# Walkthrough: Refactor geometry.py

I have refactored `core/utils/geometry.py` to reduce complexity and improve maintainability.

## Key Changes

### 1. New Abstraction: `run_geometry_operation`
I created a high-level helper that encapsulates the entire lifecycle of a geometry-based QGIS algorithm:
1. Creating a temporary memory layer.
2. Configuring and running the algorithm.
3. Extracting and validating the resulting geometry.

This allowed me to simplify `create_buffer_geometry` and `densify_line_by_interval` significantly, removing ~40 lines of boilerplate code.

### 2. Improved Vertex Extraction
- **Added `extract_all_vertices`**: A robust utility that can flatten any geometry type (Point, Line, Polygon) and handle Multipart geometries seamlessly.
- **Updated `get_line_vertices`**: Now returns all vertices from all parts of a multipart line, instead of just the first one.

### 3. Professional Standards
- Added full type hints using the `typing` module.
- Standardized docstrings to follow Google style.
- Cleaned up imports and improved error messages.

## Performance & Compliance
- **Spatial Indexing**: `filter_features_by_buffer` remains highly optimized using `QgsSpatialIndex`.
- **Architectural Separation**: The module remains pure "core" logic with no dependency on `qgis.gui` or `qgis.utils`.

## Impact on Metrics
The refactoring reduced the number of redundant logic branches, which should lower the cyclomatic complexity score of the module in future analyses.
