// =========================================================================
// Echo Voice Assistant — Web UI Client
// =========================================================================

// ---- State ----
const state = {
  ws: null,
  connected: false,
  isGenerating: false,
  isRecording: false,
  isSpeaking: false,
  currentAudio: null,
  conversations: [],
  activeConversationId: null,
  messages: [],       // { role, content, audioUrl? }
  streamingContent: "",
};

const settings = {
  voiceEnabled: true,
  autoSpeak: true,
  sidebarOpen: true,
};

// ---- DOM refs ----
const $ = (sel) => document.querySelector(sel);
const messagesEl = $("#messages");
const inputEl = $("#message-input");
const sendBtn = $("#send-btn");
const welcomeEl = $("#welcome");
const sidebarEl = $("#sidebar");
const micBtn = $("#mic-btn");
const micIcon = $("#mic-icon");
const micStop = $("#mic-stop");
const micBadge = $("#mic-badge");
const ttsBadge = $("#tts-badge");
const recIndicator = $("#recording-indicator");
const statusDot = $("#status-indicator");
const statusText = $("#status-text");
const headerTitle = $("#header-title");
const headerSubtitle = $("#header-subtitle");
const historyList = $("#history-list");

// ---- WebSocket ----
function connect() {
  const proto = location.protocol === "https:" ? "wss:" : "ws:";
  const url = `${proto}//${location.host}/ws/chat`;

  state.ws = new WebSocket(url);

  state.ws.onopen = () => {
    state.connected = true;
    statusDot.className = "status-dot online";
    statusText.textContent = "Connected";
    setSubtitle("Ready");
  };

  state.ws.onclose = () => {
    state.connected = false;
    statusDot.className = "status-dot offline";
    statusText.textContent = "Disconnected";
    setSubtitle("Disconnected — will reconnect...");
    setTimeout(connect, 3000);
  };

  state.ws.onerror = () => {
    state.connected = false;
  };

  state.ws.onmessage = (event) => {
    const data = JSON.parse(event.data);
    handleMessage(data);
  };
}

function send(data) {
  if (state.ws && state.ws.readyState === WebSocket.OPEN) {
    state.ws.send(JSON.stringify(data));
  }
}

function handleMessage(data) {
  switch (data.type) {
    case "token":
      state.streamingContent += data.text;
      updateStreamingBubble();
      break;

    case "done":
      state.isGenerating = false;
      finalizeStreaming(data.text);
      if (data.full_text) {
        updateHistoryItem(data.full_text);
      }
      setSubtitle("Ready");
      break;

    case "audio":
      if (settings.autoSpeak) {
        playAudio(data.url);
      }
      // Attach audio to last assistant message
      if (state.messages.length > 0) {
        const last = state.messages[state.messages.length - 1];
        if (last.role === "assistant") {
          last.audioUrl = data.url;
          updateSpeakButton(last);
        }
      }
      break;

    case "action":
      // Show action result as a system message
      addMessage("system", data.result, true);
      break;

    case "error":
      state.isGenerating = false;
      finalizeStreaming("");
      addMessage("assistant", data.text || "Something went wrong.");
      setSubtitle("Error");
      break;

    case "ready":
      state.isGenerating = false;
      inputEl.disabled = false;
      updateSendButton();
      break;

    case "cleared":
      state.messages = [];
      state.streamingContent = "";
      renderMessages();
      break;
  }
}

// ---- Chat ----
function sendMessage(e) {
  e.preventDefault();
  const text = inputEl.value.trim();
  if (!text || state.isGenerating) return;

  // Hide welcome
  welcomeEl.classList.add("hidden");

  // Add user message
  addMessage("user", text);
  inputEl.value = "";
  inputEl.style.height = "auto";
  updateSendButton();

  // Send to server
  state.isGenerating = true;
  state.streamingContent = "";
  inputEl.disabled = true;
  setSubtitle("Thinking...");

  // Create streaming bubble
  createStreamingBubble();
  send({ type: "chat", payload: { message: text } });
}

function addMessage(role, content, isHtml = false) {
  const msg = { role, content, audioUrl: null, isHtml };
  state.messages.push(msg);
  appendMessageDOM(msg);
  scrollToBottom();
}

function appendMessageDOM(msg) {
  const div = document.createElement("div");
  div.className = `message ${msg.role}`;
  div.dataset.role = msg.role;

  const avatar = msg.role === "user" ? userAvatar() : botAvatar();

  let contentHtml = "";
  if (msg.isHtml) {
    contentHtml = `<div class="bubble">${msg.content}</div>`;
  } else {
    contentHtml = `<div class="bubble">${escapeHtml(msg.content)}</div>`;
  }

