export function buildClaudeArgs({ prompt, sessionId, turnCount, permissionMode, outputFormat }) {
  const args = ["-p", prompt.trim()];

  // First turn: Claude creates the session. Subsequent turns: Claude resumes it.
  if (turnCount === 0) args.push("--session-id", sessionId);
  else                 args.push("-r", sessionId);

  args.push("--output-format", outputFormat);

  if (outputFormat === "stream-json") {
    args.push("--verbose", "--include-partial-messages");
  }

  if (permissionMode === "full") {
    args.push("--dangerously-skip-permissions");
  }

  return args;
}

// Parse each NDJSON line from Claude's stdout
const payload = JSON.parse(line);

// Text deltas → forward as "delta" to the frontend
if (payload.type === "stream_event" && payload.event?.type === "content_block_delta") {
  const deltaText = payload.event?.delta?.text ?? "";
  if (deltaText) {
    assistantText += deltaText;
    sendNdjson(res, { type: "delta", delta: deltaText });
  }
}

// Verbose events → forward as "verbose" to the frontend for the activity pill
else if (payload.type === "stream_event") {
  const et = payload.event?.type;
  if (et === "message_start")
    sendNdjson(res, { type: "verbose", event_type: "system_init" });
  else if (et === "content_block_start" && payload.event?.content_block?.type === "tool_use")
    sendNdjson(res, { type: "verbose", event_type: "tool_use", tool_name: payload.event?.content_block?.name });
  else if (et === "content_block_start" && payload.event?.content_block?.type === "thinking")
    sendNdjson(res, { type: "verbose", event_type: "thinking" });
  else if (et === "content_block_start" && payload.event?.content_block?.type === "text")
    sendNdjson(res, { type: "verbose", event_type: "writing" });
}

export async function readNdjsonStream(response, handlers) {
  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  let buffer = "";

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

    buffer += decoder.decode(value, { stream: true });

    while (buffer.includes("\n")) {
      const boundary = buffer.indexOf("\n");
      const line = buffer.slice(0, boundary).trim();
      buffer = buffer.slice(boundary + 1);
      if (!line) continue;
      handlers.onEvent(JSON.parse(line));
    }
  }
}

// Error recovery: always check for terminal event
let receivedTerminal = false;
await readNdjsonStream(response, {
  onEvent(event) {
    if (event.type === "done" || event.type === "error") receivedTerminal = true;
    // ...handle event
  }
});
if (!receivedTerminal) {
  setStatus("Connection lost. Please try again.");
}

{
  "sessionId": "uuid",
  "engine": "claude",
  "permissionMode": "safe",
  "turnCount": 3,
  "transcript": [
    { "id": "uuid", "role": "user",      "content": "...", "status": "completed", "mode": "stream", "createdAt": "iso" },
    { "id": "uuid", "role": "assistant", "content": "...", "status": "completed", "mode": "stream", "createdAt": "iso" }
  ],
  "createdAt": "iso",
  "updatedAt": "iso"
}

export function ensureWorkspace(appName, appDir) {
  const workDir = join(homedir(), `.${appName}`);

  // Create working folder and subdirectories
  for (const sub of ["sessions", "uploads", "output"]) {
    mkdirSync(join(workDir, sub), { recursive: true });
  }

  // Create .agents/ dir and symlink skills + agent.md
  mkdirSync(join(workDir, ".agents"), { recursive: true });
  ensureSymlink(join(appDir, "skills"),   join(workDir, ".agents", "skills"));
  ensureSymlink(join(appDir, "agent.md"), join(workDir, ".agents", "agent.md"));

  return workDir;
}

// In server.js — call on startup
const WORK_DIR = ensureWorkspace("my-app", APP_DIR);
const claudeRunner = createClaudeRunner({ timeoutMs, workingDir: WORK_DIR });

export function createActivityPill() {
  const pill = document.createElement("div");
  pill.className = "activity-pill";
  pill.dataset.expanded = "false";
  pill.innerHTML = `
    <button class="pill-header" onclick="togglePillLog(this)">
      <span class="pill-chevron">▸</span>
      <span class="pill-text">⏳ Starting...</span>
    </button>
    <div class="pill-log" hidden></div>`;
  return pill;
}

export function finalizePill(pill, toolCount) {
  if (toolCount === 0) { pill.remove(); return; }
  updatePill(pill, { text: `🔧 ${toolCount} tool call${toolCount === 1 ? "" : "s"}`, color: "orange" });
}

// In your NDJSON event handler
let pill = null, toolCount = 0;

function handleEvent(event) {
  if (event.type === "start") {
    pill = createActivityPill();
    messagesEl.appendChild(pill);
  }
  if (event.type === "verbose" && pill) {
    const label = event.event_type === "thinking"    ? "💭 Thinking..."
                : event.event_type === "tool_use"    ? `🔧 ${event.tool_name}...`
                : event.event_type === "tool_result" ? "📥 Result..."
                : event.event_type === "writing"     ? "✍️ Writing..."
                : null;
    if (label) updatePill(pill, { text: label, log: label });
    if (event.event_type === "tool_use") toolCount++;
  }
  if (event.type === "done" && pill) finalizePill(pill, toolCount);
}

SECTION_READY:{"sectionIndex":1,"docIndex":1,"title":"Executive Summary"}
TASK_LIST_READY:[{"title":"Section 1","docNumber":1,"referenceFile":"doc01.md"}, ...]

const markerIdx = fullContent.lastIndexOf("\nSECTION_READY:");
if (markerIdx !== -1) {
  const before      = fullContent.slice(0, markerIdx).trim();
  const markerLine  = fullContent.slice(markerIdx + "\nSECTION_READY:".length).split("\n")[0].trim();
  const markerData  = JSON.parse(markerLine);
  return { content: before, markerData };
}