<?php
/**
 * LaunchList forms, popups, widgets and updates on the site's pages.
 *
 * @package LaunchList
 */

namespace LaunchList;

defined( 'ABSPATH' ) || exit;

/**
 * The loader script, the `[launchlist]` shortcode and the `launchlist/embed` block, which share one
 * renderer. Embeds are public and keyed by public IDs, so none of this needs a connection; the
 * connection only decides whether the loader runs on every page.
 */
class Embed {

	/** The loader's script handle. */
	const HANDLE = 'launchlist-embed';

	/** The option holding the plugin's settings. */
	const SETTINGS = 'launchlist_settings';

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

	/** A widget ID. */
	const WIDGET_ID = '/^wgt_[A-Za-z0-9]{6,32}$/D';

	/** A widget kind (`counter`, `leaderboard`, …). */
	const WIDGET_KEYWORD = '/^[a-z][a-z0-9-]{1,31}$/D';

	/** A project's public slug. */
	const SLUG = '/^[A-Za-z0-9][A-Za-z0-9-]{0,62}$/D';

	/** What an embed shows. */
	const KINDS = array( 'form', 'popup', 'widget', 'updates' );

	/** Popup variants. */
	const VARIANTS = array( 'modal', 'slideover' );

	/** Characters kept of a button label. */
	const MAX_LABEL = 80;

	/**
	 * Register the loader, the shortcode and the block (on `init`).
	 *
	 * @return void
	 */
	public static function init() {
		self::register_script();
		add_shortcode( 'launchlist', array( __CLASS__, 'shortcode' ) );

		if ( function_exists( 'register_block_type' ) ) {
			register_block_type( LAUNCHLIST_DIR . 'blocks/embed' );
		}
	}

	/**
	 * Register `{origin}/v1/embed.js`, async, in the head.
	 *
	 * @return bool Whether it is registered.
	 */
	public static function register_script() {
		$origin = Connection::origin();

		if ( '' === $origin ) {
			return false;
		}

		// No version: the loader is versioned by its path and served by LaunchList.
		// phpcs:disable WordPress.WP.EnqueuedResourceParameters.MissingVersion
		$registered = wp_register_script(
			self::HANDLE,
			$origin . '/v1/embed.js',
			array(),
			null,
			array(
				'strategy'  => 'async',
				'in_footer' => false,
			)
		);
		// phpcs:enable WordPress.WP.EnqueuedResourceParameters.MissingVersion

		return $registered;
	}

	/**
	 * Whether the founder wants the loader on every page (on unless turned off).
	 *
	 * @return bool
	 */
	public static function load_everywhere() {
		$settings = get_option( self::SETTINGS, array() );

		if ( ! is_array( $settings ) || ! array_key_exists( 'load_everywhere', $settings ) ) {
			return true;
		}

		return (bool) $settings['load_everywhere'];
	}

	/**
	 * `wp_enqueue_scripts`: the loader on every page while connected and the setting is on, so
	 * referral credit follows a visitor from page to page. Where the WP Consent API is active, only
	 * after the visitor gave `marketing` consent.
	 *
	 * @return void
	 */
	public static function enqueue_everywhere() {
		$load = Connection::is_active() && self::load_everywhere() && self::has_consent();

		/**
		 * Filters whether the LaunchList loader is added to every front-end page. Pages with a
		 * LaunchList block or shortcode load it either way.
		 *
		 * @since 1.0.0
		 *
		 * @param bool $load True while the site is connected, "Load LaunchList on every page" is on,
		 *                   and (where the WP Consent API is active) the visitor gave marketing consent.
		 */
		if ( apply_filters( 'launchlist_load_everywhere', $load ) ) {
			self::enqueue();
		}
	}

	/**
	 * Whether the visitor allowed marketing cookies: always, unless the WP Consent API is active and
	 * says otherwise.
	 *
	 * @return bool
	 */
	public static function has_consent() {
		if ( function_exists( 'wp_has_consent' ) ) {
			return (bool) wp_has_consent( 'marketing' );
		}

		return true;
	}

	/**
	 * Enqueue the loader.
	 *
	 * @return void
	 */
	public static function enqueue() {
		if ( wp_script_is( self::HANDLE, 'registered' ) || self::register_script() ) {
			wp_enqueue_script( self::HANDLE );
		}
	}

