app/analyzer.py

import ast
from typing import List, Dict

class CodeSmellVisitor(ast.NodeVisitor):
    def __init__(self):
        self.issues = []

    def visit_FunctionDef(self, node):
        """Check for functions with too many arguments (Code Smell)"""
        if len(node.args.args) > 5:
            self.issues.append({
                "line": node.lineno,
                "type": "Complexity",
                "message": f"Function '{node.name}' has too many arguments ({len(node.args.args)}). Max is 5."
            })
        
        # Check for mutable default arguments (e.g., def foo(l=[]))
        # This is a classic Python 'gotcha' interview question
        for default in node.args.defaults:
            if isinstance(default, (ast.List, ast.Dict, ast.Set)):
                self.issues.append({
                    "line": node.lineno,
                    "type": "Bug Risk",
                    "message": f"Function '{node.name}' uses a mutable default argument. This persists state across calls!"
                })
        
        # Continue walking through the children of this node
        self.generic_visit(node)

    def visit_Call(self, node):
        """Check for dangerous function calls like eval()"""
        if isinstance(node.func, ast.Name) and node.func.id == 'eval':
            self.issues.append({
                "line": node.lineno,
                "type": "Security",
                "message": "Use of 'eval()' detected. This is a major security risk."
            })
        self.generic_visit(node)

def analyze_code(code_content: str) -> List[Dict]:
    try:
        tree = ast.parse(code_content)
        visitor = CodeSmellVisitor()
        visitor.visit(tree)
        return visitor.issues
    except SyntaxError as e:
        return [{"line": e.lineno, "type": "Syntax Error", "message": str(e)}]