<?php
/**
 * Saving the generated article as a draft.
 *
 * Nothing here ever publishes. The post status is always "draft" so that a
 * person reads the article before the public does.
 *
 * @package ACS_Article_Generator
 */

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

/**
 * Turns a generated article into a WordPress draft.
 */
class ACSAGEN_Draft {

	/**
	 * Create the draft.
	 *
	 * @param array $article Decoded article data.
	 * @param array $options {
	 *     Optional.
	 *
	 *     @type string $post_type  "post" or "page". Default "post".
	 *     @type bool   $skip_terms Skip categories and tags. Default false.
	 * }
	 * @return array|WP_Error Draft details on success.
	 */
	public static function create( $article, $options = array() ) {
		$post_type  = ( isset( $options['post_type'] ) && 'page' === $options['post_type'] ) ? 'page' : 'post';
		$skip_terms = ! empty( $options['skip_terms'] ) || 'page' === $post_type;

		// wp_insert_post() does not check capabilities itself, so the cap that
		// belongs to this post type is checked here. A page needs edit_pages,
		// which an author does not have.
		$type_object = get_post_type_object( $post_type );

		if ( ! $type_object || ! current_user_can( $type_object->cap->edit_posts ) ) {
			return new WP_Error(
				'acsagen_forbidden',
				'page' === $post_type
					? __( 'You are not allowed to create pages on this site.', 'acs-article-generator' )
					: __( 'You are not allowed to create posts on this site.', 'acs-article-generator' )
			);
		}

		$title       = sanitize_text_field( (string) $article['title'] );
		$description = self::clean_description( (string) $article['meta_description'] );
		$slug        = sanitize_title( (string) $article['slug'] );
		$content     = self::clean_content( (string) $article['content_html'] );

		if ( '' === $title ) {
			return new WP_Error(
				'acsagen_empty_title',
				__( 'The reply did not contain a usable title. Please try again.', 'acs-article-generator' )
			);
		}

		$postarr = array(
			'post_title'   => $title,
			'post_content' => $content,
			'post_excerpt' => $description,
			'post_name'    => $slug,
			'post_status'  => 'draft',
			'post_type'    => $post_type,
			'post_author'  => get_current_user_id(),
		);

		if ( ! $skip_terms && ACSAGEN_Settings::get( 'draft_category', 1 ) ) {
			$categories = self::resolve_terms(
				isset( $article['categories'] ) ? (array) $article['categories'] : array(),
				'category'
			);
			if ( ! empty( $categories ) ) {
				$postarr['post_category'] = $categories;
			}
		}

		/**
		 * Filters the draft just before it is inserted.
		 *
		 * @param array $postarr Arguments for wp_insert_post().
		 * @param array $article The decoded article data.
		 */
		$postarr = apply_filters( 'acsagen_draft_postarr', $postarr, $article );

		// Keep the status out of anyone else's hands. A draft is a promise the
		// plugin makes to the site owner, not a default.
		$postarr['post_status'] = 'draft';

		$post_id = wp_insert_post( $postarr, true );

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

		if ( ! $skip_terms && ACSAGEN_Settings::get( 'draft_category', 1 ) ) {
			$tags = self::clean_term_names( isset( $article['tags'] ) ? (array) $article['tags'] : array() );
			if ( ! empty( $tags ) ) {
				wp_set_post_terms( $post_id, $tags, 'post_tag', false );
			}
		}

		if ( ACSAGEN_Settings::get( 'sync_seo_meta', 1 ) && '' !== $description ) {
			self::sync_seo_meta( $post_id, $title, $description );
		}

		return array(
			'post_id'     => (int) $post_id,
			'title'       => (string) get_the_title( $post_id ),
			'slug'        => (string) get_post_field( 'post_name', $post_id ),
			'description' => $description,
			'edit_url'    => (string) get_edit_post_link( $post_id, 'raw' ),
		);
	}

	/**
	 * Hand the SEO title and description to whichever SEO plugin is active.
	 *
	 * The description is also kept in the post excerpt, which is where
	 * WordPress itself looks when no SEO plugin is installed.
	 *
	 * @param int    $post_id     Draft id.
	 * @param string $title       SEO title.
	 * @param string $description Meta description.
	 */
	private static function sync_seo_meta( $post_id, $title, $description ) {
		// ACS SEO Plus.
		if ( class_exists( 'ACSSEO_Meta' ) ) {
			update_post_meta( $post_id, '_acsseo_title', $title );
			update_post_meta( $post_id, '_acsseo_description', $description );
		}

		// Yoast SEO.
		if ( defined( 'WPSEO_VERSION' ) ) {
			update_post_meta( $post_id, '_yoast_wpseo_title', $title );
			update_post_meta( $post_id, '_yoast_wpseo_metadesc', $description );
		}
	}

	/**
	 * Trim a meta description to a sensible length.
	 *
	 * @param string $text Raw description.
	 * @return string
	 */
	private static function clean_description( $text ) {
		$text = sanitize_text_field( wp_strip_all_tags( $text ) );
		return mb_substr( $text, 0, 200 );
	}

	/**
	 * Strip anything from the article body that has no business in a post.
	 *
	 * The body is written by a model, so it is treated as untrusted input and
	 * run through the same filter WordPress applies to post content from a
	 * contributor, which keeps block comments but removes scripts, styles,
	 * iframes, event handlers and javascript URLs.
	 *
	 * @param string $html Raw article body.
	 * @return string
	 */
	private static function clean_content( $html ) {
		$allowed = wp_kses_allowed_html( 'post' );

		// Block editor markup lives in HTML comments, which wp_kses keeps.
		$clean = wp_kses( $html, $allowed );

		return trim( $clean );
	}

	/**
	 * Turn a list of term names into term ids, creating any that are missing.
	 *
	 * @param array  $names    Term names.
	 * @param string $taxonomy Taxonomy name.
	 * @return array Term ids.
	 */
	private static function resolve_terms( $names, $taxonomy ) {
		$ids = array();

		foreach ( self::clean_term_names( $names ) as $name ) {
			$term = get_term_by( 'name', $name, $taxonomy );

			if ( $term && ! is_wp_error( $term ) ) {
				$ids[] = (int) $term->term_id;
				continue;
			}

			if ( ! current_user_can( 'manage_categories' ) ) {
				continue;
			}

			$created = wp_insert_term( $name, $taxonomy );

			if ( ! is_wp_error( $created ) && isset( $created['term_id'] ) ) {
				$ids[] = (int) $created['term_id'];
			}
		}

		return $ids;
	}

	/**
	 * Clean a list of term names.
	 *
	 * @param array $names Raw names.
	 * @return array
	 */
	private static function clean_term_names( $names ) {
		$clean = array();

		foreach ( $names as $name ) {
			if ( ! is_string( $name ) ) {
				continue;
			}

			$name = sanitize_text_field( $name );

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

			$clean[] = mb_substr( $name, 0, 60 );

			if ( count( $clean ) >= 10 ) {
				break;
			}
		}

		return array_values( array_unique( $clean ) );
	}
}