const chatContainer = document.getElementById("chat-container");
const messageInput = document.getElementById("message-input");
const sendBtn = document.getElementById("send-btn");
const welcomeEl = document.getElementById("welcome");
const statsEl = document.getElementById("stats");

let sessionId = localStorage.getItem("erowid_session") || "";
let isStreaming = false;

// Load stats
async function loadStats() {
  try {
    const resp = await fetch("/stats");
    const data = await resp.json();
    statsEl.textContent = `${data.experiences} reports | ${data.substances} substances | ${data.chunks} chunks`;
  } catch {
    statsEl.textContent = "connecting...";
  }
}
loadStats();

// Auto-resize textarea
messageInput.addEventListener("input", () => {
  messageInput.style.height = "auto";
  messageInput.style.height = Math.min(messageInput.scrollHeight, 120) + "px";
});

// Send on Enter (Shift+Enter for newline)
messageInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter" && !e.shiftKey) {
    e.preventDefault();
    sendMessage();
  }
});

sendBtn.addEventListener("click", sendMessage);

// Suggestion clicks
document.querySelectorAll(".suggestion").forEach((el) => {
  el.addEventListener("click", () => {
    messageInput.value = el.textContent;
    sendMessage();
  });
});

function addMessage(role, content) {
  if (welcomeEl) welcomeEl.style.display = "none";

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

  const avatar = document.createElement("div");
  avatar.className = "message-avatar";
  avatar.textContent = role === "user" ? "You" : "E";

  const contentEl = document.createElement("div");
  contentEl.className = "message-content";
  contentEl.textContent = content;

  msg.appendChild(avatar);
  msg.appendChild(contentEl);
  chatContainer.appendChild(msg);
  chatContainer.scrollTop = chatContainer.scrollHeight;

  return contentEl;
}

function addTypingIndicator() {
  const msg = document.createElement("div");
  msg.className = "message assistant";
  msg.id = "typing-indicator";

  const avatar = document.createElement("div");
  avatar.className = "message-avatar";
  avatar.textContent = "E";

  const contentEl = document.createElement("div");
  contentEl.className = "message-content";
  contentEl.innerHTML = '<div class="typing"><span></span><span></span><span></span></div>';

  msg.appendChild(avatar);
  msg.appendChild(contentEl);
  chatContainer.appendChild(msg);
  chatContainer.scrollTop = chatContainer.scrollHeight;
}

function removeTypingIndicator() {
  const el = document.getElementById("typing-indicator");
  if (el) el.remove();
}

async function sendMessage() {
  const text = messageInput.value.trim();
  if (!text || isStreaming) return;

  isStreaming = true;
  sendBtn.disabled = true;
  messageInput.value = "";
  messageInput.style.height = "auto";

  addMessage("user", text);
  addTypingIndicator();

  try {
    const resp = await fetch("/chat", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ message: text, session_id: sessionId }),
    });

    removeTypingIndicator();
    const contentEl = addMessage("assistant", "");

    const reader = resp.body.getReader();
    const decoder = new TextDecoder();
    let buffer = "";
    let fullResponse = "";

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split("\n");
      buffer = lines.pop() || "";

      for (const line of lines) {
        if (!line.startsWith("data: ")) continue;
        const jsonStr = line.slice(6).trim();
        if (!jsonStr) continue;

        try {
          const data = JSON.parse(jsonStr);
          if (data.token) {
            fullResponse += data.token;
            contentEl.textContent = fullResponse;
            chatContainer.scrollTop = chatContainer.scrollHeight;
          }
          if (data.session_id) {
            sessionId = data.session_id;
            localStorage.setItem("erowid_session", sessionId);
          }
          if (data.error) {
            contentEl.textContent = `Error: ${data.error}`;
          }
        } catch {}
      }
    }
  } catch (err) {
    removeTypingIndicator();
    addMessage("assistant", `Connection error: ${err.message}`);
  }

  isStreaming = false;
  sendBtn.disabled = false;
  messageInput.focus();
}