app.py

import gradio as gr
import openai

# --- UI Configuration ---

# Extracted from the provided React code
LANGUAGES = [
    'Python', 'JavaScript', 'TypeScript', 'Java', 'C++', 'C#', 'C', 'Go', 
    'Rust', 'Swift', 'Kotlin', 'PHP', 'Ruby', 'Scala', 'R', 'MATLAB', 
    'Perl', 'Haskell', 'Lua', 'Dart', 'Elixir', 'F#', 'Clojure', 
    'Objective-C', 'Visual Basic', 'Bash', 'PowerShell', 'SQL', 'HTML', 
    'CSS', 'JSON', 'XML', 'YAML', 'Assembly', 'Fortran', 'COBOL', 
    'Pascal', 'Delphi', 'Groovy', 'Julia', 'Nim', 'Crystal', 'Zig', 
    'V', 'OCaml', 'Erlang', 'Prolog', 'Lisp', 'Scheme', 'Racket'
]

# A selection of popular and capable models available via OpenRouter
# You can expand this list with other models from openrouter.ai
MODELS = [
    "anthropic/claude-3.5-sonnet",
    "google/gemini-flash-1.5",
    "meta-llama/llama-3-8b-instruct",
    "mistralai/mistral-large",
    "openai/gpt-4o",
    "microsoft/wizardlm-2-8x22b",
]

# Default example code from the original application
DEFAULT_SOURCE_CODE = """# Example Python code
def fibonacci(n):
    if n <= 1:
        return n
    return fibonacci(n-1) + fibonacci(n-2)

print(fibonacci(10))"""

# --- Core Conversion Logic ---

def convert_code(
    source_code: str,
    source_lang: str,
    target_lang: str,
    model: str,
    api_key: str,
):
    """
    Uses an LLM via OpenRouter to convert code from one language to another.
    """
    if not source_code.strip():
        raise gr.Error("Please enter some code to convert.")
    if not api_key.strip():
        raise gr.Error("OpenRouter API key is required.")
    if not model:
        raise gr.Error("Please select a model for the conversion.")

    # Initialize the OpenAI client to point to OpenRouter's API
    client = openai.OpenAI(
        base_url="https://openrouter.ai/api/v1",
        api_key=api_key,
    )

    # Construct the prompt for the LLM
    prompt = (
        f"You are an expert programmer. Convert the following {source_lang} code "
        f"to {target_lang}. Your response should only contain the raw, converted code. "
        "Do not include any explanations, markdown formatting (like ```), or extra text."
        f"\n\n--- Start of {source_lang} Code ---\n"
        f"{source_code}\n"
        f"--- End of {source_lang} Code ---"
    )

    try:
        # Make the API call to the selected model
        completion = client.chat.completions.create(
            model=model,
            messages=[
                {"role": "user", "content": prompt},
            ],
            temperature=0.1, # Lower temperature for more deterministic output
            max_tokens=2048,
        )
        converted_code = completion.choices[0].message.content.strip()
        return converted_code

    except openai.AuthenticationError:
        raise gr.Error("Authentication failed. Please check your OpenRouter API key.")
    except Exception as e:
        # A catch-all for other potential API or network errors
        raise gr.Error(f"An error occurred during conversion: {e}")

# --- Gradio User Interface ---

with gr.Blocks(
    theme=gr.themes.Monochrome(),
    css=".gradio-container {background-color: #0f172a}" # Dark theme like the original
) as app:
    # Header
    with gr.Row():
        gr.HTML(
            """
            <div style="display: flex; align-items: center; gap: 12px; padding: 10px;">
                <svg xmlns="[http://www.w3.org/2000/svg](http://www.w3.org/2000/svg)" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="#3b82f6" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-code-xml"><path d="m18 16 4-4-4-4"/><path d="m6 8-4 4 4 4"/><path d="m14.5 4-5 16"/></svg>
                <div>
                    <h1 style="font-size: 1.5rem; font-weight: 700; color: #ffffff; margin: 0;">CodeVerter</h1>
                    <p style="font-size: 0.875rem; color: #9ca3af; margin: 0;">Programming Language Converter via OpenRouter</p>
                </div>
            </div>
            """
        )

    # API Key and Model Selection
    with gr.Accordion("⚙️ Configuration", open=True):
        openrouter_key = gr.Textbox(
            label="OpenRouter API Key",
            placeholder="Enter your OpenRouter API key here...",
            type="password",
            elem_id="api-key-textbox",
        )
        model_selection = gr.Dropdown(
            label="Select LLM Model",
            choices=MODELS,
            value=MODELS[0], # Default to the first model in the list
        )

    # Main conversion interface
    with gr.Row(equal_height=False):
        # Input column
        with gr.Column(scale=1):
            source_lang_selection = gr.Dropdown(
                label="Source Language",
                choices=LANGUAGES,
                value="Python",
            )
            source_code_input = gr.Code(
                label="Source Code",
                language="python", # Start with python syntax highlighting
                value=DEFAULT_SOURCE_CODE,
                lines=15,
            )

        # Output column
        with gr.Column(scale=1):
            target_lang_selection = gr.Dropdown(
                label="Target Language",
                choices=LANGUAGES,
                value="JavaScript",
            )
            target_code_output = gr.Code(
                label="Converted Code",
                language="javascript", # Start with javascript syntax highlighting
                lines=15,
                interactive=False, # Make it read-only
            )
    
    # Keep language highlighting in sync with dropdowns
    source_lang_selection.change(
        lambda x: gr.update(language=x.lower()),
        inputs=source_lang_selection,
        outputs=source_code_input
    )
    target_lang_selection.change(
        lambda x: gr.update(language=x.lower()),
        inputs=target_lang_selection,
        outputs=target_code_output
    )

    # Convert button and action
    convert_button = gr.Button("Convert Code", variant="primary")
    convert_button.click(
        fn=convert_code,
        inputs=[
            source_code_input,
            source_lang_selection,
            target_lang_selection,
            model_selection,
            openrouter_key,
        ],
        outputs=target_code_output,
        api_name="convert"
    )

    # Footer
    gr.HTML(
        """
        <div style="text-align: center; margin-top: 24px; color: #9ca3af; font-size: 0.875rem;">
            <p>CodeVerter uses LLMs via OpenRouter to convert code. Results may require manual review.</p>
        </div>
        """
    )

if __name__ == "__main__":
    app.launch()