# Refactoring Notes: Zabbix Partitioning Script

## Overview
The `zabbix_partitioning.py` script has been significantly refactored to improve maintainability, reliability, and compatibility with modern Zabbix versions (7.x).

## Key Changes

### 1. Architecture: Class-Based Structure
- **Old**: Procedural script with global variables and scattered logic.
- **New**: Encapsulated in a `ZabbixPartitioner` class.
- **Purpose**: Improves modularity, testability, and state management. Allows the script to be easily imported or extended.

### 2. Database Connection Management
- **Change**: Implemented `contextlib.contextmanager` for database connections.
- **Purpose**: Ensures database connections are robustly opened and closed, even if errors occur. Handles `wait_timeout` and binary logging settings automatically for every session.

### 3. Logging
- **Change**: Replaced custom `print` statements with Python's standard `logging` module.
- **Purpose**: 
  - Allows consistent log formatting.
  - Supports configurable output destinations (Console vs Syslog) via the config file.
  - Granular log levels (INFO for standard ops, DEBUG for SQL queries).

### 4. Configuration Handling
- **Change**: Improved validation and parsing of the YAML configuration.
- **Purpose**: 
  - Removed unused parameters (e.g., `timezone`, as the script relies on system local time).
  - Added support for custom database ports (critical for non-standard deployments or containerized tests).
  - Explicitly handles the `replicate_sql` flag to control binary logging (it was intergrated into the partitioning logic).

### 5. Type Safety
- **Change**: Added comprehensive Python type hinting (e.g., `List`, `Dict`, `Optional`).
- **Purpose**: Makes the code self-documenting and allows IDEs/linters to catch potential errors before execution.

### 6. Zabbix 7.x Compatibility
- **Change**: Added logic to verify Zabbix database version and schema requirements.
- **Purpose**: 
  - Checks `dbversion` table.
  - **Critical**: Validates that target tables have the `clock` column as part of their Primary Key before attempting partitioning, preventing potential data corruption or MySQL errors.
