<?php
/**
 * Who gets messages: a customer's Telegram chat is linked to an order (order meta, so it works
 * with HPOS and for guests) and, for a registered customer, to the account too so their next
 * orders are covered without asking again. The owner's chats live in the settings.
 *
 * @package Orderchirp
 */

namespace Orderchirp;

defined( 'ABSPATH' ) || exit;

final class Subscribers {

	const ORDER_META = '_orderchirp_tg_chat';
	const USER_META  = 'orderchirp_tg_chat';

	/**
	 * The chat to message about an order, or '' when the customer has not opted in.
	 *
	 * @param \WC_Order $order Order.
	 * @return string
	 */
	public static function chat_for_order( $order ) {
		$chat = (string) $order->get_meta( self::ORDER_META );
		if ( '' === $chat && $order->get_customer_id() ) {
			$chat = (string) get_user_meta( $order->get_customer_id(), self::USER_META, true );
		}
		return $chat;
	}

	/**
	 * Link a chat to an order (and its customer account).
	 *
	 * @param \WC_Order $order   Order.
	 * @param string    $chat_id Chat.
	 */
	public static function link_order( $order, $chat_id ) {
		$order->update_meta_data( self::ORDER_META, (string) $chat_id );
		$order->save();
		if ( $order->get_customer_id() ) {
			update_user_meta( $order->get_customer_id(), self::USER_META, (string) $chat_id );
		}
	}

	/**
	 * Forget a chat everywhere: orders, accounts, owner list.
	 *
	 * @param string $chat_id Chat.
	 * @return int Orders unlinked.
	 */
	public static function unlink_chat( $chat_id ) {
		$chat_id = (string) $chat_id;
		$count   = 0;
		foreach ( self::orders_of_chat( $chat_id ) as $order ) {
			$order->delete_meta_data( self::ORDER_META );
			$order->save();
			++$count;
		}
		foreach ( get_users( array( 'meta_key' => self::USER_META, 'meta_value' => $chat_id, 'fields' => 'ID' ) ) as $user_id ) { // phpcs:ignore WordPress.DB.SlowDBQuery -- runs only on /stop.
			delete_user_meta( (int) $user_id, self::USER_META );
		}
		self::remove_owner( $chat_id );
		return $count;
	}

	/**
	 * Orders linked to a chat, newest first.
	 *
	 * @param string $chat_id Chat.
	 * @param int    $limit   Limit (-1 = all).
	 * @return \WC_Order[]
	 */
	public static function orders_of_chat( $chat_id, $limit = -1 ) {
		if ( '' === (string) $chat_id ) {
			return array();
		}
		$orders = wc_get_orders(
			array(
				'limit'      => $limit,
				// By id, not date: two orders placed in the same second have the same date.
				'orderby'    => 'ID',
				'order'      => 'DESC',
				'meta_query' => array( // phpcs:ignore WordPress.DB.SlowDBQuery -- indexed meta key, rare call.
					array(
						'key'   => self::ORDER_META,
						'value' => (string) $chat_id,
					),
				),
			)
		);
		return is_array( $orders ) ? $orders : array();
	}

	/**
	 * The owner's chats: chat id → label.
	 *
	 * @return array<string,string>
	 */
	public static function owners() {
		$chats = Settings::get( 'owner_chats' );
		return is_array( $chats ) ? array_map( 'strval', $chats ) : array();
	}

	/**
	 * Whether a chat is one of the owner's.
	 *
	 * @param string $chat_id Chat.
	 * @return bool
	 */
	public static function is_owner( $chat_id ) {
		return array_key_exists( (string) $chat_id, self::owners() );
	}

	/**
	 * Add an owner chat.
	 *
	 * @param string $chat_id Chat.
	 * @param string $label   Name shown on the settings page.
	 */
	public static function add_owner( $chat_id, $label ) {
		$chats                      = self::owners();
		$chats[ (string) $chat_id ] = sanitize_text_field( $label );
		Settings::update( array( 'owner_chats' => $chats ) );
	}

	/**
	 * Remove an owner chat.
	 *
	 * @param string $chat_id Chat.
	 */
	public static function remove_owner( $chat_id ) {
		$chats = self::owners();
		if ( isset( $chats[ (string) $chat_id ] ) ) {
			unset( $chats[ (string) $chat_id ] );
			Settings::update( array( 'owner_chats' => $chats ) );
		}
	}
}