Fix: Enhanced Error Handling and Feedback for CSV Import

[RyanMarr]

Fix: Enhanced Error Handling and Feedback for CSV Import

Motivation

The CSV Import feature had a few "silent failure" modes that made debugging dificult for users:

1. Swallowed Exceptions: Critial IOException and ParseException errors during the pre-check phase (in getItemFromInstance) were caught but not logged or reported, leading to incomplete data loading.
2. Blank Error Dialog: A logic error in MainWindow.java caused the import result to be overwritten by an empty "final result" object, resulting in a blank error dialog if the pre-check failed.
3. Silent Execution Failures: If the import process crashed (e.g., RuntimeException) or failed during the actual update loop, the errors were not aggregated or displayed to the user.
4. UI Feedback: The UI would appear frozen during the pre-check phase.

Changes

JellyfinImportMetadata.java

• Pre-check: Modified startPreCheck to catch generic Exceptions and propagate them to the result object.
• Logging: In getItemFromInstance, exceptions are now explicitly logged to the differences log file (and system logger) instead of being ignored.
• Execution Debugging: Refactored startImport to:
  • Wrap the iteration loop in a try-catch block to handle unexpected crashes.
  • Use a StringBuilder to aggregate specific error messages for failed items (e.g., "Failed to refresh folder ID...").
  • Include this aggregated report in the final JellyfinResponseStandard message if the import fails.

MainWindow.java

• Progress Indicator: Added a modal "Checking CSV..." JDialog with an indeterminate progress bar during the pre-check phase to indicate activity.
• Logic Fix: Fixed the bug where processResult was unconditionally overwritten by importCSV.getProcessFinalResult() (which was empty at that stage). Now it only updates after a successful import run.
• Worker Handling: Added a try-catch block around worker.get() in the done() method to ensure that any exceptions thrown on the background thread are displayed to the user via a JOptionPane.

Testing

• Verified that bad CSV data (e.g. invalid IDs) now results in a detailed error dialog pointing to the log file.
• Verified that execution failures display a list of specific failed items.
• Verified that the "Checking CSV..." dialog appears correctly.