakeStep = 0;
      awaiting = null;
      modeText.textContent = 'Handshake';
      // if pending login already provided, we will act when user submits login
    });
    ws.addEventListener('message', (ev) => {
      let data = ev.data;
      if(data instanceof ArrayBuffer){
        // binary from server: try to treat as file (unlikely); skip for now
        appendMessage('📎 Received binary data (unsupported preview)', 'system');
        return;
      } else {
        data = stripAnsi(String(data));
      }

      // Detect server-sent file marker: '📥 filename base64'
      if(data.startsWith('📥')){
        const m = data.match(/^📥\s+(\S+)\s+([\s\S]+)$/);
        if(m){
          const fname = m[1];
          const b64 = m[2];
          try{
            const bytes = Uint8Array.from(atob(b64), c => c.charCodeAt(0));
            const blob = new Blob([bytes]);
            const isImage = /\.(png|jpe?g|gif|webp|svg)$/i.test(fname);
            appendMessage({type:'file', filename: fname, blob, isImage}, 'file');
            return;
          }catch(e){
            appendMessage('❌ File parse error: ' + e.toString());
          }
        }
      }

      appendMessage(data, 'system');
      // handshake flow handling
      if(data.toLowerCase().includes('please enter password') || data.toLowerCase().includes('enter password')){
        awaiting = 'password';
        modeText.textContent = 'Entering password';
      } else if(data.toLowerCase().includes('enter your username') || data.toLowerCase().includes('enter username')){
        awaiting = 'username';
        modeText.textContent = 'Entering username';
      } else if(data.toLowerCase().includes('welcome') || data.toLowerCase().includes('joined the chat')){
        awaiting = null;
        modeText.textContent = 'Chat';
      } else if(data.toLowerCase().includes('online users')){
        // try to parse count
        const m = data.match(/Online users\s*\(?(\d+)\)?/i);
        if(m) onlineCountEl.textContent = m[1];
      }
    });

    ws.addEventListener('close', ()=>{
      appendMessage('🔴 Connection closed.');
      setStatus(false);
      ws = null;
    });

    ws.addEventListener('error', (e)=>{
      appendMessage('❌ Connection error. Check server & console.');
      setStatus(false);
    });
  }

  function disconnect(){
    if(ws) try{ ws.close(); }catch(e){}
    ws = null;
    setStatus(false);
    appendMessage('Disconnected by client.');
  }

  // send helper
  function sendText(msg){
    if(!ws || ws.readyState !== WebSocket.OPEN){
      appendMessage('❗ Not connected.', 'system');
      return;
    }
    ws.send(msg);
    appendMessage(`[You] ${msg}`, 'me');
  }

  // file upload: read file -> base64 -> send as /send filename base64 (server expects same)
  filePicker.addEventListener('change', async (e)=>{
    const f = e.target.files && e.target.files[0];
    if(!f) return;
    const reader = new FileReader();
    reader.onload = () => {
      try{
        const ab = reader.result;
        const bytes = new Uint8Array(ab);
        let binary = '';
        const chunk = 0x8000;
        for(let i=0;i<bytes.length;i+=chunk){
          const sub = bytes.subarray(i, Math.min(i+chunk, bytes.length));
          binary += String.fromCharCode.apply(null, sub);
        }
        const b64 = btoa(binary);
        const payload = `/send ${f.name} ${b64}`;
        if(ws && ws.readyState === WebSocket.OPEN){
          ws.send(payload);
          appendMessage(`[file] ${f.name}`, 'me');
        } else appendMessage('❗ Not connected.', 'system');
      }catch(err){
        appendMessage('❌ File read error: ' + err.toString(), 'system');
      }
    };
    reader.onerror = ()=> appendMessage('❌ Could not read file.', 'system');
    reader.readAsArrayBuffer(f);
  });

  fileBtn.addEventListener('click', ()=> filePicker.click());

  // login handling: send password then username preserving handshake order
  loginForm.addEventListener('submit', (ev)=>{
    ev.preventDefault();
    const username = loginUsername.value.trim();
    const password = loginPassword.value;
    pendingLogin = {username, password};
    // ensure connected
    if(!ws || ws.readyState !== WebSocket.OPEN){
      appendMessage('Connecting to server...', 'system');
      connect();
      // wait until open
      const waitOpen = () => new Promise(res=>{
        if(ws && ws.readyState === WebSocket.OPEN) return res();
        const t = setInterval(()=>{ if(ws && ws.readyState === WebSocket.OPEN){ clearInterval(t); res(); } }, 150);
        // timeout fallback
        setTimeout(()=>res(), 5000);
      });
      waitOpen().then(()=> doHandshakeLogin(pendingLogin));
    } else doHandshakeLogin(pendingLogin);
  });

  loginGuest.addEventListener('click', ()=>{
    loginUsername.value = 'Guest' + Math.floor(Math.random()*9000+1000);
    loginPassword.value = '';
    loginForm.dispatchEvent(new Event('submit', {cancelable:true}));
  });

  function doHandshakeLogin({username,password}){
    // send password then username with slight delay to emulate terminal client handshake
    try{
      if(password) ws.send(password);
      appendMessage('[You] (password entered)', 'me');
      setTimeout(()=>{
        ws.send(username);
        appendMessage('[You] ' + username, 'me');
        // hide login overlay and switch to chat
        loginOverlay.style.display = 'none';
        // keep username stored
        lastUsername = username;
        modeText.textContent = 'Chat';
        inputEl.focus();
      }, 300);
    }catch(e){
      appendMessage('❌ Login send error: ' + e.toString(), 'system');
    }
  }

  // message send
  sendBtn.addEventListener('click', ()=>{
    const txt = inputEl.value.trim();
    if(!txt) return;
    sendText(txt);
    inputEl.value = '';
  });

  inputEl.addEventListener('keydown', (e)=>{
    if(e.key === 'Enter' && !e.shiftKey){ e.preventDefault(); sendBtn.click(); }
  });

  // connect/disconnect controls
  connectBtn.addEventListener('click', ()=> connect());
  disconnectBtn.addEventListener('click', ()=> disconnect());

  // theme toggle
  themeToggle.addEventListener('click', ()=>{
    if(root.classList.contains('theme-dark')){
      root.classList.remove('theme-dark'); root.classList.add('theme-light');
      document.documentElement.style.setProperty('--bg-dark','#f5f7fb');
      document.documentElement.style.setProperty('--text','#071029');
      themeToggle.textContent = '🌞';
    } else {
      root.classList.remove('theme-light'); root.classList.add('theme-dark');
      themeToggle.textContent = '🌗';
      document.documentElement.style.removeProperty('--bg-dark');
      document.documentElement.style.removeProperty('--text');
    }
  });

  // auto-connect on load
  window.addEventListener('load', ()=>{
    connect();
    // show login overlay (auto)
    loginOverlay.style.display = 'flex';
    loginUsername.focus();
    // register sw if available
    if('serviceWorker' in navigator){
      navigator.serviceWorker.register('service-worker.js').catch(()=>{/*ignore*/});
    }
  });

  // expose for debugging
  window._promptly = {connect,disconnect, wsRef: ()=> ws};
})();