adding local check

utils/file_viewer.py

@@ -40,10 +40,30 @@ AWS_PROFILE: str = "default"
 # ---------------------------------------------------------------------------
 
 
-def _download_from_s3(bucket: str, key: str, local_path: str) -> None:
+def _ensure_local_copy(bucket: str, key: str, local_path: str) -> None:
-    """Download *key* from *bucket* to *local_path* using a named session."""
+    """Download *key* from *bucket* to *local_path*, skipping if already present.
+
+    If *local_path* exists and its size matches the S3 object's size, the
+    download is skipped and a message is printed.
+    """
     session = boto3.Session(profile_name=AWS_PROFILE)
     s3 = session.client("s3")
+
+    remote_size = s3.head_object(Bucket=bucket, Key=key)["ContentLength"]
+
+    if os.path.exists(local_path):
+        local_size = os.path.getsize(local_path)
+        if local_size == remote_size:
+            print(
+                f"Local file {local_path} already matches s3://{bucket}/{key} "
+                f"({local_size} bytes); skipping download."
+            )
+            return
+        print(
+            f"Local file {local_path} size ({local_size} bytes) differs from "
+            f"S3 ({remote_size} bytes); re-downloading."
+        )
+
     print(f"Downloading s3://{bucket}/{key} -> {local_path}")
     s3.download_file(bucket, key, local_path)
     print("Download complete.")
@@ -106,7 +126,7 @@ if __name__ == "__main__":
     local_path = os.path.join(LOCAL_FOLDER, local_filename)
 
     try:
-        _download_from_s3(S3_BUCKET, S3_KEY, local_path)
+        _ensure_local_copy(S3_BUCKET, S3_KEY, local_path)
     except Exception as exc:
         print(f"S3 download error: {exc}", file=sys.stderr)
         sys.exit(1)