<?php
require_once 'inc/config.php';

// Sanitize incoming data using real_escape_string to prevent SQL injection
$year   = isset($_GET['year']) ? $mysqli->real_escape_string($_GET['year']) : false;
$volume = isset($_GET['volume']) ? $mysqli->real_escape_string($_GET['volume']) : false;
$issue  = isset($_GET['issue']) ? $mysqli->real_escape_string($_GET['issue']) : false;
$part   = isset($_GET['part']) ? $mysqli->real_escape_string($_GET['part']) : false;
$file   = isset($_GET['file']) ? $mysqli->real_escape_string($_GET['file']) : false;

// Check if all required parameters are provided
if (!$year || !$volume || !$issue || !$part || !$file) {
    http_response_code(400); // Bad request
    echo "Invalid parameters.";
    exit;
}

$stmt = $mysqli->prepare("SELECT * FROM archives WHERE year = ? AND volume = ? AND issue = ? AND part = ? AND (file = ? OR supplementaryfile = ?) AND status = 'enabled'");
$stmt->bind_param('sissss', $year, $volume, $issue, $part, $file, $file);
$stmt->execute();
$stmt->store_result();
$count_rows = $stmt->num_rows();
$stmt->close();

// Check if any row was returned
if ($count_rows == 1) {
    // Data exists in the database
    // Proceed to serve the file

    // Define the directory where files are stored
    $pdfDir = __DIR__ . "/uploads/archives/";
    $filePath = realpath($pdfDir . $file);

    // Ensure the file exists
    if (!file_exists($filePath)) {
        http_response_code(404); // Not found
        echo "File not found.";
        exit;
    }

    $stmt = $mysqli->prepare("UPDATE archives SET views = views + 1, downloads = downloads + 1 WHERE (file = ? OR supplementaryfile = ?) AND status = 'enabled'");
    $stmt->bind_param('ss', $file, $file);
    $stmt->execute();
    $stmt->close();
    $mysqli->close();

    // Get file extension
    $fileExtension = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));
    
    // Define MIME types for common file types
    $mimeTypes = [
        'pdf'  => 'application/pdf',
        'doc'  => 'application/msword',
        'docx' => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
        'xls'  => 'application/vnd.ms-excel',
        'xlsx' => 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        'ppt'  => 'application/vnd.ms-powerpoint',
        'pptx' => 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
        'zip'  => 'application/zip',
        'rar'  => 'application/x-rar-compressed',
        'jpg'  => 'image/jpeg',
        'jpeg' => 'image/jpeg',
        'png'  => 'image/png',
        'gif'  => 'image/gif',
        'txt'  => 'text/plain',
    ];

    // Get content type
    $contentType = isset($mimeTypes[$fileExtension]) ? $mimeTypes[$fileExtension] : 'application/octet-stream';

    // Prevent browser from caching
    header('Expires: 0');
    header('Cache-Control: no-store, no-cache, must-revalidate');
    header('Cache-Control: post-check=0, pre-check=0', false);
    header('Pragma: no-cache');

    // Set content type
    header('Content-Type: ' . $contentType);
    
    // PDF: inline (browser mein dikhe), Others: attachment (download ho)
    if ($fileExtension === 'pdf') {
        header('Content-Disposition: inline; filename="' . basename($filePath) . '"');
    } else {
        header('Content-Disposition: attachment; filename="' . basename($filePath) . '"');
    }
    
    header('Content-Length: ' . filesize($filePath));

    // Output the file content to the browser
    readfile($filePath);
    exit;
} else {
    // No matching data found in the database
    http_response_code(404); // Not found
    echo "The requested data does not exist in the archives.";
    exit;
}