<?php

/**
 * Configuration validator.
 *
 * @link https://contactform7.com/configuration-errors/
 */
class WPCF7_ConfigValidator {

	/**
	 * The plugin version in which important updates happened last time.
	 */
	const last_important_update = '5.6.1';

	const error = 100;
	const error_maybe_empty = 101;
	const error_invalid_mailbox_syntax = 102;
	const error_email_not_in_site_domain = 103;
	const error_html_in_message = 104;
	const error_multiple_controls_in_label = 105;
	const error_file_not_found = 106;
	const error_unavailable_names = 107;
	const error_invalid_mail_header = 108;
	const error_deprecated_settings = 109;
	const error_file_not_in_content_dir = 110;
	const error_unavailable_html_elements = 111;
	const error_attachments_overweight = 112;
	const error_dots_in_names = 113;
	const error_colons_in_names = 114;
	const error_upload_filesize_overlimit = 115;


	/**
	 * Returns a URL linking to the documentation page for the error type.
	 */
	public static function get_doc_link( $error_code = '' ) {
		$url = __( 'https://contactform7.com/configuration-errors/',
			'contact-form-7'
		);

		if ( '' !== $error_code ) {
			$error_code = strtr( $error_code, '_', '-' );

			$url = sprintf( '%s/%s', untrailingslashit( $url ), $error_code );
		}

		return esc_url( $url );
	}


	private $contact_form;
	private $errors = array();

	public function __construct( WPCF7_ContactForm $contact_form ) {
		$this->contact_form = $contact_form;
	}


	/**
	 * Returns the contact form object that is tied to this validator.
	 */
	public function contact_form() {
		return $this->contact_form;
	}


	/**
	 * Returns true if no error has been detected.
	 */
	public function is_valid() {
		return ! $this->count_errors();
	}


	/**
	 * Counts detected errors.
	 */
	public function count_errors( $args = '' ) {
		$args = wp_parse_args( $args, array(
			'section' => '',
			'code' => '',
		) );

		$count = 0;

		foreach ( $this->errors as $key => $errors ) {
			if ( preg_match( '/^mail_[0-9]+\.(.*)$/', $key, $matches ) ) {
				$key = sprintf( 'mail.%s', $matches[1] );
			}

			if ( $args['section']
			and $key != $args['section']
			and preg_replace( '/\..*$/', '', $key, 1 ) != $args['section'] ) {
				continue;
			}

			foreach ( $errors as $error ) {
				if ( empty( $error ) ) {
					continue;
				}

				if ( $args['code'] and $error['code'] != $args['code'] ) {
					continue;
				}

				$count += 1;
			}
		}

		return $count;
	}


	/**
	 * Collects messages for detected errors.
	 */
	public function collect_error_messages() {
		$error_messages = array();

		foreach ( $this->errors as $section => $errors ) {
			$error_messages[$section] = array();

			foreach ( $errors as $error ) {
				if ( empty( $error['args']['message'] ) ) {
					$message = $this->get_default_message( $error['code'] );
				} elseif ( empty( $error['args']['params'] ) ) {
					$message = $error['args']['message'];
				} else {
					$message = $this->build_message(
						$error['args']['message'],
						$error['args']['params'] );
				}

				$link = '';

				if ( ! empty( $error['args']['link'] ) ) {
					$link = $error['args']['link'];
				}

				$error_messages[$section][] = array(
					'message' => $message,
					'link' => esc_url( $link ),
				);
			}
		}

		return $error_messages;
	}


	/**
	 * Builds an error message by replacing placeholders.
	 */
	public function build_message( $message, $params = '' ) {
		$params = wp_parse_args( $params, array() );

		foreach ( $params as $key => $val ) {
			if ( ! preg_match( '/^[0-9A-Za-z_]+$/', $key ) ) { // invalid key
				continue;
			}

