<?php
/**
 * The Telegram bot as an assistant: voice messages, short commands and conversations passed on.
 *
 * @package Dealroot
 */

namespace Dealroot;

defined( 'ABSPATH' ) || exit;

/**
 * What the owner sends the bot becomes work done in Dealroot:
 *
 * - A voice message after a call, e.g. "Müller called about the roof, about 2,000 euros", becomes a
 *   lead. When a visitor clicked the phone number on the site shortly before, the lead takes the
 *   source of that click, so calls show up in the reports and can be reported to the ad platform.
 * - Short orders, spoken or typed: "Müller won, 1,500 euros", "remind me on Friday about Schmidt",
 *   "answer Mrs Schmidt that I will call back at 2 pm", a note, or a question about the numbers.
 * - A conversation passed on, e.g. a chat copied from WhatsApp, its export as a text file, a message
 *   forwarded from Telegram or an email pasted in, becomes a lead with its summary and budget.
 *
 * The speech is written down by Whisper on the server of Dealroot and the meaning is read by the AI
 * assistant; what happens is done here, by the plugin, and every step is answered in the chat.
 *
 * phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
 */
class Telegram_Assistant {

	const VOICE_HOOK  = 'dealroot_telegram_voice';
	const TEXT_HOOK   = 'dealroot_telegram_text';
	const REMIND_HOOK = 'dealroot_telegram_follow_up';

	/**
	 * Hours before a voice message in which a click on the phone number counts as that call.
	 */
	const CALL_HOURS = 3;

	/**
	 * What is said while an order given on the screen is carried out, instead of Telegram.
	 *
	 * @var string[]|null
	 */
	private static $here = null;

	/**
	 * The lead an order given on the screen was about.
	 *
	 * @var int
	 */
	private static $here_lead = 0;

	/**
	 * Largest voice message and text file accepted.
	 */
	const MAX_AUDIO = 450000;
	const MAX_TEXT  = 200000;

	/**
	 * Hooks.
	 */
	public function register() {
		add_action( self::VOICE_HOOK, array( __CLASS__, 'voice' ), 10, 2 );
		add_action( self::TEXT_HOOK, array( __CLASS__, 'text' ), 10, 3 );
		add_action( self::REMIND_HOOK, array( __CLASS__, 'remind' ), 10, 2 );
	}

	/**
	 * A message in the chat of the owner. The work is done after Telegram got its answer.
	 *
	 * @param array $message Telegram message.
	 */
	public static function received( array $message ) {
		$voice = $message['voice'] ?? ( $message['audio'] ?? null );

		if ( is_array( $voice ) && ! empty( $voice['file_id'] ) ) {
			if ( (int) ( $voice['duration'] ?? 0 ) > 120 ) {
				self::say( __( 'Voice messages can be up to two minutes long.', 'dealroot' ) );
				return;
			}

			self::later( self::VOICE_HOOK, array( (string) $voice['file_id'], (int) ( $message['date'] ?? time() ) ) );
			return;
		}

		// A chat exported from WhatsApp comes as a text file.
		$document = $message['document'] ?? null;

		if ( is_array( $document ) && ! empty( $document['file_id'] ) ) {
			if ( 'text/plain' !== ( $document['mime_type'] ?? '' ) ) {
				self::say( __( 'Send a voice message, a text, or a chat exported from WhatsApp as a text file.', 'dealroot' ) );
				return;
			}

			self::later( self::TEXT_HOOK, array( 'file:' . $document['file_id'], 'conversation', '' ) );
			return;
		}

		$text = trim( (string) ( $message['text'] ?? '' ) );

		if ( '' === $text ) {
			return;
		}

		if ( preg_match( '#^/(start|help)\b#', $text ) ) {
			self::say( self::help() );
			return;
		}

		$forwarded = $message['forward_origin'] ?? null;

		if ( is_array( $forwarded ) || self::looks_like_chat( $text ) ) {
			self::later( self::TEXT_HOOK, array( $text, 'conversation', is_array( $forwarded ) ? self::forwarded_name( $forwarded ) : '' ) );
			return;
		}

