# Knowledge Graph Build Progress Bars - Implementation Summary

## Objective

Add progress bars to the `kg build` command to provide visibility during slow operations (30-60+ seconds).

## What Was Changed

### 1. Core Progress Tracking (`src/mcp_vector_search/core/kg_builder.py`)

Modified `build_from_chunks_sync()` method to add progress bars at key stages:

#### Phase 1: Scanning Chunks (Lines 382-420)

**Code Chunks Loop:**
- Added progress tracking with ETA estimation
- Updates every 500 chunks
- Displays: `Scanning code chunks... ━━━━━━ 67% 2,277/4,532 [00:05 remaining]`

**Text Chunks Loop:**
- Added progress tracking with ETA estimation
- Updates every 100 chunks
- Displays: `Scanning text chunks... ━━━━━━ 45% 25,906/57,812 [01:23 remaining]`

```python
# Code chunks
start_time = time.time()
for i, chunk in enumerate(code_chunks, 1):
    # ... process chunk ...

    # Show progress every 500 chunks
    if progress_tracker and (i % 500 == 0 or i == len(code_chunks)):
        progress_tracker.progress_bar_with_eta(
            i, len(code_chunks),
            prefix="Scanning code chunks",
            start_time=start_time
        )

# Text chunks
text_start_time = time.time()
for i, chunk in enumerate(text_chunks, 1):
    # ... process chunk ...

    # Show progress every 100 chunks
    if progress_tracker and (i % 100 == 0 or i == len(text_chunks)):
        progress_tracker.progress_bar_with_eta(
            i, len(text_chunks),
            prefix="Scanning text chunks",
            start_time=text_start_time
        )
```

#### Phase 3: Building Relationships (Lines 563-630)

**Validation Loop:**
- Added progress tracking across all relationship types
- Updates every 1,000 relationships
- Displays: `Validating calls... ━━━━━━ 67% 17,000/25,691 [00:08 remaining]`

**Insertion Progress:**
- Added status messages before/after each type
- Shows: `→ Inserting 2,500 calls relationships...`
- Then: `✓ 2,500 calls inserted`

```python
# Count total relationships for progress tracking
total_rels_count = sum(len(rels) for rels in relationships.values())
processed_rels = 0
rel_start_time = time.time()

for rel_type, rels in relationships.items():
    if rels:
        valid_rels = []

        for i, rel in enumerate(rels, 1):
            # ... validate rel ...

            processed_rels += 1
            # Show progress every 1000 relationships
            if progress_tracker and (processed_rels % 1000 == 0 or processed_rels == total_rels_count):
                progress_tracker.progress_bar_with_eta(
                    processed_rels, total_rels_count,
                    prefix=f"Validating {rel_type.lower()}",
                    start_time=rel_start_time
                )

        # Show insertion status
        if progress_tracker and len(valid_rels) > 0:
            progress_tracker.item(
                f"Inserting {len(valid_rels):,} {rel_type.lower()} relationships...",
                done=False
            )

        count = self.kg.add_relationships_batch_sync(valid_rels, batch_size=safe_batch_size)

        if progress_tracker:
            progress_tracker.item(f"{count:,} {rel_type.lower()} inserted", done=True)
```

### 2. Subprocess Integration (Already Present)

The subprocess script (`src/mcp_vector_search/cli/commands/_kg_subprocess.py`) already had ProgressTracker integration:

```python
from mcp_vector_search.core.progress import ProgressTracker

# Create progress tracker
progress_tracker = ProgressTracker(console, verbose=args.verbose)

build_stats = builder.build_from_chunks_sync(
    chunks,
    show_progress=True,
    skip_documents=args.skip_documents,
    progress_tracker=progress_tracker,
)
```

## Progress Bar Features

The `ProgressTracker` class provides:

1. **Inline updates**: Progress bars update in-place using `\r` (carriage return)
2. **ETA estimation**: Shows estimated time remaining based on current rate
3. **Percentage and counts**: `67% 54,234/81,238`
4. **Thread-safe**: Uses `sys.stderr.write()` without background threads (Kuzu-safe)
5. **Phase tracking**: Clear separation of build phases with timing

