prepare("SELECT COUNT(*) FROM patients WHERE DATE(created_at) BETWEEN ? AND ?");
$stmt->execute([$start_date, $end_date]);
$new_patients = $stmt->fetchColumn();
// 2. Total Visits
$stmt = $db->prepare("SELECT COUNT(*) FROM visits WHERE DATE(visit_date) BETWEEN ? AND ?");
$stmt->execute([$start_date, $end_date]);
$total_visits = $stmt->fetchColumn();
// 3. Total Revenue
$stmt = $db->prepare("SELECT SUM(total_amount) FROM bills WHERE DATE(created_at) BETWEEN ? AND ?");
$stmt->execute([$start_date, $end_date]);
$total_revenue = $stmt->fetchColumn() ?: 0;
// 4. Pending Bills (Outstanding amount for bills created in this period)
$stmt = $db->prepare("SELECT SUM(patient_payable) FROM bills WHERE status != 'Paid' AND DATE(created_at) BETWEEN ? AND ?");
$stmt->execute([$start_date, $end_date]);
$pending_bills = $stmt->fetchColumn() ?: 0;
// 5. Visits by Status
$stmt = $db->prepare("SELECT status, COUNT(*) as count FROM visits WHERE DATE(visit_date) BETWEEN ? AND ? GROUP BY status");
$stmt->execute([$start_date, $end_date]);
$visits_by_status = $stmt->fetchAll(PDO::FETCH_KEY_PAIR);
// 6. Revenue Trend (Daily)
$stmt = $db->prepare("SELECT DATE(created_at) as date, SUM(total_amount) as total FROM bills WHERE DATE(created_at) BETWEEN ? AND ? GROUP BY DATE(created_at) ORDER BY date ASC");
$stmt->execute([$start_date, $end_date]);
$revenue_trend = $stmt->fetchAll(PDO::FETCH_ASSOC);
// 7. Visits by Doctor
$stmt = $db->prepare("
SELECT d.name_$lang as doctor_name, COUNT(v.id) as count
FROM visits v
JOIN doctors d ON v.doctor_id = d.id
WHERE DATE(v.visit_date) BETWEEN ? AND ?
GROUP BY v.doctor_id
ORDER BY count DESC
LIMIT 5
");
$stmt->execute([$start_date, $end_date]);
$visits_by_doctor = $stmt->fetchAll(PDO::FETCH_ASSOC);
// 8. Patient Gender Distribution (All time or filtered? Let's do filtered by creation date to match "New Patients")
$stmt = $db->prepare("SELECT gender, COUNT(*) as count FROM patients WHERE DATE(created_at) BETWEEN ? AND ? GROUP BY gender");
$stmt->execute([$start_date, $end_date]);
$patients_by_gender = $stmt->fetchAll(PDO::FETCH_KEY_PAIR);
// --- PREPARE DATA FOR JS ---
$chart_status_labels = array_keys($visits_by_status);
$chart_status_data = array_values($visits_by_status);
$chart_revenue_labels = array_column($revenue_trend, 'date');
$chart_revenue_data = array_column($revenue_trend, 'total');
$chart_doctor_labels = array_column($visits_by_doctor, 'doctor_name');
$chart_doctor_data = array_column($visits_by_doctor, 'count');
$chart_gender_labels = array_keys($patients_by_gender);
$chart_gender_data = array_values($patients_by_gender);
?>