app.py

import gradio as gr
import os
import requests
from pygments.lexers import guess_lexer_for_filename
from pygments.util import ClassNotFound

# Fetch OpenRouter API key from environment variable (set in HF secrets or local .env)
OPENROUTER_API_KEY = os.getenv("OPENROUTER_API_KEY", "sk-...")  # Replace with your actual key if testing locally

# Function to detect source programming language
def detect_language(code_snippet):
    try:
        lexer = guess_lexer_for_filename("example.py", code_snippet)
        return lexer.name
    except ClassNotFound:
        return "Unknown"

# Function to translate code using OpenRouter + DeepSeek Coder
def translate_code(code_snippet, target_language):
    detected_lang = detect_language(code_snippet)
    prompt = f"""You are a coding assistant. Translate the following {detected_lang} code to {target_language}:\n\n```{detected_lang}\n{code_snippet}\n```"""

    headers = {
        "Authorization": f"Bearer {OPENROUTER_API_KEY}",
        "HTTP-Referer": "https://huggingface.co/spaces/Raahulthakur/codeswitch",  # Optional, but recommended for OpenRouter free tier
        "Content-Type": "application/json"
    }

    payload = {
        "model": "deepseek-coder-6.7b",  # ✅ Correct model format
        "messages": [
            {"role": "system", "content": "You are an expert code translator."},
            {"role": "user", "content": prompt}
        ]
    }

    try:
        response = requests.post("https://openrouter.ai/api/v1/chat/completions", headers=headers, json=payload)
        response.raise_for_status()
        result = response.json()

        # Safe access to output
        translated_code = result.get("choices", [{}])[0].get("message", {}).get("content", "⚠️ No output from model.")
        return detected_lang, translated_code.strip()
    except Exception as e:
        return detected_lang, f"Error: {str(e)}"

# Gradio UI
with gr.Blocks() as demo:
    gr.Markdown("## 🚀 CodeSwitch: Translate Code Between Languages")

    code_input = gr.Code(label="Paste your Code", language="python", lines=20)
    target_lang = gr.Dropdown(
        choices=["Python", "JavaScript", "C++", "Java", "Go", "C", "PHP", "Ruby"],
        label="Translate To",
        value="JavaScript"
    )

    detect_btn = gr.Button("Detect Language")
    translate_btn = gr.Button("Translate Code")

    detected_lang_output = gr.Textbox(label="Detected Language")
    translated_output = gr.Code(label="Translated Code")

    detect_btn.click(fn=detect_language, inputs=code_input, outputs=detected_lang_output)
    translate_btn.click(fn=translate_code, inputs=[code_input, target_lang], outputs=[detected_lang_output, translated_output])

demo.launch()