<?php
/**
 * Plugin constants.
 *
 * @package PluginBrewery\AdClickTracking
 */

namespace PluginBrewery\AdClickTracking;

defined( 'ABSPATH' ) || exit;

/**
 * Central registry for option keys, shared prefixes and plugin metadata.
 */
class Constants {
	const OPTION_PREFIX          = 'pluginbrewery_act_';
	const DEFAULT_ENABLED_OPTION = self::OPTION_PREFIX . 'tracking_default';
	const ENABLE_SETTING_KEY     = self::OPTION_PREFIX . 'enable_tracking';
	const ATTRIBUTION_OPTION     = self::OPTION_PREFIX . 'attribution';
	const COOKIE_PREFIX          = 'pb-act-';
	const FIELD_CSS_PREFIX       = 'pb-act-';
	const JS_CONFIG_GLOBAL       = 'PBAdClickTracking';
	const COOKIE_EXPIRY_DAYS     = 30;
	const UPGRADE_URL            = 'https://pluginbrewery.com/wordpress-plugins/gravity-forms-referral-tracking/';

	/**
	 * Gravity Forms hidden-field IDs. A high base avoids colliding with real
	 * user-defined field IDs; the offsets are concatenated onto it.
	 *
	 * @var array<string,int>
	 */
	private array $gfield_ids = array(
		'base'    => 218523,
		'source'  => 0,
		'network' => 9,
		'clid'    => 10,
	);

	/**
	 * Plugin header metadata, read once from the main file.
	 *
	 * @var array<string,string>
	 */
	private array $plugin_data = array(
		'name'        => '',
		'version'     => '',
		'url'         => '',
		'path'        => '',
		'main_file'   => '',
		'text_domain' => '',
	);

	/**
	 * Singleton instance.
	 *
	 * @var Constants|null
	 */
	private static $instance = null;

	/**
	 * Reads plugin header data once on construction.
	 */
	private function __construct() {
		if ( ! function_exists( 'get_plugin_data' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}

		$main_file = dirname( __DIR__ ) . '/ad-click-tracking-for-gravity-forms.php';
		// Avoid triggering just-in-time translation loading before init.
		$data = get_plugin_data( $main_file, false, false );

		$this->plugin_data['main_file']   = $main_file;
		$this->plugin_data['name']        = isset( $data['Name'] ) ? (string) $data['Name'] : '';
		$this->plugin_data['version']     = isset( $data['Version'] ) ? (string) $data['Version'] : '';
		$this->plugin_data['url']         = rtrim( plugin_dir_url( $main_file ), '/' );
		$this->plugin_data['path']        = rtrim( plugin_dir_path( $main_file ), '/' );
		$this->plugin_data['text_domain'] = isset( $data['TextDomain'] ) ? (string) $data['TextDomain'] : '';
	}

	/**
	 * Returns the shared instance.
	 */
	public static function get_instance(): Constants {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Returns a single plugin metadata value.
	 *
	 * @param string $key Metadata key (name|version|url|path|main_file|text_domain).
	 */
	public function get_plugin_data( string $key ): string {
		return isset( $this->plugin_data[ $key ] ) ? (string) $this->plugin_data[ $key ] : '';
	}

	/**
	 * Returns the base Gravity Forms field ID.
	 */
	public function get_base_gfield_id(): int {
		return (int) $this->gfield_ids['base'];
	}

	/**
	 * Returns the offset for a given Gravity Forms tracking field.
	 *
	 * @param string $field_type One of source|network|clid.
	 */
	public function get_gfield_id( string $field_type ): int {
		return isset( $this->gfield_ids[ $field_type ] ) ? (int) $this->gfield_ids[ $field_type ] : 0;
	}

	/**
	 * Returns the Referral Source Tracking for Gravity Forms upgrade URL,
	 * campaign-tagged so each placement can be told apart in analytics.
	 *
	 * @param string $placement Placement slug used as utm_content, e.g. "plugins-row".
	 */
	public static function upgrade_url( string $placement = '' ): string {
		$args = array(
			'utm_source'   => 'ad-click-tracking-for-gravity-forms',
			'utm_medium'   => 'wp-admin',
			'utm_campaign' => 'free-to-pro',
		);

		if ( '' !== $placement ) {
			$args['utm_content'] = $placement;
		}

		$url = add_query_arg( $args, self::UPGRADE_URL );

		return (string) apply_filters( 'pb_act_upgrade_url', $url, $placement );
	}

	/**
	 * Prevents cloning of the singleton.
	 */
	private function __clone() {}
}