feat(*): Add AI functionality to grading endpoint

src/lib/utils/ai.ts

@@ -0,0 +1,89 @@
+import type { OpenAIResponse } from './types';
+
+const OPENAI_API_KEY = process.env['AZURE_OPENAI_API_KEY'];
+const OPENAI_ENDPOINT = process.env['AZURE_OPENAI_ENDPOINT'];
+const OPENAI_DEPLOYMENT = process.env['AZURE_OPENAI_DEPLOYMENT'] || 'gpt-4';
+
+// Prompt template for grading and feedback
+export function buildGradingPrompt(submission: string) {
+  return `You are an expert secondary school teacher and AI assessment agent. Assess the following student submission using the following steps:
+1. Grade the work out of 10, using clear, objective criteria.
+2. Identify specific strengths, referencing the success criteria.
+3. Identify misconceptions or areas for improvement, using formative assessment language.
+4. Design an individualized activity or exercise for the student to address their misconceptions or extend their learning. This activity should be:
+   - Appropriately scaffolded for the student's current level.
+   - Specific and actionable (e.g., a short written task, a practical exercise, or a quiz question).
+   - Aligned with the curriculum and learning objectives.
+5. Write a reflection question for the student to encourage metacognition.
+6. Suggest to the teacher one way to support this student in the next lesson.
+7. Show your reasoning step by step (chain-of-thought).
+
+STUDENT SUBMISSION:
+${submission}
+
+RESPONSE FORMAT:
+Grade: <number>/10
+Strengths: <text>
+Areas for Improvement: <text>
+Individualized Activity: <text>
+Reflection Question: <text>
+Teacher Suggestion: <text>
+Reasoning: <step-by-step explanation>`;
+}
+
+export async function gradeWithOpenAI(submission: string): Promise<OpenAIResponse> {
+  if (!OPENAI_API_KEY || !OPENAI_ENDPOINT) {
+    // Fallback for local/demo mode
+    return {
+      grade: '7/10',
+      strengths: 'Clear argument and good evidence.',
+      areas_for_improvement: 'Needs deeper analysis and more examples.',
+      individualized_activity: 'Write a paragraph expanding on your main point and provide two additional examples to support your argument.',
+      reflection_question: 'What was the most challenging part of this assignment for you, and why?',
+      teacher_suggestion: 'In the next lesson, review how to develop arguments with supporting evidence and provide a model answer for comparison.',
+      reasoning: 'The submission demonstrates a good structure and evidence, but lacks depth and breadth of analysis. The activity and suggestions are designed to target this gap.'
+    };
+  }
+
+  const prompt = buildGradingPrompt(submission);
+
+  const res = await fetch(`${OPENAI_ENDPOINT}/openai/deployments/${OPENAI_DEPLOYMENT}/chat/completions?api-version=2024-02-15-preview`, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      'api-key': OPENAI_API_KEY
+    },
+    body: JSON.stringify({
+      messages: [
+        { role: 'system', content: 'You are a helpful, fair, and transparent grading assistant.' },
+        { role: 'user', content: prompt }
+      ],
+      max_tokens: 500,
+      temperature: 0.2,
+      stream: false
+    })
+  });
+
+  if (!res.ok) throw new Error('OpenAI API error');
+  const data = await res.json();
+  const content = data.choices?.[0]?.message?.content || '';
+
+  // Parse the response using regex
+  const gradeMatch = content.match(/Grade:\s*(.*)/i);
+  const strengthsMatch = content.match(/Strengths:\s*([\s\S]*?)Areas for Improvement:/i);
+  const improvementMatch = content.match(/Areas for Improvement:\s*([\s\S]*?)Individualized Activity:/i);
+  const activityMatch = content.match(/Individualized Activity:\s*([\s\S]*?)Reflection Question:/i);
+  const reflectionMatch = content.match(/Reflection Question:\s*([\s\S]*?)Teacher Suggestion:/i);
+  const teacherSuggestionMatch = content.match(/Teacher Suggestion:\s*([\s\S]*?)Reasoning:/i);
+  const reasoningMatch = content.match(/Reasoning:\s*([\s\S]*)/i);
+
+  return {
+    grade: gradeMatch?.[1]?.trim() || '',
+    strengths: strengthsMatch?.[1]?.trim() || '',
+    areas_for_improvement: improvementMatch?.[1]?.trim() || '',
+    individualized_activity: activityMatch?.[1]?.trim() || '',
+    reflection_question: reflectionMatch?.[1]?.trim() || '',
+    teacher_suggestion: teacherSuggestionMatch?.[1]?.trim() || '',
+    reasoning: reasoningMatch?.[1]?.trim() || ''
+  };
+}

src/lib/utils/types.ts

@@ -0,0 +1,9 @@
+export interface OpenAIResponse {
+  grade: string;
+  strengths: string;
+  areas_for_improvement: string;
+  individualized_activity: string;
+  reflection_question: string;
+  teacher_suggestion: string;
+  reasoning: string;
+}

src/routes/api/grade/+server.ts

@@ -1,25 +1,40 @@
 import type { RequestHandler } from '@sveltejs/kit';
 import type { RequestEvent } from '@sveltejs/kit';
+import { gradeWithOpenAI } from '$lib/utils/ai';
 
-// TODO - don't just mock the grading logic
 export const POST: RequestHandler = async (event: RequestEvent) => {
-  const data = await event.request.formData();
-  const file = data.get('file');
-  const text = data.get('text');
+  try {
+    const data = await event.request.formData();
+    const file = data.get('file');
+    const text = data.get('text');
+    let submission = '';
 
-  // Simulation of grading and feedback
-  let feedback = '';
-  if (file) {
-    feedback = 'Received file: ' + (file as File).name + '. [AI feedback coming soon]';
-  } else if (typeof text === 'string' && text.trim().length > 0) {
-    feedback = 'Received text submission. [AI feedback coming soon]';
-  } else {
-    return new Response(JSON.stringify({ error: 'No valid input provided.' }), { status: 400 });
+    if (file && typeof file === 'object' && 'arrayBuffer' in file && 'name' in file) {
+      // Only support .txt for now for hackathon speed
+      const fileObj = file as File;
+      if (!fileObj.name.endsWith('.txt')) {
+        return new Response(JSON.stringify({ error: 'Only .txt files are supported at this time.' }), { status: 400 });
+      }
+      const buffer = await fileObj.arrayBuffer();
+      submission = new TextDecoder('utf-8').decode(buffer);
+    } else if (typeof text === 'string' && text.trim().length > 0) {
+      submission = text.trim();
+    } else {
+      return new Response(JSON.stringify({ error: 'No valid input provided.' }), { status: 400 });
+    }
+
+    // Call the AI grading agent
+    const aiResult = await gradeWithOpenAI(submission);
+
+    return new Response(JSON.stringify({
+      success: true,
+      feedback: `Grade: ${aiResult.grade}\nStrengths: ${aiResult.strengths}\nWeaknesses: ${aiResult.weaknesses}\nIndividualized Activity: ${aiResult.individualized_activity}\nReasoning: ${aiResult.reasoning}`,
+      ...aiResult
+    }), {
+      status: 200,
+      headers: { 'Content-Type': 'application/json' }
+    });
+  } catch (err: any) {
+    return new Response(JSON.stringify({ error: err.message || 'Internal server error.' }), { status: 500 });
   }
-
-  // Return mock feedback for now
-  return new Response(JSON.stringify({ success: true, feedback }), {
-    status: 200,
-    headers: { 'Content-Type': 'application/json' }
-  });
 };