		self::later( self::TEXT_HOOK, array( $text, 'command', '' ) );
	}

	/**
	 * Whether a text is a conversation pasted in rather than an order: lines of a chat with times
	 * and names, as WhatsApp copies them, or an email with its header lines.
	 *
	 * @param string $text Text.
	 * @return bool
	 */
	public static function looks_like_chat( $text ) {
		$chat  = preg_match_all( '/^\[?\d{1,2}[.\/]\d{1,2}[.\/]\d{2,4},? \d{1,2}:\d{2}(:\d{2})?\]?\s*(-\s*)?[^:\n]{1,40}:/mu', $text );
		$email = preg_match( '/^(from|von|de|da|van|od|от|від):\s.+$/mui', $text ) && preg_match( '/^(subject|betreff|objet|asunto|oggetto|onderwerp|temat|тема):\s.+$/mui', $text );

		return $chat >= 1 || $email || mb_strlen( $text ) > 600;
	}

	/**
	 * A voice message: written down, then read like a typed order.
	 *
	 * @param string $file_id Telegram file ID.
	 * @param int    $sent    When it was recorded.
	 */
	public static function voice( $file_id, $sent = 0 ) {
		self::typing();

		$audio = Telegram_Bot::download( $file_id, self::MAX_AUDIO );
		$text  = is_wp_error( $audio ) ? $audio : Ai::transcribe( $audio );

		if ( is_wp_error( $text ) ) {
			self::say( $text->get_error_message() );
			return;
		}

		if ( '' === $text ) {
			self::say( __( 'I could not hear anything in this voice message. Please record it again.', 'dealroot' ) );
			return;
		}

		self::command( $text, $sent ? (int) $sent : time() );
	}

	/**
	 * A text: an order or a conversation passed on.
	 *
	 * @param string $text Text, or "file:" and the Telegram file ID of a text file.
	 * @param string $kind "command" or "conversation".
	 * @param string $name Name of the person a message was forwarded from.
	 */
	public static function text( $text, $kind, $name = '' ) {
		self::typing();

		if ( 0 === strpos( (string) $text, 'file:' ) ) {
			$text = Telegram_Bot::download( substr( $text, 5 ), self::MAX_TEXT );

			if ( is_wp_error( $text ) ) {
				self::say( $text->get_error_message() );
				return;
			}

			$text = wp_check_invalid_utf8( (string) preg_replace( '/^\xEF\xBB\xBF/', '', $text ) );
		}

		if ( 'conversation' === $kind ) {
			self::conversation( (string) $text, (string) $name );
			return;
		}

		self::command( (string) $text, time() );
	}

	/**
	 * Carries out an order typed or spoken on the overview, e.g. "Move Meier to contacted", and
	 * says what was done there instead of in Telegram.
	 *
	 * @param string $text Order.
	 * @return array{action: string, text: string, lead: int}
	 */
	public static function on_screen( $text ) {
		self::$here      = array();
		self::$here_lead = 0;

		$action = self::command( $text, time() );
		$said   = self::$here;

		self::$here = null;

		return array(
			'action' => $action,
			'text'   => trim( implode( "\n", $said ) ),
			'lead'   => self::$here_lead,
		);
	}

	/**
	 * Reads an order and does it.
	 *
	 * @param string $text Order, typed or written down from speech.
	 * @param int    $sent When it was sent.
	 * @return string What was done: the action, or "".
	 */
	public static function command( $text, $sent ) {
		$order = Ai::ask(
			'command',
			array(
				'text'   => mb_substr( $text, 0, 2000 ),
				'today'  => wp_date( 'Y-m-d' ),
				'people' => self::people(),
			),
			90
		);

		if ( is_wp_error( $order ) ) {
			self::say( $order->get_error_message() );
			return '';
		}

		$action = (string) ( $order['action'] ?? 'unknown' );

		if ( 'new_lead' === $action ) {
			self::new_lead( $order, $text, $sent );
			return $action;
		}

		if ( 'ask' === $action ) {
			// On the screen the question was already counted as one.
			if ( is_array( self::$here ) ) {
				self::say( __( 'I did not see what to change. Say who and what, e.g. “Move Meier to contacted”.', 'dealroot' ) );
				return '';
			}

			self::answer_question( '' !== (string) ( $order['question'] ?? '' ) ? (string) $order['question'] : $text );
			return $action;
		}

		if ( ! in_array( $action, array( 'won', 'lost', 'status', 'follow_up', 'reply', 'note' ), true ) ) {
			/* translators: %s: what the owner said */
			self::say( sprintf( __( 'I did not understand what to do with “%s”.', 'dealroot' ), wp_html_excerpt( $text, 120, '…' ) ) . "\n\n" . self::help() );
			return '';
		}

