app.py

#!/usr/bin/env python3
"""
Code Flow Analyzer with Gradio Interface - Hugging Face Spaces & Colab Compatible
A single-file application that uses LangChain agents with the Gemini model to analyze code structure
and generate Mermaid.js flowchart diagrams through a web interface.
"""

import ast
import re
import os
import traceback
import sys
from typing import Dict, Any, List, Tuple
import getpass

# Check if running in Colab
try:
    import google.colab
    IN_COLAB = True
    print("🟢 Running in Google Colab")
except ImportError:
    IN_COLAB = False
    print("🟡 Running locally or in Hugging Face Spaces")

# Install dependencies if in Colab
if IN_COLAB:
    print("📦 Installing dependencies...")
    os.system("pip install -q gradio langchain langgraph langchain-google-genai")
    print("✅ Dependencies installed")

import gradio as gr
from langchain.chat_models import init_chat_model
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain.tools import tool
from langgraph.prebuilt import create_react_agent
from langgraph.checkpoint.memory import MemorySaver

# Sample code examples (unchanged)
SAMPLE_PYTHON = '''def main():
    user_input = get_user_input()
    if user_input:
        result = process_data(user_input)
        if result > 0:
            display_result(result)
        else:
            show_error()
    else:
        show_help()

def get_user_input():
    return input("Enter data: ")

def process_data(data):
    for i in range(len(data)):
        if data[i].isdigit():
            return int(data[i])
    return -1

def display_result(result):
    print(f"Result: {result}")

def show_error():
    print("Error processing data")

def show_help():
    print("Please provide valid input")'''

SAMPLE_JAVASCRIPT = '''function calculateTotal(items) {
    let total = 0;
    for (let item of items) {
        if (item.price > 0) {
            total += item.price;
        }
    }
    return total;
}

function processOrder(order) {
    if (validateOrder(order)) {
        const total = calculateTotal(order.items);
        if (total > 100) {
            applyDiscount(order);
        }
        return generateReceipt(order);
    } else {
        throw new Error("Invalid order");
    }
}

function validateOrder(order) {
    return order && order.items && order.items.length > 0;
}

function applyDiscount(order) {
    order.discount = 0.1; // 10% discount
}

function generateReceipt(order) {
    return {
        items: order.items,
        total: calculateTotal(order.items),
        timestamp: new Date()
    };
}'''

SAMPLE_JAVA = '''public class Calculator {
    public static void main(String[] args) {
        Calculator calc = new Calculator();
        int result = calc.performCalculation();
        calc.displayResult(result);
    }

    public int performCalculation() {
        int a = getUserInput();
        int b = getUserInput();

        if (a > b) {
            return multiply(a, b);
        } else {
            return add(a, b);
        }
    }

    private int add(int x, int y) {
        return x + y;
    }

    private int multiply(int x, int y) {
        return x * y;
    }

    private int getUserInput() {
        return 5; // Simplified for demo
    }

    private void displayResult(int result) {
        System.out.println("Result: " + result);
    }
}'''

# --- Gemini API Key Setup ---
def setup_api_key():
    """Setup API key for Colab, Hugging Face Spaces, and local environments"""
    api_key = os.getenv("GOOGLE_API_KEY")

    if not api_key:
        if IN_COLAB:
            print("🔑 Please enter your Google API key:")
            print("   Get a key from: https://aistudio.google.com/app/apikey")
            api_key = getpass.getpass("GOOGLE_API_KEY: ")
            if api_key:
                os.environ["GOOGLE_API_KEY"] = api_key
                print("✅ API key set successfully")
            else:
                print("⚠️ No API key provided - agent features will be disabled")
        else:
            print("⚠️ GOOGLE_API_KEY not found in environment variables")
            print("   Set it with: export GOOGLE_API_KEY='your-key-here'")
            print("   In Hugging Face Spaces, use the 'Secrets' tab to set the key.")
    else:
        print("✅ Google API key found")

    return api_key or os.getenv("GOOGLE_API_KEY")

