<?php
require_once 'includes/config.php';
require_once 'includes/functions.php';
require_once 'includes/auth.php';
require_once 'includes/db.php';

$auth = new Auth();

// Check if user is logged in
if (!$auth->isLoggedIn()) {
    die('Unauthorized access');
}

$db = Database::getInstance();

// Set headers for CSV download
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename="statistics_' . date('Y-m-d') . '.csv"');

// Create output stream
$output = fopen('php://output', 'w');

// Add BOM for Excel UTF-8 compatibility
fprintf($output, chr(0xEF).chr(0xBB).chr(0xBF));

// Write headers
$headers = ['Statistic Name', 'Type', 'Attributes', 'Combination', 'Target %', 'Panel %', 'Deviation %', 'Created By', 'Created Date'];
fputcsv($output, $headers);

// Get statistics data with combinations
$query = $db->query("
    SELECT 
        s.name as statistic_name,
        s.type,
        u.full_name as creator_name,
        DATE_FORMAT(s.created_at, '%Y-%m-%d %H:%i:%S') as formatted_date,
        GROUP_CONCAT(DISTINCT a.name ORDER BY sa.id) as attribute_names,
        sc.combination_values,
        sc.percentage as target_percentage,
        sc.actual_percentage
    FROM statistics s
    LEFT JOIN users u ON s.created_by = u.id
    JOIN statistic_attributes sa ON s.id = sa.statistic_id
    JOIN attributes a ON a.id = sa.attribute_id
    JOIN statistic_combinations sc ON s.id = sc.statistic_id
    GROUP BY s.id, sc.id
    ORDER BY s.name, sc.id
");

// Write data rows
while ($stat = $query->fetch_assoc()) {
    $targetPct = floatval($stat['target_percentage']);
    $actualPct = floatval($stat['actual_percentage'] ?? 0);
    $deviation = $targetPct > 0 ? (($actualPct - $targetPct) / $targetPct) * 100 : 0;
    
    // Format the combination values
    $combinationValues = json_decode($stat['combination_values'], true);
    $combinationText = implode(' × ', $combinationValues);
    
    $row = [
        $stat['statistic_name'],
        $stat['type'],
        $stat['attribute_names'],
        $combinationText,
        number_format($targetPct, 2),
        number_format($actualPct, 2),
        number_format($deviation, 2),
        $stat['creator_name'],
        $stat['formatted_date']
    ];
    
    fputcsv($output, $row);
}

fclose($output);
exit;