feat: implement /v1/translate and /v1/explain routes and preserve legacy / endpoint

Author: hemanth5055

backend/src/index.ts

@@ -16,39 +16,85 @@ export default {
 			return new Response(null, { headers: corsHeaders });
 		}
 
-		try {
-			const { code, targetLanguage } = await request.json<{ code: string; targetLanguage: string }>();
-
-			if (!code || !targetLanguage) {
-				return new Response(JSON.stringify({ error: "Missing 'code' or 'targetLanguage' in request body." }), {
-					status: 400,
-					headers: { ...corsHeaders, 'Content-Type': 'application/json' },
-				});
-			}
+		const url = new URL(request.url);
+		const path = url.pathname;
+		const genAI = new GoogleGenerativeAI(env.GEMINI_API_KEY);
+		const model = genAI.getGenerativeModel({ model: 'gemini-2.0-flash' });
 
-			const genAI = new GoogleGenerativeAI(env.GEMINI_API_KEY);
+		try {
+			//Function for handling the translation
+			const handleTranslate = async () => {
+				const { code, targetLanguage } = await request.json<{ code: string; targetLanguage: string }>();
 
-			const model = genAI.getGenerativeModel({ model: 'gemini-2.0-flash' });
+				if (!code || !targetLanguage) {
+					return new Response(JSON.stringify({ error: "Missing 'code' or 'targetLanguage' in request body." }), {
+						status: 400,
+						headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+					});
+				}
 
-			const prompt = `Translate the following code snippet to ${targetLanguage}.
+				const prompt = `Translate the following code snippet to ${targetLanguage}.
 Do not add any explanation, commentary, or markdown formatting like \`\`\` around the code.
-**IMPORTANT: Preserve all original comments and their exact placement in the translated code. do not add extra spaces in between.**
+**IMPORTANT: Preserve all original comments and their exact placement in the translated code. Do not add extra spaces in between.**
 Only provide the raw, translated code itself.
 
 Original Code:
 ${code}`;
 
-			const result = await model.generateContent(prompt);
-			const geminiResponse = result.response;
-			const translatedCode = geminiResponse.text();
+				const result = await model.generateContent(prompt);
+				const translatedCode = result.response.text();
+
+				return new Response(JSON.stringify({ translation: translatedCode }), {
+					status: 200,
+					headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+				});
+			};
+			//Function for handling the explanation
+			const handleExplain = async () => {
+				const { code } = await request.json<{ code: string }>();
+
+				if (!code) {
+					return new Response(JSON.stringify({ error: "Missing 'code' in request body." }), {
+						status: 400,
+						headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+					});
+				}
 
-			return new Response(JSON.stringify({ translation: translatedCode }), {
-				status: 200,
+				const prompt = `Explain the following code snippet in detail:
+1. Provide a clear breakdown of what each part (functions, variables, logic blocks) does.
+2. If applicable, describe the overall purpose or intent of the code.
+3. Offer a step-by-step explanation of how the code executes.
+4. If the code is executable, show a sample input and the corresponding output.
+5. Keep the explanation beginner-friendly but technically accurate.
+
+Code:
+${code}`;
+
+				const result = await model.generateContent(prompt);
+				const explanation = result.response.text();
+
+				return new Response(JSON.stringify({ explanation }), {
+					status: 200,
+					headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+				});
+			};
+			if (path === '/') {
+				return handleTranslate();
+			}
+			if (path === '/v1/translate') {
+				return handleTranslate();
+			}
+			if (path === '/v1/explain') {
+				return handleExplain();
+			}
+			// Fallback for unknown paths
+			return new Response(JSON.stringify({ error: 'Route not found.' }), {
+				status: 404,
 				headers: { ...corsHeaders, 'Content-Type': 'application/json' },
 			});
 		} catch (error) {
-			console.error('Error during translation:', error);
-			return new Response(JSON.stringify({ error: 'An error occurred while translating the code.' }), {
+			console.error('Error during request:', error);
+			return new Response(JSON.stringify({ error: 'An internal error occurred.' }), {
 				status: 500,
 				headers: { ...corsHeaders, 'Content-Type': 'application/json' },
 			});