		$lead = self::find( (string) ( $order['person'] ?? '' ) );

		if ( ! $lead ) {
			self::say(
				'' !== (string) ( $order['person'] ?? '' )
					/* translators: %s: name */
					? sprintf( __( 'I found no lead named %s from the last twelve months.', 'dealroot' ), $order['person'] )
					: __( 'Whom do you mean? Please say the name of the customer.', 'dealroot' )
			);
			return '';
		}

		$name = self::name( $lead );

		switch ( $action ) {
			case 'won':
				$changes = array( 'status' => 'won' );

				if ( (float) ( $order['amount'] ?? 0 ) > 0 ) {
					$changes['value']    = (float) $order['amount'];
					$changes['currency'] = self::currency( $order['currency'] ?? '' );
				}

				Leads::update( (int) $lead->id, $changes );
				$lead = Leads::get( (int) $lead->id );

				self::say(
					null !== $lead->value
						/* translators: 1: name, 2: amount */
						? sprintf( __( '✓ %1$s: won, %2$s.', 'dealroot' ), $name, Admin\Format::money( (float) $lead->value, (string) $lead->currency ) )
						/* translators: %s: name */
						: sprintf( __( '✓ %s: won. Send the amount too, e.g. “1,500 euros”, so the revenue is right.', 'dealroot' ), $name ),
					$lead
				);
				break;

			case 'lost':
				// "Müller cancelled, too expensive" says why, too.
				Leads::update(
					(int) $lead->id,
					array(
						'status'      => 'lost',
						'lost_reason' => Lost_Reasons::guess( $text ),
					)
				);
				$reason = Lost_Reasons::guess( $text );
				self::say(
					'' !== $reason
						/* translators: 1: name, 2: reason */
						? sprintf( __( '✓ %1$s: lost – %2$s.', 'dealroot' ), $name, Lost_Reasons::labels()[ $reason ] )
						/* translators: %s: name */
						: sprintf( __( '✓ %s: lost.', 'dealroot' ), $name ),
					$lead
				);
				break;

			case 'status':
				$stage = in_array( $order['status'] ?? '', array( 'new', 'contacted', 'qualified' ), true ) ? (string) $order['status'] : 'contacted';

				Leads::update( (int) $lead->id, array( 'status' => $stage ) );
				/* translators: 1: name, 2: status */
				self::say( sprintf( __( '✓ %1$s: %2$s.', 'dealroot' ), $name, Leads::status_labels()[ $stage ] ), $lead );
				break;

			case 'follow_up':
				self::follow_up( $lead, (string) ( $order['date'] ?? '' ), (string) ( $order['time'] ?? '' ), (string) ( $order['message'] ?? '' ) );
				break;

			case 'reply':
				if ( ! empty( $lead->ai_abusive ) ) {
					self::say( Ai::abusive_note(), $lead );
					break;
				}

				// On the screen the assistant writes the answer into the lead, to read and send there.
				if ( is_array( self::$here ) ) {
					$draft = Ai::draft( $lead, (string) ( $order['message'] ?? '' ) );

					if ( is_string( $draft ) && '' !== $draft ) {
						Inbox::store_draft( (int) $lead->id, $draft );
						/* translators: %s: name */
						self::say( sprintf( __( '✓ The answer to %s is written. Open the lead to read it, add photos or documents and send it.', 'dealroot' ), $name ) . "\n\n" . $draft, $lead );
					} else {
						/* translators: %s: name */
						self::say( sprintf( __( 'Open %s to write the answer and send it with photos or documents.', 'dealroot' ), $name ), $lead );
					}
					break;
				}

				Telegram_Bot::write_draft( (int) $lead->id, (string) ( $order['message'] ?? '' ) );
				break;

			case 'note':
				$note = trim( (string) ( $order['message'] ?? '' ) );
				$line = wp_date( get_option( 'date_format' ) ) . ': ' . ( '' !== $note ? $note : $text );

				Leads::update( (int) $lead->id, array( 'note' => trim( (string) $lead->note . "\n" . $line ) ) );
				/* translators: %s: name */
				self::say( sprintf( __( '✓ Noted for %s.', 'dealroot' ), $name ), $lead );
				break;
		}

		return $action;
	}

	/**
	 * A new lead from what the owner tells about it.
	 *
	 * @param array  $order What the assistant read.
	 * @param string $text  What the owner said.
	 * @param int    $sent  When it was said.
	 * @return int Lead ID.
	 */
	private static function new_lead( array $order, $text, $sent ) {
		$how     = (string) ( $order['how'] ?? 'other' );
		$lead_id = self::create(
			array(
				'name'     => (string) ( $order['person'] ?? '' ),
				'message'  => $text,
				'summary'  => (string) ( $order['summary'] ?? '' ),
				'topic'    => (string) ( $order['topic'] ?? '' ),
				'budget'   => (float) ( $order['amount'] ?? 0 ),
				'currency' => (string) ( $order['currency'] ?? '' ),
				'how'      => $how,
				'form'     => __( 'Telegram, voice message or note', 'dealroot' ),
			)
		);

		if ( ! $lead_id ) {
			self::say( __( 'Something went wrong. Please reload the page and try again.', 'dealroot' ) );
			return 0;
		}

