Kordant/tasks/android-production/13-call-screening.md

13. Call Screening Service Production Hardening

meta: id: android-production-13 feature: android-production priority: P1 depends_on: [] tags: [native-features, spamshield, production]

objective:

• Harden the CallScreeningService for production use with robust spam detection and minimal latency

deliverables:

• CallScreeningService production-ready
• Spam database local caching
• Real-time caller lookup
• Permission handling and user guidance

steps:

1. Audit existing service:
   • Review android/app/.../service/CallScreeningService.kt
   • Identify gaps in production readiness
   • Test current functionality
2. Implement local spam database:
   • Cache spam numbers locally (Room database)
   • Sync with backend periodically
   • Hash numbers for privacy
   • Support pattern matching (wildcards)
3. Optimize lookup performance:
   • Use indexed database queries
   • Target <100ms lookup time
   • Cache frequent lookups in memory
   • Use Bloom filter for fast negative checks
4. Add caller identification:
   • Display caller info for known contacts
   • Show spam likelihood percentage
   • Show spam category (telemarketer, scam, etc.)
5. Handle permissions:
   • Request CALL_SCREENING role
   • Guide user to Default Apps settings
   • Handle permission denial gracefully
   • Re-check permission on app launch
6. Add user controls:
   • Toggle for call screening
   • Toggle for call blocking
   • Manage blocked numbers
   • Report false positives/negatives
7. Add logging and analytics:
   • Log screened calls (anonymized)
   • Track block rate and accuracy
   • Report metrics to backend
8. Test thoroughly:
   • Test with simulated calls
   • Test on physical devices
   • Test with various carriers

tests:

• Unit: Test spam lookup logic
• Integration: Test CallScreeningService binding
• Device: Test with actual incoming calls

acceptance_criteria:

• CallScreeningService registered and active
• Local spam database synced daily
• Caller lookup <100ms
• Known spam calls blocked or flagged
• User can enable/disable screening
• Block list manageable from app
• Permission handling with user guidance
• False positive reporting mechanism
• No crashes during call handling
• Works on Android 10+ (API 29+)
• Battery impact minimal

validation:

• Enable call screening → incoming spam call blocked
• Check database → spam numbers cached locally
• Measure lookup time → <100ms
• Report false positive → number removed from block list
• Disable in app → screening stops

notes:

• CallScreeningService requires special role (not just permission)
• User must set app as default call screening app in Settings
• Different carriers may handle call screening differently
• Test thoroughly on physical devices with real SIM cards