<?php
/**
 * Main plugin class.
 *
 * @package ROBOTSTXT_SMTP_Newsletter
 */

namespace Robotstxt_SMTP_Newsletter;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Plugin main class.
 *
 * Extends NewsletterMailerAddon to integrate with Newsletter plugin.
 */
class Plugin extends \NewsletterMailerAddon {

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

	/**
	 * Default options.
	 *
	 * @var array<string, mixed>
	 */
	private static $defaults = array(
		'enabled'    => false,
		'batch_size' => 10,
	);

	/**
	 * Plugin display name.
	 *
	 * @var string
	 */
	public $name;

	/**
	 * Plugin slug.
	 *
	 * @var string
	 */
	public $slug;

	/**
	 * Menu title.
	 *
	 * @var string
	 */
	public $menu_title;

	/**
	 * Get singleton instance.
	 *
	 * @return Plugin
	 */
	public static function get_instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Initialize plugin (called on newsletter_loaded hook).
	 *
	 * @return void
	 */
	public static function instance_init() {
		$instance = self::get_instance();
		$instance->init();
	}

	/**
	 * Constructor.
	 */
	private function __construct() {
		parent::__construct( 'robotstxt-smtp-newsletter', ROBOTSTXT_SMTP_NEWSLETTER_VERSION, ROBOTSTXT_SMTP_NEWSLETTER_PATH );
		$this->name        = 'SMTP (by ROBOTSTXT)';
		$this->slug        = 'robotstxt-smtp-newsletter';
		$this->menu_title  = 'SMTP (by ROBOTSTXT)';
	}

	/**
	 * Setup options.
	 *
	 * Overrides parent to use our custom option name.
	 *
	 * @return void
	 */
	public function setup_options() {
		if ( $this->options ) {
			return;
		}
		// Load our options using our custom option name (not newsletter_ prefix).
		$this->options = get_option( 'robotstxt_smtp_newsletter_options', array() );
		$this->options = wp_parse_args( $this->options, self::$defaults );
	}

	/**
	 * Initialize plugin hooks.
	 *
	 * Overrides parent init() method.
	 *
	 * @return void
	 */
	public function init() {
		parent::init();

		// Load required classes.
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-queue.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-statistics.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-email-message.php';

		// Initialize database tables.
		Queue::get_instance();
		Statistics::get_instance();

		// Load text domain.
		add_action( 'init', array( $this, 'load_textdomain' ) );

		// Force batch size in Newsletter cron.
		add_filter( 'newsletter_max_emails', array( $this, 'filter_max_emails' ), 999 );

		// Register admin pages.
		if ( is_admin() ) {
			require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'admin/class-settings-page.php';
			require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'admin/class-emails-list-page.php';
			require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'admin/class-statistics-page.php';

			add_action( 'admin_init', array( 'Robotstxt_SMTP_Newsletter\Admin\Settings_Page', 'register_settings_static' ) );
			add_action( 'admin_menu', array( 'Robotstxt_SMTP_Newsletter\Admin\Emails_List_Page', 'register' ) );
			add_action( 'admin_menu', array( 'Robotstxt_SMTP_Newsletter\Admin\Statistics_Page', 'register' ) );
		}
	}

	/**
	 * Filter Newsletter's max emails per execution.
	 *
	 * Forces Newsletter to use our configured batch_size.
	 *
	 * @param int $max_emails Newsletter's calculated max emails.
	 *
	 * @return int Our configured batch_size.
	 */
	public function filter_max_emails( $max_emails ) {
		// Only apply if our addon is enabled.
		$settings = $this->get_settings();
		if ( empty( $settings['enabled'] ) ) {
			return $max_emails;
		}

		return absint( $settings['batch_size'] ?? 10 );
	}

	/**
	 * Load plugin text domain for translations.
	 *
	 * @return void
	 */
	public function load_textdomain() {
		load_plugin_textdomain(
			'robotstxt-smtp-newsletter',
			false,
			dirname( plugin_basename( ROBOTSTXT_SMTP_NEWSLETTER_FILE ) ) . '/languages'
		);
	}

	/**
	 * Get the mailer instance.
	 *
	 * This method is called by the parent class to get the mailer
	 * that should be registered with Newsletter.
	 *
	 * @return \NewsletterMailer
	 */
	public function get_mailer() {
		// Load required classes.
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-queue.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-statistics.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-email-message.php';

		// Get our settings and map to Newsletter's expected format.
		$settings      = $this->get_settings();
		$smtp_settings = $this->get_smtp_settings();

		// Calculate optimal speed (emails per hour) based on rate limits.
		$speed = $this->calculate_optimal_speed( $smtp_settings );

		// CRITICAL: For queue-based architecture, speed must be high enough
		// that Newsletter loads all emails at once. Newsletter calculates:
		// batch_size = speed / (3600 / NEWSLETTER_CRON_INTERVAL)
		// To get batch_size = configured value, we need:
		// speed = batch_size * (3600 / NEWSLETTER_CRON_INTERVAL)
		$batch_size = $settings['batch_size'] ?? 10;

