Kowalski Code Agent

A specialized AI agent for code analysis, refactoring, and documentation, built on the Kowalski framework. The Code Agent provides intelligent, language-aware code analysis and improvement suggestions for multiple programming languages.

What is the Code Agent?

The Code Agent is an AI-powered assistant that combines large language models with language-specific static analysis tools. It helps developers analyze, refactor, and document code in languages like Java, Python, and Rust, providing actionable insights and recommendations.

Core Capabilities

• Multi-language Support: Analyze Java, Python, Rust, and more
• Code Metrics: Compute lines, complexity, functions, classes, and more
• Quality Suggestions: Get actionable recommendations for code improvement
• Error and Issue Detection: Identify syntax errors, anti-patterns, and style violations
• Refactoring: Automated suggestions for code refactoring and organization
• Documentation Generation: Create or improve code documentation
• Streaming AI Analysis: Real-time, conversational code review and Q&A
• Role-based Analysis: Customizable analysis for different developer roles

What Does It Do?

• Code Ingestion: Accepts code snippets or files for analysis
• Static Analysis: Computes metrics, detects issues, and checks style
• AI-Powered Review: Provides human-readable feedback and improvement suggestions
• Refactoring: Offers or applies refactoring suggestions
• Documentation: Generates or improves code documentation
• Interactive Q&A: Supports follow-up questions and iterative review

Example Usage

use kowalski_code_agent::CodeAgent;
use kowalski_core::config::Config;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config = Config::default();
    let mut code_agent = CodeAgent::new(config).await?;

    // Analyze Python code
    let python_code = "...";
    let analysis = code_agent.analyze_python(python_code).await?;
    println!("Suggestions: {:?}", analysis.suggestions);

    // Analyze Rust code
    let rust_code = "...";
    let analysis = code_agent.analyze_rust(rust_code).await?;
    println!("Rust Issues: {:?}", analysis.issues);

    Ok(())
}

How Could It Be Extended?

• Additional Language Support: Add tools for C++, Go, JavaScript, etc.
• Deeper Static Analysis: Integrate with Clippy, pylint, SonarQube, etc.
• Security Auditing: Add static and dynamic security analysis tools
• Performance Profiling: Integrate with profilers for runtime analysis
• Automated Test Generation: Suggest or generate unit and integration tests
• Continuous Integration: Integrate with CI/CD pipelines for automated code review
• Visualization: Generate call graphs, dependency diagrams, and more

Potential Benefits

For Developers

• Faster Code Review: Automated, actionable feedback
• Improved Code Quality: Early detection of bugs and anti-patterns
• Learning: Understand best practices and idioms for each language

For Teams

• Consistency: Enforce style and quality standards
• Productivity: Reduce manual review time
• Onboarding: Help new team members understand codebases

For Organizations

• Security: Early detection of vulnerabilities
• Maintainability: Cleaner, more robust codebases
• Scalability: Handle large codebases and multiple languages

---

Key Features of the Code Analysis Tools

Each tool provides:

• Metrics Analysis: Lines, characters, functions, classes, complexity

• Language-Specific Checks: Syntax, style, best practices

• Quality Suggestions: Specific recommendations for improvement

• Error Detection: Syntax errors, potential issues, anti-patterns

• Proper Tool Trait Implementation: Full integration with the Kowalski framework

Three Comprehensive Examples

Java Example (java_analysis.rs)

• Analyzes a Calculator class with arithmetic operations
• Demonstrates Java-specific analysis and suggestions
• Shows proper error handling and logging recommendations

Python Example (python_analysis.rs)

• Analyzes a DataProcessor class with statistical operations
• Demonstrates PEP 8 compliance checking
• Shows Python-specific improvements and best practices

Rust Example (rust_analysis.rs)

• Analyzes a DataProcessor struct with caching functionality

• Demonstrates Rust-specific safety and error handling analysis

• Shows ownership, borrowing, and memory safety considerations

Output of java_analysis

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 Running `/opt/ml/kowalski/target/debug/examples/java_analysis`

☕ Starting Java Code Analysis... Code Agent Conversation ID: 67677c04-2d1a-49e8-8b6d-8c18f7f180d9

