<?php
/**
 * SMS replies from customers: storage, STOP words, order notes, e-mail to the owner (background job).
 *
 * @package Smsportal
 */

namespace Smsportal;

use Smsportal\Admin\Menu;

defined( 'ABSPATH' ) || exit;

/**
 * Rows of {prefix}smsportal_replies. smsportal only forwards replies from numbers this site
 * texted in the last 7 days.
 */
class Replies {

	const TABLE = 'smsportal_replies';

	/**
	 * Option: '0' turns off the e-mail to the owner about each reply.
	 */
	const EMAIL_OPTION = 'smsportal_reply_email';

	/**
	 * Background job that e-mails the owner about one reply (args: reply ID, 1 when it blocked the number).
	 */
	const MAIL_HOOK = 'smsportal_reply_mail';

	/**
	 * Comment meta on the WooCommerce order notes that hold a reply's text (erased with the person's data).
	 */
	const NOTE_META = 'smsportal_reply';

	/**
	 * Whole-message opt-out words, already upper-cased and without diacritics.
	 */
	const STOP_WORDS = array( 'STOP', 'STOP SMS', 'NIE', 'REZYGNUJE', 'UNSUBSCRIBE' );

	const MAX_SENDER_LENGTH = 32;
	const MAX_TEXT_LENGTH   = 2000;

	/**
	 * Register the e-mail job.
	 *
	 * @return void
	 */
	public static function register(): void {
		add_action( self::MAIL_HOOK, array( self::class, 'send_mail' ), 10, 2 );
	}

	/**
	 * Full table name.
	 *
	 * @return string
	 */
	public static function table(): string {
		global $wpdb;
		return $wpdb->prefix . self::TABLE;
	}

	/**
	 * CREATE TABLE statement for dbDelta.
	 *
	 * @return string
	 */
	public static function schema(): string {
		global $wpdb;
		$table   = self::table();
		$charset = $wpdb->get_charset_collate();
		return "CREATE TABLE {$table} (
  id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  received_at datetime NOT NULL,
  sender varchar(32) NOT NULL,
  text text NOT NULL,
  message_id bigint(20) unsigned DEFAULT NULL,
  PRIMARY KEY  (id),
  KEY sender (sender),
  KEY received_at (received_at)
) {$charset};";
	}

	/**
	 * Handle an incoming reply: store it, block STOP senders, note it on the order and schedule the
	 * e-mail to the owner (sent by a background job, so the webhook answers quickly).
	 *
	 * @param string $sender      Number as smsportal sends it.
	 * @param string $text        SMS text.
	 * @param string $received_at ISO 8601 time.
	 * @return int Reply ID (0 when it could not be stored).
	 */
	public static function receive( string $sender, string $text, string $received_at ): int {
		$phone   = self::sender_number( $sender );
		$sent    = null === $phone ? null : Messages::latest_for_recipient( $phone );
		$id      = self::insert( $sender, $phone, $sent, $text, $received_at );
		$blocked = self::is_stop( $text ) && Blocklist::add( $sender, 'stop' );

		$order = self::order_of( $sent );
		if ( null !== $order ) {
			/* translators: %s: text of the customer's SMS. */
			$note = $order->add_order_note( sprintf( __( 'SMS reply from the customer: %s', '85pl-android-sms-api' ), esc_html( $text ) ) );
			if ( $note > 0 ) {
				add_comment_meta( (int) $note, self::NOTE_META, 1, true );
			}
		}
		if ( $id > 0 && self::mail_enabled() ) {
			Queue::schedule_hook( self::MAIL_HOOK, array( $id, $blocked ? 1 : 0 ), time() );
		}
		return $id;
	}

	/**
	 * Job: e-mail the owner about a stored reply.
	 *
	 * @param int|string $reply_id Reply ID.
	 * @param int|string $blocked  1 when the reply put the number on the block list.
	 * @return void
	 */
	public static function send_mail( $reply_id, $blocked = 0 ): void {
		$reply = self::get( absint( $reply_id ) );
		if ( null === $reply || ! self::mail_enabled() ) {
			return;
		}
		$sent = null === $reply['message_id'] ? null : Messages::get( (int) $reply['message_id'] );
		self::mail_owner( (string) $reply['sender'], (string) $reply['text'], self::order_of( $sent ), 1 === absint( $blocked ) );
	}

	/**
	 * One reply.
	 *
	 * @param int $id Reply ID.
	 * @return array<string,string|null>|null
	 */
	public static function get( int $id ): ?array {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table.
		$row = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->prefix}smsportal_replies WHERE id = %d", $id ), ARRAY_A );
		return is_array( $row ) ? $row : null;
	}

	/**
	 * Whether the owner wants an e-mail about each reply.
	 *
	 * @return bool
	 */
	private static function mail_enabled(): bool {
		return '0' !== (string) get_option( self::EMAIL_OPTION, '1' );
	}

	/**
	 * Store a reply, linked to the newest SMS this site sent to that number.
	 *
	 * @param string $sender      Number as smsportal sends it.
	 * @param string $text        SMS text.
	 * @param string $received_at ISO 8601 time.
	 * @return int Reply ID (0 when the insert failed).
	 */
	public static function record( string $sender, string $text, string $received_at ): int {
		$phone = self::sender_number( $sender );
		$sent  = null === $phone ? null : Messages::latest_for_recipient( $phone );
		return self::insert( $sender, $phone, $sent, $text, $received_at );
	}