		$click = in_array( $how, array( 'phone', 'whatsapp' ), true ) ? self::link_click( $lead_id, 'phone' === $how ? 'phone' : 'whatsapp', $sent ) : null;
		$lead  = Leads::get( $lead_id );
		$lines = array(
			/* translators: %s: name */
			sprintf( __( '✓ New lead: %s', 'dealroot' ), self::name( $lead ) ),
		);

		if ( '' !== (string) $lead->ai_summary ) {
			$lines[] = $lead->ai_summary;
		}

		if ( null !== $lead->ai_budget ) {
			$lines[] = __( 'Budget', 'dealroot' ) . ': ' . Admin\Format::money( (float) $lead->ai_budget, (string) $lead->ai_currency );
		}

		$buttons = array( array( Telegram_Bot::open_button( $lead, __( 'Open lead', 'dealroot' ) ) ) );

		if ( $click ) {
			$lines[] = '';
			$lines[] = sprintf(
				/* translators: 1: time, 2: where the visitor came from */
				__( 'Linked to the click on your phone number at %1$s – from %2$s. The call now counts for this source.', 'dealroot' ),
				wp_date( get_option( 'time_format' ), (int) strtotime( $click->created_at . ' UTC' ) ),
				Attribution::channel_label( (string) $click->channel ) . ( '' !== (string) $click->campaign ? ', ' . $click->campaign : '' )
			);
			$buttons[] = array(
				array(
					'text'          => __( 'It was not that call', 'dealroot' ),
					'callback_data' => 'unlink:' . (int) $lead_id,
				),
			);
		}

		self::say( implode( "\n", $lines ), $lead, array( 'inline_keyboard' => $buttons ) );

		return $lead_id;
	}

	/**
	 * A conversation passed on, filed as a lead.
	 *
	 * @param string $text Conversation.
	 * @param string $name Name of the person it was forwarded from.
	 * @return int Lead ID.
	 */
	public static function conversation( $text, $name = '' ) {
		$read = self::read( $text );

		if ( is_wp_error( $read ) ) {
			self::say( $read->get_error_message() );
			return 0;
		}

		if ( '' !== $name ) {
			$read['name'] = $name;
		}

		$lead_id = self::create( $read + array( 'form' => __( 'Telegram, conversation passed on', 'dealroot' ) ) );

		if ( ! $lead_id ) {
			self::say( __( 'Something went wrong. Please reload the page and try again.', 'dealroot' ) );
			return 0;
		}

		$lead  = Leads::get( $lead_id );
		$lines = array(
			/* translators: %s: name */
			sprintf( __( '✓ New lead from the conversation: %s', 'dealroot' ), self::name( $lead ) ),
		);

		foreach ( array( $lead->ai_summary, $lead->email, $lead->phone ) as $value ) {
			if ( '' !== (string) $value ) {
				$lines[] = (string) $value;
			}
		}

		if ( null !== $lead->ai_budget ) {
			$lines[] = __( 'Budget', 'dealroot' ) . ': ' . Admin\Format::money( (float) $lead->ai_budget, (string) $lead->ai_currency );
		}

		self::say( implode( "\n", $lines ), $lead, Telegram_Bot::lead_buttons( $lead ) );

		return $lead_id;
	}

	/**
	 * What a conversation says about the customer: name, email, phone, summary, topic, urgency,
	 * budget and how they got in touch. Email address and phone number are found here and never
	 * sent to the assistant.
	 *
	 * @param string $text Conversation.
	 * @return array|\WP_Error
	 */
	public static function read( $text ) {
		$text = mb_substr( trim( (string) $text ), 0, 20000 );
		$read = Ai::ask( 'conversation', array( 'text' => mb_substr( $text, 0, 8000 ) ), 90 );

		if ( is_wp_error( $read ) ) {
			return $read;
		}

		$how = (string) ( $read['how'] ?? 'other' );

		return array(
			'name'     => (string) ( $read['name'] ?? '' ),
			'email'    => self::find_email( $text ),
			'phone'    => self::find_phone( $text ),
			'message'  => $text,
			'summary'  => (string) ( $read['summary'] ?? '' ),
			'topic'    => (string) ( $read['topic'] ?? '' ),
			'urgent'   => ! empty( $read['urgent'] ),
			'budget'   => (float) ( $read['budget'] ?? 0 ),
			'currency' => self::currency( $read['currency'] ?? '' ),
			'how'      => $how,
			'channel'  => self::way( $how )[0],
			'source'   => self::way( $how )[1],
		);
	}