📝 Java Code to Analyze:

import java.util.*;

public class Calculator { private int result;

public Calculator() {
    this.result = 0;
}

public int add(int a, int b) {
    result = a + b;
    return result;
}

public int subtract(int a, int b) {
    result = a - b;
    return result;
}

public int multiply(int a, int b) {
    result = a * b;
    return result;
}

public double divide(int a, int b) {
    if (b == 0) {
        System.out.println("Error: Division by zero");
        return 0;
    }
    result = a / b;
    return (double) result;
}

public static void main(String[] args) {
    Calculator calc = new Calculator();
    System.out.println("Addition: " + calc.add(10, 5));
    System.out.println("Subtraction: " + calc.subtract(10, 5));
    System.out.println("Multiplication: " + calc.multiply(10, 5));
    System.out.println("Division: " + calc.divide(10, 5));
}

}

📊 Java Analysis Results: Language: java Metrics: { "characters": 1008, "classes": 1, "comments": 0, "complexity": { "cyclomatic_complexity": 2, "for_loops": 0, "if_statements": 1, "level": "Low", "switch_statements": 0, "while_loops": 0 }, "imports": 1, "lines": 42, "methods": 8, "words": 122 } Suggestions: ["Consider using a proper logging framework instead of System.out.println", "Main method found - ensure proper exception handling"] Issues: []

🤖 AI Analysis: Code Analysis and Recommendations

The provided Java code implements a basic calculator class with methods for addition, subtraction, multiplication, and division. The analysis highlights several areas for improvement.

Code Quality and Best Practices

1. Naming Conventions: While the variable names result and a, b are concise, they do not follow standard Java naming conventions (e.g., using camelCase instead of underscore notation). Consider renaming them to calculateResult and num1, respectively.
2. Method Signatures: The methods have unclear return types for division (double or int). To avoid ambiguity, use a more explicit return type, such as double in the case of division by zero handling.
3. Exception Handling: Although we've handled division by zero explicitly, consider throwing an exception instead of printing an error message and returning 0. This approach is more robust and allows for better error handling.

Code Improvements

1. Extracting Methods: Consider extracting separate methods for handling division by zero errors, calculating results in a loop, or performing input validation.
2. Input Validation: Add checks to ensure the inputs are valid (e.g., numbers only) before performing calculations.
3. Code Organization: Consider separating the calculator logic from the main method into its own class or module.

Code Refactoring

Here's an updated version of the code incorporating these recommendations:

import java.util.InputMismatchException;
import java.util.Scanner;

public class Calculator {
    private double result;

    public Calculator() {}

    public int add(int a, int b) {
        return (int) calculateResult(a, b);
    }

    public int subtract(int a, int b) {
        return (int) calculateResult(a, -b);
    }

    public int multiply(int a, int b) {
        return (int) calculateResult(a, 1 * b); // Use implicit multiplication
    }

    private double calculateResult(int num1, int num2) {
        if (num2 == 0) {
            throw new ArithmeticException("Division by zero");
        }
        return (double) num1 / num2;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter numbers:");
        int num1 = getValidNumber(scanner, "First number: ");
        int num2 = getValidNumber(scanner, "Second number: ");

        Calculator calc = new Calculator();
        System.out.println("Addition: " + calc.add(num1, num2));
        System.out.println("Subtraction: " + calc.subtract(num1, num2));
        System.out.println("Multiplication: " + calc.multiply(num1, num2));
    }

    private static int getValidNumber(Scanner scanner, String prompt) {
        while (true) {
            try {
                System.out.print(prompt);
                return scanner.nextInt();
            } catch (InputMismatchException e) {
                System.out.println("Invalid input. Please enter a number.");
                scanner.next(); // Consume invalid input
            }
        }
    }
}

This refactored code includes:

• Improved variable names and method signatures
• Exception handling for division by zero errors
• Input validation using Scanner to ensure numbers are entered correctly
• Extracted methods for better organization and reusability

These changes enhance the overall quality of the code, making it more robust, maintainable, and efficient. ✅ Analysis complete!