	/**
	 * Newest replies first, with the label of the SMS they answer.
	 *
	 * @param int $limit  Rows.
	 * @param int $offset Rows to skip.
	 * @return array<int,array<string,string|null>>
	 */
	public static function recent( int $limit, int $offset = 0 ): array {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom tables, the list must be current.
		$rows = $wpdb->get_results( $wpdb->prepare( "SELECT r.id, r.received_at, r.sender, r.text, r.message_id, m.event_label, m.object_type, m.object_id FROM {$wpdb->prefix}smsportal_replies r LEFT JOIN {$wpdb->prefix}smsportal_messages m ON m.id = r.message_id ORDER BY r.id DESC LIMIT %d OFFSET %d", max( 1, $limit ), max( 0, $offset ) ), ARRAY_A );
		return is_array( $rows ) ? $rows : array();
	}

	/**
	 * Number of replies.
	 *
	 * @return int
	 */
	public static function count(): int {
		global $wpdb;
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- custom table.
		return (int) $wpdb->get_var( "SELECT COUNT(*) FROM {$wpdb->prefix}smsportal_replies" );
	}

	/**
	 * Insert the reply row.
	 *
	 * @param string                         $sender      Sender as received.
	 * @param string|null                    $phone       Sender in E.164, or null.
	 * @param array<string,string|null>|null $sent        Newest SMS to that number.
	 * @param string                         $text        SMS text.
	 * @param string                         $received_at ISO 8601 time.
	 * @return int Reply ID (0 when the insert failed).
	 */
	private static function insert( string $sender, ?string $phone, ?array $sent, string $text, string $received_at ): int {
		global $wpdb;
		$time = strtotime( $received_at );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- custom table.
		$inserted = $wpdb->insert(
			self::table(),
			array(
				'received_at' => false === $time ? current_time( 'mysql', true ) : gmdate( 'Y-m-d H:i:s', $time ),
				'sender'      => null === $phone ? mb_substr( sanitize_text_field( $sender ), 0, self::MAX_SENDER_LENGTH ) : $phone,
				'text'        => mb_substr( wp_check_invalid_utf8( $text, true ), 0, self::MAX_TEXT_LENGTH ),
				'message_id'  => null === $sent ? null : (int) $sent['id'],
			)
		);
		return false === $inserted ? 0 : (int) $wpdb->insert_id;
	}

	/**
	 * Whether the whole message is an opt-out word (case, diacritics and outer spaces ignored).
	 *
	 * @param string $text SMS text.
	 * @return bool
	 */
	public static function is_stop( string $text ): bool {
		$plain = trim( (string) preg_replace( '/\s+/u', ' ', remove_accents( $text ) ) );
		return in_array( strtoupper( $plain ), self::STOP_WORDS, true );
	}

	/**
	 * Sender in E.164, or null when it is not a phone number (e.g. a name).
	 *
	 * @param string $sender Sender.
	 * @return string|null
	 */
	private static function sender_number( string $sender ): ?string {
		return Phone::normalize( $sender, Phone::default_country_code() );
	}

	/**
	 * WooCommerce order the earlier SMS was about.
	 *
	 * @param array<string,string|null>|null $sent Messages row.
	 * @return \WC_Order|null
	 */
	private static function order_of( ?array $sent ) {
		if ( null === $sent || 'wc_order' !== $sent['object_type'] || ! function_exists( 'wc_get_order' ) ) {
			return null;
		}
		$order = wc_get_order( absint( $sent['object_id'] ) );
		return $order instanceof \WC_Order ? $order : null;
	}

	/**
	 * Plain-text e-mail to the site owner. The SMS text goes only into the body, never the headers.
	 *
	 * @param string         $sender  Sender.
	 * @param string         $text    SMS text.
	 * @param \WC_Order|null $order   Order the earlier SMS was about.
	 * @param bool           $blocked Whether the reply put the number on the block list.
	 * @return void
	 */
	private static function mail_owner( string $sender, string $text, $order, bool $blocked ): void {
		$lines = array(
			/* translators: %s: phone number. */
			sprintf( __( 'A customer replied by SMS from %s:', '85pl-android-sms-api' ), $sender ),
			'',
			$text,
			'',
		);
		if ( $blocked ) {
			$lines[] = __( 'This reply is an opt-out word: the number will not get SMS from this site any more.', '85pl-android-sms-api' );
		}
		$lines[] = null === $order
			/* translators: %s: address of the replies screen. */
			? sprintf( __( 'All replies: %s', '85pl-android-sms-api' ), Menu::tab_url( 'replies' ) )
			/* translators: %s: address of the order screen. */
			: sprintf( __( 'Order: %s', '85pl-android-sms-api' ), $order->get_edit_order_url() );

		// The SMS text is not HTML: keep the mail plain even if another plugin switches mail to HTML.
		$plain = static function () {
			return 'text/plain';
		};
		add_filter( 'wp_mail_content_type', $plain, PHP_INT_MAX );
		try {
			wp_mail(
				(string) get_option( 'admin_email' ),
				__( 'SMS reply from a customer', '85pl-android-sms-api' ),
				implode( "\n", $lines ),
				array( 'Content-Type: text/plain; charset=UTF-8' )
			);
		} finally {
			remove_filter( 'wp_mail_content_type', $plain, PHP_INT_MAX );
		}
	}
}