<?php
/**
 * Daily reminder e-mails. Participants can opt in ("Erinnere mich") when they
 * take part. A once-daily WP-Cron job mails every subscriber that a new door is
 * open. Each mail carries a one-click unsubscribe link (token based).
 */

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

class ADVK_Reminders {

	const STORE     = 'advk_reminder_subscribers';
	const CRON_HOOK = 'advk_daily_reminder';

	public function hooks() {
		add_action( 'advk_entry_created', array( $this, 'maybe_subscribe' ), 10, 5 );
		add_action( self::CRON_HOOK, array( $this, 'send_due_reminders' ) );
		add_action( 'init', array( $this, 'ensure_schedule' ) );
		add_action( 'init', array( $this, 'handle_unsubscribe' ) );
		add_action( 'init', array( $this, 'handle_confirm' ) );
	}

	/* ---------------- scheduling ---------------- */

	public function ensure_schedule() {
		$opts = ADVK_Settings::get_options();
		if ( empty( $opts['reminder_enabled'] ) ) {
			// Feature off: make sure no orphan event lingers.
			$ts = wp_next_scheduled( self::CRON_HOOK );
			if ( $ts ) {
				wp_unschedule_event( $ts, self::CRON_HOOK );
			}
			return;
		}
		if ( ! wp_next_scheduled( self::CRON_HOOK ) ) {
			// First run tomorrow ~08:00 site time, then daily.
			$first = strtotime( 'tomorrow 08:00', current_time( 'timestamp' ) );
			wp_schedule_event( $first, 'daily', self::CRON_HOOK );
		}
	}

	public static function clear_schedule() {
		$ts = wp_next_scheduled( self::CRON_HOOK );
		if ( $ts ) {
			wp_unschedule_event( $ts, self::CRON_HOOK );
		}
	}

	/* ---------------- subscriber storage ---------------- */

	private function get_subscribers() {
		$list = get_option( self::STORE, array() );
		return is_array( $list ) ? $list : array();
	}

	/**
	 * @param int    $id    Entry id.
	 * @param int    $day   Door day.
	 * @param string $email Participant e-mail.
	 * @param string $losnr Lot number.
	 * @param array  $extra first, last, newsletter, reminder, ref.
	 */
	public function maybe_subscribe( $id, $day, $email, $losnr, $extra = array() ) {
		if ( empty( $extra['reminder'] ) ) {
			return;
		}
		$opts = ADVK_Settings::get_options();
		if ( empty( $opts['reminder_enabled'] ) ) {
			return;
		}

		$key  = strtolower( $email );
		$list = $this->get_subscribers();
		if ( isset( $list[ $key ] ) ) {
			return; // Already subscribed (pending or confirmed).
		}

		$doi = ! empty( $opts['reminder_double_optin'] );

		$sub = array(
			'email'     => $email,
			'first'     => isset( $extra['first'] ) ? (string) $extra['first'] : '',
			'token'     => wp_generate_password( 20, false ), // unsubscribe token
			'added'     => current_time( 'mysql' ),
			'confirmed' => $doi ? false : true,
		);
		if ( $doi ) {
			$sub['confirm'] = wp_generate_password( 24, false ); // double-opt-in token
		}
		$list[ $key ] = $sub;
		update_option( self::STORE, $list, false );

		if ( $doi ) {
			$this->send_confirmation( $sub, $opts );
		}
	}

	/**
	 * Send the double-opt-in confirmation e-mail with an activation button.
	 *
	 * @param array $sub  Subscriber record.
	 * @param array $opts Plugin options.
	 */
	private function send_confirmation( $sub, $opts ) {
		if ( ! is_email( $sub['email'] ) || empty( $sub['confirm'] ) ) {
			return;
		}
		$sitename    = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
		$confirm_url = add_query_arg(
			array( 'advk_confirm' => 1, 'token' => rawurlencode( $sub['confirm'] ) ),
			home_url( '/' )
		);
		$first   = isset( $sub['first'] ) && '' !== $sub['first'] ? $sub['first'] : '';
		$subject = sprintf(
			/* translators: %s: site name. */
			__( 'Bitte bestätige deine Erinnerungen für %s', 'adventura-interactive-advent-calendar' ),
			$sitename
		);
		$greet = '' !== $first ? sprintf( /* translators: %s: first name. */ __( 'Hallo %s,', 'adventura-interactive-advent-calendar' ), $first ) : __( 'Hallo,', 'adventura-interactive-advent-calendar' );
		$body  = $greet . "\n\n"
			. sprintf(
				/* translators: %s: site name. */
				__( 'du möchtest tägliche Erinnerungen an ein neues Türchen von %s erhalten. Bitte bestätige das mit einem Klick auf den Button unten. Ohne Bestätigung senden wir dir keine Erinnerungen.', 'adventura-interactive-advent-calendar' ),
				$sitename
			)
			. "\n\n"
			. __( 'Falls du dich nicht angemeldet hast, ignoriere diese E-Mail einfach.', 'adventura-interactive-advent-calendar' );

		$cta  = array(
			'label' => __( 'Erinnerungen bestätigen', 'adventura-interactive-advent-calendar' ),
			'url'   => $confirm_url,
		);
		$html = ADVK_Emails::html_wrap( $subject, $body, $opts, '', $cta );
		wp_mail( $sub['email'], $subject, $html, ADVK_Emails::mail_headers( $opts, true ) );
	}