	/**
	 * Channel and source for how someone got in touch.
	 *
	 * @param string $how phone, whatsapp, email, telegram, sms, visit, recommendation or other.
	 * @return array{0: string, 1: string}
	 */
	public static function way( $how ) {
		$ways = array(
			'phone'          => array( 'phone_call', '' ),
			'visit'          => array( 'walk_in', '' ),
			'recommendation' => array( 'word_of_mouth', '' ),
			'whatsapp'       => array( 'direct', 'WhatsApp' ),
			'telegram'       => array( 'direct', 'Telegram' ),
			'email'          => array( 'email', 'Email' ),
			'sms'            => array( 'direct', 'SMS' ),
		);

		return $ways[ $how ] ?? array( '', '' );
	}

	/**
	 * Stores a lead the owner told about or passed on.
	 *
	 * @param array $values name, email, phone, message, summary, topic, urgent, budget, currency, how, form.
	 * @return int Lead ID.
	 */
	private static function create( array $values ) {
		global $wpdb;

		$values = wp_parse_args(
			$values,
			array(
				'name'     => '',
				'email'    => '',
				'phone'    => '',
				'message'  => '',
				'summary'  => '',
				'topic'    => '',
				'urgent'   => false,
				'budget'   => 0,
				'currency' => '',
				'how'      => 'other',
				'form'     => '',
			)
		);

		$way = self::way( (string) $values['how'] );

		$fields = array();
		foreach ( array(
			'name'    => array( __( 'Name', 'dealroot' ), 'text' ),
			'email'   => array( __( 'Email', 'dealroot' ), 'email' ),
			'phone'   => array( __( 'Phone', 'dealroot' ), 'tel' ),
			'message' => array( __( 'Message', 'dealroot' ), 'textarea' ),
		) as $key => $field ) {
			if ( '' !== trim( (string) $values[ $key ] ) ) {
				$fields[] = array(
					'label' => $field[0],
					'name'  => $key,
					'type'  => $field[1],
					'value' => trim( (string) $values[ $key ] ),
				);
			}
		}

		$budget = (float) $values['budget'] > 0 ? round( (float) $values['budget'], 2 ) : null;
		$data   = array(
			'form_plugin'  => 'manual',
			'form_name'    => $values['form'],
			'name'         => mb_substr( sanitize_text_field( $values['name'] ), 0, 191 ),
			'email'        => is_email( $values['email'] ) ? $values['email'] : '',
			'phone'        => mb_substr( sanitize_text_field( $values['phone'] ), 0, 50 ),
			'fields'       => wp_json_encode( $fields ),
			'channel'      => $way[0],
			'last_channel' => $way[0],
			'source'       => $way[1],
			'last_source'  => $way[1],
			'currency'     => self::currency( $values['currency'] ),
			'value'        => $budget,
		);

		$lead_id = Leads::insert( $data );

		if ( ! $lead_id ) {
			return 0;
		}

		$wpdb->update(
			Installer::table(),
			array(
				'ai_summary'  => mb_substr( sanitize_text_field( $values['summary'] ), 0, 255 ),
				'ai_topics'   => mb_substr( sanitize_text_field( $values['topic'] ), 0, 40 ),
				'ai_urgent'   => $values['urgent'] ? 1 : 0,
				'ai_kind'     => 'enquiry',
				'ai_state'    => 'done',
				'ai_budget'   => $budget,
				'ai_currency' => null !== $budget ? self::currency( $values['currency'] ) : '',
			),
			array( 'id' => (int) $lead_id )
		);

		/** This action is documented in includes/class-capture.php */
		do_action( 'dealroot_lead_created', $lead_id, $data );

		return (int) $lead_id;
	}

	/**
	 * Gives a lead the source of the last click on the phone number or WhatsApp before the call,
	 * when it is recent and not taken by another lead.
	 *
	 * @param int    $lead_id Lead ID.
	 * @param string $type    "phone" or "whatsapp".
	 * @param int    $before  Time of the voice message.
	 * @return object|null The click.
	 */
	public static function link_click( $lead_id, $type, $before ) {
		global $wpdb;

