<?php
/**
 * Sign-ups from the site's other forms (Contact Form 7, WPForms, Elementor):
 * for each of those forms the site owner chooses which 404 Emails form its
 * sign-ups join, and who counts as signing up - only people who tick a
 * permission checkbox on it, or everyone who sends it (a form that is only
 * a newsletter sign-up). Set up on 404 Emails → Other forms (Other_Forms_Page).
 *
 * Permission is never assumed: without a saved choice nothing is sent, an
 * unticked box sends nothing, and the wording the person actually agreed
 * to goes to 404 Emails as the consent text. The sign-up goes through the
 * chosen 404 Emails form, so its double opt-in, groups and welcome emails
 * apply exactly as on the form itself. Only the email address, names and
 * that wording leave the site - never a message or any other field.
 *
 * @package Emails404
 */

namespace Emails404;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class Form_Connections {

	const OPTION = 'emails404_form_connections';

	/** "Who is added": everyone who sends the form. Otherwise it's a consent field's key. */
	const EVERYONE = '*';

	const KIND_EMAIL      = 'email';
	const KIND_FIRST_NAME = 'first_name';
	const KIND_LAST_NAME  = 'last_name';
	const KIND_FULL_NAME  = 'full_name';
	const KIND_CONSENT    = 'consent';
	const KIND_OTHER      = 'other';

	const CONSENT_TEXT_MAX = 1000;

	/** @var Sync_Service|null */
	private static $sync_service = null;

	public static function set_sync_service( Sync_Service $sync_service ) {
		self::$sync_service = $sync_service;
	}

	/** Sends a sign-up made elsewhere in this plugin (Event_Page_Forms) the same way. */
	public static function send( Signup_Dto $dto, $source_slug ) {
		if ( Settings::is_connected() && null !== self::$sync_service ) {
			self::$sync_service->send( $dto, $source_slug );
		}
	}

	/** @return array<string, array{form:string, consent:string}> Keyed "{source}:{form id}". */
	public static function all() {
		$saved = get_option( self::OPTION, array() );
		return is_array( $saved ) ? $saved : array();
	}

	public static function key( $source_slug, $form_id ) {
		return $source_slug . ':' . $form_id;
	}

	/** @return array{form:string, consent:string}|null */
	public static function get( $source_slug, $form_id ) {
		$all = self::all();
		$key = self::key( $source_slug, $form_id );
		if ( ! isset( $all[ $key ]['form'], $all[ $key ]['consent'] ) || '' === $all[ $key ]['form'] || '' === $all[ $key ]['consent'] ) {
			return null;
		}
		return $all[ $key ];
	}

	public static function save( array $connections ) {
		update_option( self::OPTION, $connections, false );
	}

	/**
	 * Cleans what Other_Forms_Page posted. A form is connected only with a
	 * 404 Emails form that exists and a "who" that is either everyone or one
	 * of that form's own consent fields.
	 *
	 * @param array $raw       emails404_connections[{key}][form|consent], unslashed.
	 * @param array $forms     The site's forms, keyed like self::key() => source form (see Form_Source_Interface).
	 * @param array $known_ids Published 404 Emails form ids.
	 * @return array{connections: array, incomplete: string[]} `incomplete` - keys with a 404 Emails form but no "who".
	 */
	public static function sanitize( array $raw, array $forms, array $known_ids ) {
		$connections = array();
		$incomplete  = array();
		foreach ( $forms as $key => $form ) {
			if ( ! isset( $raw[ $key ] ) || ! is_array( $raw[ $key ] ) ) {
				continue;
			}
			$target  = isset( $raw[ $key ]['form'] ) && is_string( $raw[ $key ]['form'] ) ? trim( $raw[ $key ]['form'] ) : '';
			$consent = isset( $raw[ $key ]['consent'] ) && is_string( $raw[ $key ]['consent'] ) ? $raw[ $key ]['consent'] : '';
			if ( '' === $target || ! in_array( $target, $known_ids, true ) || ! self::find_field( $form, self::KIND_EMAIL ) ) {
				continue;
			}
			if ( self::EVERYONE !== $consent && ! self::consent_field( $form, $consent ) ) {
				$incomplete[] = $key;
				continue;
			}
			$connections[ $key ] = array(
				'form'    => $target,
				'consent' => $consent,
			);
		}
		return array(
			'connections' => $connections,
			'incomplete'  => $incomplete,
		);
	}

