<?php
/**
 * Settings → Asklet: the site key, which post types get the survey, and how it is displayed by
 * default. Each post can override the display (Asklet_Post_Display).
 *
 * @package Asklet
 */

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

/**
 * Stores everything in one option, `asklet_settings`.
 */
class Asklet_Settings {

	const OPTION = 'asklet_settings';
	const PAGE   = 'asklet';

	/** A site key is the website's UUID in Asklet. Used on save and as the field's HTML `pattern`. */
	const SITE_KEY_PATTERN = '[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}';

	/** The tab colour of the side panel until one is chosen (the widget-ideas recipes' teal). */
	const DEFAULT_TAB_COLOR = '#0f766e';

	/** Fixed height limits in px: below 200 the widget's header and buttons don't fit. */
	const MIN_HEIGHT     = 200;
	const MAX_HEIGHT     = 1200;
	const DEFAULT_HEIGHT = 480;

	/** Maximum width limits in px. 0 means the full width of the content column. */
	const MIN_WIDTH = 240;
	const MAX_WIDTH = 2000;

	/**
	 * Site-wide display choices. `after`/`before` put the widget inline in the post, `panel` is a
	 * tab on the right edge that slides a panel in, `slidein` is a card that appears when the
	 * reader reaches the end, and `manual` shows it only where the block or shortcode is placed.
	 *
	 * @return array<string, string> Value => label.
	 */
	public static function displays() {
		return array(
			'after'   => __( 'Inline, after the content', 'asklet' ),
			'before'  => __( 'Inline, before the content', 'asklet' ),
			'panel'   => __( 'Side panel: a Feedback tab on the right edge opens it', 'asklet' ),
			'slidein' => __( 'Slide-in: a card appears in the corner when the reader reaches the end', 'asklet' ),
			'manual'  => __( 'Only where I add the Asklet block or [asklet] shortcode', 'asklet' ),
		);
	}

	/**
	 * Hooks the settings page and the plugin-list link.
	 */
	public static function init() {
		add_action( 'admin_init', array( __CLASS__, 'register' ) );
		add_action( 'admin_menu', array( __CLASS__, 'add_page' ) );
		add_filter( 'plugin_action_links_' . plugin_basename( ASKLET_PLUGIN_FILE ), array( __CLASS__, 'action_links' ) );
		add_action( 'admin_notices', array( __CLASS__, 'missing_key_notice' ) );
	}

	/**
	 * The saved settings merged over the defaults.
	 *
	 * @return array{site_key: string, post_types: string[], display: string, title: string, tab_label: string, tab_color: string, height_mode: string, height: int, max_width: int, align: string}
	 */
	public static function get() {
		$saved    = get_option( self::OPTION, array() );
		$settings = wp_parse_args(
			is_array( $saved ) ? $saved : array(),
			array(
				'site_key'    => '',
				'post_types'  => array( 'post' ),
				'display'     => 'after',
				'title'       => '',
				'tab_label'   => '',
				'tab_color'   => self::DEFAULT_TAB_COLOR,
				'height_mode' => 'fit',
				'height'      => self::DEFAULT_HEIGHT,
				'max_width'   => 0,
				'align'       => 'center',
			)
		);

		// The option can be edited outside this page (wp-cli, a migration, another plugin): coerce
		// every value to its type so the front end never fails on a bad one.
		$settings['site_key']    = self::validate_site_key( is_string( $settings['site_key'] ) ? $settings['site_key'] : '' );
		$settings['post_types']  = is_array( $settings['post_types'] ) ? array_values( array_filter( $settings['post_types'], 'is_string' ) ) : array();
		$settings['display']     = is_string( $settings['display'] ) && array_key_exists( $settings['display'], self::display_values() ) ? $settings['display'] : 'after';
		$settings['title']       = is_string( $settings['title'] ) ? $settings['title'] : '';
		$settings['tab_label']   = is_string( $settings['tab_label'] ) ? $settings['tab_label'] : '';
		$tab_color               = is_string( $settings['tab_color'] ) ? sanitize_hex_color( $settings['tab_color'] ) : '';
		$settings['tab_color']   = $tab_color ? $tab_color : self::DEFAULT_TAB_COLOR;
		$settings['height_mode'] = 'fixed' === $settings['height_mode'] ? 'fixed' : 'fit';
		$settings['height']      = self::clamp_height( $settings['height'] );
		$settings['max_width']   = self::clamp_width( $settings['max_width'] );
		$settings['align']       = 'left' === $settings['align'] ? 'left' : 'center';