🔍 Follow-up Analysis: Based on the provided Java code, here are some specific improvements that can be made:

1. Extract a separate class for Calculator Operations: The current Calculator class has multiple methods (addition, subtraction, multiplication, division) that perform similar operations. Consider extracting each operation into its own separate method or even better, create a new class Operation with different implementations for each operation.

public enum Operation {
    ADDITION,
    SUBTRACTION,
    Multiplication,
    DIVISION
}

// In the Calculator class
private Operation operation;

public void setOperation(Operation operation) {
    this.operation = operation;
}

// Then in the main method
Calculator calc = new Calculator();
calc.setOperation(Operation.ADDITION);
System.out.println("Addition: " + calc.calculate(10, 5));

2. Use a switch statement for handling different operations: The current code uses if-else statements to handle each operation separately. This can be improved by using a switch statement which is more efficient and concise.

public int calculate(int num1, int num2) {
    switch (operation) {
        case ADDITION:
            return num1 + num2;
        case SUBTRACTION:
            return num1 - num2;
        case Multiplication:
            return num1 * num2;
        case DIVISION:
            if (num2 == 0) {
                throw new ArithmeticException("Division by zero");
            }
            return (int) num1 / num2;
    }
}

3. Use a more robust method for handling division by zero: Instead of throwing an exception, consider returning a special value (e.g., Double.NaN) to indicate division by zero.

public int calculate(int num1, int num2) {
    if (num2 == 0) {
        return Double.NaN;
    }
    return (int) num1 / num2;
}

4. Use a consistent naming convention: The code uses both camelCase and underscore notation for variable names. Choose one convention throughout the codebase.

5. Add input validation: Currently, the code does not validate user input. Consider adding checks to ensure that users enter valid numbers.

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.println("Enter two numbers:");
    int num1 = getValidNumber(scanner, "First number: ");
    int num2 = getValidNumber(scanner, "Second number: ");

    Calculator calc = new Calculator();
    System.out.println("Addition: " + calc.calculate(num1, num2));
}

6. Use a more robust way to handle exceptions: Instead of catching the InputMismatchException, consider using a more general exception handler (e.g., try-catch block with multiple catches).

public static void main(String[] args) {
    try {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter two numbers:");
        int num1 = scanner.nextInt();
        int num2 = scanner.nextInt();

        Calculator calc = new Calculator();
        System.out.println("Addition: " + calc.calculate(num1, num2));
    } catch (Exception e) {
        System.err.println("Error: " + e.getMessage());
    }
}

These improvements can enhance the code's maintainability, readability, and robustness.

---

Output of python example

---

 Running `/opt/ml/kowalski/target/debug/examples/python_analysis`

🐍 Starting Python Code Analysis... Code Agent Conversation ID: 073f9369-9381-4eff-8305-5e7b28451b48

📝 Python Code to Analyze:

import os
import sys
from typing import List, Optional

class DataProcessor:
    def __init__(self, data: List[int]):
        self.data = data
        self.result = 0
    
    def calculate_sum(self) -> int:
        """Calculate the sum of all data points."""
        total = 0
        for item in self.data:
            total += item
        return total
    
    def calculate_average(self) -> float:
        """Calculate the average of all data points."""
        if len(self.data) == 0:
            print("Error: No data to calculate average")
            return 0.0
        return self.calculate_sum() / len(self.data)
    
    def find_max(self) -> Optional[int]:
        """Find the maximum value in the data."""
        if not self.data:
            return None
        max_val = self.data[0]
        for item in self.data:
            if item > max_val:
                max_val = item
        return max_val

def main():
    # Sample data
    numbers = [10, 20, 30, 40, 50]
    
    # Create processor
    processor = DataProcessor(numbers)
    
    # Calculate statistics
    print(f"Sum: {processor.calculate_sum()}")
    print(f"Average: {processor.calculate_average()}")
    print(f"Maximum: {processor.find_max()}")
    
    # Process empty data
    empty_processor = DataProcessor([])
    print(f"Empty average: {empty_processor.calculate_average()}")

if __name__ == "__main__":
    main()

📊 Python Analysis Results:

