/**
 * Notify Extension
 *
 * Sends a native notification when the pi agent finishes and is waiting for
 * input. Useful when you step away during a long task.
 *
 * Only fires when the agent ran for longer than --notify-min-secs (default 8).
 * Short responses are silently skipped to avoid notification noise.
 *
 * Terminal detection (in priority order):
 *   KITTY_WINDOW_ID → OSC 99  (Kitty)
 *   WT_SESSION      → Windows toast  (Windows Terminal / WSL)
 *   otherwise       → OSC 777  (iTerm2, WezTerm, Ghostty, rxvt-unicode)
 */

import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";

// ── Notification backends ─────────────────────────────────────────────────────

function notifyKitty(title: string, body: string): void {
  // OSC 99: two-part protocol — title first, then body
  process.stdout.write(`\x1b]99;i=1:d=0;${title}\x1b\\`);
  process.stdout.write(`\x1b]99;i=1:p=body;${body}\x1b\\`);
}

function notifyOSC777(title: string, body: string): void {
  process.stdout.write(`\x1b]777;notify;${title};${body}\x07`);
}

function notifyWindows(title: string, body: string): void {
  const type = "Windows.UI.Notifications";
  const script = [
    `[${type}.ToastNotificationManager, ${type}, ContentType = WindowsRuntime] > $null`,
    `$xml = [${type}.ToastNotificationManager]::GetTemplateContent([${type}.ToastTemplateType]::ToastText01)`,
    `$xml.GetElementsByTagName('text')[0].AppendChild($xml.CreateTextNode('${body}')) > $null`,
    `[${type}.ToastNotificationManager]::CreateToastNotifier('${title}').Show([${type}.ToastNotification]::new($xml))`,
  ].join("; ");
  const { execFile } = require("node:child_process");
  execFile("powershell.exe", ["-NoProfile", "-Command", script]);
}

function notify(title: string, body: string): void {
  if (process.env.KITTY_WINDOW_ID) {
    notifyKitty(title, body);
  } else if (process.env.WT_SESSION) {
    notifyWindows(title, body);
  } else {
    notifyOSC777(title, body);
  }
}

// ── Extension ─────────────────────────────────────────────────────────────────

export default function (pi: ExtensionAPI) {
  pi.registerFlag("notify-min-secs", {
    description: "Minimum agent run time in seconds before a notification fires (default: 8)",
    type: "number",
    default: 8,
  });

  let startedAt: number | undefined;

  pi.on("agent_start", async () => {
    startedAt = Date.now();
  });

  pi.on("agent_end", async () => {
    if (startedAt === undefined) return;

    const elapsed = (Date.now() - startedAt) / 1000;
    startedAt = undefined;

    const minSecs = (pi.getFlag("notify-min-secs") as number | undefined) ?? 8;
    if (elapsed < minSecs) return;

    notify("Pi", `Done (${Math.round(elapsed)}s)`);
  });
}