feat(background-notification): add completion notification hook

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src/hooks/background-notification/index.ts

@@ -0,0 +1,103 @@
+import type { BackgroundManager, BackgroundTask } from "../../features/background-agent"
+
+interface Event {
+  type: string
+  properties?: Record<string, unknown>
+}
+
+interface EventInput {
+  event: Event
+}
+
+interface ChatMessageInput {
+  sessionID: string
+  [key: string]: unknown
+}
+
+interface ChatMessageOutput {
+  parts: Array<{ type: string; text: string }>
+  [key: string]: unknown
+}
+
+function formatDuration(start: Date, end?: Date): string {
+  const duration = (end ?? new Date()).getTime() - start.getTime()
+  const seconds = Math.floor(duration / 1000)
+  const minutes = Math.floor(seconds / 60)
+  const hours = Math.floor(minutes / 60)
+
+  if (hours > 0) {
+    return `${hours}h ${minutes % 60}m ${seconds % 60}s`
+  } else if (minutes > 0) {
+    return `${minutes}m ${seconds % 60}s`
+  } else {
+    return `${seconds}s`
+  }
+}
+
+function formatNotifications(tasks: BackgroundTask[]): string {
+  if (tasks.length === 0) {
+    return ""
+  }
+
+  if (tasks.length > 1) {
+    let message = `✅ **Background Tasks Complete (${tasks.length})**\n\n`
+
+    for (const task of tasks) {
+      const duration = formatDuration(task.startedAt, task.completedAt)
+      const toolCalls = task.progress?.toolCalls ?? 0
+
+      message += `• **${task.id}** - ${task.description}\n`
+      message += `  Duration: ${duration} | Tool calls: ${toolCalls}\n\n`
+    }
+
+    message += `Use \`background_result\` tool to retrieve results.`
+
+    return message
+  }
+
+  const task = tasks[0]
+  const duration = formatDuration(task.startedAt, task.completedAt)
+  const toolCalls = task.progress?.toolCalls ?? 0
+
+  return `✅ **Background Task Complete**
+
+**Task ID:** ${task.id}
+**Description:** ${task.description}
+**Duration:** ${duration}
+**Tool calls:** ${toolCalls}
+
+The background task has finished. Use \`background_result\` tool with task ID \`${task.id}\` to retrieve the full result.`
+}
+
+export function createBackgroundNotificationHook(manager: BackgroundManager) {
+  const eventHandler = async ({ event }: EventInput) => {
+    manager.handleEvent(event)
+  }
+
+  const chatMessageHandler = async (
+    input: ChatMessageInput,
+    output: ChatMessageOutput
+  ) => {
+    const notifications = manager.getPendingNotifications(input.sessionID)
+
+    if (notifications.length === 0) {
+      return
+    }
+
+    const message = formatNotifications(notifications)
+
+    output.parts.unshift({
+      type: "text",
+      text: message,
+    })
+
+    manager.clearNotifications(input.sessionID)
+  }
+
+  return {
+    event: eventHandler,
+    "chat.message": chatMessageHandler,
+  }
+}
+
+export type { BackgroundNotificationHookConfig } from "./types"