Language: python
Metrics: {
  "characters": 1407,
  "classes": 1,
  "comments": 4,
  "complexity": {
    "cyclomatic_complexity": 7,
    "for_loops": 2,
    "if_statements": 4,
    "level": "Medium",
    "try_blocks": 0,
    "while_loops": 0
  },
  "functions": 5,
  "imports": 4,
  "lines": 52,
  "words": 145
}
Suggestions: ["Consider using logging instead of print statements"]
PEP 8 Issues: ["Line 10: Trailing whitespace", "Line 17: Trailing whitespace", "Line 24: Trailing whitespace", "Line 38: Trailing whitespace", "Line 41: Trailing whitespace", "Line 46: Trailing whitespace"]

🤖 AI Analysis: Code Analysis and Recommendations

The provided Python code defines a DataProcessor class with methods to calculate the sum, average, and maximum of a list of integers. The code also includes a main function for testing.

Code Quality

The code is generally well-structured and readable. However, there are some areas that can be improved:

• Type Hints: While type hints are used for method parameters and return types, it's good practice to include them for all variables to make the code more self-documenting.
• Error Handling: The find_max method prints an error message if the data is empty. Instead, consider raising a custom exception or returning a specific value (e.g., None) to indicate an error condition.
• Logging: The code uses print statements for debugging purposes. Consider using Python's built-in logging module (logging) instead, which provides more flexibility and control over log output.

PEP 8 Compliance

The code generally adheres to PEP 8 guidelines. However, there are a few instances of trailing whitespace that need attention:

• Line 10: total += item
• Line 17: max_val = self.data[0]
• Line 24: if len(self.data) == 0: (trailing whitespace on the same line as the condition)
• Line 38: return self.calculate_sum() / len(self.data)
• Line 41: print(f"Maximum: {processor.find_max()}") (missing closing parenthesis)
• Line 46: return max_val

To fix these issues, remove the trailing whitespace and ensure that each statement or block of code is on a new line.

Suggestions for Improvement

Based on the analysis, here are some suggestions:

1. Use logging instead of print statements: Replace all print statements with logging calls to improve log output control and flexibility.
2. Rearrange method logic: Consider reorganizing the methods in the DataProcessor class to reduce code duplication and make it easier to add new functionality.
3. Add docstrings for custom exceptions: If you plan to raise custom exceptions, consider adding docstrings to explain how they should be used.

Refactored Code

Here's an updated version of the code incorporating some of these suggestions:

import logging

logging.basicConfig(level=logging.INFO)

class DataProcessor:
    def __init__(self, data: list[int]):
        """
        Initialize the data processor with sample input data.
        
        Args:
            input_data (list): List of numbers to process.
        """
        self.input_data = data
        self.result = 0
    
    def calculate_sum(self) -> int:
        """
        Calculate the sum of all data points.
        
        Returns:
            int: The calculated sum.
        """
        total = 0
        for item in self.input_data:
            total += item
        return total
    
    def calculate_average(self) -> float:
        """
        Calculate the average of all data points.
        
        Raises:
            ValueError: If input data is empty.
        
        Returns:
            float: The calculated average.
        """
        if not self.input_data:
            raise ValueError("Cannot calculate average with empty data")
        return self.calculate_sum() / len(self.input_data)
    
    def find_max(self) -> Optional[int]:
        """
        Find the maximum value in all data points.
        
        Returns:
            int or None: The calculated max value or None if input data is empty.
        """
        if not self.input_data:
            return None
        max_val = self.input_data[0]
        for item in self.input_data:
            if item > max_val:
                max_val = item
        return max_val

def main():
    sample_numbers = [10, 20, 30, 40, 50]
    
    processor = DataProcessor(sample_numbers)
    
    logging.info(f"Sum: {processor.calculate_sum()}")
    logging.info(f"Average: {processor.calculate_average()}")
    logging.info(f"Maximum: {processor.find_max()}")

    empty_processor = DataProcessor([])
    try:
        logging.info(f"Empty average: {empty_processor.calculate_average()}")
    except ValueError as e:
        logging.error(e)

if __name__ == "__main__":
    main()

Changes and Improvements

• Replaced print statements with logging calls for more flexible log output control.
• Rearranged method logic to reduce code duplication in the find_max method.
• Raised a custom exception (ValueError) instead of printing an error message in the calculate_average method.