  // Add speak button for assistant messages
  if (msg.role === "assistant" && !msg.isHtml) {
    const speakBtn = `<button class="speak-btn" onclick="replayMessage(this)" title="Play audio">
      <svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2">
        <polygon points="11 5 6 9 2 9 2 15 6 15 11 19 11 5"/>
        <path d="M15.54 8.46a5 5 0 0 1 0 7.07"/>
      </svg>
    </button>`;
    contentHtml = speakBtn + contentHtml;
  }

  div.innerHTML = avatar + contentHtml;
  messagesEl.appendChild(div);
}

function userAvatar() {
  return `<div class="avatar">
    <svg viewBox="0 0 24 24" width="16" height="16" fill="none" stroke="currentColor" stroke-width="2">
      <path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2"/>
      <circle cx="12" cy="7" r="4"/>
    </svg>
  </div>`;
}

function botAvatar() {
  return `<div class="avatar">
    <svg viewBox="0 0 24 24" width="16" height="16" fill="none" stroke="currentColor" stroke-width="2">
      <path d="M12 2a2 2 0 0 1 2 2c0 .74-.4 1.39-1 1.73V7h1a7 7 0 0 1 7 7h1a1 1 0 0 1 1 1v3a1 1 0 0 1-1 1h-1v1a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2v-1H3a1 1 0 0 1-1-1v-3a1 1 0 0 1 1-1h1a7 7 0 0 1 7-7h1V5.73A2 2 0 0 1 12 2z"/>
    </svg>
  </div>`;
}

// ---- Streaming ----
let streamingEl = null;

function createStreamingBubble() {
  const div = document.createElement("div");
  div.className = "message assistant";
  div.id = "streaming-msg";

  div.innerHTML = `
    ${botAvatar()}
    <div class="bubble">
      <span class="typing-indicator">
        <span></span><span></span><span></span>
      </span>
    </div>
  `;
  messagesEl.appendChild(div);
  streamingEl = div.querySelector(".bubble");
  scrollToBottom();
}

function updateStreamingBubble() {
  if (!streamingEl) return;
  streamingEl.innerHTML = escapeHtml(state.streamingContent) + '<span class="streaming-cursor"></span>';
  scrollToBottom();
}

function finalizeStreaming(text) {
  if (streamingEl) {
    if (text) {
      streamingEl.innerHTML = escapeHtml(text);
      // Update the streaming message to a normal one
      const msgDiv = document.getElementById("streaming-msg");
      if (msgDiv) msgDiv.removeAttribute("id");
      state.messages.push({ role: "assistant", content: text, audioUrl: null, isHtml: false });

      // Add speak button
      const speakBtn = document.createElement("button");
      speakBtn.className = "speak-btn";
      speakBtn.onclick = function () { replayMessage(this); };
      speakBtn.title = "Play audio";
      speakBtn.innerHTML = `<svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2">
        <polygon points="11 5 6 9 2 9 2 15 6 15 11 19 11 5"/>
        <path d="M15.54 8.46a5 5 0 0 1 0 7.07"/>
      </svg>`;
      streamingEl.parentElement.insertBefore(speakBtn, streamingEl);
    } else {
      streamingEl.parentElement.remove();
    }
    streamingEl = null;
  }
  scrollToBottom();
}

// ---- Audio ----
function playAudio(url) {
  if (state.currentAudio) {
    state.currentAudio.pause();
    state.currentAudio = null;
  }
  state.currentAudio = new Audio(url);
  state.isSpeaking = true;
  ttsBadge.classList.add("active");

  state.currentAudio.onended = () => {
    state.isSpeaking = false;
    ttsBadge.classList.remove("active");
  };
  state.currentAudio.onerror = () => {
    state.isSpeaking = false;
    ttsBadge.classList.remove("active");
  };
  state.currentAudio.play();
}

function replayMessage(btn) {
  // Find the closest message div
  const msgDiv = btn.closest(".message");
  if (!msgDiv) return;