# Setup API key
api_key = setup_api_key()

# Initialize LangChain components
model = None
memory = None
agent_executor = None

if api_key:
    try:
        # Use a stable, updated model name to avoid the 404 error
        model = ChatGoogleGenerativeAI(model="gemini-2.0-flash-001", temperature=0)
        print("✅ Gemini model initialized successfully: gemini-2.0-flash-001")
        memory = MemorySaver()
    except Exception as e:
        print(f"❌ Could not initialize Gemini model: {e}")
        print("   Please check your API key and internet connection.")
        model = None
        memory = None

# --- Tool Definitions (unchanged) ---
@tool
def analyze_code_structure(source_code: str) -> Dict[str, Any]:
    """
    Analyzes source code structure to identify functions, control flow, and dependencies.
    Returns structured data about the code that can be used to generate flow diagrams.
    """
    try:
        # Try to parse as Python first
        try:
            tree = ast.parse(source_code)
            return _analyze_python_ast(tree)
        except SyntaxError:
            # If Python parsing fails, do basic text analysis
            return _analyze_code_text(source_code)

    except Exception as e:
        return {"error": f"Analysis error: {str(e)}"}

def _analyze_python_ast(tree) -> Dict[str, Any]:
    """Analyze Python AST"""
    analysis = {
        "functions": [],
        "classes": [],
        "control_flows": [],
        "imports": [],
        "call_graph": {}
    }

    class CodeAnalyzer(ast.NodeVisitor):
        def __init__(self):
            self.current_function = None

        def visit_FunctionDef(self, node):
            func_info = {
                "name": node.name,
                "line": node.lineno,
                "args": [arg.arg for arg in node.args.args],
                "calls": [],
                "conditions": [],
                "loops": []
            }

            self.current_function = node.name
            analysis["call_graph"][node.name] = []

            # Analyze function body
            for child in ast.walk(node):
                if isinstance(child, ast.Call):
                    if hasattr(child.func, 'id'):
                        func_info["calls"].append(child.func.id)
                        analysis["call_graph"][node.name].append(child.func.id)
                    elif hasattr(child.func, 'attr'):
                        func_info["calls"].append(child.func.attr)
                elif isinstance(child, ast.If):
                    func_info["conditions"].append(f"if condition at line {child.lineno}")
                elif isinstance(child, (ast.For, ast.While)):
                    loop_type = "for" if isinstance(child, ast.For) else "while"
                    func_info["loops"].append(f"{loop_type} loop at line {child.lineno}")

            analysis["functions"].append(func_info)
            self.generic_visit(node)

        def visit_ClassDef(self, node):
            class_info = {
                "name": node.name,
                "line": node.lineno,
                "methods": []
            }

            for item in node.body:
                if isinstance(item, ast.FunctionDef):
                    class_info["methods"].append(item.name)

            analysis["classes"].append(class_info)
            self.generic_visit(node)

        def visit_Import(self, node):
            for alias in node.names:
                analysis["imports"].append(alias.name)
            self.generic_visit(node)

        def visit_ImportFrom(self, node):
            module = node.module or ""
            for alias in node.names:
                analysis["imports"].append(f"{module}.{alias.name}")
            self.generic_visit(node)

    analyzer = CodeAnalyzer()
    analyzer.visit(tree)
    return analysis

def _analyze_code_text(source_code: str) -> Dict[str, Any]:
    """Basic text-based code analysis for non-Python code"""
    lines = source_code.split('\n')
    analysis = {
        "functions": [],
        "classes": [],
        "control_flows": [],
        "imports": [],
        "call_graph": {}
    }

    for i, line in enumerate(lines, 1):
        line = line.strip()

        # JavaScript function detection
        js_func_match = re.match(r'function\s+(\w+)\s*\(', line)
        if js_func_match:
            func_name = js_func_match.group(1)
            analysis["functions"].append({
                "name": func_name,
                "line": i,
                "args": [],
                "calls": [],
                "conditions": [],
                "loops": []
            })
            analysis["call_graph"][func_name] = []

        # Java/C++ method detection
        java_method_match = re.match(r'(?:public|private|protected)?\s*(?:static)?\s*\w+\s+(\w+)\s*\(', line)
        if java_method_match and not js_func_match:
            func_name = java_method_match.group(1)
            if func_name not in ['class', 'if', 'for', 'while']:  # Avoid keywords
                analysis["functions"].append({
                    "name": func_name,
                    "line": i,
                    "args": [],
                    "calls": [],
                    "conditions": [],
                    "loops": []
                })
                analysis["call_graph"][func_name] = []