This refactored code maintains the same functionality as the original version but with improved code quality, readability, and maintainability. ✅ Analysis complete!

🔍 Follow-up Analysis: Here are some suggestions on how to improve the provided Python code to better follow PEP 8 guidelines:

1. Use Meaningful Variable Names

Variable names like data, result, and numbers should be more descriptive. Consider using names that indicate what these variables represent, such as input_data, calculated_sum, and sample_numbers.

input_data = [10, 20, 30, 40, 50]

2. Follow PEP 8 Line Length

PEP 8 recommends keeping lines under 79 characters. The current code has some long lines; consider breaking them up to adhere to this guideline.

# Current line: 88 characters
long_line = (
    "for item in self.data:"
    "    total += item"
)

# Refactored line (under 79 characters)
for item in self.data:
    total += item

3. Indentation and Spacing

PEP 8 requires consistent indentation (4 spaces) and spacing between statements.

# Current code has inconsistent indentation and spacing
if len(self.data):
    print("Error: Data is empty")
else:
    # Code here

# Refactored code with consistent indentation and spacing
if len(self.data):
    logging.error("Data is empty")
else:
    # Code here

4. Use Comments and Docstrings

Comments should explain why the code is doing something, not what it's doing. Consider using docstrings to document your classes, methods, and functions.

# Current comment: "This is a sample data"
# Refactored comment: "Sample input data for testing purposes"

class DataProcessor:
    """
    A class to calculate statistics from input data.
    
    Attributes:
        input_data (list): List of numbers to process.
        
    Methods:
        calculate_sum(): Calculate the sum of input data.
        calculate_average(): Calculate the average of input data.
        find_max(): Find the maximum value in input data.
    """

5. Remove Redundant if __name__ == "__main__":

PEP 8 advises against using this construct when running tests or other scripts.

# Current code has redundant if statement
if __name__ == "__main__":
    main()

6. Consider Using Type Hints

Type hints can make your code more readable and self-documenting.

def calculate_sum(self) -> int:
    """Calculate the sum of all data points."""
    total = 0
    for item in self.data:
        total += item
    return total

# Current function definition: no type hint

7. Fix PEP 8 Violations

The code has several PEP 8 violations, including:

• Trailing whitespace on some lines.
• Inconsistent indentation and spacing.

# Original line with trailing whitespace
print("Error: Data is empty")

# Refactored line without trailing whitespace
if len(self.data):
    logging.error("Data is empty")
else:
    # Code here

Improved Code

Here's the refactored code incorporating these improvements:

import logging

logging.basicConfig(level=logging.INFO)

class DataProcessor:
    def __init__(self, input_data: list[int]):
        """
        Initialize the data processor with sample input data.
        
        Args:
            input_data (list): List of numbers to process.
        """
        self.input_data = input_data
        self.result = 0
    
    def calculate_sum(self) -> int:
        """
        Calculate the sum of all data points.
        
        Returns:
            int: The calculated sum.
        """
        total = 0
        for item in self.input_data:
            total += item
        return total
    
    def calculate_average(self) -> float:
        """
        Calculate the average of all data points.
        
        Raises:
            ValueError: If input data is empty.
        
        Returns:
            float: The calculated average.
        """
        if not self.input_data:
            raise ValueError("Data is empty")
        return self.calculate_sum() / len(self.input_data)
    
    def find_max(self) -> Optional[int]:
        """
        Find the maximum value in all data points.
        
        Returns:
            int or None: The calculated max value or None if input data is empty.
        """
        if not self.input_data:
            return None
        max_val = self.input_data[0]
        for item in self.input_data:
            if item > max_val:
                max_val = item
        return max_val

def main():
    sample_numbers = [10, 20, 30, 40, 50]
    
    processor = DataProcessor(sample_numbers)
    
    logging.info(f"Sum: {processor.calculate_sum()}")
    logging.info(f"Average: {processor.calculate_average()}")
    logging.info(f"Maximum: {processor.find_max()}")

    empty_processor = DataProcessor([])
    try:
        logging.info(f"Empty average: {empty_processor.calculate_average()}")
    except ValueError as e:
        logging.error(e)

if __name__ == "__main__":
    main()

This refactored code adheres to most PEP 8 guidelines, making it more readable and maintainable.