  // Find the message in state
  const bubbleText = msgDiv.querySelector(".bubble").textContent;
  const msg = state.messages.find(m => m.content === bubbleText && m.role === "assistant");

  if (msg && msg.audioUrl) {
    if (state.isSpeaking) {
      state.currentAudio?.pause();
      state.isSpeaking = false;
      ttsBadge.classList.remove("active");
      return;
    }
    playAudio(msg.audioUrl);
  } else {
    // No server audio — use browser TTS
    if ("speechSynthesis" in window) {
      if (state.isSpeaking) {
        speechSynthesis.cancel();
        state.isSpeaking = false;
        return;
      }
      const utterance = new SpeechSynthesisUtterance(bubbleText);
      utterance.onstart = () => { state.isSpeaking = true; };
      utterance.onend = () => { state.isSpeaking = false; };
      utterance.onerror = () => { state.isSpeaking = false; };
      speechSynthesis.speak(utterance);
    }
  }
}

function updateSpeakButton(msg) {
  // Find the last assistant message DOM element
  const allMsgs = messagesEl.querySelectorAll(".message.assistant");
  if (allMsgs.length === 0) return;
  const lastMsg = allMsgs[allMsgs.length - 1];
  const existingBtn = lastMsg.querySelector(".speak-btn");
  if (existingBtn) {
    existingBtn.style.opacity = "1";
  }
}

// ---- Voice Input (Web Speech API) ----
let recognition = null;

function toggleMic() {
  if (state.isRecording) {
    stopRecording();
  } else {
    startRecording();
  }
}

function startRecording() {
  if (!settings.voiceEnabled) {
    alert("Voice input is disabled. Enable it in Settings.");
    return;
  }

  const SpeechRecognition = window.SpeechRecognition || window.webkitSpeechRecognition;
  if (!SpeechRecognition) {
    alert("Speech recognition is not supported in this browser. Try Chrome.");
    return;
  }

  recognition = new SpeechRecognition();
  recognition.continuous = false;
  recognition.interimResults = true;
  recognition.lang = "en-US";

  let finalTranscript = "";

  recognition.onresult = (event) => {
    let interim = "";
    for (let i = event.resultIndex; i < event.results.length; i++) {
      if (event.results[i].isFinal) {
        finalTranscript += event.results[i][0].transcript;
      } else {
        interim += event.results[i][0].transcript;
      }
    }
    inputEl.value = finalTranscript || interim;
    updateSendButton();
  };

  recognition.onend = () => {
    state.isRecording = false;
    setRecordingUI(false);
    if (finalTranscript.trim()) {
      // Auto-send
      inputEl.value = finalTranscript.trim();
      sendMessage(new Event("submit"));
    }
    recognition = null;
  };

  recognition.onerror = (event) => {
    console.error("Speech recognition error:", event.error);
    state.isRecording = false;
    setRecordingUI(false);
    recognition = null;
  };

  recognition.start();
  state.isRecording = true;
  setRecordingUI(true);
}

function stopRecording() {
  if (recognition) {
    recognition.stop();
  }
}

function setRecordingUI(recording) {
  micBtn.classList.toggle("recording", recording);
  micIcon.classList.toggle("hidden", recording);
  micStop.classList.toggle("hidden", !recording);
  recIndicator.classList.toggle("hidden", !recording);
  micBadge.classList.toggle("recording", recording);
  if (recording) {
    inputEl.placeholder = "Listening...";
    setSubtitle("Listening...");
  } else {
    inputEl.placeholder = "Type a message or use the mic...";
  }
}

// ---- TTS Toggle ----
function toggleTTS() {
  settings.autoSpeak = !settings.autoSpeak;
  ttsBadge.classList.toggle("active", settings.autoSpeak);
  document.getElementById("setting-tts").checked = settings.autoSpeak;
}

// ---- Sidebar ----
function toggleSidebar(force) {
  const show = force !== undefined ? force : !settings.sidebarOpen;
  settings.sidebarOpen = show;
  sidebarEl.classList.toggle("collapsed", !show);
}

// ---- Settings ----
function toggleSettings() {
  const panel = $("#settings-panel");
  const overlay = $("#settings-overlay");
  panel.classList.toggle("hidden");
  overlay.classList.toggle("hidden");
}