        # Control structures
        if re.match(r'\s*(if|else|elif|switch)\s*[\(\{]', line):
            analysis["control_flows"].append(f"condition at line {i}")

        if re.match(r'\s*(for|while|do)\s*[\(\{]', line):
            analysis["control_flows"].append(f"loop at line {i}")

    return analysis

@tool
def generate_mermaid_diagram(analysis_data: Dict[str, Any]) -> str:
    """
    Generates a Mermaid.js flowchart diagram from code analysis data.
    Creates a visual representation of the code flow including function calls and control structures.
    """
    if "error" in analysis_data:
        return f"flowchart TD\n    Error[❌ {analysis_data['error']}]"

    functions = analysis_data.get("functions", [])
    call_graph = analysis_data.get("call_graph", {})

    if not functions:
        return """flowchart TD
    Start([🚀 Program Start]) --> NoFunc[No Functions Found]
    NoFunc --> End([🏁 Program End])

    classDef startEnd fill:#e1f5fe,stroke:#01579b,stroke-width:2px
    classDef warning fill:#fff3e0,stroke:#e65100,stroke-width:2px

    class Start,End startEnd
    class NoFunc warning"""

    mermaid_lines = ["flowchart TD"]
    mermaid_lines.append("    Start([🚀 Program Start]) --> Main")

    # Create nodes for each function
    func_nodes = []
    for i, func in enumerate(functions):
        func_name = func["name"]
        safe_name = re.sub(r'[^a-zA-Z0-9_]', '_', func_name)
        node_id = f"F{i}_{safe_name}"
        func_nodes.append(node_id)

        # Function node with emoji
        mermaid_lines.append(f"    {node_id}[⚙️ {func_name}()]")

        # Add control structures within function
        conditions = func.get("conditions", [])
        loops = func.get("loops", [])

        if conditions:
            for j, condition in enumerate(conditions[:2]):  # Limit to 2 conditions per function
                cond_id = f"{node_id}_C{j}"
                mermaid_lines.append(f"    {node_id} --> {cond_id}{{🤔 Decision}}")
                mermaid_lines.append(f"    {cond_id} -->|Yes| {node_id}_Y{j}[✅ True Path]")
                mermaid_lines.append(f"    {cond_id} -->|No| {node_id}_N{j}[❌ False Path]")

        if loops:
            for j, loop in enumerate(loops[:1]):  # Limit to 1 loop per function
                loop_id = f"{node_id}_L{j}"
                loop_type = "🔄 Loop" if "for" in loop else "⏰ While Loop"
                mermaid_lines.append(f"    {node_id} --> {loop_id}[{loop_type}]")
                mermaid_lines.append(f"    {loop_id} --> {loop_id}")  # Self-loop

    # Connect main flow
    if func_nodes:
        mermaid_lines.append(f"    Main --> {func_nodes[0]}")

        # Connect functions in sequence (simplified)
        for i in range(len(func_nodes) - 1):
            mermaid_lines.append(f"    {func_nodes[i]} --> {func_nodes[i + 1]}")

        # Connect to end
        mermaid_lines.append(f"    {func_nodes[-1]} --> End([🏁 Program End])")

    # Add function call relationships (simplified to avoid clutter)
    call_count = 0
    for caller, callees in call_graph.items():
        if call_count >= 3:  # Limit number of call relationships
            break
        caller_node = None
        for node in func_nodes:
            if caller.lower() in node.lower():
                caller_node = node
                break

        if caller_node:
            for callee in callees[:2]:  # Limit callees per function
                callee_node = None
                for node in func_nodes:
                    if callee.lower() in node.lower():
                        callee_node = node
                        break
                if callee_node and callee_node != caller_node:
                    mermaid_lines.append(f"    {caller_node} -.->|calls| {callee_node}")
                    call_count += 1