---

Output of rust example

---

 Running `/opt/ml/kowalski/target/debug/examples/rust_analysis`

🦀 Starting Rust Code Analysis... Code Agent Conversation ID: 33142869-16b7-4cad-bcc2-8b981abf82a3

📝 Rust Code to Analyze:

use std::collections::HashMap;
use std::error::Error;

#[derive(Debug)]
struct DataProcessor {
    data: Vec<i32>,
    cache: HashMap<String, i32>,
}

impl DataProcessor {
    fn new(data: Vec<i32>) -> Self {
        Self {
            data,
            cache: HashMap::new(),
        }
    }
    
    fn calculate_sum(&self) -> i32 {
        self.data.iter().sum()
    }
    
    fn calculate_average(&self) -> Option<f64> {
        if self.data.is_empty() {
            None
        } else {
            Some(self.calculate_sum() as f64 / self.data.len() as f64)
        }
    }
    
    fn find_max(&self) -> Option<&i32> {
        self.data.iter().max()
    }
    
    fn process_with_cache(&mut self, key: String) -> Result<i32, Box<dyn Error>> {
        if let Some(&cached_value) = self.cache.get(&key) {
            return Ok(cached_value);
        }
        
        let result = self.calculate_sum();
        self.cache.insert(key, result);
        Ok(result)
    }
}

fn main() {
    let numbers = vec![10, 20, 30, 40, 50];
    let mut processor = DataProcessor::new(numbers);
    
    println!("Sum: {}", processor.calculate_sum());
    
    match processor.calculate_average() {
        Some(avg) => println!("Average: {}", avg),
        None => println!("No data to calculate average"),
    }
    
    match processor.find_max() {
        Some(max) => println!("Maximum: {}", max),
        None => println!("No data to find maximum"),
    }
    
    match processor.process_with_cache("sum".to_string()) {
        Ok(result) => println!("Cached result: {}", result),
        Err(e) => println!("Error: {}", e),
    }
}

📊 Rust Analysis Results: Language: rust Metrics: { "characters": 1634, "comments": 0, "complexity": { "cyclomatic_complexity": 6, "for_loops": 0, "if_statements": 2, "let_statements": 4, "level": "Medium", "match_statements": 3, "while_loops": 0 }, "enums": 0, "functions": 6, "lines": 66, "modules": 0, "structs": 1, "traits": 0, "words": 160 } Suggestions: ["Consider using a proper logging framework instead of println!"] Rust Issues: ["Line 5: Possible missing semicolon", "Line 7: Possible missing semicolon", "Line 8: Possible missing semicolon", "Line 14: Possible missing semicolon", "Line 15: Possible missing semicolon", "Line 20: Possible missing semicolon", "Line 25: Possible missing semicolon", "Line 27: Possible missing semicolon", "Line 32: Possible missing semicolon", "Line 42: Possible missing semicolon", "Line 53: Possible missing semicolon", "Line 54: Possible missing semicolon", "Line 58: Possible missing semicolon", "Line 59: Possible missing semicolon", "Line 63: Possible missing semicolon", "Line 64: Possible missing semicolon"]

🤖 AI Analysis: Code Analysis Report

Overall Assessment

The provided Rust code is well-structured and easy to read. It demonstrates a good understanding of the Rust language and its idioms.

Insights and Suggestions

1. Logging: Instead of using println! for logging, consider using a proper logging framework like log or env_logger. This will provide more flexibility and control over the logging behavior.

2. Semicolons: There are several lines where semicolons are missing. For example, Result<i32, Box<dyn Error>> should have a semicolon at the end of the declaration.

3. Functionality: The code is well-organized and easy to follow. However, some functions like calculate_average could be refactored to reduce duplication. Instead of calculating the sum and then dividing by the length, consider using the iter() method to calculate the average directly.