		$click = $wpdb->get_row(
			$wpdb->prepare(
				'SELECT * FROM %i WHERE type = %s AND lead_id = 0 AND created_at >= %s AND created_at <= %s ORDER BY created_at DESC LIMIT 1',
				Installer::events_table(),
				$type,
				gmdate( 'Y-m-d H:i:s', $before - self::CALL_HOURS * HOUR_IN_SECONDS ),
				gmdate( 'Y-m-d H:i:s', $before )
			)
		);

		if ( ! $click || '' === (string) $click->channel ) {
			return null;
		}

		$columns = array();
		foreach ( array( 'channel', 'source', 'medium', 'campaign', 'last_channel', 'last_source', 'last_medium', 'last_campaign', 'landing_page', 'gclid', 'gbraid', 'wbraid', 'fbclid', 'msclkid' ) as $column ) {
			$columns[ $column ] = (string) ( $click->$column ?? '' );
		}

		$wpdb->update( Installer::table(), $columns, array( 'id' => (int) $lead_id ) );
		$wpdb->update( Installer::events_table(), array( 'lead_id' => (int) $lead_id ), array( 'id' => (int) $click->id ) );

		return $click;
	}

	/**
	 * Takes the source of a click away from a lead again, when the call was another one.
	 *
	 * @param int $lead_id Lead ID.
	 * @return bool
	 */
	public static function unlink_click( $lead_id ) {
		global $wpdb;

		$lead = Leads::get( (int) $lead_id );

		if ( ! $lead || 'manual' !== $lead->form_plugin ) {
			return false;
		}

		$wpdb->update( Installer::events_table(), array( 'lead_id' => 0 ), array( 'lead_id' => (int) $lead_id ) );
		$wpdb->update(
			Installer::table(),
			array(
				'channel'       => 'phone_call',
				'last_channel'  => 'phone_call',
				'source'        => '',
				'last_source'   => '',
				'medium'        => '',
				'last_medium'   => '',
				'campaign'      => '',
				'last_campaign' => '',
				'landing_page'  => '',
				'gclid'         => '',
				'gbraid'        => '',
				'wbraid'        => '',
				'fbclid'        => '',
				'msclkid'       => '',
			),
			array( 'id' => (int) $lead_id )
		);

		return true;
	}

	/**
	 * A reminder of a lead, in Telegram and, with Dealroot Pro, as its follow-up date.
	 *
	 * @param object $lead Lead.
	 * @param string $date Day, YYYY-MM-DD.
	 * @param string $time Time, HH:MM, optional.
	 * @param string $note What it is about, optional.
	 */
	private static function follow_up( $lead, $date, $time, $note ) {
		$when = '' !== $date ? date_create_immutable( $date . ' ' . ( '' !== $time ? $time : '09:00' ), wp_timezone() ) : false;

		if ( ! $when || $when->getTimestamp() <= time() ) {
			self::say( __( 'When should I remind you? Please say a day, e.g. “on Friday” or “tomorrow at 10”.', 'dealroot' ), $lead );
			return;
		}

		wp_schedule_single_event( $when->getTimestamp(), self::REMIND_HOOK, array( (int) $lead->id, mb_substr( sanitize_text_field( $note ), 0, 300 ) ) );

		/**
		 * Fires when the owner asked to be reminded of a lead, e.g. to keep it as follow-up date.
		 *
		 * @param int    $lead_id Lead ID.
		 * @param string $time    UTC time, Y-m-d H:i:s.
		 */
		do_action( 'dealroot_follow_up_set', (int) $lead->id, gmdate( 'Y-m-d H:i:s', $when->getTimestamp() ) );

		self::say(
			sprintf(
				/* translators: 1: name, 2: date and time */
				__( '✓ I will remind you of %1$s on %2$s.', 'dealroot' ),
				self::name( $lead ),
				wp_date( 'l, ' . get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), $when->getTimestamp() )
			),
			$lead
		);
	}

	/**
	 * Sends a reminder that is due.
	 *
	 * @param int    $lead_id Lead ID.
	 * @param string $note    What it is about.
	 */
	public static function remind( $lead_id, $note = '' ) {
		$lead = Leads::get( (int) $lead_id );

		if ( ! $lead || in_array( $lead->status, array( 'won', 'lost', 'spam' ), true ) ) {
			return;
		}

