<?php

namespace ChargeForms\Includes;

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

/**
 * Wraps every owner-notification send with logging (Notification_Log)
 * and an automatic WP-Cron retry on failure — roadmap issue #20
 * ("Notifications Are Too Basic for Production Reliability": "There is
 * no queue, retry... beyond failure logs"). `wp_mail()` fails silently
 * on a huge number of hosts (blocked PHP mail(), no SMTP configured);
 * previously that meant one lost notification with only a generic
 * Activity Log line to show for it. Now: up to MAX_ATTEMPTS total tries,
 * each one logged, each retry scheduled RETRY_DELAY_SECONDS after the
 * last failure — and Tools > Notifications (admin/class-tools-page.php)
 * gives an admin somewhere to actually see delivery status instead of
 * having to dig through Activity Log or a host's mail log.
 *
 * Deliberately NOT a generic outgoing-mail queue for every wp_mail() call
 * ChargeForms makes (double-optin emails, Email Summaries) — those have
 * different retry semantics worth designing separately; this is scoped
 * to the one notification type the audit specifically flagged.
 */
class Notifications {
	const RETRY_HOOK          = 'chargeforms_retry_notification';
	const MAX_ATTEMPTS        = 3;
	const RETRY_DELAY_SECONDS = 300; // 5 minutes — long enough that a transient host mail hiccup has usually cleared, short enough an admin isn't left wondering for hours.

	public static function boot() {
		add_action( self::RETRY_HOOK, [ __CLASS__, 'handle_retry' ], 10, 7 );
	}

	/**
	 * Sends one notification email. Returns the same true/false wp_mail()
	 * itself would have, so SubmissionHandler's existing call site didn't
	 * need to change how it treats the return value — only what happens
	 * behind it.
	 *
	 * @param string[] $headers     Raw wp_mail()-style header lines (e.g.
	 *                               'Cc: a@x.com, b@x.com') — built by the
	 *                               caller so this class stays unopinionated
	 *                               about where Cc/Bcc/From come from.
	 * @param string[] $attachments Absolute file paths, passed straight
	 *                               through to wp_mail().
	 */
	public static function send( $form_id, $entry_id, $to, $subject, $body, array $headers = [], array $attachments = [] ) {
		$log_id = Notification_Log::create( $form_id, $entry_id, $to, $subject );
		return self::attempt( $log_id, $form_id, $entry_id, $to, $subject, $body, $headers, $attachments );
	}

	/** WP-Cron callback — re-attempts a specific previously-logged send. */
	public static function handle_retry( $log_id, $form_id, $entry_id, $to, $subject, $body, $headers = [], $attachments = [] ) {
		self::attempt( $log_id, $form_id, $entry_id, $to, $subject, $body, $headers, $attachments );
	}

	private static function attempt( $log_id, $form_id, $entry_id, $to, $subject, $body, array $headers = [], array $attachments = [] ) {
		$error_message = '';
		// A temporary, request-scoped hook just to capture THIS attempt's
		// failure reason — Activity_Log::log_mail_failure() (already
		// hooked in SubmissionHandler's constructor) still fires too and
		// keeps doing its own thing; this doesn't replace it.
		$capture_error = function ( $wp_error ) use ( &$error_message ) {
			$error_message = $wp_error->get_error_message();
		};
		add_action( 'wp_mail_failed', $capture_error );
		// Tags this one wp_mail() call for Email\Email_Log's generic
		// wp_mail_succeeded/failed hooks — see docs/SMTP_ARCHITECTURE.md
		// §8. Purely additive: Notification_Log (above) is unaffected,
		// this only enriches the separate, broader SMTP delivery log.
		\ChargeForms\Includes\Email\Email_Log::set_next_context( [
			'email_type' => 'notification',
			'form_id'    => $form_id,
			'entry_id'   => $entry_id,
		] );
		$sent = wp_mail( $to, $subject, $body, $headers, $attachments );
		remove_action( 'wp_mail_failed', $capture_error );

		if ( $sent ) {
			Notification_Log::mark_sent( $log_id );
			return true;
		}

		$row               = Notification_Log::get( $log_id );
		$attempts_so_far    = (int) ( $row['attempts'] ?? 0 );
		$will_retry        = ( $attempts_so_far + 1 ) < self::MAX_ATTEMPTS;

		Notification_Log::mark_failed(
			$log_id,
			'' !== $error_message ? $error_message : __( 'wp_mail() returned false.', 'chargeforms' ),
			$will_retry
		);

		if ( $will_retry ) {
			wp_schedule_single_event(
				time() + self::RETRY_DELAY_SECONDS,
				self::RETRY_HOOK,
				[ $log_id, $form_id, $entry_id, $to, $subject, $body, $headers, $attachments ]
			);
		}

		return false;
	}
}