<?php
require_once "../config.php";

$student_id = $_SESSION['student_id'];
$track = "Python Basics Track";

// Count completed challenges
$stmt = $conn->prepare("
  SELECT COUNT(DISTINCT challenge_id) AS completed 
  FROM challenge_submissions 
  WHERE student_id = ? AND is_correct = 1
");
$stmt->bind_param("i", $student_id);
$stmt->execute();
$result = $stmt->get_result()->fetch_assoc();

$completed = $result['completed'];

// Rule: 5 challenges
if ($completed >= 5) {

  // Check already issued?
  $check = $conn->prepare("
    SELECT id FROM certificates 
    WHERE student_id = ? AND certificate_type = 'Participation'
  ");
  $check->bind_param("i", $student_id);
  $check->execute();
  $checkResult = $check->get_result();

  if ($checkResult->num_rows == 0) {
    // Issue certificate
    $insert = $conn->prepare("
      INSERT INTO certificates (student_id, certificate_type, track_name)
      VALUES (?, 'Participation', ?)
    ");
    $insert->bind_param("is", $student_id, $track);
    $insert->execute();
  }
}