$file = [
    'ID'                       => 3737,                                 // The WordPress post ID for the file
    'post_author'              => 1,                                    // The ID of the author of the post
    'post_date'                => '2025-01-01 12:00:00',                // The date the post was published
    'post_date_gmt'            => '2025-01-01 12:00:00',                // The GMT date the post was published
    'post_title'               => 'File Title',                         // The title of the file (usually the file name)
    'post_name'                => 'file-title',                         // The slug (URL-friendly name) of the post
    'post_modified'            => '2025-01-01 12:00:00',                // The date the post was last modified
    'post_modified_gmt'        => '2025-01-01 12:00:00',                // The GMT date the post was last modified
    'url'                      => 'https://example.com/file.zip',       // The URL to the actual file, stored in custom post meta
    'description'              => 'File description',                   // Description of the file
    'download_count'           => 10,                                   // The download count for the file
    'required_roles'           => 'administrator,subscriber',           // The required user roles for accessing the file
    'required_meta_key'        => 'can_download',                       // A meta key for additional file restrictions
    'last_downloaded'          => '2025-01-01 12:00:00',                // The last download date/time
    'last_downloaded_by'       => 123,                                  // The user ID of the last person who downloaded the file
];

/**
 * Modify the file download URL by adding a cache busting parameter.
 *
 * @param string $url → The original download URL.
 * @param array  $file → An associative array containing the file metadata.
 * @param int    $user_id → The ID of the user who downloaded the file if logged in.
 * @param string $user_ip → The IP address of the user who downloaded the file if logged out.
 *
 * @return string → The modified download URL.
 */
add_filter( 'erifl_download_file_url', function( $url, $file, $user_id, $user_ip ) {
    // Add a 'clear_cache' parameter to ensure the latest version of the file is used
    $url = add_query_arg( 'clear_cache', time(), $url );
    
    return $url;
}, 10, 4 );

/**
 * Perform an action after a file has been downloaded.
 *
 * @param array  $file → An associative array containing the full file and meta data.
 * @param int    $user_id → The ID of the user who downloaded the file if logged in.
 * @param string $user_ip → The IP address of the user who downloaded the file if logged out.
 */
add_action( 'erifl_after_file_downloaded', function( $file, $user_id, $user_ip ) {
    // Log info every 100 downloads
    if ( $file[ 'download_count' ] > 0 && $file[ 'download_count' ] % 100 === 0 ) {
        $user = ( $user_id ? ) 'ID ' . $user_id : 'with IP ' . $user_ip;
        error_log( "User {$user} requested '{$file['post_title']}' on its {$file['download_count']}th download." );
    }
}, 10, 3 );

/**
 * Override file download access requirements based on custom logic.
 *
 * @param bool   $meets_requirements → Whether the user currently passes the access checks.
 * @param array  $file → An associative array containing the full file and meta data.
 * @param int    $user_id → The ID of the user who downloaded the file if logged in.
 * @param string $user_ip → The IP address of the user who downloaded the file if logged out.
 *
 * @return bool → True if the user should be allowed to download, false otherwise.
 */
add_filter( 'erifl_user_meets_requirements', function( $meets_requirements, $file, $user_id, $user_ip ) {
    // Block users with ID 1 from downloading any files (example only)
    if ( $user_id === 1 ) {
        return false;
    }

    return $meets_requirements;
}, 10, 4 );

/**
 * Add custom classes based on file format or display type.
 *
 * @param string $classes → The existing string of custom classes passed via the shortcode.
 * @param array  $file → An associative array containing the file data from get_file().
 * @param string $type → The display type (e.g., 'link', 'button', 'post', etc.) passed via the shortcode.
 *
 * @return string → The modified string of CSS classes.
 */
add_filter( 'erifl_classes', function( $classes, $file, $type ) {
    if ( $type === 'post' && !empty( $file[ 'download_count' ] ) && $file[ 'download_count' ] > 100 ) {
        $classes .= ' popular-file';
    }

    return $classes;
}, 10, 3 );