			$placeholder = '%' . $key . '%';

			if ( false !== stripos( $message, $placeholder ) ) {
				$message = str_ireplace( $placeholder, $val, $message );
			}
		}

		return $message;
	}


	/**
	 * Returns a default message that is used when the message for the error
	 * is not specified.
	 */
	public function get_default_message( $code ) {
		switch ( $code ) {
			case self::error_maybe_empty:
				return __( "There is a possible empty field.", 'contact-form-7' );
			case self::error_invalid_mailbox_syntax:
				return __( "Invalid mailbox syntax is used.", 'contact-form-7' );
			case self::error_email_not_in_site_domain:
				return __( "Sender email address does not belong to the site domain.", 'contact-form-7' );
			case self::error_html_in_message:
				return __( "HTML tags are used in a message.", 'contact-form-7' );
			case self::error_multiple_controls_in_label:
				return __( "Multiple form controls are in a single label element.", 'contact-form-7' );
			case self::error_invalid_mail_header:
				return __( "There are invalid mail header fields.", 'contact-form-7' );
			case self::error_deprecated_settings:
				return __( "Deprecated settings are used.", 'contact-form-7' );
			default:
				return '';
		}
	}


	/**
	 * Adds a validation error.
	 *
	 * @param string $section The section where the error detected.
	 * @param int $code The unique code of the error.
	 *            This must be one of the class constants.
	 * @param string|array $args Optional options for the error.
	 */
	public function add_error( $section, $code, $args = '' ) {
		$args = wp_parse_args( $args, array(
			'message' => '',
			'params' => array(),
		) );

		if ( ! isset( $this->errors[$section] ) ) {
			$this->errors[$section] = array();
		}

		$this->errors[$section][] = array( 'code' => $code, 'args' => $args );

		return true;
	}


	/**
	 * Removes an error.
	 */
	public function remove_error( $section, $code ) {
		if ( empty( $this->errors[$section] ) ) {
			return;
		}

		foreach ( (array) $this->errors[$section] as $key => $error ) {
			if ( isset( $error['code'] )
			and $error['code'] == $code ) {
				unset( $this->errors[$section][$key] );
			}
		}

		if ( empty( $this->errors[$section] ) ) {
			unset( $this->errors[$section] );
		}
	}


	/**
	 * The main validation runner.
	 *
	 * @return bool True if there is no error detected.
	 */
	public function validate() {
		$this->errors = array();

		$this->validate_form();
		$this->validate_mail( 'mail' );
		$this->validate_mail( 'mail_2' );
		$this->validate_messages();
		$this->validate_additional_settings();

		do_action( 'wpcf7_config_validator_validate', $this );

		return $this->is_valid();
	}


	/**
	 * Saves detected errors as a post meta data.
	 */
	public function save() {
		if ( $this->contact_form->initial() ) {
			return;
		}

		delete_post_meta( $this->contact_form->id(), '_config_errors' );

		if ( $this->errors ) {
			update_post_meta(
				$this->contact_form->id(), '_config_errors', $this->errors
			);
		}
	}


	/**
	 * Restore errors from the database.
	 */
	public function restore() {
		$config_errors = get_post_meta(
			$this->contact_form->id(), '_config_errors', true
		);

		foreach ( (array) $config_errors as $section => $errors ) {
			if ( empty( $errors ) ) {
				continue;
			}

			if ( ! is_array( $errors ) ) { // for back-compat
				$code = $errors;
				$this->add_error( $section, $code );
			} else {
				foreach ( (array) $errors as $error ) {
					if ( ! empty( $error['code'] ) ) {
						$code = $error['code'];
						$args = isset( $error['args'] ) ? $error['args'] : '';
						$this->add_error( $section, $code, $args );
					}
				}
			}
		}
	}


	/**
	 * Callback function for WPCF7_MailTaggedText. Replaces mail-tags with
	 * the most conservative inputs.
	 */
	public function replace_mail_tags_with_minimum_input( $matches ) {
		// allow [[foo]] syntax for escaping a tag
		if ( $matches[1] == '[' && $matches[4] == ']' ) {
			return substr( $matches[0], 1, -1 );
		}

