<?php
/**
 * Handles what people send to the bot: /start with a link payload connects a customer to an
 * order or adds a shop-owner chat, /stop forgets the chat, and any other text from a customer
 * is added to their order as a note and passed on to the owner. Only private chats are served.
 *
 * @package Orderchirp
 */

namespace Orderchirp;

defined( 'ABSPATH' ) || exit;

final class Updates_Handler {

	const INVITE_OPTION = 'orderchirp_owner_invite';
	const INVITE_TTL    = 3600;

	/**
	 * Handle one Telegram update.
	 *
	 * @param array<string,mixed> $update Update object.
	 * @return string What happened (for tests and the log).
	 */
	public static function handle( array $update ) {
		if ( empty( $update['message'] ) || ! is_array( $update['message'] ) ) {
			return 'ignored';
		}
		$message = $update['message'];
		if ( empty( $message['chat']['id'] ) || ( isset( $message['chat']['type'] ) && 'private' !== $message['chat']['type'] ) ) {
			return 'ignored';
		}
		$chat = (string) $message['chat']['id'];
		$text = isset( $message['text'] ) ? trim( (string) $message['text'] ) : '';
		$name = trim( ( isset( $message['from']['first_name'] ) ? (string) $message['from']['first_name'] : '' ) . ' ' . ( isset( $message['from']['last_name'] ) ? (string) $message['from']['last_name'] : '' ) );

		if ( 1 === preg_match( '/^\/start(?:@\w+)?(?:\s+(\S+))?$/', $text, $m ) ) {
			return self::start( $chat, isset( $m[1] ) ? $m[1] : '', $name );
		}
		if ( 1 === preg_match( '/^\/stop(?:@\w+)?$/', $text ) ) {
			return self::stop( $chat );
		}
		if ( '' === $text || '/' === $text[0] ) {
			return 'ignored';
		}
		return self::customer_text( $chat, $text, $name );
	}

	/**
	 * /start [payload].
	 *
	 * @param string $chat    Chat.
	 * @param string $payload Payload.
	 * @param string $name    Sender's name.
	 * @return string
	 */
	private static function start( $chat, $payload, $name ) {
		$shop = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
		if ( '' === $payload ) {
			/* translators: %s: shop name */
			self::reply( $chat, sprintf( __( 'Hi! This is the order-updates bot of %s. To get updates about an order, open the Telegram link on your order confirmation page or in your order email.', 'orderchirp' ), $shop ) );
			return 'start:help';
		}
		$parsed = Link_Token::parse( $payload );
		if ( $parsed && 'owner' === $parsed['type'] ) {
			return self::link_owner( $chat, $parsed['code'], $name, $shop );
		}
		if ( $parsed && 'order' === $parsed['type'] ) {
			$order = wc_get_order( $parsed['order_id'] );
			if ( $order instanceof \WC_Order && Link_Token::verify_order( $order->get_id(), $order->get_order_key(), $parsed['mac'], Settings::secret() ) ) {
				Subscribers::link_order( $order, $chat );
				Message_Log::add(
					array(
						'order_id'  => $order->get_id(),
						'direction' => 'in',
						'event'     => 'customer:subscribed',
						'chat_id'   => $chat,
						'body'      => '/start',
						'status'    => 'received',
					)
				);
				$order->add_order_note( __( 'The customer turned on order updates on Telegram (Orderchirp).', 'orderchirp' ) );
				self::reply(
					$chat,
					sprintf(
						/* translators: 1: shop name, 2: order number, 3: order status. */
						__( "You're connected ✅\n%1\$s will message you here about order #%2\$s.\nCurrent status: %3\$s\n\nSend /stop at any time to stop these messages.", 'orderchirp' ),
						$shop,
						$order->get_order_number(),
						wc_get_order_status_name( $order->get_status() )
					)
				);
				return 'start:order';
			}
		}
		self::reply( $chat, __( 'This link is not valid any more. Please open the Telegram link on your order page again.', 'orderchirp' ) );
		return 'start:invalid';
	}

