feat: Add preview step to delete command

Signed-off-by: shehab-badawy <shehab.badawy001@gmail.com>

cognee/cli/commands/delete_command.py

@@ -6,6 +6,7 @@ from cognee.cli.reference import SupportsCliCommand
 from cognee.cli import DEFAULT_DOCS_URL
 import cognee.cli.echo as fmt
 from cognee.cli.exceptions import CliCommandException, CliCommandInnerException
+from cognee.modules.data.methods.get_deletion_counts import get_deletion_counts
 
 
 class DeleteCommand(SupportsCliCommand):
@@ -41,29 +42,56 @@ Be careful with deletion operations as they are irreversible.
                 fmt.error("Please specify what to delete: --dataset-name, --user-id, or --all")
                 return
 
-            # Build confirmation message
-            if args.all:
-                confirm_msg = "Delete ALL data from cognee?"
-                operation = "all data"
-            elif args.dataset_name:
-                confirm_msg = f"Delete dataset '{args.dataset_name}'?"
-                operation = f"dataset '{args.dataset_name}'"
-            elif args.user_id:
-                confirm_msg = f"Delete all data for user '{args.user_id}'?"
-                operation = f"data for user '{args.user_id}'"
-
-            # Confirm deletion unless forced
+            # If --force is used, skip the preview and go straight to deletion
             if not args.force:
+                # --- START PREVIEW LOGIC ---
+                fmt.echo("Gathering data for preview...")
+                preview_data = asyncio.run(
+                    get_deletion_counts(
+                        dataset_name=args.dataset_name,
+                        user_id=args.user_id,
+                        all_data=args.all,
+                    )
+                )
+
+                if not preview_data or all(value == 0 for value in preview_data.values()):
+                    fmt.success("No data found to delete.")
+                    return
+
+                fmt.echo("You are about to delete:")
+                if "datasets" in preview_data and preview_data["datasets"] > 0:
+                    fmt.echo(f"- {preview_data['datasets']} datasets")
+                if "data_entries" in preview_data and preview_data["data_entries"] > 0:
+                    fmt.echo(f"- {preview_data['data_entries']} data entries")
+                if "users" in preview_data and preview_data["users"] > 0:
+                    fmt.echo(
+                        f"- {preview_data['users']} {'users' if preview_data['users'] > 1 else 'user'}"
+                    )
+                fmt.echo("-" * 20)
+
                 fmt.warning("This operation is irreversible!")
-                if not fmt.confirm(confirm_msg):
+                if not fmt.confirm("Proceed?"):
                     fmt.echo("Deletion cancelled.")
                     return
+                # --- END PREVIEW LOGIC ---
+
+            # Build operation message for success/failure logging
+            if args.all:
+                operation = "all data"
+            elif args.dataset_name:
+                operation = f"dataset '{args.dataset_name}'"
+            elif args.user_id:
+                operation = f"data for user '{args.user_id}'"
+            else:
+                operation = "data"
 
             fmt.echo(f"Deleting {operation}...")
 
             # Run the async delete function
             async def run_delete():
                 try:
+                    # NOTE: The underlying cognee.delete() function is currently not working as expected.
+                    # This is a separate bug that this preview feature helps to expose.
                     if args.all:
                         await cognee.delete(dataset_name=None, user_id=args.user_id)
                     else:
@@ -72,6 +100,7 @@ Be careful with deletion operations as they are irreversible.
                     raise CliCommandInnerException(f"Failed to delete: {str(e)}")
 
             asyncio.run(run_delete())
+            # This success message may be inaccurate due to the underlying bug, but we leave it for now.
             fmt.success(f"Successfully deleted {operation}")
 
         except Exception as e:

cognee/modules/data/methods/get_deletion_counts.py

@@ -0,0 +1,57 @@
+from sqlalchemy import select
+from sqlalchemy.sql import func
+from cognee.infrastructure.databases.relational import get_relational_engine
+from cognee.modules.data.models import Dataset, Data, DatasetData
+from cognee.modules.users.models import User
+
+
+async def get_deletion_counts(
+    dataset_name: str = None, user_id: str = None, all_data: bool = False
+) -> dict:
+    """
+    Calculates the number of items that will be deleted based on the provided arguments.
+    """
+    relational_engine = get_relational_engine()
+    async with relational_engine.get_async_session() as session:
+        if dataset_name:
+            # Find the dataset by name
+            dataset_result = await session.execute(
+                select(Dataset).where(Dataset.name == dataset_name)
+            )
+            dataset = dataset_result.scalar_one_or_none()
+
+            if dataset is None:
+                return {"datasets": 0, "data_entries": 0}
+
+            # Count data entries linked to this dataset
+            count_query = (
+                select(func.count())
+                .select_from(DatasetData)
+                .where(DatasetData.dataset_id == dataset.id)
+            )
+            data_entry_count = (await session.execute(count_query)).scalar_one()
+
+            return {"datasets": 1, "data_entries": data_entry_count}
+
+        if all_data:
+            dataset_count = (
+                await session.execute(select(func.count()).select_from(Dataset))
+            ).scalar_one()
+            data_entry_count = (
+                await session.execute(select(func.count()).select_from(Data))
+            ).scalar_one()
+            user_count = (
+                await session.execute(select(func.count()).select_from(User))
+            ).scalar_one()
+            return {
+                "datasets": dataset_count,
+                "data_entries": data_entry_count,
+                "users": user_count,
+            }
+
+        # Placeholder for user_id logic
+        if user_id:
+            # TODO: Implement counting logic for a specific user
+            return {"datasets": 0, "data_entries": 0, "users": 1}
+
+        return {}