Fix: Sort emails by date instead of UID order (#98)

The order parameter was sorting by IMAP UID order, which doesn't
guarantee chronological order on all servers. ProtonMail Bridge
(and potentially others) assign UIDs in non-chronological order,
causing order=desc to return oldest emails instead of newest.

This fix:
- Fetches metadata for all matching emails
- Sorts by the actual email Date header
- Applies pagination after sorting

Fixes #97

Co-authored-by: Jack Koch <jack@jbkjr.me>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: 3 people

mcp_email_server/emails/classic.py

@@ -267,14 +267,12 @@ async def get_emails_metadata_stream(  # noqa: C901
             else:
                 email_ids = messages[0].split()
                 logger.info(f"Found {len(email_ids)} email IDs")
-            start = (page - 1) * page_size
-            end = start + page_size
-
-            if order == "desc":
-                email_ids.reverse()
+            # Fetch metadata for all emails first, then sort by date
+            # (UID order doesn't guarantee chronological order on all IMAP servers)
+            all_metadata: list[dict[str, Any]] = []
 
             # Fetch each message's metadata only
-            for _, email_id in enumerate(email_ids[start:end]):
+            for _, email_id in enumerate(email_ids):
                 try:
                     # Convert email_id from bytes to string
                     email_id_str = email_id.decode("utf-8")
@@ -343,14 +341,23 @@ async def get_emails_metadata_stream(  # noqa: C901
                                 "date": date,
                                 "attachments": [],  # We don't fetch attachment info for metadata
                             }
-                            yield metadata
+                            all_metadata.append(metadata)
                         except Exception as e:
                             # Log error but continue with other emails
                             logger.error(f"Error parsing email metadata: {e!s}")
                     else:
                         logger.error(f"Could not find header data in response for email ID: {email_id_str}")
                 except Exception as e:
                     logger.error(f"Error fetching email metadata {email_id}: {e!s}")
+
+            # Sort by date (desc = newest first, asc = oldest first)
+            all_metadata.sort(key=lambda x: x["date"], reverse=(order == "desc"))
+
+            # Apply pagination after sorting
+            start = (page - 1) * page_size
+            end = start + page_size
+            for metadata in all_metadata[start:end]:
+                yield metadata
         finally:
             # Ensure we logout properly
             try: