Screenshot Sync

Overview

Screenshot sync is Evatar's core entry feature. The Android client automatically discovers new screenshots by monitoring the system MediaStore, uploads them to the backend after incremental comparison. The backend handles file storage, thumbnail generation, and automatic AI analysis pipeline triggering.

Key Features

• MediaStore Monitoring: ContentResolver queries the system MediaStore for screenshots
• Incremental Sync: Server-driven timestamp approach -- only uploads screenshots after last sync time
• Deduplication: device_id + local_media_store_id unique constraint prevents duplicates
• Concurrent Upload: Kotlin Coroutines Semaphore limits concurrency to 3
• App Exclusion: Users can exclude specific apps' screenshots from sync
• Dual Scheduling: Foreground Service (60s) + WorkManager (30min)

API Endpoints

Method	Path	Description
POST	/api/photos/upload	Upload single screenshot
POST	/api/photos/upload-batch	Batch upload (up to 50)
GET	/api/photos/sync-state	Query device sync state
POST	/api/photos/sync-state	Set sync start time
GET	/api/photos	Paginated screenshot list
GET	/api/photos/{id}	Get screenshot details with analysis
GET	/api/photos/{id}/image	Get original image file
GET	/api/photos/{id}/thumbnail	Get thumbnail file
GET	/api/photos/devices	List all synced devices
DELETE	/api/photos/{id}	Delete screenshot and files