    # Add styling
    mermaid_lines.extend([
        "",
        "    classDef startEnd fill:#e1f5fe,stroke:#01579b,stroke-width:3px,color:#000",
        "    classDef process fill:#f3e5f5,stroke:#4a148c,stroke-width:2px,color:#000",
        "    classDef decision fill:#fff3e0,stroke:#e65100,stroke-width:2px,color:#000",
        "    classDef success fill:#e8f5e8,stroke:#2e7d32,stroke-width:2px,color:#000",
        "    classDef error fill:#ffebee,stroke:#c62828,stroke-width:2px,color:#000",
        "",
        "    class Start,End startEnd",
        f"    class {','.join(func_nodes)} process" if func_nodes else ""
    ])

    return "\n".join(mermaid_lines)

@tool
def calculate_complexity_score(analysis_data: Dict[str, Any]) -> int:
    """
    Calculates a complexity score for the code based on various metrics.
    Higher scores indicate more complex code structure.
    """
    if "error" in analysis_data:
        return 0

    score = 0
    functions = analysis_data.get("functions", [])

    # Base score for number of functions
    score += len(functions) * 3

    # Add score for control structures
    for func in functions:
        score += len(func.get("conditions", [])) * 4  # Conditions add complexity
        score += len(func.get("loops", [])) * 3       # Loops add complexity
        score += len(func.get("calls", [])) * 1       # Function calls add some complexity
        score += len(func.get("args", [])) * 1        # Parameters add complexity

    # Add score for classes
    score += len(analysis_data.get("classes", [])) * 5

    return min(score, 100)  # Cap at 100

# Create the agent if model is available
if model and memory:
    tools = [analyze_code_structure, generate_mermaid_diagram, calculate_complexity_score]
    agent_executor = create_react_agent(model, tools, checkpointer=memory)
    print("✅ LangChain agent created successfully")
else:
    agent_executor = None
    print("❌ LangChain agent not available")

def analyze_code_with_agent(source_code: str, language: str = "auto") -> Tuple[str, str, List[str], int, str]:
    """
    Main function that uses the LangChain agent to analyze code and generate diagrams.
    Returns: (mermaid_diagram, analysis_summary, functions_found, complexity_score, error_message)
    """
    if not source_code.strip():
        return "", "No code provided", [], 0, "Please enter some source code to analyze"

    if not agent_executor:
        return "", "Agent not available", [], 0, "❌ LangChain agent not initialized. Please check your GOOGLE_API_KEY"

    try:
        # Detect language if auto
        if language == "auto":
            if "def " in source_code or "import " in source_code:
                language = "Python"
            elif "function " in source_code or "const " in source_code or "let " in source_code:
                language = "JavaScript"
            elif ("public " in source_code and "class " in source_code) or "System.out" in source_code:
                language = "Java"
            elif "#include" in source_code or "std::" in source_code:
                language = "C++"
            else:
                language = "Unknown"

        config = {
            "configurable": {"thread_id": f"session_{hash(source_code) % 10000}"},
            "recursion_limit": 100
        }

        # Refined prompt for better tool use
        prompt = f"""
        You are a code analysis expert. Analyze the following {language} source code.
        Your task is to:
        1. Use the 'analyze_code_structure' tool with the full source code provided below.
        2. Use the 'generate_mermaid_diagram' tool with the output of the first tool.
        3. Use the 'calculate_complexity_score' tool with the output of the first tool.
        4. Provide a brief, human-readable summary of the analysis, including the generated Mermaid diagram, complexity score, and a list of functions found.
        5. Present the final result in a clear, easy-to-read format.
        
        Source Code to Analyze:
        ```{language.lower()}
        {source_code}
        ```
        """

        result = agent_executor.invoke(
            {"messages": [{"role": "user", "content": prompt}]},
            config
        )

        if result and "messages" in result:
            response_content = result["messages"][-1].content
            
            # Extract Mermaid diagram
            mermaid_match = re.search(r'```mermaid\n(.*?)\n```', response_content, re.DOTALL)
            mermaid_diagram = mermaid_match.group(1) if mermaid_match else ""

            # Extract complexity score
            complexity_match = re.search(r'complexity.*?(\d+)', response_content, re.IGNORECASE)
            complexity_score = int(complexity_match.group(1)) if complexity_match else 0

            # Extract functions
            functions_found = []
            func_matches = re.findall(r'Functions found:.*?([^\n]+)', response_content, re.IGNORECASE)
            if func_matches:
                functions_found = [f.strip() for f in func_matches[0].split(',')]
            else:
                # Fallback: extract from analysis
                analysis_result = analyze_code_structure.invoke({"source_code": source_code})
                functions_found = [f["name"] for f in analysis_result.get("functions", [])]