## Example Output

```
Building Knowledge Graph
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Phase 1/4: Scanning chunks
  Scanning code chunks... ━━━━━━━━━━━━━━━━ 100% 4,532/4,532
  Scanning text chunks... ━━━━━━━━━━━━━━━━ 100% 57,812/57,812
  ✓ Processed 62,344 chunks
  ✓ Found 4,532 code entities
  ✓ Found 57,812 doc sections
  ✓ Found 26 tags
  (completed in 2.1s)

Phase 2/4: Inserting entities
  ✓ 4,532 code entities
  ✓ 57,812 doc sections
  ✓ 26 tags
  (completed in 1.5s)

Phase 3/4: Building relationships
  Validating calls... ━━━━━━━━━━━━━━━━ 100% 2,500/2,500
  → Inserting 2,500 calls relationships...
  ✓ 2,500 calls inserted
  Validating imports... ━━━━━━━━━━━━━━━━ 100% 3,200/3,200
  → Inserting 3,200 imports relationships...
  ✓ 3,200 imports inserted
  (completed in 8.7s)

Phase 4/4: Extracting git metadata
  ✓ 5 persons
  ✓ 1 project
  (completed in 0.8s)

✓ Knowledge graph built successfully! Total: 62,370 entities, 12,764 relationships
  Time: 13.1s
```

## Testing

**Simulation Test:**
```bash
source .venv/bin/activate
python scripts/tmp/test_progress_bars.py
```

**Real KG Build:**
```bash
mcp-vector-search kg build --force
```

Expected behavior:
- Progress bars appear during Phase 1 (scanning) and Phase 3 (relationships)
- Each progress bar updates in-place with ETA estimates
- No background threads spawned (Kuzu-safe)

## Key Design Decisions

### 1. Update Frequency

Chosen frequencies balance responsiveness vs. overhead:

- **Code chunks**: Every 500 (typical count: 4-5k)
- **Text chunks**: Every 100 (typical count: 50-60k)
- **Relationships**: Every 1,000 (typical count: 10-30k)

### 2. Thread Safety

All progress tracking uses simple `sys.stderr.write()` without Rich's background rendering threads, ensuring compatibility with Kuzu's single-threaded requirements.

### 3. Optional Progress Tracker

The `progress_tracker` parameter is optional (`Optional[ProgressTracker] = None`), maintaining backward compatibility with other callers.

## Performance Impact

- **Minimal overhead**: Progress updates occur only every N items
- **No additional computation**: Uses existing loop counters
- **No threading**: Safe for Kuzu's Rust bindings
- **Estimated overhead**: <0.1% of total build time

## Files Modified

1. **src/mcp_vector_search/core/kg_builder.py**
   - Modified `build_from_chunks_sync()` method
   - Added progress bars to Phase 1 (scanning) and Phase 3 (relationships)

2. **scripts/tmp/test_progress_bars.py** (new)
   - Simulation test for progress bars
   - Demonstrates expected output

## Verification

✅ Syntax validation passed:
```bash
python -m py_compile src/mcp_vector_search/core/kg_builder.py
python -m py_compile src/mcp_vector_search/cli/commands/_kg_subprocess.py
```

✅ Simulation test passed:
```bash
python scripts/tmp/test_progress_bars.py
```

Shows correct progress bar output with ETA estimation.

## Next Steps

To test with actual KG build:

```bash
# Run on this project
mcp-vector-search kg build --force

# Expected: Progress bars show during scanning and relationship validation
# Typical build time: 10-60 seconds depending on codebase size
```

## Future Enhancements

Possible improvements:

1. Add progress to Phase 4 (git metadata extraction) if it becomes slow
2. Add configurable update frequency via `--progress-interval` flag
3. Add `--no-progress` flag to disable progress bars
4. Add progress to Phase 2 (entity insertion) if batches become large