		$tag = $matches[0];
		$tagname = $matches[2];
		$values = $matches[3];

		$mail_tag = new WPCF7_MailTag( $tag, $tagname, $values );
		$field_name = $mail_tag->field_name();

		$example_email = 'example@example.com';
		$example_text = 'example';
		$example_blank = '';

		$form_tags = $this->contact_form->scan_form_tags(
			array( 'name' => $field_name )
		);

		if ( $form_tags ) {
			$form_tag = new WPCF7_FormTag( $form_tags[0] );

			$is_required = ( $form_tag->is_required() || 'radio' == $form_tag->type );

			if ( ! $is_required ) {
				return $example_blank;
			}

			if ( wpcf7_form_tag_supports( $form_tag->type, 'selectable-values' ) ) {
				if ( $form_tag->pipes instanceof WPCF7_Pipes ) {
					if ( $mail_tag->get_option( 'do_not_heat' ) ) {
						$before_pipes = $form_tag->pipes->collect_befores();
						$last_item = array_pop( $before_pipes );
					} else {
						$after_pipes = $form_tag->pipes->collect_afters();
						$last_item = array_pop( $after_pipes );
					}
				} else {
					$last_item = array_pop( $form_tag->values );
				}

				if ( $last_item and wpcf7_is_mailbox_list( $last_item ) ) {
					return $example_email;
				} else {
					return $example_text;
				}
			}

			if ( 'email' == $form_tag->basetype ) {
				return $example_email;
			} else {
				return $example_text;
			}

		} else { // maybe special mail tag
			// for back-compat
			$field_name = preg_replace( '/^wpcf7\./', '_', $field_name );

			if ( '_site_admin_email' == $field_name ) {
				return get_bloginfo( 'admin_email', 'raw' );

			} elseif ( '_user_agent' == $field_name ) {
				return $example_text;

			} elseif ( '_user_email' == $field_name ) {
				return $this->contact_form->is_true( 'subscribers_only' )
					? $example_email
					: $example_blank;

			} elseif ( '_user_' == substr( $field_name, 0, 6 ) ) {
				return $this->contact_form->is_true( 'subscribers_only' )
					? $example_text
					: $example_blank;

			} elseif ( '_' == substr( $field_name, 0, 1 ) ) {
				return '_email' == substr( $field_name, -6 )
					? $example_email
					: $example_text;

			}
		}

		return $tag;
	}


	/**
	 * Runs error detection for the form section.
	 */
	public function validate_form() {
		$section = 'form.body';
		$form = $this->contact_form->prop( 'form' );
		$this->detect_multiple_controls_in_label( $section, $form );
		$this->detect_unavailable_names( $section, $form );
		$this->detect_unavailable_html_elements( $section, $form );
		$this->detect_dots_in_names( $section, $form );
		$this->detect_colons_in_names( $section, $form );
		$this->detect_upload_filesize_overlimit( $section, $form );
	}


	/**
	 * Detects errors of multiple form controls in a single label.
	 *
	 * @link https://contactform7.com/configuration-errors/multiple-controls-in-label/
	 */
	public function detect_multiple_controls_in_label( $section, $content ) {
		$pattern = '%<label(?:[ \t\n]+.*?)?>(.+?)</label>%s';

		if ( preg_match_all( $pattern, $content, $matches ) ) {
			$form_tags_manager = WPCF7_FormTagsManager::get_instance();

			foreach ( $matches[1] as $insidelabel ) {
				$tags = $form_tags_manager->scan( $insidelabel );
				$fields_count = 0;

				foreach ( $tags as $tag ) {
					$is_multiple_controls_container = wpcf7_form_tag_supports(
						$tag->type, 'multiple-controls-container'
					);