/**
 * Filter the icon used for file downloads.
 *
 * @param string $default_icon The default icon HTML.
 * @param string $icon_type The requested icon type (e.g., 'logo-full', 'logo-file', 'uni', 'fa', 'cs').
 * @param array $file The file data.
 * @param string $ext The file extension (e.g., 'pdf', 'mp3').
 *
 * @return string The HTML for the icon to display.
 */
add_filter( 'erifl_download_icon', function( $default_icon, $icon_type, $file, $ext ) {
    // Use a custom Font Awesome icon for PDF files
    if ( $icon_type === 'fa' && $ext === 'pdf' ) {
        return '<i class="fas fa-file-pdf"></i>';
    }

    // Fallback to the default icon for all other cases
    return $default_icon;
}, 10, 4 );

/**
 * Filter the string used to display the download count in the "post" type links.
 *
 * @param string $downloaded_string The default string for displaying the download count.
 * @param int $count The number of times the file has been downloaded.
 * @param array $file The file data array.
 *
 * @return string The string to display the download count.
 */
add_filter( 'erifl_downloaded_count_string', function( $downloaded_string, $count, $file ) {
    // Customize the downloaded string for a specific file
    if ( $file['post_title'] === 'Example File' ) {
        return sprintf( __( 'This file has been downloaded %d times. Enjoy!', 'eri-file-library' ), $count );
    }

    // Use the default string for other files
    return $downloaded_string;
}, 10, 3 );

/**
 * Filter the prefixes added to the displayed title of the link based on the file format.
 *
 * @param array $format_prefixes The array of prefixes for different formats.
 * @param array $file The file data array.
 * @param string $type The type of the file (e.g., 'pdf', 'docx').
 *
 * @return array The array of format-specific prefixes.
 */
add_filter( 'erifl_format_specific_prefixes', function( $format_prefixes, $file, $type ) {
    if ( 'pdf' === $type ) {
        $format_prefixes[ 'pdf' ] = '<i class="fas fa-file-pdf"></i>';
    } elseif ( 'doc' === $type || 'docx' === $type ) {
        $format_prefixes[ 'docx' ] = '<i class="fas fa-file-word"></i>';
    } elseif ( 'xls' === $type || 'xlsx' === $type ) {
        $format_prefixes[ 'xls' ] = '<i class="fas fa-file-excel"></i>';
    } elseif ( 'ppt' === $type || 'pptx' === $type ) {
        $format_prefixes[ 'ppt' ] = '<i class="fas fa-file-powerpoint"></i>';
    } elseif ( 'zip' === $type || 'rar' === $type ) {
        $format_prefixes[ 'zip' ] = '<i class="fas fa-file-archive"></i>';
    } elseif ( 'txt' === $type ) {
        $format_prefixes[ 'txt' ] = '<i class="fas fa-file-alt"></i>';
    }

    return $format_prefixes;
}, 10, 3 );

/**
 * Filter the link used for looking up a logged-out user's IP address on the Downloads page.
 *
 * @param string $ip_address_link The link used to look up the IP address.
 *
 * @return string The modified IP address lookup link. Must include {ip} that will be replaced with the actual IP address.
 */
add_filter( 'erifl_ip_lookup_path', function( $ip_address_link ) {
    return 'https://www.ip2location.com/demo/{ip}';
}, 10, 1 );

/**
 * Filter the list of post types where the shortcode is used.
 *
 * @param array $post_types The array of post types where the shortcode is used.
 *
 * @return array The modified list of post types.
 */
add_filter( 'erifl_where_used_post_types', function( $post_types ) {
    // Example: Add 'custom_post_type' to the list of post types
    $post_types[] = 'custom_post_type';
    
    return $post_types;
}, 10, 1 );

/**
 * Filter the post metadata for a file post.
 *
 * @param array $meta The array of post metadata.
 * @param array $file The file post data.
 *
 * @return array The modified array of post metadata.
 */
add_filter( 'erifl_post_meta', function( $meta, $file ) {
    // Example: Add custom metadata for a file post
    $meta[] = '<span class="erifl-custom-meta">Custom Meta Data</span>';
    
    return $meta;
}, 10, 2 );