		$lines = array(
			/* translators: %s: name */
			'⏰ ' . sprintf( __( 'Reminder: %s', 'dealroot' ), self::name( $lead ) ),
		);

		foreach ( array( $note, $lead->ai_summary, $lead->phone ) as $value ) {
			if ( '' !== (string) $value ) {
				$lines[] = (string) $value;
			}
		}

		// Without Telegram the reminder comes by email.
		if ( ! Notifier::telegram_ready() ) {
			Ai::in_locale(
				Ai::team_locale(),
				fn() => Mail::owner(
					Digest::recipients(),
					/* translators: %s: name */
					sprintf( __( 'Reminder: %s', 'dealroot' ), self::name( $lead ) ),
					array(
						/* translators: %s: name */
						'title'  => sprintf( __( 'Reminder: %s', 'dealroot' ), self::name( $lead ) ),
						'text'   => implode( "\n", array_slice( $lines, 1 ) ),
						'button' => array(
							'url'   => admin_url( 'admin.php?page=dealroot&lead=' . (int) $lead->id ),
							'label' => __( 'Open the lead', 'dealroot' ),
						),
					)
				)
			);
			return;
		}

		self::say( implode( "\n", $lines ), $lead, Telegram_Bot::lead_buttons( $lead ) );
	}

	/**
	 * Answers a question about the own enquiries with the numbers.
	 *
	 * @param string $question Question.
	 */
	private static function answer_question( $question ) {
		$answer = Ai_Ask::answer( $question );

		if ( is_wp_error( $answer ) ) {
			self::say( $answer->get_error_message() );
			return;
		}

		$lines = array();

		if ( '' !== (string) ( $answer['title'] ?? '' ) ) {
			$lines[] = $answer['title'] . ( '' !== (string) ( $answer['period'] ?? '' ) ? ' (' . $answer['period'] . ')' : '' );
		}

		foreach ( array_slice( (array) ( $answer['rows'] ?? array() ), 0, 12 ) as $row ) {
			$lines[] = '• ' . $row[0] . ': ' . $row[1];
		}

		if ( '' !== (string) ( $answer['total'] ?? '' ) ) {
			$lines[] = ( ! empty( $answer['rows'] ) ? __( 'In all', 'dealroot' ) . ': ' : '' ) . $answer['total'];
		}

		if ( '' !== (string) ( $answer['text'] ?? '' ) ) {
			$lines[] = $answer['text'];
		}

		self::say( implode( "\n", $lines ) );
	}

	/**
	 * The lead a name means: the most recent one with that name, open ones first.
	 *
	 * @param string $person Name as said.
	 * @return object|null
	 */
	public static function find( $person ) {
		global $wpdb;

		$person = trim( (string) $person );

		if ( mb_strlen( $person ) < 2 ) {
			return null;
		}

		$words = array_filter(
			preg_split( '/\s+/u', $person ),
			static function ( $word ) {
				return mb_strlen( $word ) >= 3 && ! preg_match( '/^(herr|frau|mr|mrs|ms|monsieur|madame|señor|señora|signor|signora|pan|pani|meneer|mevrouw|пан|пані|господин|госпожа)\.?$/iu', $word );
			}
		);

		// The whole name first, then each of its words, the surname usually last.
		foreach ( array_merge( array( $person ), array_reverse( $words ) ) as $term ) {
			$lead = $wpdb->get_row(
				$wpdb->prepare(
					"SELECT * FROM %i WHERE status <> 'spam' AND created_at >= %s AND ( name LIKE %s OR email LIKE %s )
					ORDER BY status IN ('new', 'contacted', 'qualified') DESC, created_at DESC LIMIT 1",
					Installer::table(),
					gmdate( 'Y-m-d H:i:s', time() - YEAR_IN_SECONDS ),
					'%' . $wpdb->esc_like( $term ) . '%',
					$wpdb->esc_like( $term ) . '%'
				)
			);

			if ( $lead ) {
				return $lead;
			}
		}

		return null;
	}

	/**
	 * Names of recent leads, so the assistant writes them as they are stored.
	 *
	 * @return string[]
	 */
	private static function people() {
		global $wpdb;

