Synkronisér kun hvis SharePoint-filen er nyere end lokal kopi

- Implementerer sammenligning af lastModifiedDateTime fra SharePoint med lokal mtime
- Konverterer ISO8601 UTC-tidsstempler til unix timestamp for præcis sammenligning
- Tilføjer 1-sekunds tolerance for at håndtere filsystemets tidspræcision
- Sikrer at data kun hentes ned hvis kilden er opdateret, eller hvis lokal fil er korrupt

download_sharepoint.py

@@ -211,7 +211,7 @@ def get_fresh_download_url(app, drive_id, item_id):
             
     return None, "Item returned but '@microsoft.graph.downloadUrl' was missing after 3 attempts."
 
-def download_single_file(app, drive_id, item_id, local_path, expected_size, display_name, remote_hash=None, initial_url=None):
+def download_single_file(app, drive_id, item_id, local_path, expected_size, display_name, remote_hash=None, initial_url=None, remote_mtime_str=None):
     try:
         file_mode = 'wb'
         resume_header = {}
@@ -220,14 +220,30 @@ def download_single_file(app, drive_id, item_id, local_path, expected_size, disp
 
         if os.path.exists(local_path):
             existing_size = os.path.getsize(local_path)
+            local_mtime = os.path.getmtime(local_path)
+            
+            # Konvertér SharePoint ISO8601 UTC tid (f.eks. 2024-03-29T12:00:00Z) til unix timestamp
+            # Vi fjerner 'Z' og bruger datetime.fromisoformat
+            remote_mtime = datetime.fromisoformat(remote_mtime_str.replace('Z', '+00:00')).timestamp()
+
+            # Hvis filen findes, har rigtig størrelse OG lokal er ikke ældre end remote -> SKIP
             if existing_size == expected_size:
+                if local_mtime >= (remote_mtime - 1): # Vi tillader 1 sekuds difference pga. filsystem-præcision
                     if verify_integrity(local_path, remote_hash):
-                    logger.info(f"Skipped (complete): {display_name}")
+                        logger.info(f"Skipped (up-to-date): {display_name}")
                         return True, None
                     else:
                         logger.warning(f"Hash mismatch on existing file: {display_name}. Re-downloading.")
                         existing_size = 0
+                else:
+                    logger.info(f"Update available: {display_name} (Remote is newer)")
+                    existing_size = 0
             elif existing_size < expected_size:
+                # Ved resume tjekker vi også om kilden er ændret siden vi startede
+                if local_mtime < (remote_mtime - 1):
+                    logger.warning(f"Remote file changed during partial download: {display_name}. Restarting.")
+                    existing_size = 0
+                else:
                     logger.info(f"Resuming: {display_name} from {format_size(existing_size)}")
                     resume_header = {'Range': f'bytes={existing_size}-'}
                     file_mode = 'ab'
@@ -306,12 +322,13 @@ def process_item_list(app, drive_id, item_path, local_root_path, report, executo
                     item_id = item['id']
                     download_url = item.get('@microsoft.graph.downloadUrl')
                     remote_hash = item.get('file', {}).get('hashes', {}).get('quickXorHash')
+                    remote_mtime = item.get('lastModifiedDateTime')
                     
                     future = executor.submit(
                         download_single_file, 
                         app, drive_id, item_id, 
                         local_path, item['size'], display_path, 
-                        remote_hash, download_url
+                        remote_hash, download_url, remote_mtime
                     )
                     futures[future] = display_path