		// Ensure NEWSLETTER_CRON_INTERVAL is loaded
		if ( ! defined( 'NEWSLETTER_CRON_INTERVAL' ) ) {
			$cron_file = WP_PLUGIN_DIR . '/newsletter/includes/cron.php';
			if ( file_exists( $cron_file ) ) {
				require_once $cron_file;
			}
		}

		// Calculate runs per hour based on Newsletter's cron interval
		$cron_interval = defined( 'NEWSLETTER_CRON_INTERVAL' ) ? NEWSLETTER_CRON_INTERVAL : 300;
		$runs_per_hour = (int) ( 3600 / $cron_interval );
		$calculated_speed = max( $speed, $batch_size * $runs_per_hour );

		// Newsletter expects 'turbo' for batch_size and 'speed' for emails/hour.
		$mailer_options = array(
			'turbo' => $batch_size,
			'speed' => $calculated_speed,
		);

		// Detect if Amazon SES is active.
		if ( $this->is_amazon_ses_active() ) {
			require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-amazonses-mailer.php';
			return new AmazonSES_Mailer( $mailer_options );
		} else {
			require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-smtp-mailer.php';
			return new SMTP_Mailer( $mailer_options );
		}
	}

	/**
	 * Get maximum emails per execution.
	 *
	 * Newsletter checks this method to determine batch size.
	 *
	 * @return int
	 */
	public function get_max_emails() {
		$settings = $this->get_settings();
		return absint( $settings['batch_size'] ?? 10 );
	}

	/**
	 * Get batch size.
	 *
	 * Alternative method that Newsletter may check.
	 *
	 * @return int
	 */
	public function get_batch() {
		return $this->get_max_emails();
	}

	/**
	 * Override Newsletter's calculation of emails per run.
	 *
	 * Newsletter normally calculates: batch = speed / runs_per_hour
	 * For queue-based architecture, we want to enqueue all emails at once.
	 *
	 * @return int Configured batch_size.
	 */
	public function get_emails_per_run() {
		$settings = $this->get_settings();
		if ( empty( $settings['enabled'] ) ) {
			// If addon is disabled, use parent's calculation.
			return parent::get_emails_per_run();
		}

		return absint( $settings['batch_size'] ?? 10 );
	}

	/**
	 * Calculate optimal speed (emails per hour) based on rate limits.
	 *
	 * @param array<string, mixed> $smtp_settings SMTP settings with rate limits.
	 *
	 * @return int Emails per hour.
	 */
	private function calculate_optimal_speed( $smtp_settings ) {
		// Get rate limits from ROBOTSTXT SMTP settings.
		$rate_per_hour = absint( $smtp_settings['rate_limit_per_hour'] ?? 0 );

		// If hourly limit is set, use it (with 90% safety margin).
		if ( $rate_per_hour > 0 ) {
			return (int) floor( $rate_per_hour * 0.9 );
		}

		// If no hourly limit, calculate from per-second limit.
		$rate_per_second = absint( $smtp_settings['rate_limit_per_second'] ?? 0 );
		if ( $rate_per_second > 0 ) {
			return (int) floor( $rate_per_second * 3600 * 0.9 );
		}

		// If no limits set, use a conservative default based on delivery method.
		$is_ses = $this->is_amazon_ses_active();
		return $is_ses ? 1000 : 500;
	}

	/**
	 * Check if Amazon SES integration is active.
	 *
	 * @return bool
	 */
	private function is_amazon_ses_active() {
		if ( ! class_exists( '\Robotstxt_SMTP\Plugin' ) ) {
			return false;
		}

		return \Robotstxt_SMTP\Plugin::is_amazon_ses_integration_active();
	}

	/**
	 * Get plugin settings with defaults.
	 *
	 * @return array<string, mixed>
	 */
	public function get_settings() {
		$options = get_option( 'robotstxt_smtp_newsletter_options', array() );

		return wp_parse_args( $options, self::$defaults );
	}

	/**
	 * Get SMTP settings from robotstxt-smtp plugin.
	 *
	 * @return array<string, mixed>
	 */
	public function get_smtp_settings() {
		if ( ! class_exists( '\Robotstxt_SMTP\Plugin' ) || ! class_exists( '\Robotstxt_SMTP\Admin\Settings_Page' ) ) {
			return array();
		}

		// Check if network mode is enabled.
		$scope = get_site_option( 'robotstxt_smtp_configuration_scope', 'site' );

		if ( 'network' === $scope ) {
			$settings = get_site_option( 'robotstxt_smtp_network_options', array() );
		} else {
			$settings = get_option( 'robotstxt_smtp_options', array() );
		}

		return $settings;
	}

	/**
	 * Plugin activation hook.
	 *
	 * Creates database tables and migrates settings.
	 *
	 * @return void
	 */
	public static function activation_hook() {
		// Load required classes.
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-queue.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-statistics.php';
		require_once ROBOTSTXT_SMTP_NEWSLETTER_PATH . 'includes/class-email-message.php';

		// Tables are created automatically via __construct().
		Queue::get_instance();
		Statistics::get_instance();

		// Migrate settings: remove deprecated max_per_connection.
		$options = get_option( 'robotstxt_smtp_newsletter_options', array() );
		if ( isset( $options['max_per_connection'] ) ) {
			unset( $options['max_per_connection'] );
			update_option( 'robotstxt_smtp_newsletter_options', $options );
		}
	}
}