test_ollama_backend.php

<?php
/**
 * Ollama Direct Test - PHP Backend
 */

header('Content-Type: application/json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

// Handle preflight
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    exit;
}

// Only POST allowed
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    echo json_encode(['status' => 'error', 'message' => 'Only POST allowed']);
    exit;
}

// Get input
$input = json_decode(file_get_contents('php://input'), true);

if (!$input) {
    echo json_encode(['status' => 'error', 'message' => 'No input data']);
    exit;
}

$question = $input['question'] ?? '';
$reference_answer = $input['reference_answer'] ?? '';
$student_answer = $input['student_answer'] ?? '';
$rubric = $input['rubric'] ?? [];

if (empty($question) || empty($reference_answer) || empty($student_answer)) {
    echo json_encode(['status' => 'error', 'message' => 'Missing fields']);
    exit;
}

// Config
$ollama_url = 'http://localhost:11434';
$model = 'mistral';

// Build prompt
$rubric_text = "Evaluation Rubric:\n";
$total_marks = 0;
foreach ($rubric as $r) {
    $rubric_text .= "- {$r['criteria']}: {$r['marks']} marks\n";
    $total_marks += (int)$r['marks'];
}

$prompt = "You are an expert examiner evaluating a student's answer.

QUESTION: $question

REFERENCE ANSWER: $reference_answer

$rubric_text

STUDENT'S ANSWER: $student_answer

---

Evaluate strictly based on the rubric. Return ONLY valid JSON in this exact format:
{
  \"total_score\": 8,
  \"criterion_marks\": [
    {\"criteria\": \"Understanding\", \"awarded_marks\": 4, \"reason\": \"Good grasp of concepts\"},
    {\"criteria\": \"Accuracy\", \"awarded_marks\": 3, \"reason\": \"Mostly correct\"},
    {\"criteria\": \"Completeness\", \"awarded_marks\": 1, \"reason\": \"Missing details\"}
  ],
  \"feedback\": \"Overall good answer but needs more detail.\",
  \"strengths\": [\"Clear explanation\", \"Good structure\"],
  \"improvements\": [\"Add more examples\", \"Explain edge cases\"]
}

Return ONLY the JSON, no other text.";

// Call Ollama
$start = microtime(true);

$ch = curl_init("{$ollama_url}/api/generate");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 120,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS => json_encode([
        'model' => $model,
        'prompt' => $prompt,
        'stream' => false,
        'temperature' => 0.3,
        'format' => 'json'
    ])
]);

$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$curl_error = curl_error($ch);
curl_close($ch);

$elapsed = round(microtime(true) - $start, 2);

if ($curl_error) {
    echo json_encode(['status' => 'error', 'message' => "Curl error: $curl_error", 'elapsed' => $elapsed]);
    exit;
}

if ($http_code !== 200) {
    echo json_encode(['status' => 'error', 'message' => "HTTP $http_code", 'elapsed' => $elapsed]);
    exit;
}

// Parse Ollama response
$data = json_decode($response, true);
if (!$data || !isset($data['response'])) {
    echo json_encode(['status' => 'error', 'message' => 'Invalid Ollama response', 'elapsed' => $elapsed]);
    exit;
}

$generated = $data['response'];

// Extract JSON from response
$generated = trim($generated);
// Remove markdown code blocks if present
$generated = preg_replace('/^```json\s*/i', '', $generated);
$generated = preg_replace('/\s*```$/', '', $generated);
$generated = trim($generated);

// Parse evaluation JSON
$evaluation = json_decode($generated, true);

if (json_last_error() !== JSON_ERROR_NONE) {
    // Try to find JSON in text
    if (preg_match('/\{.*\}/s', $generated, $matches)) {
        $evaluation = json_decode($matches[0], true);
    }

    if (json_last_error() !== JSON_ERROR_NONE) {
        echo json_encode([
            'status' => 'error',
            'message' => 'JSON parse error: ' . json_last_error_msg(),
            'generated_text' => substr($generated, 0, 500),
            'elapsed' => $elapsed
        ]);
        exit;
    }
}

// Validate and fill defaults
if (!isset($evaluation['total_score'])) {
    $score = 0;
    if (isset($evaluation['criterion_marks'])) {
        foreach ($evaluation['criterion_marks'] as $c) {
            $score += (int)($c['awarded_marks'] ?? 0);
        }
    }
    $evaluation['total_score'] = $score;
}

$evaluation['feedback'] = $evaluation['feedback'] ?? 'No feedback provided';
$evaluation['criterion_marks'] = $evaluation['criterion_marks'] ?? [];
$evaluation['strengths'] = $evaluation['strengths'] ?? [];
$evaluation['improvements'] = $evaluation['improvements'] ?? [];

// Success
echo json_encode([
    'status' => 'success',
    'message' => 'Evaluation completed',
    'elapsed' => $elapsed,
    'model_used' => $model,
    'evaluation' => $evaluation
]);