<?php
/**
 * Drafts in the style of the owner.
 *
 * @package Dealroot
 */

namespace Dealroot;

defined( 'ABSPATH' ) || exit;

/**
 * Keeps the last answers the owner really sent through Dealroot – from the lead screen, from
 * Telegram or from "Go through new enquiries", also after changing a draft – and gives the newest
 * to the AI assistant with each draft. After a few answers the drafts greet, close and sound like
 * the owner, without anyone pasting examples into a box.
 *
 * Kept on the site only, without the name, email address and phone number of the person.
 */
class Reply_Style {

	const OPTION = 'dealroot_reply_style';

	/**
	 * Answers kept.
	 */
	const KEEP = 12;

	/**
	 * Answers given to the assistant with a draft.
	 */
	const USE = 3;

	/**
	 * Shorter texts say too little about a style.
	 */
	const MIN_LENGTH = 60;

	/**
	 * Hooks.
	 */
	public function register() {
		add_action( 'wp_ajax_dealroot_reply_sent', array( __CLASS__, 'ajax' ) );
		add_action( 'dealroot_telegram_answer_sent', array( __CLASS__, 'learn' ), 10, 2 );
		add_action( 'dealroot_answer_sent', array( __CLASS__, 'learn' ), 10, 2 );
	}

	/**
	 * Whether answers are learned from.
	 *
	 * @return bool
	 */
	public static function enabled() {
		return (bool) Settings::get( 'learn_style' );
	}

	/**
	 * An answer was sent from the lead screen, by email or WhatsApp.
	 */
	public static function ajax() {
		check_ajax_referer( 'dealroot_quick_status', 'nonce' );

		if ( ! current_user_can( Admin\Admin::capability() ) ) {
			wp_send_json_error( null, 403 );
		}

		$lead_id = isset( $_POST['lead'] ) ? absint( $_POST['lead'] ) : 0;
		$text    = isset( $_POST['text'] ) ? sanitize_textarea_field( wp_unslash( $_POST['text'] ) ) : '';

		wp_send_json_success( array( 'learned' => self::learn( $lead_id, $text ) ) );
	}

	/**
	 * Keeps an answer that was sent.
	 *
	 * @param int    $lead_id Lead it answered.
	 * @param string $text    Text sent.
	 * @return bool Whether it was kept.
	 */
	public static function learn( $lead_id, $text ) {
		$lead = Leads::get( (int) $lead_id );
		$text = trim( str_replace( "\r", '', (string) $text ) );

		if ( ! $lead || ! self::enabled() || mb_strlen( $text ) < self::MIN_LENGTH || self::is_template( $text, $lead ) ) {
			return false;
		}

		$text    = self::anonymize( $text, $lead );
		$answers = array_values(
			array_filter(
				self::all(),
				static function ( $answer ) use ( $text ) {
					return $answer['text'] !== $text;
				}
			)
		);

		array_unshift(
			$answers,
			array(
				'text' => mb_substr( $text, 0, 1500 ),
				'lang' => (string) $lead->ai_lang,
				'time' => time(),
			)
		);

		return update_option( self::OPTION, array_slice( $answers, 0, self::KEEP ), false );
	}

	/**
	 * The answers kept, newest first.
	 *
	 * @return array<int, array{text: string, lang: string, time: int}>
	 */
	public static function all() {
		$answers = get_option( self::OPTION, array() );

		return is_array( $answers ) ? array_values( array_filter( $answers, 'is_array' ) ) : array();
	}

	/**
	 * Answers for a draft: the newest in the language of the reply first, then the others.
	 *
	 * @param string $lang Language of the reply, or "".
	 * @return string[]
	 */
	public static function examples( $lang = '' ) {
		if ( ! self::enabled() ) {
			return array();
		}

		$same  = array();
		$other = array();

		foreach ( self::all() as $answer ) {
			if ( '' !== $lang && $answer['lang'] === $lang ) {
				$same[] = $answer['text'];
			} else {
				$other[] = $answer['text'];
			}
		}

		// Answers in another language still show greeting and length, but only when none fit.
		return array_slice( $same ? $same : $other, 0, self::USE );
	}

	/**
	 * How many answers the drafts learn from.
	 *
	 * @return int
	 */
	public static function count() {
		return count( self::all() );
	}

	/**
	 * Forgets all answers.
	 */
	public static function forget() {
		delete_option( self::OPTION );
	}

	/**
	 * Whether a text is one of the quick replies as written in the settings, not the owner's own.
	 *
	 * @param string $text Text.
	 * @param object $lead Lead.
	 * @return bool
	 */
	private static function is_template( $text, $lead ) {
		foreach ( Replies::all() as $reply ) {
			if ( trim( Replies::fill( $reply['body'], $lead ) ) === $text ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * The text without the name, email address and phone number of the person.
	 *
	 * @param string $text Text.
	 * @param object $lead Lead.
	 * @return string
	 */
	private static function anonymize( $text, $lead ) {
		$text = (string) preg_replace( '/[^\s@<>]+@[^\s@<>]+\.[a-z]{2,}/iu', '[email]', $text );
		$text = (string) preg_replace_callback(
			'/(?<![\w.])\+?\d[\d\s\/().-]{6,}\d/u',
			static function ( $found ) {
				// Dates and times stay.
				$date = preg_match( '/^\d{1,2}\.\d{1,2}\.(\d{2}|\d{4})$/', trim( $found[0] ) );

				return ! $date && preg_match_all( '/\d/', $found[0] ) >= 7 ? '[phone]' : $found[0];
			},
			$text
		);

		$names = array_filter(
			preg_split( '/\s+/u', trim( (string) $lead->name ) ),
			static function ( $part ) {
				return mb_strlen( $part ) >= 2;
			}
		);

		// The longest first, so "Anna-Lena" goes before "Anna".
		usort(
			$names,
			static function ( $a, $b ) {
				return mb_strlen( $b ) <=> mb_strlen( $a );
			}
		);

		foreach ( $names as $part ) {
			$text = (string) preg_replace( '/(?<!\pL)' . preg_quote( $part, '/' ) . '(?!\pL)/iu', '[name]', $text );
		}

		return $text;
	}
}