					$is_zero_controls_container = wpcf7_form_tag_supports(
						$tag->type, 'zero-controls-container'
					);

					if ( $is_multiple_controls_container ) {
						$fields_count += count( $tag->values );

						if ( $tag->has_option( 'free_text' ) ) {
							$fields_count += 1;
						}
					} elseif ( $is_zero_controls_container ) {
						$fields_count += 0;
					} elseif ( ! empty( $tag->name ) ) {
						$fields_count += 1;
					}

					if ( 1 < $fields_count ) {
						return $this->add_error( $section,
							self::error_multiple_controls_in_label, array(
								'link' => self::get_doc_link( 'multiple_controls_in_label' ),
							)
						);
					}
				}
			}
		}

		return false;
	}


	/**
	 * Detects errors of unavailable form-tag names.
	 *
	 * @link https://contactform7.com/configuration-errors/unavailable-names/
	 */
	public function detect_unavailable_names( $section, $content ) {
		$public_query_vars = array( 'm', 'p', 'posts', 'w', 'cat',
			'withcomments', 'withoutcomments', 's', 'search', 'exact', 'sentence',
			'calendar', 'page', 'paged', 'more', 'tb', 'pb', 'author', 'order',
			'orderby', 'year', 'monthnum', 'day', 'hour', 'minute', 'second',
			'name', 'category_name', 'tag', 'feed', 'author_name', 'static',
			'pagename', 'page_id', 'error', 'attachment', 'attachment_id',
			'subpost', 'subpost_id', 'preview', 'robots', 'taxonomy', 'term',
			'cpage', 'post_type', 'embed',
		);

		$form_tags_manager = WPCF7_FormTagsManager::get_instance();

		$ng_named_tags = $form_tags_manager->filter( $content, array(
			'name' => $public_query_vars,
		) );

		$ng_names = array();

		foreach ( $ng_named_tags as $tag ) {
			$ng_names[] = sprintf( '"%s"', $tag->name );
		}

		if ( $ng_names ) {
			$ng_names = array_unique( $ng_names );

			return $this->add_error( $section,
				self::error_unavailable_names,
				array(
					'message' =>
						/* translators: %names%: a list of form control names */
						__( "Unavailable names (%names%) are used for form controls.", 'contact-form-7' ),
					'params' => array( 'names' => implode( ', ', $ng_names ) ),
					'link' => self::get_doc_link( 'unavailable_names' ),
				)
			);
		}

		return false;
	}


	/**
	 * Detects errors of unavailable HTML elements.
	 *
	 * @link https://contactform7.com/configuration-errors/unavailable-html-elements/
	 */
	public function detect_unavailable_html_elements( $section, $content ) {
		$pattern = '%(?:<form[\s\t>]|</form>)%i';

		if ( preg_match( $pattern, $content ) ) {
			return $this->add_error( $section,
				self::error_unavailable_html_elements,
				array(
					'message' => __( "Unavailable HTML elements are used in the form template.", 'contact-form-7' ),
					'link' => self::get_doc_link( 'unavailable_html_elements' ),
				)
			);
		}

		return false;
	}


	/**
	 * Detects errors of dots in form-tag names.
	 *
	 * @link https://contactform7.com/configuration-errors/dots-in-names/
	 */
	public function detect_dots_in_names( $section, $content ) {
		$form_tags_manager = WPCF7_FormTagsManager::get_instance();

		$tags = $form_tags_manager->filter( $content, array(
			'feature' => 'name-attr',
		) );

		foreach ( $tags as $tag ) {
			if ( false !== strpos( $tag->raw_name, '.' ) ) {
				return $this->add_error( $section,
					self::error_dots_in_names,
					array(
						'message' => __( "Dots are used in form-tag names.", 'contact-form-7' ),
						'link' => self::get_doc_link( 'dots_in_names' ),
					)
				);
			}
		}

		return false;
	}


	/**
	 * Detects errors of colons in form-tag names.
	 *
	 * @link https://contactform7.com/configuration-errors/colons-in-names/
	 */
	public function detect_colons_in_names( $section, $content ) {
		$form_tags_manager = WPCF7_FormTagsManager::get_instance();