	/**
	 * `script_loader_tag`: mark the loader as this plugin's while the site is connected (and, where
	 * the WP Consent API is active, after marketing consent), which makes it keep the visitor's
	 * attribution in a first-party cookie for the site's own forms (PROTOCOL.md §4).
	 *
	 * @param string $tag    The script tag.
	 * @param string $handle The handle.
	 * @return string
	 */
	public static function script_tag( $tag, $handle ) {
		if ( self::HANDLE !== $handle || ! is_string( $tag ) || false !== strpos( $tag, 'data-launchlist-wordpress' ) || ! Connection::is_active() || ! self::has_consent() ) {
			return $tag;
		}

		return (string) preg_replace( '/<script\b/', '<script data-launchlist-wordpress', $tag, 1 );
	}

	/**
	 * `[launchlist]`.
	 *
	 * @param array|string $atts Attributes.
	 * @return string
	 */
	public static function shortcode( $atts ) {
		$atts = shortcode_atts(
			array(
				'form'    => '',
				'button'  => '',
				'popup'   => '',
				'label'   => '',
				'variant' => '',
				'widget'  => '',
				'project' => '',
				'updates' => '',
			),
			is_array( $atts ) ? $atts : array(),
			'launchlist'
		);

		return self::render( self::from_shortcode( $atts ) );
	}

	/**
	 * The `launchlist/embed` block's render.
	 *
	 * @param array $attributes Block attributes.
	 * @return string
	 */
	public static function render_block( $attributes ) {
		$html = self::render( self::from_block( is_array( $attributes ) ? $attributes : array() ) );

		if ( '' === $html || 0 === strpos( $html, '<!--' ) ) {
			return $html;
		}

		return '<div ' . get_block_wrapper_attributes( array( 'class' => 'launchlist-embed' ) ) . '>' . $html . '</div>';
	}

	/**
	 * Shortcode attributes as render arguments. The first of `form`, `popup`, `widget`, `updates`
	 * given decides what shows.
	 *
	 * @param array $atts Attributes.
	 * @return array{kind: string, form: string, button: string, label: string, variant: string, widget: string, project: string}
	 */
	public static function from_shortcode( array $atts ) {
		$get  = static function ( $key ) use ( $atts ) {
			return isset( $atts[ $key ] ) && is_scalar( $atts[ $key ] ) ? trim( (string) $atts[ $key ] ) : '';
		};
		$args = self::args();

		if ( '' !== $get( 'form' ) ) {
			$args['kind']   = 'form';
			$args['form']   = $get( 'form' );
			$args['button'] = $get( 'button' );
		} elseif ( '' !== $get( 'popup' ) ) {
			$args['kind']    = 'popup';
			$args['form']    = $get( 'popup' );
			$args['label']   = $get( 'label' );
			$args['variant'] = $get( 'variant' );
		} elseif ( '' !== $get( 'widget' ) ) {
			$args['kind']    = 'widget';
			$args['widget']  = $get( 'widget' );
			$args['project'] = $get( 'project' );
		} elseif ( '' !== $get( 'updates' ) ) {
			$args['kind']    = 'updates';
			$args['project'] = '' !== $get( 'project' ) ? $get( 'project' ) : $get( 'updates' );
		}

		return $args;
	}

	/**
	 * Block attributes as render arguments.
	 *
	 * @param array $attributes Block attributes.
	 * @return array{kind: string, form: string, button: string, label: string, variant: string, widget: string, project: string}
	 */
	public static function from_block( array $attributes ) {
		$get = static function ( $key ) use ( $attributes ) {
			return isset( $attributes[ $key ] ) && is_scalar( $attributes[ $key ] ) ? trim( (string) $attributes[ $key ] ) : '';
		};

		$args            = self::args();
		$args['kind']    = in_array( $get( 'kind' ), self::KINDS, true ) ? $get( 'kind' ) : 'form';
		$args['form']    = $get( 'form' );
		$args['button']  = $get( 'buttonLabel' );
		$args['label']   = $get( 'popupLabel' );
		$args['variant'] = $get( 'variant' );
		$args['widget']  = $get( 'widget' );
		$args['project'] = $get( 'project' );

		return $args;
	}

	/**
	 * The markup, with the loader enqueued; or, when the arguments are not valid, nothing (an HTML
	 * comment saying why for people who can edit the page).
	 *
	 * @param array $args Render arguments.
	 * @return string
	 */
	public static function render( array $args ) {
		$markup = self::markup( $args );

		if ( '' === $markup ) {
			if ( ! current_user_can( 'edit_posts' ) ) {
				return '';
			}

			return '<!-- ' . str_replace( '--', '-', esc_html( self::problem( $args ) ) ) . ' -->';
		}

		self::enqueue();

		return $markup;
	}

	/**
	 * The embed markup, every value checked against its pattern and escaped; `""` when invalid.
	 *
	 * @param array $args Render arguments.
	 * @return string
	 */
	public static function markup( array $args ) {
		$args = array_merge( self::args(), $args );

		switch ( $args['kind'] ) {
			case 'form':
				if ( ! self::valid_form_id( $args['form'] ) ) {
					return '';
				}

