graders/code_structure.py

"""
graders/code_structure.py — Code structure quality grader.
Weight: 3% of total reward.

Checks:
  - No bare print() statements (production code uses logging)
  - Handles None/empty inputs (edge case awareness)
  - No bare except clauses (too broad)
  - No global mutable state (thread safety)
"""
import ast
import re
from typing import Dict, Any


def grade_code_structure(code: str) -> Dict[str, Any]:
    checks = {}

    # Check 1: No print statements
    checks["no_print"] = "print(" not in code

    # Check 2: Has some error handling
    checks["has_error_handling"] = "try:" in code or "raise" in code or "ValueError" in code

    # Check 3: No bare except
    checks["no_bare_except"] = "except:" not in code

    # Check 4: No hardcoded credentials pattern
    has_hardcoded = bool(re.search(
        r'(password|secret|api_key|token)\s*=\s*["\'][^"\']{3,}["\']',
        code, re.IGNORECASE
    ))
    checks["no_hardcoded_creds"] = not has_hardcoded

    # Check 5: Has type annotations (bonus)
    checks["has_type_hints"] = "->" in code or ": str" in code or ": int" in code or ": bool" in code

    passed = sum(checks.values())
    total = len(checks)
    score = round(passed / total, 4)

    issues = [k for k, v in checks.items() if not v]
    feedback = "Clean structure." if not issues else f"Issues: {', '.join(issues)}"

    return {"score": score, "feedback": feedback, "checks": checks}