4. Error Handling: While the code handles errors properly, it's always a good practice to use Result or Option extensively throughout the codebase. This will help catch errors earlier and make the code more robust.

5. Type Inference: Rust is known for its type inference capabilities. In some places, explicit type annotations would be sufficient to make the code more readable.

6. Naming Conventions: The function names are clear and concise. However, consider using more descriptive names like calculate_total_sum instead of calculate_sum.

7. Code Duplication: There is a small amount of code duplication in the find_max method. Consider extracting this logic into a separate function to reduce duplication.

8. Documentation: While the code has some comments, it's always a good practice to include documentation for functions and methods using doc comments.

Recommendations

1. Refactor calculate_average to use the iter() method.
2. Add more descriptive function names like calculate_total_sum.
3. Extract logic from find_max into a separate function.
4. Use a proper logging framework instead of println!.
5. Add documentation for functions and methods using doc comments.

Updated Code

use std::collections::{HashMap, HashSet};
use std::error::Error;
use std::fmt;

// Define a struct to represent a cache entry.
struct CacheEntry {
    key: String,
    value: i32,
}

impl CacheEntry {
    fn new(key: &str) -> Self {
        Self {
            key: key.to_string(),
            value: 0,
        }
    }

    fn get(&self, cache: &mut HashMap<String, CacheEntry>) -> Option<i32> {
        if let Some(entry) = cache.get(&self.key) {
            return Some(entry.value);
        }
        None
    }

    fn update(&mut self, value: i32) {
        self.value = value;
    }
}

impl fmt::Display for CacheEntry {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({} : {})", self.key, self.value)
    }
}

#[derive(Debug)]
struct DataProcessor {
    data: Vec<i32>,
    cache: HashMap<String, i32>,
}

impl DataProcessor {
    fn new(data: Vec<i32>) -> Self {
        Self {
            data,
            cache: HashMap::new(),
        }
    }

    /// Calculate the total sum of all elements in the data.
    fn calculate_total_sum(&self) -> Result<i32, Box<dyn Error>> {
        let mut total = 0;
        for value in self.data.into_iter() {
            total += value;
        }
        Ok(total)
    }

    /// Calculate the average of all elements in the data if it's not empty.
    fn calculate_average(&self) -> Result<f64, Box<dyn Error>> {
        let sum = self.calculate_total_sum()?;
        if sum.is_null() || self.data.is_empty() {
            return Err(Box::new(std::error::Error::msg("No data to calculate average")));
        }
        Ok(sum as f64 / self.data.len() as f64)
    }

    /// Find the maximum element in the data.
    fn find_max(&self) -> Result<Option<&i32>, Box<dyn Error>> {
        let max = self
            .data
            .into_iter()
            .max()
            .ok_or(Box::new(std::error::Error::msg("No data to find maximum")));
        match max {
            Some(value) => Ok(Some(value)),
            None => Err(Box::new(std::error::Error::msg("No data to find maximum"))),
        }
    }

    /// Process a key with caching. Returns an error if the result is not found in the cache.
    fn process_with_cache(&mut self, key: &str) -> Result<i32, Box<dyn Error>> {
        let mut cache = HashMap::new();
        for (k, v) in &self.cache {
            cache.insert(k.to_string(), v.clone());
        }

        if let Some(entry) = cache.get_mut(key) {
            entry.update(self.calculate_total_sum()?);
        } else {
            let total = self.calculate_total_sum()?;
            cache.insert(key.to_string(), total);
        }

        Ok(cache.get(key)?.clone())
    }
}

fn main() {
    let numbers = vec![10, 20, 30, 40, 50];
    let mut processor = DataProcessor::new(numbers);

    println!("Sum: {}", processor.calculate_total_sum()?);

    match processor.calculate_average() {
        Ok(avg) => println!("Average: {:?}", avg),
        Err(e) => eprintln!("Error: {}", e),
    }

    match processor.find_max() {
        Ok(Some(max)) => println!("Maximum: {:?}", max),
        Err(e) => eprintln!("Error: {}", e),
    }

    match processor.process_with_cache("sum") {
        Ok(result) => println!("Cached result: {}", result),
        Err(e) => eprintln!("Error: {}", e),
    }
}

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