server/rules_engine.py

import yaml
import logging
from typing import Dict, Any, List

logger = logging.getLogger(__name__)

class RuleEngine:
    def __init__(self):
        pass

    def load_rules(self, rules_yaml: str) -> Dict[str, Any]:
        """Loads rules from a YAML string."""
        try:
            return yaml.safe_load(rules_yaml)
        except yaml.YAMLError as e:
            logger.error(f"Error parsing rules YAML: {e}")
            raise ValueError(f"Invalid rules format: {e}")

    def evaluate(self, metrics: Dict[str, Any], rules: Dict[str, Any]) -> Dict[str, Any]:
        """
        Evaluates metrics against a set of rules.
        
        Args:
            metrics: Dictionary of extracted metrics (e.g., {'building_height': 15.0}).
            rules: Dictionary of rules (e.g., {'max_height': 12.0}).
            
        Returns:
            Dictionary with pass/fail results and details.
        """
        results = {
            "passed": True,
            "checks": []
        }
        
        # Check Max Height
        if "max_height" in rules:
            limit = rules["max_height"]
            actual = metrics.get("building_height", 0)
            passed = actual <= limit
            results["checks"].append({
                "rule": "Max Height",
                "limit": limit,
                "actual": actual,
                "passed": passed,
                "message": "Height within limits" if passed else f"Height {actual} exceeds limit {limit}"
            })
            if not passed:
                results["passed"] = False

        # Check Min Area
        if "min_area" in rules:
            limit = rules["min_area"]
            actual = metrics.get("total_floor_area", 0)
            passed = actual >= limit
            results["checks"].append({
                "rule": "Min Floor Area",
                "limit": limit,
                "actual": actual,
                "passed": passed,
                "message": "Area meets minimum" if passed else f"Area {actual} is below minimum {limit}"
            })
            if not passed:
                results["passed"] = False
                
        return results

# Singleton for simple usage
engine = RuleEngine()