---
story_id: sprint_2_story_2
sprint: sprint_2
priority: P0
status: not_started
story_points: 8
estimated_days: 3-4
created_date: 2025-11-05
assignee: Backend Team
---

# Story 2: Audit Log Core Features (Phase 2)

**Sprint**: Sprint 2
**Priority**: P0 (Must Have)
**Estimated**: 3-4 days (Day 27-30)
**Owner**: Backend Team

## Description

Enhance audit logging with core features including changed fields detection (old vs new values JSON diff), user context tracking, multi-tenant isolation, query API, and integration tests.

## Acceptance Criteria

- [ ] Changed fields tracking implemented with JSON diff
- [ ] User context (UserId) automatically captured
- [ ] Multi-tenant isolation for audit logs enforced
- [ ] Query API implemented for retrieving audit history
- [ ] Integration tests with >= 90% coverage
- [ ] Performance target met (< 5ms overhead)
- [ ] All tests passing

## Technical Requirements

**Enhanced Features**:
- Changed Fields Detection: Compare old vs new values, store only changed fields
- User Context: Automatically capture current user from HTTP context
- Multi-Tenant Isolation: Filter audit logs by TenantId
- Query API: REST endpoints for audit history retrieval

**Technology Stack**:
- System.Text.Json for JSON diffing
- PostgreSQL JSONB for flexible storage
- CQRS pattern for query handlers

## Tasks

- [ ] [Task 1](sprint_2_story_2_task_1.md) - Implement Changed Fields Detection (JSON Diff)
- [ ] [Task 2](sprint_2_story_2_task_2.md) - Integrate User Context Tracking
- [ ] [Task 3](sprint_2_story_2_task_3.md) - Add Multi-Tenant Isolation
- [ ] [Task 4](sprint_2_story_2_task_4.md) - Implement Audit Query API
- [ ] [Task 5](sprint_2_story_2_task_5.md) - Write Integration Tests

**Progress**: 0/5 tasks completed

## Dependencies

**Prerequisites**:
- ✅ Story 1 completed (Audit Log Foundation)
- ✅ EF Core Interceptor implemented
- ✅ AuditLog entity and repository ready

## Definition of Done

- All 5 tasks completed
- Changed fields detection working correctly
- User context captured from HTTP context
- Multi-tenant isolation verified
- Query API endpoints working
- All tests passing (>= 90% coverage)
- Performance benchmark met (< 5ms overhead)
- Code reviewed and approved
- Git commit created

## Notes

**Performance Target**: < 5ms overhead per SaveChanges operation
**JSON Diff**: Store only changed fields, not full entity snapshots (storage optimization)

---

**Created**: 2025-11-05 by Backend Agent
