<?php
/**
 * ConvertKit Pre-publish Action class.
 *
 * @package ConvertKit
 * @author ConvertKit
 */

/**
 * ConvertKit Pre-publish Action definition for Gutenberg and Shortcode.
 *
 * @package ConvertKit
 * @author  ConvertKit
 */
class ConvertKit_Pre_Publish_Action {

	/**
	 * Holds the Post Meta Key prefix that stores the ConvertKit pre-publish action setting on a per-Post basis.
	 *
	 * @var     string
	 *
	 * @since   2.4.0
	 */
	const POST_META_KEY_PREFIX = '_convertkit_action_';

	/**
	 * Holds the Post Meta Key that stores whether to run a given ConvertKit pre-publish action on a per-Post basis.
	 *
	 * @var     string
	 *
	 * @since   2.4.0
	 */
	private $meta_key = '';

	/**
	 * Constructor
	 *
	 * @since   2.4.0
	 */
	public function __construct() {

		// Define the meta key.
		$this->meta_key = self::POST_META_KEY_PREFIX . $this->get_name();

		// Register this as a pre-publish action in the ConvertKit Plugin.
		add_filter( 'convertkit_get_pre_publish_actions', array( $this, 'register' ) );

		// Register meta key for Gutenberg.
		add_action( 'init', array( $this, 'register_meta_key' ) );

		// Perform pre-publish action.
		add_action( 'transition_post_status', array( $this, 'run' ), 10, 3 );

		// Save whether to run the pre-publish action when the Post is saved.
		add_action( 'save_post', array( $this, 'save_post_meta' ) );

	}

	/**
	 * Registers this pre-publish action with the ConvertKit Plugin.
	 *
	 * @since   2.4.0
	 *
	 * @param   array $pre_publish_actions    Pre-publish actions to register.
	 * @return  array                         Pre-publish actions to register.
	 */
	public function register( $pre_publish_actions ) {

		$pre_publish_actions[ $this->get_name() ] = array(
			'name'        => $this->get_name(),
			'label'       => $this->get_label(),
			'description' => $this->get_description(),
		);

		return $pre_publish_actions;

	}

	/**
	 * Registers the action's meta key in WordPress.
	 * This is required for Gutenberg to save the '_convertkit_action_{$name}'
	 * meta key/value pair when a Post is saved.
	 *
	 * @since   2.4.0
	 */
	public function register_meta_key() {

		// Register action as a meta key.
		register_post_meta(
			'post',
			$this->meta_key,
			array(
				'show_in_rest'  => true,
				'single'        => true,
				'type'          => 'boolean',
				'auth_callback' => '__return_true',
			)
		);

	}

	/**
	 * Performs the pre-publish action, if the Post has been transitioned to published.
	 *
	 * @since   2.4.0
	 *
	 * @param   string  $new_status     New Status.
	 * @param   string  $old_status     Old Status.
	 * @param   WP_Post $post           Post.
	 */
	public function run( $new_status, $old_status, $post ) {

		// Remove actions registered by this Plugin.
		// This ensures that when Page Builders call trigger actions via AJAX, we don't run this multiple times.
		remove_action( 'wp_insert_post', array( $this, 'classic_editor_post_published' ), 999 );
		remove_action( 'rest_after_insert_' . $post->post_type, array( $this, 'rest_api_post_published' ), 10 );

		// Ignore if the Post is not transitioning to published.
		if ( $new_status !== 'publish' ) {
			return;
		}

		// Ignore if the statuses match i.e. it's already a published Post that is being updated.
		if ( $new_status === $old_status ) {
			return;
		}

		// REST API and Gutenberg / Block Editor.
		if ( $this->is_rest_api_request() ) {
			add_action( 'rest_after_insert_' . $post->post_type, array( $this, 'rest_api_post_publish' ), 10 );
			return;
		}

		// Classic Editor.
		// transition_post_status hooks are always called before save_post hooks.  Therefore, if a Post
		// is created and immediately published (it's not saved as a draft first), we need to
		// manually call the save_post_meta() function now, before checking whether the action is enabled.
		// Otherwise, is_enabled() will return false because save_post_meta() has not yet been triggered.
		$this->save_post_meta( $post->ID );