            # Clean up the response for summary
            summary = re.sub(r'```mermaid.*?```', '', response_content, flags=re.DOTALL)
            summary = re.sub(r'flowchart TD.*?(?=\n\n|\Z)', '', summary, flags=re.DOTALL)
            summary = summary.strip()

            if not mermaid_diagram and not summary:
                # Last resort fallback if agent fails entirely
                analysis_result = analyze_code_structure.invoke({"source_code": source_code})
                mermaid_diagram = generate_mermaid_diagram.invoke({"analysis_data": analysis_result})
                complexity_score = calculate_complexity_score.invoke({"analysis_data": analysis_result})
                functions_found = [f["name"] for f in analysis_result.get("functions", [])]
                summary = "Agent failed to provide a detailed summary, but a fallback analysis was successful."

            return mermaid_diagram, summary, functions_found, complexity_score, ""

    except Exception as e:
        error_msg = f"❌ Analysis failed: {str(e)}"
        print(f"Error details: {traceback.format_exc()}")
        return "", "", [], 0, error_msg

def create_mermaid_html(mermaid_code: str) -> str:
    """Create HTML to render Mermaid diagram"""
    if not mermaid_code.strip():
        return "<div style='text-align: center; padding: 20px; color: #666;'>No diagram to display</div>"
    
    # Escape the mermaid code for HTML
    escaped_code = mermaid_code.replace('`', '\\`').replace('${', '\\${')
    
    html = f"""
    <div id="mermaid-container" style="text-align: center; padding: 20px; min-height: 400px;">
        <div class="mermaid">
{mermaid_code}
        </div>
    </div>
    
    <script src="https://cdnjs.cloudflare.com/ajax/libs/mermaid/10.6.1/mermaid.min.js"></script>
    <script>
        mermaid.initialize({{ 
            startOnLoad: true,
            theme: 'default',
            flowchart: {{
                useMaxWidth: true,
                htmlLabels: true
            }}
        }});
        
        // Re-render mermaid diagrams
        setTimeout(() => {{
            mermaid.init(undefined, document.querySelectorAll('.mermaid'));
        }}, 100);
    </script>
    """
    return html

# --- Gradio Interface Setup (FIXED) ---
def create_gradio_interface():
    """Create and configure the Gradio interface"""

    def analyze_code_gradio(code, language):
        """Wrapper function for Gradio interface"""
        if not code.strip():
            return (
                "Please enter some code to analyze",
                "<div style='text-align: center; padding: 20px; color: #666;'>No code to analyze</div>",
                "",
                "No analysis performed",
                "Functions: 0 | Complexity: 0/100",
                ""
            )

        mermaid, summary, functions, complexity, error = analyze_code_with_agent(code, language)

        if error:
            return (
                error,
                "<div style='text-align: center; padding: 20px; color: #c62828;'>Analysis failed</div>",
                "",
                "Analysis failed",
                "Functions: 0 | Complexity: 0/100",
                ""
            )

        # Format the outputs
        mermaid_html = create_mermaid_html(mermaid)
        mermaid_code_display = f"```mermaid\n{mermaid}\n```" if mermaid else "No diagram generated"
        functions_display = f"**Functions Found:** {', '.join(functions)}" if functions else "No functions detected"
        stats_display = f"Functions: {len(functions)} | Complexity: {complexity}/100"

        return (
            "✅ Analysis completed successfully!",
            mermaid_html,  # HTML for rendering the Mermaid diagram
            mermaid_code_display, # Markdown-formatted code for the textbox
            summary,
            stats_display,
            functions_display
        )

    # Define the interface
    with gr.Blocks(
        title="🔄 Code Flow Analyzer",
        theme=gr.themes.Soft(),
        css="""
        .gradio-container {
            max-width: 1200px !important;
        }
        .code-input {
            font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace !important;
        }
        """
    ) as interface:

        gr.Markdown("""
        # 🔄 Code Flow Analyzer

        **LangChain Agent + Mermaid.js** • Visualize Your Code Flow

        This tool uses AI agents to analyze your source code and generate visual flowchart diagrams.
        """)

