Migrate to synctools library for iCalendar handling

[patrickunterwegs]

Summary

Refactored Ical4androidUtil to use the new synctools library for iCalendar parsing, object mapping, and storage operations, replacing the previous ical4android-based implementation.

Key Changes

• Updated imports: Replaced ical4android imports with synctools equivalents (ICalendarParser, CalendarUidSplitter, JtxObjectBuilder, JtxObjectHandler, etc.)

• Refactored getICSFormatForCollectionFromProvider():

  • Now uses JtxCollectionProvider and JtxObjectHandler for mapping objects to iCalendar components
  • Iterates through main jtx objects and their exceptions separately
  • Properly handles resource cleanup with try-finally block

• Refactored writeICSFormatFromProviderToOS():

  • Simplified to use new componentsForObject() helper method
  • Uses JtxObjectHandler for consistent component mapping
  • Improved error handling and resource management

• Refactored insertFromReader():

  • Replaced JtxICalObject.fromReader() with ICalendarParser and CalendarUidSplitter
  • Uses JtxObjectBuilder to construct jtx objects from parsed components
  • Uses JtxRecurringCollection for proper insertion of objects with exceptions
  • Updated sequence comparison logic to work with new data structures

• Added helper methods:

  • jtxObjectHandler(): Creates a configured JtxObjectHandler with attachment fetching
  • componentsForObject(): Maps a main jtx object and its exceptions to iCalendar components
  • buildCalendar(): Constructs a Calendar object from components
  • writeComponents(): Overloaded methods to write components to OutputStream or Writer

• Removed legacy classes: Deleted LocalJtxICalObject and LocalJtxCollection wrapper classes (now handled by synctools)

• Updated test expectations: Adjusted Ical4androidUtilTest to reflect that synctools' CalendarUidSplitter merges duplicate components with the same UID during parsing

Implementation Details

• All public methods now properly acquire and release content provider clients with try-finally blocks
• Exception handling logs warnings and returns appropriate default values (null or empty pairs)
• The new implementation leverages synctools' built-in support for handling recurrence exceptions and attachment fetching
• Component mapping is now centralized through JtxObjectHandler for consistency across export operations

https://claude.ai/code/session_011JEizQuqZkmoSJf6saEPDH