	/**
	 * What "Who is added" starts as for a form not set up yet: a checkbox
	 * whose wording is about emails or news. Otherwise nothing, and the owner
	 * chooses - a form's first checkbox is often "I agree to the privacy
	 * policy", which isn't permission to send newsletters.
	 */
	public static function suggested_consent( array $form ) {
		foreach ( self::consent_fields( $form ) as $field ) {
			if ( preg_match( '/(*UCP)(news|e-?mail|marketing|offers|updates|subscribe|novink|zpravodaj|nabídk|newsletter|odběr)/iu', $field['label'] ) ) {
				return $field['key'];
			}
		}
		return '';
	}

	/**
	 * Called by a source when one of its forms was sent.
	 *
	 * @param Form_Source_Interface $source
	 * @param string                $form_id   The form's id in that plugin.
	 * @param array                 $values    Field key => submitted value (string or array).
	 * @param string                $entity_id Unique to this submission (an entry id, or a random one).
	 * @param array|null            $form      The form's description, when the source already has it.
	 */
	public static function receive( Form_Source_Interface $source, $form_id, array $values, $entity_id, $form = null ) {
		if ( ! Settings::is_connected() || null === self::$sync_service ) {
			return;
		}
		$connection = self::get( $source->get_slug(), (string) $form_id );
		if ( null === $connection ) {
			return;
		}
		if ( ! is_array( $form ) ) {
			$form = $source->describe_form( (string) $form_id );
		}
		if ( ! is_array( $form ) ) {
			return;
		}
		$dto = self::build_signup( $source->get_slug(), $form, $values, $connection, $entity_id, self::site_host() );
		if ( null !== $dto ) {
			self::$sync_service->send( $dto, $source->get_slug() );
		}
	}

	/**
	 * The sign-up to send, or null when there's nothing to send: no valid
	 * email, or the person didn't tick the permission box.
	 *
	 * @return Signup_Dto|null
	 */
	public static function build_signup( $source_slug, array $form, array $values, array $connection, $entity_id, $site_host ) {
		if ( self::EVERYONE === $connection['consent'] ) {
			/* translators: 1: a form's title, 2: the website, e.g. "example.com". */
			$consent_text = sprintf( __( 'Sent the "%1$s" sign-up form on %2$s', '404-emails' ), $form['title'], $site_host );
		} else {
			$field = self::consent_field( $form, $connection['consent'] );
			if ( ! $field ) {
				return null;
			}
			$ticked = self::is_ticked( isset( $values[ $field['key'] ] ) ? $values[ $field['key'] ] : '' );
			if ( ! empty( $field['invert'] ) ) {
				$ticked = ! $ticked;
			}
			if ( ! $ticked ) {
				return null;
			}
			$consent_text = '' !== trim( (string) $field['label'] ) ? (string) $field['label'] : null;
		}

		$email = '';
		foreach ( $form['fields'] as $field ) {
			if ( self::KIND_EMAIL === $field['kind'] ) {
				$candidate = sanitize_email( self::text( $values, $field['key'] ) );
				if ( '' !== $candidate && is_email( $candidate ) ) {
					$email = $candidate;
					break;
				}
			}
		}
		if ( '' === $email ) {
			return null;
		}

		list( $first_name, $last_name ) = self::names( $form, $values );

		if ( null !== $consent_text ) {
			$consent_text = function_exists( 'mb_substr' ) ? mb_substr( $consent_text, 0, self::CONSENT_TEXT_MAX ) : substr( $consent_text, 0, self::CONSENT_TEXT_MAX );
		}

		return new Signup_Dto(
			$email,
			$first_name,
			$last_name,
			true,
			sprintf( 'wordpress-%s:form-%s', $source_slug, $form['id'] ),
			$connection['form'],
			Idempotency::build_key( $source_slug, 'form-' . $form['id'] . '-' . $entity_id, $connection['form'] ),
			$consent_text
		);
	}

