migrate compress command (#4271)

packages/cli/src/ui/commands/compressCommand.ts

@@ -0,0 +1,77 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { HistoryItemCompression, MessageType } from '../types.js';
+import { SlashCommand } from './types.js';
+
+export const compressCommand: SlashCommand = {
+  name: 'compress',
+  altName: 'summarize',
+  description: 'Compresses the context by replacing it with a summary.',
+  action: async (context) => {
+    const { ui } = context;
+    if (ui.pendingItem) {
+      ui.addItem(
+        {
+          type: MessageType.ERROR,
+          text: 'Already compressing, wait for previous request to complete',
+        },
+        Date.now(),
+      );
+      return;
+    }
+
+    const pendingMessage: HistoryItemCompression = {
+      type: MessageType.COMPRESSION,
+      compression: {
+        isPending: true,
+        originalTokenCount: null,
+        newTokenCount: null,
+      },
+    };
+
+    try {
+      ui.setPendingItem(pendingMessage);
+      const promptId = `compress-${Date.now()}`;
+      const compressed = await context.services.config
+        ?.getGeminiClient()
+        ?.tryCompressChat(promptId, true);
+      if (compressed) {
+        ui.addItem(
+          {
+            type: MessageType.COMPRESSION,
+            compression: {
+              isPending: false,
+              originalTokenCount: compressed.originalTokenCount,
+              newTokenCount: compressed.newTokenCount,
+            },
+          } as HistoryItemCompression,
+          Date.now(),
+        );
+      } else {
+        ui.addItem(
+          {
+            type: MessageType.ERROR,
+            text: 'Failed to compress chat history.',
+          },
+          Date.now(),
+        );
+      }
+    } catch (e) {
+      ui.addItem(
+        {
+          type: MessageType.ERROR,
+          text: `Failed to compress chat history: ${
+            e instanceof Error ? e.message : String(e)
+          }`,
+        },
+        Date.now(),
+      );
+    } finally {
+      ui.setPendingItem(null);
+    }
+  },
+};