	/**
	 * Handle the double-opt-in confirmation link (?advk_confirm=1&token=…).
	 */
	public function handle_confirm() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- One-click e-mail confirmation; the per-subscriber token below is the authenticator (verified with hash_equals).
		if ( empty( $_GET['advk_confirm'] ) || empty( $_GET['token'] ) ) {
			return;
		}
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- See above; secret token verified via hash_equals().
		$token = sanitize_text_field( wp_unslash( $_GET['token'] ) );
		$list  = $this->get_subscribers();
		$found = false;
		foreach ( $list as $key => $sub ) {
			if ( ! empty( $sub['confirm'] ) && hash_equals( (string) $sub['confirm'], $token ) ) {
				$list[ $key ]['confirmed'] = true;
				unset( $list[ $key ]['confirm'] );
				$found = true;
				break;
			}
		}
		if ( $found ) {
			update_option( self::STORE, $list, false );
		}

		wp_die(
			esc_html__( 'Danke! Deine Erinnerungen sind jetzt bestätigt. Du kannst dieses Fenster schließen.', 'adventura-interactive-advent-calendar' ),
			esc_html__( 'Bestätigt', 'adventura-interactive-advent-calendar' ),
			array( 'response' => 200 )
		);
	}

	/* ---------------- unsubscribe ---------------- */

	private function unsubscribe_url( $token ) {
		return add_query_arg(
			array(
				'advk_unsub' => 1,
				'token'      => rawurlencode( $token ),
			),
			home_url( '/' )
		);
	}

	public function handle_unsubscribe() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- One-click email unsubscribe; the per-subscriber token below is the authenticator (verified with hash_equals).
		if ( empty( $_GET['advk_unsub'] ) || empty( $_GET['token'] ) ) {
			return;
		}
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- See above; secret token verified via hash_equals().
		$token = sanitize_text_field( wp_unslash( $_GET['token'] ) );
		$list  = $this->get_subscribers();
		$found = false;
		foreach ( $list as $key => $sub ) {
			if ( isset( $sub['token'] ) && hash_equals( (string) $sub['token'], $token ) ) {
				unset( $list[ $key ] );
				$found = true;
				break;
			}
		}
		if ( $found ) {
			update_option( self::STORE, $list, false );
		}

		wp_die(
			esc_html__( 'Du erhältst keine Erinnerungen mehr. Du kannst dieses Fenster schließen.', 'adventura-interactive-advent-calendar' ),
			esc_html__( 'Abgemeldet', 'adventura-interactive-advent-calendar' ),
			array( 'response' => 200 )
		);
	}

	/* ---------------- sending ---------------- */

	public function send_due_reminders() {
		$opts = ADVK_Settings::get_options();
		if ( empty( $opts['reminder_enabled'] ) ) {
			return;
		}

		$day = ADVK_Data::today_day();
		if ( $day < 1 || $day > ADVK_Data::door_count() ) {
			return; // Outside the calendar window.
		}

		// Guard against duplicate sends on the same calendar day.
		$stamp = wp_date( 'Y-m-d' );
		if ( get_option( 'advk_reminder_last_sent' ) === $stamp ) {
			return;
		}
		update_option( 'advk_reminder_last_sent', $stamp, false );

		$list = $this->get_subscribers();
		if ( empty( $list ) ) {
			return;
		}

		// Resolve the prize for today's door for nicer copy.
		$prize = '';
		foreach ( ADVK_Data::get_calendar() as $d ) {
			if ( (int) $d['day'] === (int) $day ) {
				$prize = (string) $d['prize'];
				break;
			}
		}

		$sitename = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
		$headers  = ADVK_Emails::mail_headers( $opts, true );
		$subject_tpl = isset( $opts['reminder_subject'] ) ? $opts['reminder_subject'] : '';
		$body_tpl    = isset( $opts['reminder_body'] ) ? $opts['reminder_body'] : '';

		foreach ( $list as $sub ) {
			$email = isset( $sub['email'] ) ? $sub['email'] : '';
			if ( ! is_email( $email ) ) {
				continue;
			}
			// Double-opt-in: skip subscribers who have not confirmed yet.
			// (Legacy subscribers without the flag were added under single opt-in.)
			if ( isset( $sub['confirmed'] ) && ! $sub['confirmed'] ) {
				continue;
			}
			$repl = array(
				'{first}'    => isset( $sub['first'] ) ? $sub['first'] : '',
				'{day}'      => (string) $day,
				'{prize}'    => $prize,
				'{sitename}' => $sitename,
			);
			$subject = strtr( $subject_tpl, $repl );
			$body    = strtr( $body_tpl, $repl );

			$unsub  = '<a href="' . esc_url( $this->unsubscribe_url( $sub['token'] ) ) . '" style="color:#b7ada2;">'
				. esc_html__( 'Keine Erinnerungen mehr erhalten', 'adventura-interactive-advent-calendar' ) . '</a>';
			$html   = ADVK_Emails::html_wrap( $subject, $body, $opts, $unsub );

			wp_mail( $email, $subject, $html, $headers );
		}
	}
}