	/**
	 * Add the shop owner's chat from a one-time invite.
	 *
	 * @param string $chat Chat.
	 * @param string $code Invite code.
	 * @param string $name Sender's name.
	 * @param string $shop Shop name.
	 * @return string
	 */
	private static function link_owner( $chat, $code, $name, $shop ) {
		$invite = get_option( self::INVITE_OPTION );
		$valid  = is_array( $invite ) && isset( $invite['hash'], $invite['expires'] )
			&& (int) $invite['expires'] >= time()
			&& hash_equals( (string) $invite['hash'], hash( 'sha256', $code ) );
		if ( ! $valid ) {
			self::reply( $chat, __( 'This invite has expired. Create a new one on the Orderchirp settings page.', 'orderchirp' ) );
			return 'start:owner-invalid';
		}
		delete_option( self::INVITE_OPTION );
		Subscribers::add_owner( $chat, '' !== $name ? $name : $chat );
		/* translators: %s: shop name */
		self::reply( $chat, sprintf( __( 'Done ✅ This chat will now get Orderchirp alerts for %s: new orders, low stock and customer replies.', 'orderchirp' ), $shop ) );
		return 'start:owner';
	}

	/**
	 * Create a one-time owner invite and return its payload.
	 *
	 * @return string Payload for t.me/{bot}?start=
	 */
	public static function new_owner_invite() {
		$code = Link_Token::new_owner_code();
		update_option(
			self::INVITE_OPTION,
			array(
				'hash'    => hash( 'sha256', $code ),
				'expires' => time() + self::INVITE_TTL,
			),
			false
		);
		return 'a' . $code;
	}

	/**
	 * /stop.
	 *
	 * @param string $chat Chat.
	 * @return string
	 */
	private static function stop( $chat ) {
		Subscribers::unlink_chat( $chat );
		$shop = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
		/* translators: %s: shop name */
		self::reply( $chat, sprintf( __( "Done. You won't get any more messages from %s here.", 'orderchirp' ), $shop ) );
		return 'stop';
	}

	/**
	 * Free text from a customer: note on their newest order, copy to the owner.
	 *
	 * @param string $chat Chat.
	 * @param string $text Text.
	 * @param string $name Sender's name.
	 * @return string
	 */
	private static function customer_text( $chat, $text, $name ) {
		if ( Subscribers::is_owner( $chat ) ) {
			return 'ignored:owner';
		}
		$orders = Subscribers::orders_of_chat( $chat, 1 );
		if ( ! $orders ) {
			return 'ignored:unknown';
		}
		$order = $orders[0];
		$text  = Template::truncate( wp_strip_all_tags( $text ) );
		/* translators: %s: message text */
		$order->add_order_note( sprintf( __( 'Customer message on Telegram: %s', 'orderchirp' ), $text ) );
		Message_Log::add(
			array(
				'order_id'  => $order->get_id(),
				'direction' => 'in',
				'event'     => 'customer:message',
				'chat_id'   => $chat,
				'body'      => $text,
				'status'    => 'received',
			)
		);
		/**
		 * A customer wrote to the bot about an order.
		 *
		 * @param \WC_Order $order Order.
		 * @param string    $text  Text.
		 * @param string    $chat  Chat id.
		 */
		do_action( 'orderchirp_customer_message', $order, $text, $chat );

		if ( Settings::get( 'owner_replies' ) ) {
			foreach ( array_keys( Subscribers::owners() ) as $owner ) {
				Dispatcher::queue(
					array(
						'order_id'  => $order->get_id(),
						'recipient' => 'owner',
						'event'     => 'owner:customer_message',
						'chat_id'   => (string) $owner,
						'body'      => sprintf(
							/* translators: 1: customer name, 2: order number, 3: message */
							__( "💬 %1\$s about order #%2\$s:\n%3\$s", 'orderchirp' ),
							'' !== $name ? $name : __( 'A customer', 'orderchirp' ),
							$order->get_order_number(),
							$text
						),
						'link'      => $order->get_edit_order_url(),
					)
				);
			}
		}
		return 'customer:message';
	}

	/**
	 * Answer right away (replies to the person who just wrote are not queued).
	 *
	 * @param string $chat Chat.
	 * @param string $text Text.
	 */
	private static function reply( $chat, $text ) {
		/**
		 * Whether to send direct replies. Tests switch this off.
		 *
		 * @param bool $send Default true.
		 */
		if ( ! apply_filters( 'orderchirp_send_replies', true ) || ! Settings::connected() ) {
			return;
		}
		Telegram_Api::from_settings()->send_message( $chat, $text );
	}
}