		$tags = $form_tags_manager->filter( $content, array(
			'feature' => 'name-attr',
		) );

		foreach ( $tags as $tag ) {
			if ( false !== strpos( $tag->raw_name, ':' ) ) {
				return $this->add_error( $section,
					self::error_colons_in_names,
					array(
						'message' => __( "Colons are used in form-tag names.", 'contact-form-7' ),
						'link' => self::get_doc_link( 'colons_in_names' ),
					)
				);
			}
		}

		return false;
	}


	/**
	 * Detects errors of uploadable file size overlimit.
	 *
	 * @link https://contactform7.com/configuration-errors/upload-filesize-overlimit
	 */
	public function detect_upload_filesize_overlimit( $section, $content ) {
		$upload_max_filesize = ini_get( 'upload_max_filesize' );

		if ( ! $upload_max_filesize ) {
			return false;
		}

		$upload_max_filesize = strtolower( $upload_max_filesize );
		$upload_max_filesize = trim( $upload_max_filesize );

		if ( ! preg_match( '/^(\d+)([kmg]?)$/', $upload_max_filesize, $matches ) ) {
			return false;
		}

		if ( 'k' === $matches[2] ) {
			$upload_max_filesize = (int) $matches[1] * KB_IN_BYTES;
		} elseif ( 'm' === $matches[2] ) {
			$upload_max_filesize = (int) $matches[1] * MB_IN_BYTES;
		} elseif ( 'g' === $matches[2] ) {
			$upload_max_filesize = (int) $matches[1] * GB_IN_BYTES;
		} else {
			$upload_max_filesize = (int) $matches[1];
		}

		$form_tags_manager = WPCF7_FormTagsManager::get_instance();

		$tags = $form_tags_manager->filter( $content, array(
			'basetype' => 'file',
		) );

		foreach ( $tags as $tag ) {
			if ( $upload_max_filesize < $tag->get_limit_option() ) {
				return $this->add_error( $section,
					self::error_upload_filesize_overlimit,
					array(
						'message' => __( "Uploadable file size exceeds PHP’s maximum acceptable size.", 'contact-form-7' ),
						'link' => self::get_doc_link( 'upload_filesize_overlimit' ),
					)
				);
			}
		}

		return false;
	}


	/**
	 * Runs error detection for the mail sections.
	 */
	public function validate_mail( $template = 'mail' ) {
		$components = (array) $this->contact_form->prop( $template );

		if ( ! $components ) {
			return;
		}

		if ( 'mail' !== $template and empty( $components['active'] ) ) {
			return;
		}

		$components = wp_parse_args( $components, array(
			'subject' => '',
			'sender' => '',
			'recipient' => '',
			'additional_headers' => '',
			'body' => '',
			'attachments' => '',
		) );

		$callback = array( $this, 'replace_mail_tags_with_minimum_input' );

		$subject = new WPCF7_MailTaggedText(
			$components['subject'],
			array( 'callback' => $callback )
		);

		$subject = $subject->replace_tags();
		$subject = wpcf7_strip_newline( $subject );

		$this->detect_maybe_empty( sprintf( '%s.subject', $template ), $subject );

		$sender = new WPCF7_MailTaggedText(
			$components['sender'],
			array( 'callback' => $callback )
		);

		$sender = $sender->replace_tags();
		$sender = wpcf7_strip_newline( $sender );

		$invalid_mailbox = $this->detect_invalid_mailbox_syntax(
			sprintf( '%s.sender', $template ),
			$sender
		);

		if ( ! $invalid_mailbox and ! wpcf7_is_email_in_site_domain( $sender ) ) {
			$this->add_error( sprintf( '%s.sender', $template ),
				self::error_email_not_in_site_domain, array(
					'link' => self::get_doc_link( 'email_not_in_site_domain' ),
				)
			);
		}