// ---- Conversations (local only for now) ----
function newChat() {
  // Clear current messages
  state.messages = [];
  state.streamingContent = "";
  messagesEl.innerHTML = "";

  // Send clear to server
  send({ type: "clear" });

  // Show welcome
  welcomeEl.classList.remove("hidden");
  headerTitle.textContent = "Echo";

  // Create local history entry
  const id = Date.now().toString();
  const conv = { id, title: "New Conversation", time: new Date() };
  state.conversations.unshift(conv);
  state.activeConversationId = id;
  renderHistory();
}

function updateHistoryItem(text) {
  const conv = state.conversations.find(c => c.id === state.activeConversationId);
  if (conv && conv.title === "New Conversation") {
    conv.title = text.slice(0, 40) + (text.length > 40 ? "..." : "");
    renderHistory();
  }
}

function renderHistory() {
  if (state.conversations.length === 0) {
    historyList.innerHTML = '<p class="empty-state">No conversations yet</p>';
    return;
  }
  historyList.innerHTML = state.conversations.map(conv => `
    <div class="history-item ${conv.id === state.activeConversationId ? 'active' : ''}" onclick="loadConversation('${conv.id}')">
      <span class="title">${escapeHtml(conv.title)}</span>
      <span class="time">${timeAgo(conv.time)}</span>
      <button class="delete-btn" onclick="event.stopPropagation(); deleteConversation('${conv.id}')">
        <svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2">
          <line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/>
        </svg>
      </button>
    </div>
  `).join("");
}

function loadConversation(id) {
  // For now, conversations are in-memory only
  state.activeConversationId = id;
  renderHistory();
  const conv = state.conversations.find(c => c.id === id);
  if (conv) {
    headerTitle.textContent = conv.title;
  }
}

function deleteConversation(id) {
  state.conversations = state.conversations.filter(c => c.id !== id);
  if (state.activeConversationId === id) {
    state.activeConversationId = null;
    headerTitle.textContent = "Echo";
  }
  renderHistory();
}

// ---- Helpers ----
function escapeHtml(text) {
  const div = document.createElement("div");
  div.textContent = text;
  return div.innerHTML;
}

function scrollToBottom() {
  const area = $(".chat-area");
  requestAnimationFrame(() => {
    area.scrollTop = area.scrollHeight;
  });
}

function setSubtitle(text) {
  headerSubtitle.textContent = text;
}

function updateSendButton() {
  sendBtn.disabled = !inputEl.value.trim() || state.isGenerating;
}

function handleKeyDown(e) {
  if (e.key === "Enter" && !e.shiftKey) {
    e.preventDefault();
    sendMessage(e);
  }
}

function autoResize(el) {
  el.style.height = "auto";
  el.style.height = Math.min(el.scrollHeight, 160) + "px";
  updateSendButton();
}

function timeAgo(date) {
  const seconds = Math.floor((new Date() - date) / 1000);
  if (seconds < 60) return "Just now";
  const minutes = Math.floor(seconds / 60);
  if (minutes < 60) return `${minutes}m ago`;
  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${hours}h ago`;
  return `${Math.floor(hours / 24)}d ago`;
}

function renderMessages() {
  messagesEl.innerHTML = "";
  if (state.messages.length === 0) {
    welcomeEl.classList.remove("hidden");
  } else {
    welcomeEl.classList.add("hidden");
    state.messages.forEach(msg => appendMessageDOM(msg));
    scrollToBottom();
  }
}

// ---- Theme (dark mode) ----
function initTheme() {
  const prefersDark = window.matchMedia("(prefers-color-scheme: dark)").matches;
  if (prefersDark) {
    document.body.classList.add("dark");
  }
  window.matchMedia("(prefers-color-scheme: dark)").addEventListener("change", (e) => {
    document.body.classList.toggle("dark", e.matches);
  });
}

// ---- Init ----
document.addEventListener("DOMContentLoaded", () => {
  initTheme();
  connect();

  // Focus input on click in chat area
  $(".chat-area").addEventListener("click", (e) => {
    if (e.target.closest(".bubble") || e.target.closest(".speak-btn")) return;
    inputEl.focus();
  });

  // Mobile: collapse sidebar by default
  if (window.innerWidth < 768) {
    toggleSidebar(false);
  }
});