	/**
	 * First and last name: from separate fields, or a single "name" field
	 * split at its first space ("Jana Nová Malá" → "Jana", "Nová Malá").
	 *
	 * @return array{0:string|null, 1:string|null}
	 */
	public static function names( array $form, array $values ) {
		$first = null;
		$last  = null;
		$full  = null;
		foreach ( $form['fields'] as $field ) {
			$value = self::text( $values, $field['key'] );
			if ( '' === $value ) {
				continue;
			}
			if ( self::KIND_FIRST_NAME === $field['kind'] && null === $first ) {
				$first = $value;
			} elseif ( self::KIND_LAST_NAME === $field['kind'] && null === $last ) {
				$last = $value;
			} elseif ( self::KIND_FULL_NAME === $field['kind'] && null === $full ) {
				$full = $value;
			}
		}
		if ( null === $first && null === $last && null !== $full ) {
			$parts = preg_split( '/\s+/u', $full, 2 );
			$first = $parts[0];
			$last  = isset( $parts[1] ) && '' !== $parts[1] ? $parts[1] : null;
		}
		return array( self::limit( $first ), self::limit( $last ) );
	}

	/**
	 * A field's kind from its name and label, for plugins that only know
	 * "text" (Contact Form 7, a text field in WPForms or Elementor).
	 * English and Czech words.
	 */
	public static function kind_from_words( $key, $label ) {
		$words = strtolower( $key . ' ' . $label );
		if ( function_exists( 'mb_strtolower' ) ) {
			$words = mb_strtolower( $key . ' ' . $label );
		}
		$words = str_replace( array( '-', '_' ), ' ', $words );
		if ( preg_match( '/(*UCP)\b(full ?name|your name|jméno a příjmení|celé jméno|vaše jméno|tvoje jméno)\b/u', $words ) || preg_match( '/^\s*(name|jméno)\s*\*?\s*$/iu', $label ) || in_array( trim( strtolower( $key ) ), array( 'name', 'your-name', 'jmeno' ), true ) ) {
			return self::KIND_FULL_NAME;
		}
		if ( preg_match( '/(*UCP)\b(last ?name|surname|family name|příjmení|prijmeni)\b/u', $words ) ) {
			return self::KIND_LAST_NAME;
		}
		if ( preg_match( '/(*UCP)\b(first ?name|given name|křestní|krestni|jméno|jmeno)\b/u', $words ) ) {
			return self::KIND_FIRST_NAME;
		}
		return self::KIND_OTHER;
	}

	/** A checkbox's submitted value: ticked when it has any value other than an "off" one. */
	public static function is_ticked( $value ) {
		if ( is_array( $value ) ) {
			foreach ( $value as $item ) {
				if ( self::is_ticked( $item ) ) {
					return true;
				}
			}
			return false;
		}
		$value = strtolower( trim( (string) $value ) );
		return '' !== $value && ! in_array( $value, array( '0', 'no', 'false', 'off' ), true );
	}

	/** @return array|null The form's first field of that kind. */
	public static function find_field( array $form, $kind ) {
		foreach ( $form['fields'] as $field ) {
			if ( $kind === $field['kind'] ) {
				return $field;
			}
		}
		return null;
	}

	/** @return array[] The form's consent checkboxes. */
	public static function consent_fields( array $form ) {
		return array_values(
			array_filter(
				$form['fields'],
				static function ( $field ) {
					return Form_Connections::KIND_CONSENT === $field['kind'];
				}
			)
		);
	}

	private static function consent_field( array $form, $key ) {
		foreach ( self::consent_fields( $form ) as $field ) {
			if ( (string) $key === (string) $field['key'] ) {
				return $field;
			}
		}
		return null;
	}

	private static function text( array $values, $key ) {
		if ( ! isset( $values[ $key ] ) ) {
			return '';
		}
		$value = $values[ $key ];
		if ( is_array( $value ) ) {
			$value = implode( ' ', array_filter( array_map( 'strval', $value ) ) );
		}
		return trim( sanitize_text_field( (string) $value ) );
	}

	private static function limit( $value ) {
		if ( null === $value ) {
			return null;
		}
		return function_exists( 'mb_substr' ) ? mb_substr( $value, 0, 200 ) : substr( $value, 0, 200 );
	}

	private static function site_host() {
		$host = function_exists( 'home_url' ) ? wp_parse_url( home_url(), PHP_URL_HOST ) : '';
		return $host ? (string) $host : 'this website';
	}
}