		$recipient = new WPCF7_MailTaggedText(
			$components['recipient'],
			array( 'callback' => $callback )
		);

		$recipient = $recipient->replace_tags();
		$recipient = wpcf7_strip_newline( $recipient );

		$this->detect_invalid_mailbox_syntax(
			sprintf( '%s.recipient', $template ),
			$recipient
		);

		$additional_headers = new WPCF7_MailTaggedText(
			$components['additional_headers'],
			array( 'callback' => $callback )
		);

		$additional_headers = $additional_headers->replace_tags();
		$additional_headers = explode( "\n", $additional_headers );
		$mailbox_header_types = array( 'reply-to', 'cc', 'bcc' );
		$invalid_mail_header_exists = false;

		foreach ( $additional_headers as $header ) {
			$header = trim( $header );

			if ( '' === $header ) {
				continue;
			}

			if ( ! preg_match( '/^([0-9A-Za-z-]+):(.*)$/', $header, $matches ) ) {
				$invalid_mail_header_exists = true;
			} else {
				$header_name = $matches[1];
				$header_value = trim( $matches[2] );

				if ( in_array( strtolower( $header_name ), $mailbox_header_types )
				and '' !== $header_value ) {
					$this->detect_invalid_mailbox_syntax(
						sprintf( '%s.additional_headers', $template ),
						$header_value,
						array(
							'message' =>
								__( "Invalid mailbox syntax is used in the %name% field.", 'contact-form-7' ),
							'params' => array( 'name' => $header_name )
						)
					);
				}
			}
		}

		if ( $invalid_mail_header_exists ) {
			$this->add_error( sprintf( '%s.additional_headers', $template ),
				self::error_invalid_mail_header, array(
					'link' => self::get_doc_link( 'invalid_mail_header' ),
				)
			);
		}

		$body = new WPCF7_MailTaggedText(
			$components['body'],
			array( 'callback' => $callback )
		);

		$body = $body->replace_tags();

		$this->detect_maybe_empty( sprintf( '%s.body', $template ), $body );

		if ( '' !== $components['attachments'] ) {
			$attachables = array();

			$tags = $this->contact_form->scan_form_tags(
				array( 'type' => array( 'file', 'file*' ) )
			);

			foreach ( $tags as $tag ) {
				$name = $tag->name;

				if ( false === strpos( $components['attachments'], "[{$name}]" ) ) {
					continue;
				}

				$limit = (int) $tag->get_limit_option();

				if ( empty( $attachables[$name] )
				or $attachables[$name] < $limit ) {
					$attachables[$name] = $limit;
				}
			}

			$total_size = array_sum( $attachables );

			$has_file_not_found = false;
			$has_file_not_in_content_dir = false;

			foreach ( explode( "\n", $components['attachments'] ) as $line ) {
				$line = trim( $line );

				if ( '' === $line or '[' == substr( $line, 0, 1 ) ) {
					continue;
				}

				$has_file_not_found = $this->detect_file_not_found(
					sprintf( '%s.attachments', $template ), $line
				);

				if ( ! $has_file_not_found and ! $has_file_not_in_content_dir ) {
					$has_file_not_in_content_dir = $this->detect_file_not_in_content_dir(
						sprintf( '%s.attachments', $template ), $line
					);
				}

				if ( ! $has_file_not_found ) {
					$path = path_join( WP_CONTENT_DIR, $line );
					$total_size += (int) @filesize( $path );
				}
			}

			$max = 25 * MB_IN_BYTES; // 25 MB

			if ( $max < $total_size ) {
				$this->add_error( sprintf( '%s.attachments', $template ),
					self::error_attachments_overweight,
					array(
						'message' => __( "The total size of attachment files is too large.", 'contact-form-7' ),
						'link' => self::get_doc_link( 'attachments_overweight' ),
					)
				);
			}
		}
	}