        # API Status
        model_info = ""
        if agent_executor and model:
            model_info = " (Gemini LLM)"
        api_status = f"🟢 Gemini LangChain Agent Ready{model_info}" if agent_executor else "🔴 Agent Not Available (Check GOOGLE_API_KEY)"
        gr.Markdown(f"**Status:** {api_status}")

        with gr.Row():
            with gr.Column(scale=1):
                gr.Markdown("### 📝 Source Code Input")

                language_dropdown = gr.Dropdown(
                    choices=["auto", "Python", "JavaScript", "Java", "C++", "Other"],
                    value="auto",
                    label="Programming Language",
                    info="Auto-detection usually works well"
                )

                code_input = gr.TextArea(
                    placeholder="Paste your source code here...",
                    lines=15,
                    label="Source Code",
                    elem_classes=["code-input"]
                )

                with gr.Row():
                    gr.Examples(
                        examples=[
                            [SAMPLE_PYTHON, "Python"],
                            [SAMPLE_JAVASCRIPT, "JavaScript"],
                            [SAMPLE_JAVA, "Java"]
                        ],
                        inputs=[code_input, language_dropdown],
                        label="Quick Examples"
                    )

                analyze_btn = gr.Button(
                    "🚀 Analyze Code Flow",
                    variant="primary",
                    size="lg"
                )

            with gr.Column(scale=1):
                gr.Markdown("### 📊 Analysis Results")

                status_output = gr.Textbox(
                    label="Status",
                    interactive=False
                )

                stats_output = gr.Textbox(
                    label="Statistics",
                    interactive=False
                )

                functions_output = gr.Markdown(
                    label="Functions Found"
                )

        with gr.Row():
            with gr.Column():
                gr.Markdown("### 🎨 Generated Mermaid Diagram")
                # Use HTML component to render the diagram
                mermaid_output = gr.HTML(
                    label="Flowchart Diagram",
                    value="<div style='text-align: center; padding: 20px; color: #666;'>Diagram will appear here after analysis</div>"
                )

                # Keep the code in a collapsible block for users who want to copy it
                with gr.Accordion("Mermaid Code (for copying)", open=False):
                    mermaid_code_output = gr.Textbox(
                        label="Mermaid Code",
                        lines=10,
                        interactive=True,
                        show_copy_button=True
                    )
        
        with gr.Row():
            with gr.Column():
                gr.Markdown("### 📋 Analysis Summary")
                summary_output = gr.Textbox(
                    label="AI Agent Analysis",
                    lines=8,
                    interactive=False
                )

        # Connect the analyze button
        analyze_btn.click(
            fn=analyze_code_gradio,
            inputs=[code_input, language_dropdown],
            outputs=[status_output, mermaid_output, mermaid_code_output, summary_output, stats_output, functions_output]
        )

        # Footer
        environment_info = "Google Colab" if IN_COLAB else "Hugging Face Spaces or Local Environment"
        gr.Markdown(f"""
        ---
        **🛠️ Running in:** {environment_info}

        **📦 Dependencies:** gradio, langchain, langgraph, langchain-google-genai

        **🔧 Powered by:** LangChain Agents, Google Gemini, Mermaid.js, Gradio

        **🆓 Get Google API Key:** [aistudio.google.com/app/apikey](https://aistudio.google.com/app/apikey)
        """)

    return interface

def main():
    """Main function to run the application"""
    print("🔄 Code Flow Analyzer with Gradio")
    print("=" * 50)
    print(f"🌐 Environment: {'Google Colab' if IN_COLAB else 'Hugging Face Spaces or Local'}")

    if agent_executor:
        print("✅ LangChain agent ready")
    else:
        print("❌ LangChain agent not available")
        if IN_COLAB:
            print("   💡 Restart this cell and enter your GOOGLE_API_KEY when prompted")
        else:
            print("   💡 Please set your GOOGLE_API_KEY as an environment variable or secret")

    print("\n🚀 Starting Gradio interface...")

    # Create and launch the interface
    interface = create_gradio_interface()

    # Launch configuration for Colab vs local/Spaces
    interface.launch(
        share=True if IN_COLAB else False,
        debug=False,
        height=600,
        show_error=True
    )

# Auto-run if in Colab or when script is executed directly
if __name__ == "__main__" or IN_COLAB:
    main()