		// Check the action was enabled on this Post by the user.
		if ( ! $this->is_enabled( $post->ID ) ) {
			return;
		}

		/**
		 * Run this pre-publish action, as the WordPress Post has just transitioned to publish
		 * from another state.
		 *
		 * @since   2.4.0
		 *
		 * @param   WP_Post     $post   Post.
		 */
		do_action( 'convertkit_pre_publish_action_run_' . $this->get_name(), $post );

	}

	/**
	 * Called when a Post is created or updated via the REST API, including Gutenberg.
	 *
	 * @since   2.4.0
	 *
	 * @param   WP_Post $post     Post.
	 */
	public function rest_api_post_publish( $post ) {

		// Check the action was enabled on this Post by the user.
		if ( ! $this->is_enabled( $post->ID ) ) {
			return;
		}

		/**
		 * Run this pre-publish action, as the WordPress Post has just transitioned to publish
		 * from another state.
		 *
		 * @since   2.4.0
		 *
		 * @param   WP_Post     $post   Post.
		 */
		do_action( 'convertkit_pre_publish_action_run_' . $this->get_name(), $post );

	}

	/**
	 * Saves a meta key/value pair against the Post in the Classic Editor, based on whether the user has permitted
	 * that the pre-publish action should run when the Post is published.
	 *
	 * @since  2.4.0
	 *
	 * @param   int $post_id    Post ID.
	 */
	public function save_post_meta( $post_id ) {

		// Bail if this is an autosave.
		if ( wp_is_post_autosave( $post_id ) ) {
			return;
		}

		// Bail if this is a post revision.
		if ( wp_is_post_revision( $post_id ) ) {
			return;
		}

		// Bail if no nonce field exists.
		if ( ! isset( $_POST['wp-convertkit-pre-publish-actions-nonce'] ) ) {
			return;
		}

		// Bail if the nonce verification fails.
		if ( ! wp_verify_nonce( sanitize_key( wp_unslash( $_POST['wp-convertkit-pre-publish-actions-nonce'] ) ), 'wp-convertkit-pre-publish-actions' ) ) {
			return;
		}

		// Bail if the current user cannot edit this Post.
		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			return;
		}

		// Delete meta key if this action's checkbox has not been checked.
		if ( ! array_key_exists( $this->meta_key, $_POST ) ) {
			return delete_post_meta( $post_id, $this->meta_key );
		}

		// Save setting.
		update_post_meta( $post_id, $this->meta_key, true );

	}

	/**
	 * Deletes the action's meta key and value from the given Post.
	 *
	 * @since   2.4.0
	 *
	 * @param   int $post_id    Post ID.
	 */
	public function delete_post_meta( $post_id ) {

		delete_post_meta( $post_id, $this->meta_key );

	}

	/**
	 * Returns this action's programmatic name, excluding the convertkit- prefix.
	 *
	 * @since   2.4.0
	 *
	 * @return  string
	 */
	public function get_name() {

		/**
		 * This will register as:
		 * - a Classic Editor pre-publish action, displayed as a checkbox on a draft Post.
		 * - a Gutenberg pre-publish action, with the name convertkit-action-{$name}.
		 */
		return '';

	}

	/**
	 * Returns this action's label.
	 *
	 * @since   2.4.0
	 *
	 * @return  string
	 */
	public function get_label() {

		return '';

	}

	/**
	 * Returns this action's description.
	 *
	 * @since   2.4.0
	 *
	 * @return  string
	 */
	public function get_description() {

		return '';

	}

	/**
	 * Returns whether this action has been enabled by the user to be run
	 * when the Post is published.
	 *
	 * @since   2.4.0
	 *
	 * @param   int $post_id    Post ID.
	 * @return  bool
	 */
	public function is_enabled( $post_id ) {

		return (bool) get_post_meta( $post_id, $this->meta_key, true );

	}

	/**
	 * Helper function to determine if the request is a REST API request.
	 *
	 * @since   2.4.0
	 *
	 * @return  bool    Is REST API Request
	 */
	public function is_rest_api_request() {

		if ( ! defined( 'REST_REQUEST' ) ) {
			return false;
		}

		if ( ! REST_REQUEST ) {
			return false;
		}

		return true;

	}

}