	/**
	 * Detects errors of invalid mailbox syntax.
	 *
	 * @link https://contactform7.com/configuration-errors/invalid-mailbox-syntax/
	 */
	public function detect_invalid_mailbox_syntax( $section, $content, $args = '' ) {
		$args = wp_parse_args( $args, array(
			'link' => self::get_doc_link( 'invalid_mailbox_syntax' ),
			'message' => '',
			'params' => array(),
		) );

		if ( ! wpcf7_is_mailbox_list( $content ) ) {
			return $this->add_error( $section,
				self::error_invalid_mailbox_syntax, $args
			);
		}

		return false;
	}


	/**
	 * Detects errors of empty message fields.
	 *
	 * @link https://contactform7.com/configuration-errors/maybe-empty/
	 */
	public function detect_maybe_empty( $section, $content ) {
		if ( '' === $content ) {
			return $this->add_error( $section,
				self::error_maybe_empty, array(
					'link' => self::get_doc_link( 'maybe_empty' ),
				)
			);
		}

		return false;
	}


	/**
	 * Detects errors of nonexistent attachment files.
	 *
	 * @link https://contactform7.com/configuration-errors/file-not-found/
	 */
	public function detect_file_not_found( $section, $content ) {
		$path = path_join( WP_CONTENT_DIR, $content );

		if ( ! is_readable( $path ) or ! is_file( $path ) ) {
			return $this->add_error( $section,
				self::error_file_not_found,
				array(
					'message' =>
						__( "Attachment file does not exist at %path%.", 'contact-form-7' ),
					'params' => array( 'path' => $content ),
					'link' => self::get_doc_link( 'file_not_found' ),
				)
			);
		}

		return false;
	}


	/**
	 * Detects errors of attachment files out of the content directory.
	 *
	 * @link https://contactform7.com/configuration-errors/file-not-in-content-dir/
	 */
	public function detect_file_not_in_content_dir( $section, $content ) {
		$path = path_join( WP_CONTENT_DIR, $content );

		if ( ! wpcf7_is_file_path_in_content_dir( $path ) ) {
			return $this->add_error( $section,
				self::error_file_not_in_content_dir,
				array(
					'message' =>
						__( "It is not allowed to use files outside the wp-content directory.", 'contact-form-7' ),
					'link' => self::get_doc_link( 'file_not_in_content_dir' ),
				)
			);
		}

		return false;
	}


	/**
	 * Runs error detection for the messages section.
	 */
	public function validate_messages() {
		$messages = (array) $this->contact_form->prop( 'messages' );

		if ( ! $messages ) {
			return;
		}

		if ( isset( $messages['captcha_not_match'] )
		and ! wpcf7_use_really_simple_captcha() ) {
			unset( $messages['captcha_not_match'] );
		}

		foreach ( $messages as $key => $message ) {
			$section = sprintf( 'messages.%s', $key );
			$this->detect_html_in_message( $section, $message );
		}
	}


	/**
	 * Detects errors of HTML uses in a message.
	 *
	 * @link https://contactform7.com/configuration-errors/html-in-message/
	 */
	public function detect_html_in_message( $section, $content ) {
		$stripped = wp_strip_all_tags( $content );

		if ( $stripped != $content ) {
			return $this->add_error( $section,
				self::error_html_in_message,
				array(
					'link' => self::get_doc_link( 'html_in_message' ),
				)
			);
		}

		return false;
	}


	/**
	 * Runs error detection for the additional settings section.
	 */
	public function validate_additional_settings() {
		$deprecated_settings_used =
			$this->contact_form->additional_setting( 'on_sent_ok' ) ||
			$this->contact_form->additional_setting( 'on_submit' );

		if ( $deprecated_settings_used ) {
			return $this->add_error( 'additional_settings.body',
				self::error_deprecated_settings,
				array(
					'link' => self::get_doc_link( 'deprecated_settings' ),
				)
			);
		}
	}

}
