<?php
/**
 * The workspace's LaunchList forms and projects.
 *
 * @package LaunchList
 */

namespace LaunchList;

defined( 'ABSPATH' ) || exit;

/**
 * `GET /wordpress/forms`, cleaned and cached for ten minutes. Holds no secret, so the block editor
 * may read it (through {@see Rest}).
 */
class Forms {

	/** Transient holding the cleaned answer. */
	const TRANSIENT = 'launchlist_forms';

	/** Seconds the list is cached. */
	const TTL = 600;

	/** A form ID: `frm_` and letters and digits. */
	const FORM_ID = '/^frm_[A-Za-z0-9]{6,32}$/D';

	/**
	 * The forms and projects, from the cache or LaunchList.
	 *
	 * @param bool $refresh Ask LaunchList even when the cache is fresh.
	 * @return array{forms: array, projects: array}|null Null when LaunchList could not be asked.
	 */
	public static function get( $refresh = false ) {
		if ( ! $refresh ) {
			$cached = self::cached();

			if ( null !== $cached ) {
				return $cached;
			}
		}

		if ( ! Connection::is_active() ) {
			return null;
		}

		$result = Client::signed( 'GET', '/wordpress/forms' );

		if ( ! $result->ok() ) {
			return null;
		}

		$list = self::clean( $result->body );
		set_transient( self::TRANSIENT, $list, self::TTL );

		return $list;
	}

	/**
	 * The cached list, without asking LaunchList.
	 *
	 * @return array{forms: array, projects: array}|null
	 */
	public static function cached() {
		$cached = get_transient( self::TRANSIENT );

		return is_array( $cached ) && isset( $cached['forms'], $cached['projects'] ) ? $cached : null;
	}

	/**
	 * Drop the cache.
	 *
	 * @return void
	 */
	public static function forget() {
		delete_transient( self::TRANSIENT );
	}

	/**
	 * One form from a list.
	 *
	 * @param array|null $list The list.
	 * @param string     $id   Form ID.
	 * @return array|null
	 */
	public static function find( $list, $id ) {
		if ( ! is_array( $list ) || empty( $list['forms'] ) ) {
			return null;
		}

		foreach ( $list['forms'] as $form ) {
			if ( $form['id'] === $id ) {
				return $form;
			}
		}

		return null;
	}

	/**
	 * The field LaunchList identifies a signup by: the one flagged `identity`, else the one keyed
	 * `email`, else `email` of type `email`.
	 *
	 * @param array|null $form A form from the list.
	 * @return array{key: string, type: string}
	 */
	public static function identity( $form ) {
		$fields = is_array( $form ) && isset( $form['fields'] ) ? $form['fields'] : array();

		foreach ( $fields as $field ) {
			if ( ! empty( $field['identity'] ) ) {
				return array(
					'key'  => $field['key'],
					'type' => $field['type'],
				);
			}
		}

		foreach ( $fields as $field ) {
			if ( 'email' === strtolower( $field['key'] ) ) {
				return array(
					'key'  => $field['key'],
					'type' => $field['type'],
				);
			}
		}

		return array(
			'key'  => 'email',
			'type' => 'email',
		);
	}

	/**
	 * Keep only the parts of the answer this plugin uses, each checked.
	 *
	 * @param array $body The answer.
	 * @return array{forms: array, projects: array}
	 */
	public static function clean( array $body ) {
		$list = array(
			'forms'    => array(),
			'projects' => array(),
		);

		$forms = isset( $body['forms'] ) && is_array( $body['forms'] ) ? $body['forms'] : array();

		foreach ( $forms as $form ) {
			if ( ! is_array( $form ) || ! isset( $form['id'] ) || ! is_string( $form['id'] ) || ! preg_match( self::FORM_ID, $form['id'] ) ) {
				continue;
			}

			$project = isset( $form['project'] ) && is_array( $form['project'] ) ? $form['project'] : array();
			$fields  = array();

			foreach ( ( isset( $form['fields'] ) && is_array( $form['fields'] ) ? $form['fields'] : array() ) as $field ) {
				if ( ! is_array( $field ) || ! isset( $field['key'] ) || ! is_string( $field['key'] ) || '' === trim( $field['key'] ) ) {
					continue;
				}

				$key = Connection::truncate( trim( $field['key'] ), 100 );

				$fields[] = array(
					'key'      => $key,
					'label'    => self::text( isset( $field['label'] ) ? $field['label'] : '', $key ),
					'type'     => self::slug( isset( $field['type'] ) ? $field['type'] : '' ),
					'required' => ! empty( $field['required'] ),
					'identity' => ! empty( $field['identity'] ),
				);
			}

			$list['forms'][] = array(
				'id'      => $form['id'],
				'name'    => self::text( isset( $form['name'] ) ? $form['name'] : '', $form['id'] ),
				'project' => array(
					'name' => self::text( isset( $project['name'] ) ? $project['name'] : '', '' ),
					'slug' => self::project_slug( isset( $project['slug'] ) ? $project['slug'] : '' ),
				),
				'fields'  => $fields,
			);
		}

		$projects = isset( $body['projects'] ) && is_array( $body['projects'] ) ? $body['projects'] : array();

		foreach ( $projects as $project ) {
			if ( ! is_array( $project ) ) {
				continue;
			}

			$slug = self::project_slug( isset( $project['slug'] ) ? $project['slug'] : '' );

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

			$widgets = array();

			foreach ( ( isset( $project['widgets'] ) && is_array( $project['widgets'] ) ? $project['widgets'] : array() ) as $widget ) {
				if ( ! is_array( $widget ) || ! isset( $widget['id'] ) || ! is_string( $widget['id'] ) || ! Embed::valid_widget( $widget['id'] ) ) {
					continue;
				}

				$widgets[] = array(
					'id'   => $widget['id'],
					'kind' => self::slug( isset( $widget['kind'] ) ? $widget['kind'] : '' ),
					'name' => self::text( isset( $widget['name'] ) ? $widget['name'] : '', $widget['id'] ),
				);
			}

			$list['projects'][] = array(
				'name'    => self::text( isset( $project['name'] ) ? $project['name'] : '', $slug ),
				'slug'    => $slug,
				'widgets' => $widgets,
			);
		}

		return $list;
	}

	/**
	 * A plain display string, or a fallback when empty.
	 *
	 * @param mixed  $value    The value.
	 * @param string $fallback Used when the value is empty.
	 * @return string
	 */
	private static function text( $value, $fallback ) {
		$value = is_string( $value ) ? trim( sanitize_text_field( $value ) ) : '';

		return '' === $value ? $fallback : Connection::truncate( $value, 200 );
	}

	/**
	 * A lowercase type or kind.
	 *
	 * @param mixed $value The value.
	 * @return string
	 */
	private static function slug( $value ) {
		return is_string( $value ) ? substr( (string) preg_replace( '/[^a-z0-9_\-]/', '', strtolower( $value ) ), 0, 32 ) : '';
	}

	/**
	 * A project slug, or `""` when it is not one.
	 *
	 * @param mixed $value The value.
	 * @return string
	 */
	private static function project_slug( $value ) {
		return is_string( $value ) && Embed::valid_slug( $value ) ? $value : '';
	}
}