		$names = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT name FROM %i WHERE name <> '' AND status <> 'spam' AND created_at >= %s GROUP BY name ORDER BY MAX(created_at) DESC LIMIT 40",
				Installer::table(),
				gmdate( 'Y-m-d H:i:s', time() - 90 * DAY_IN_SECONDS )
			)
		);

		return array_values( array_map( 'strval', (array) $names ) );
	}

	/**
	 * Name of a person a message was forwarded from.
	 *
	 * @param array $origin forward_origin of a message.
	 * @return string
	 */
	private static function forwarded_name( array $origin ) {
		if ( isset( $origin['sender_user'] ) ) {
			return trim( ( $origin['sender_user']['first_name'] ?? '' ) . ' ' . ( $origin['sender_user']['last_name'] ?? '' ) );
		}

		return (string) ( $origin['sender_user_name'] ?? ( $origin['chat']['title'] ?? '' ) );
	}

	/**
	 * The first email address in a text that is not the one of the site.
	 *
	 * @param string $text Text.
	 * @return string
	 */
	private static function find_email( $text ) {
		preg_match_all( '/[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}/i', $text, $matches );

		$own = array( strtolower( (string) get_option( 'admin_email' ) ) );

		foreach ( $matches[0] as $email ) {
			if ( is_email( $email ) && ! in_array( strtolower( $email ), $own, true ) ) {
				return $email;
			}
		}

		return '';
	}

	/**
	 * The first phone number in a text.
	 *
	 * @param string $text Text.
	 * @return string
	 */
	private static function find_phone( $text ) {
		return preg_match( '/(?<![\w])(?:\+|00|0)\d[\d \/()-]{6,}\d/u', $text, $match ) ? trim( $match[0] ) : '';
	}

	/**
	 * A currency code, or the one of the site.
	 *
	 * @param string $code Code.
	 * @return string
	 */
	private static function currency( $code ) {
		$code = strtoupper( (string) $code );

		return preg_match( '/^[A-Z]{3}$/', $code ) ? $code : (string) Settings::get( 'currency' );
	}

	/**
	 * Name of a lead for the chat.
	 *
	 * @param object $lead Lead.
	 * @return string
	 */
	private static function name( $lead ) {
		return '' !== trim( (string) $lead->name ) ? (string) $lead->name : ( '' !== (string) $lead->email ? (string) $lead->email : '#' . (int) $lead->id );
	}

	/**
	 * What the bot understands.
	 *
	 * @return string
	 */
	public static function help() {
		return implode(
			"\n",
			array(
				__( 'Send me a voice message or a text, for example:', 'dealroot' ),
				'• ' . __( '“Müller called about the roof, wants an estimate, about 2,000 euros”', 'dealroot' ),
				'• ' . __( '“Müller won, 1,500 euros” or “Müller cancelled”', 'dealroot' ),
				'• ' . __( '“Remind me on Friday about Schmidt”', 'dealroot' ),
				'• ' . __( '“Answer Mrs Schmidt that I will call back at 2 pm”', 'dealroot' ),
				'• ' . __( '“How many enquiries came from Google this month?”', 'dealroot' ),
				'',
				__( 'Paste or forward a conversation, e.g. copied from WhatsApp, and it becomes a lead.', 'dealroot' ),
			)
		);
	}

	/**
	 * Runs a step right after Telegram got its answer.
	 *
	 * @param string $hook Hook.
	 * @param array  $args Arguments.
	 */
	private static function later( $hook, array $args ) {
		wp_schedule_single_event( time(), $hook, $args );
		spawn_cron();
	}

	/**
	 * Shows "typing…" in the chat while the assistant works.
	 */
	private static function typing() {
		Telegram_Bot::call(
			'sendChatAction',
			array(
				'chat_id' => Settings::get( 'telegram_chat_id' ),
				'action'  => 'typing',
			)
		);
	}

	/**
	 * Answers in the chat.
	 *
	 * @param string      $text    Plain text.
	 * @param object|null $lead    Lead to open with a button.
	 * @param array|null  $buttons Buttons instead.
	 */
	private static function say( $text, $lead = null, $buttons = null ) {
		if ( is_array( self::$here ) ) {
			self::$here[] = (string) $text;

			if ( $lead ) {
				self::$here_lead = (int) $lead->id;
			}

			return;
		}

		if ( null === $buttons && $lead ) {
			$buttons = array( 'inline_keyboard' => array( array( Telegram_Bot::open_button( $lead, __( 'Open lead', 'dealroot' ) ) ) ) );
		}

		Notifier::send_telegram( Settings::get( 'telegram_token' ), Settings::get( 'telegram_chat_id' ), htmlspecialchars( (string) $text, ENT_NOQUOTES, 'UTF-8' ), $buttons );
	}
}