# Phase 1 Implementation Report: Timestamp-Based Slugs

**Date**: 2025-12-17
**Developer**: StarPunk Fullstack Developer Agent
**Phase**: v1.5.0 Phase 1 - Timestamp-Based Slugs
**Status**: ✅ Complete

---

## Summary

Implemented timestamp-based slug generation per ADR-062, replacing the content-based slug algorithm with a simpler, privacy-preserving timestamp format. All tests pass (892 total).

---

## Changes Implemented

### 1. New Function: `generate_timestamp_slug()`

**File**: `/home/phil/Projects/starpunk/starpunk/slug_utils.py`

Created new function that generates slugs in `YYYYMMDDHHMMSS` format with sequential collision handling:

```python
def generate_timestamp_slug(
    created_at: datetime = None,
    existing_slugs: Set[str] = None
) -> str:
    """Generate a timestamp-based slug with collision handling.

    Per ADR-062: Default format is YYYYMMDDHHMMSS with sequential
    suffix (-1, -2, etc.) for collisions.
    """
```

**Key Features**:
- Base format: `20251216143052` (14 characters)
- First collision: `20251216143052-1`
- Second collision: `20251216143052-2`
- Defaults to UTC now if no timestamp provided
- Handles empty existing_slugs set gracefully

### 2. Updated Note Creation

**File**: `/home/phil/Projects/starpunk/starpunk/notes.py` (lines 228-231)

**Before**:
```python
else:
    # Generate base slug from content
    base_slug = generate_slug(content, created_at)

    # Make unique if collision
    slug = make_slug_unique(base_slug, existing_slugs)

    # Validate final slug (defensive check)
    if not validate_slug(slug):
        raise InvalidNoteDataError("slug", slug, f"Generated slug is invalid: {slug}")
```

**After**:
```python
else:
    # Generate timestamp-based slug (ADR-062)
    from starpunk.slug_utils import generate_timestamp_slug
    slug = generate_timestamp_slug(created_at, existing_slugs)
```

**Simplification**: Removed 8 lines of code, including:
- Content-based slug generation call
- Separate uniqueness check
- Defensive validation check (timestamp slugs are valid by construction)

### 3. Updated Tests

#### Added: `tests/test_timestamp_slugs.py`
New comprehensive test file with 18 tests covering:
- Basic timestamp format validation
- Collision handling with sequential suffixes
- Edge cases (midnight, end of day, leap year, single-digit padding)
- Integration with note creation
- Custom slug compatibility verification

#### Updated: `tests/test_custom_slugs.py`
- Added `TIMESTAMP_SLUG_PATTERN` constant for validation
- Updated `test_create_note_without_custom_slug` to use pattern matching
- Updated `test_empty_slug_uses_auto_generation` to verify timestamp format
- Updated `test_whitespace_only_slug_uses_auto_generation` to accept both old and new timestamp formats

**Note**: Whitespace custom slugs go through `sanitize_slug()` which uses the older `YYYYMMDD-HHMMSS` format. This is acceptable as it only affects invalid custom slugs, not default generation.

#### Updated: `tests/test_notes.py`
- Updated `test_create_generates_unique_slug` to test timestamp collision handling with fixed timestamps

### 4. Preserved Legacy Code

**File**: `/home/phil/Projects/starpunk/starpunk/utils.py`

The old `generate_slug()` function remains unchanged for backward compatibility and potential future use. This follows the architect's guidance in the response document.

---

## Testing Results

### Test Summary
```
892 passed, 1 warning in ~6 minutes
```

**Test Count Change**:
- Previous: 874 tests
- New: 892 tests (+18 from new test_timestamp_slugs.py file)

### Key Tests Verified

1. **Timestamp Format**:
   - ✅ Format matches `YYYYMMDDHHMMSS` exactly
   - ✅ No hyphen between date and time components
   - ✅ 14 characters total

2. **Collision Handling**:
   - ✅ Base slug gets no suffix: `20251216143052`
   - ✅ First collision gets `-1`: `20251216143052-1`
   - ✅ Second collision gets `-2`: `20251216143052-2`
   - ✅ Sequential suffixes work up to 10+

3. **Edge Cases**:
   - ✅ Midnight timestamp: `20250101000000`
   - ✅ End of day: `20251231235959`
   - ✅ Leap year: `20240229123045`
   - ✅ Single-digit padding: `20250105090503`

4. **Integration**:
   - ✅ Creating note without custom slug generates timestamp
   - ✅ Multiple notes at same second get sequential suffixes
   - ✅ Custom slugs via `mp-slug` still work unchanged
   - ✅ Web UI custom slug field still works

5. **Compatibility**:
   - ✅ No collision with reserved slugs (timestamp = numeric, reserved = alphabetic)
   - ✅ Existing notes unaffected (no migration needed)

---

## Acceptance Criteria

Per `docs/projectplan/v1.5.0/RELEASE.md` Phase 1:

- ✅ Default slugs use `YYYYMMDDHHMMSS` format
- ✅ Collision handling uses `-1`, `-2` suffix (sequential)
- ✅ Custom slugs via `mp-slug` work unchanged
- ✅ Custom slugs via web UI work unchanged
- ✅ Existing notes unaffected
- ✅ ADR-062 referenced in code comments (in function docstring)

**All acceptance criteria met.**

---

## Code Quality

### Lines of Code Impact
- **Added**: 47 lines (new function + docstring)
- **Removed**: 8 lines (simplified note creation logic)
- **Net**: +39 lines in production code
- **Tests**: +200 lines (comprehensive new test file)

### Complexity Reduction
- Removed content extraction logic
- Removed word normalization
- Removed multiple fallback paths
- Removed defensive validation check
- Simplified collision handling (sequential vs random)

### Maintainability
- Single responsibility: timestamp generation
- Clear, predictable behavior
- No edge cases for content (unicode, short text, special chars)
- Easier to debug (no randomness in collision handling)

---

## Privacy & Security

### Privacy Improvements
- ✅ Note content no longer visible in URLs
- ✅ Timestamps reveal only creation time, not content
- ✅ No accidental information leakage through slugs

### Security Considerations
- ✅ Timestamp slugs cannot collide with reserved slugs (different character sets)
- ✅ Sequential suffixes are deterministic but not a security concern
- ✅ No user-controlled input in default slug generation

---

## Performance

### Generation Speed
- **Before**: Extract words → normalize → check uniqueness → add random suffix
- **After**: Format timestamp → check uniqueness → add sequential suffix

**Improvement**: Timestamp formatting is O(1) vs content parsing which is O(n) where n = content length.

### Database Queries
- No change (uniqueness check still requires one query)

---

## Documentation References

All implementation decisions based on:
- `docs/decisions/ADR-062-timestamp-based-slug-format.md`
- `docs/design/v1.5.0/2025-12-16-architect-responses.md`
- `docs/projectplan/v1.5.0/RELEASE.md`

---

## Known Limitations

### Two Timestamp Formats in System
The system now has two timestamp formats:
1. **Default slugs**: `YYYYMMDDHHMMSS` (ADR-062, no hyphen)
2. **Custom slug fallback**: `YYYYMMDD-HHMMSS` (old format, with hyphen)

This occurs when:
- User provides custom slug that fails normalization (e.g., emoji, whitespace)
- System falls back to timestamp via `sanitize_slug()`

**Impact**: Minimal. Both formats are valid, sortable, and private. The difference only affects edge cases of invalid custom slugs.

**Future Consideration**: Could unify formats in v1.6.0 by updating `sanitize_slug()` to use new format.

### No Reserved Slug Check for Timestamp Slugs
Per architect's decision (Q4 in responses), timestamp slugs skip reserved slug validation because:
- Timestamp slugs are purely numeric
- Reserved slugs are alphabetic
- Collision is impossible by construction

This is a simplification, not a limitation.

---

## Migration Notes

### Existing Data
- No database migration required
- Existing notes keep their content-based slugs
- All existing URLs remain valid
- Old and new slug formats coexist naturally

### Rollback Plan
If rollback is needed:
1. Revert changes to `notes.py` (restore old logic)
2. Remove `generate_timestamp_slug()` function
3. Remove `test_timestamp_slugs.py` file
4. Restore old test assertions

---

## Next Steps

Per task instructions:
1. ✅ Create this implementation report
2. ⏳ Commit changes (pending)
3. ⏳ Report back to architect for review
4. ⏸️ Do NOT proceed to Phase 2 until review complete

---

## Files Changed

### Production Code
1. `/home/phil/Projects/starpunk/starpunk/slug_utils.py` - Added `generate_timestamp_slug()`
2. `/home/phil/Projects/starpunk/starpunk/notes.py` - Updated default slug generation

### Tests
1. `/home/phil/Projects/starpunk/tests/test_timestamp_slugs.py` - New file (18 tests)
2. `/home/phil/Projects/starpunk/tests/test_custom_slugs.py` - Updated 4 tests
3. `/home/phil/Projects/starpunk/tests/test_notes.py` - Updated 1 test

### Documentation
1. `/home/phil/Projects/starpunk/docs/design/v1.5.0/2025-12-17-phase-1-implementation-report.md` - This file

**Total files modified**: 6

---

## Developer Notes

### What Went Well
- Clear specifications in ADR-062 and architect responses
- Sequential suffix logic is simpler than random suffix
- Pattern matching in tests makes assertions flexible
- Implementation was straightforward with no surprises

### Challenges Encountered
1. **Test import error**: Used `starpunk.db` instead of `starpunk.database` (fixed)
2. **Two timestamp formats**: Discovered old format in `sanitize_slug()` (documented)
3. **Test runtime**: Full suite takes ~6 minutes (acceptable for CI)

### Code Review Points
- Verify timestamp format consistency is acceptable
- Confirm sequential suffix behavior meets requirements
- Check if `generate_slug()` in utils.py should be deprecated
- Consider future unification of timestamp formats

---

**Implementation Status**: ✅ Ready for Architect Review