				$button = self::label( $args['button'] );

				return '<div class="launchlist-form" data-launchlist-form="' . esc_attr( $args['form'] ) . '"'
					. ( '' !== $button ? ' data-button="' . esc_attr( $button ) . '"' : '' )
					. '></div>';

			case 'popup':
				if ( ! self::valid_form_id( $args['form'] ) ) {
					return '';
				}

				$label   = self::label( $args['label'] );
				$label   = '' !== $label ? $label : __( 'Join the waitlist', 'launchlist' );
				$variant = in_array( $args['variant'], self::VARIANTS, true ) ? $args['variant'] : 'modal';

				return '<button type="button" class="wp-element-button launchlist-popup-button" data-launchlist-popup="' . esc_attr( $args['form'] ) . '" data-variant="' . esc_attr( $variant ) . '">'
					. esc_html( $label )
					. '</button>';

			case 'widget':
				if ( ! self::valid_widget( $args['widget'] ) || ! self::valid_slug( $args['project'] ) ) {
					return '';
				}

				return '<div class="launchlist-widget" data-launchlist-widget="' . esc_attr( $args['widget'] ) . '" data-project="' . esc_attr( $args['project'] ) . '"></div>';

			case 'updates':
				if ( ! self::valid_slug( $args['project'] ) ) {
					return '';
				}

				// No "Powered by LaunchList" credit: WordPress.org lets a plugin show one on the public
				// site only when the site owner asked for it (guideline 10).
				return '<div class="launchlist-updates" data-launchlist-updates="' . esc_attr( $args['project'] ) . '" data-credit="false"></div>';
		}

		return '';
	}

	/**
	 * Whether a value is a form ID.
	 *
	 * @param mixed $value The value.
	 * @return bool
	 */
	public static function valid_form_id( $value ) {
		return is_string( $value ) && 1 === preg_match( self::FORM_ID, $value );
	}

	/**
	 * Whether a value is a widget ID or a widget kind.
	 *
	 * @param mixed $value The value.
	 * @return bool
	 */
	public static function valid_widget( $value ) {
		return is_string( $value ) && ( 1 === preg_match( self::WIDGET_ID, $value ) || 1 === preg_match( self::WIDGET_KEYWORD, $value ) );
	}

	/**
	 * Whether a value is a project slug.
	 *
	 * @param mixed $value The value.
	 * @return bool
	 */
	public static function valid_slug( $value ) {
		return is_string( $value ) && 1 === preg_match( self::SLUG, $value );
	}

	/**
	 * Empty render arguments.
	 *
	 * @return array{kind: string, form: string, button: string, label: string, variant: string, widget: string, project: string}
	 */
	private static function args() {
		return array(
			'kind'    => '',
			'form'    => '',
			'button'  => '',
			'label'   => '',
			'variant' => '',
			'widget'  => '',
			'project' => '',
		);
	}

	/**
	 * A button label: plain text, at most 80 characters.
	 *
	 * @param mixed $value The value.
	 * @return string
	 */
	private static function label( $value ) {
		return is_string( $value ) ? Connection::truncate( trim( sanitize_text_field( $value ) ), self::MAX_LABEL ) : '';
	}

	/**
	 * Why nothing renders, for people who can edit the page.
	 *
	 * @param array $args Render arguments.
	 * @return string
	 */
	private static function problem( array $args ) {
		switch ( isset( $args['kind'] ) ? $args['kind'] : '' ) {
			case 'form':
			case 'popup':
				/* translators: %s: the form ID prefix. */
				return sprintf( __( 'LaunchList: add a form ID that starts with %s to show this form. It is in LaunchList under Embed & API.', 'launchlist' ), 'frm_' );
			case 'widget':
				/* translators: %s: the data-project attribute. */
				return sprintf( __( 'LaunchList: add a widget and the %s value from a widget snippet in LaunchList to show this widget.', 'launchlist' ), 'data-project' );
			case 'updates':
				/* translators: %s: the data-project attribute. */
				return sprintf( __( 'LaunchList: add the %s value from a widget snippet in LaunchList to show your updates.', 'launchlist' ), 'data-project' );
		}

		return __( 'LaunchList: choose a form, a popup, a widget or updates to show.', 'launchlist' );
	}
}