		return $settings;
	}

	/**
	 * The display values, without labels: get() runs on every request, before translations may
	 * be loaded, so it must not call __().
	 *
	 * @return array<string, true>
	 */
	private static function display_values() {
		return array_fill_keys( array( 'after', 'before', 'panel', 'slidein', 'manual' ), true );
	}

	/**
	 * A fixed height in px, within the limits. Anything that isn't a number gives the default.
	 *
	 * @param mixed $value Raw value.
	 * @return int
	 */
	public static function clamp_height( $value ) {
		if ( ! is_numeric( $value ) ) {
			return self::DEFAULT_HEIGHT;
		}
		return (int) min( max( (int) round( (float) $value ), self::MIN_HEIGHT ), self::MAX_HEIGHT );
	}

	/**
	 * A maximum width in px, within the limits, or 0 (the full column) for empty, zero or
	 * anything that isn't a number.
	 *
	 * @param mixed $value Raw value.
	 * @return int
	 */
	public static function clamp_width( $value ) {
		if ( ! is_numeric( $value ) || (float) $value <= 0 ) {
			return 0;
		}
		return (int) min( max( (int) round( (float) $value ), self::MIN_WIDTH ), self::MAX_WIDTH );
	}

	/**
	 * Validates a site key: a bare UUID, surrounding spaces allowed. Anything else (a link, the
	 * snippet, a partial key) is rejected.
	 *
	 * @param string $input Raw field value.
	 * @return string The lower-case key, or '' when the input is not a UUID.
	 */
	public static function validate_site_key( $input ) {
		$input = trim( (string) $input );
		return preg_match( '/^' . self::SITE_KEY_PATTERN . '$/D', $input ) ? strtolower( $input ) : '';
	}

	/**
	 * The site key in what was pasted into the field: the key itself, or the survey link or
	 * whole snippet from Asklet's Copy website snippet, whose /embed/s/<key> carries it. Any
	 * other text, or a UUID outside that path, gives ''.
	 *
	 * @param string $input Raw field value.
	 * @return string The lower-case key, or ''.
	 */
	public static function extract_site_key( $input ) {
		$input = trim( (string) $input );
		$key   = self::validate_site_key( $input );
		if ( '' === $key && preg_match( '#/embed/s/(' . self::SITE_KEY_PATTERN . ')(?![0-9a-fA-F-])#', $input, $match ) ) {
			$key = strtolower( $match[1] );
		}
		return $key;
	}

	/**
	 * Registers the option and its fields.
	 */
	public static function register() {
		register_setting(
			self::PAGE,
			self::OPTION,
			array(
				'type'              => 'array',
				'sanitize_callback' => array( __CLASS__, 'sanitize' ),
				'default'           => array(),
			)
		);

		add_settings_section( 'asklet_main', '', '__return_false', self::PAGE );

		add_settings_field( 'asklet_site_key', __( 'Site key', 'asklet' ), array( __CLASS__, 'field_site_key' ), self::PAGE, 'asklet_main', array( 'label_for' => 'asklet_site_key' ) );
		add_settings_field( 'asklet_post_types', __( 'Show on', 'asklet' ), array( __CLASS__, 'field_post_types' ), self::PAGE, 'asklet_main' );
		add_settings_field( 'asklet_display', __( 'Display', 'asklet' ), array( __CLASS__, 'field_display' ), self::PAGE, 'asklet_main' );
		add_settings_field( 'asklet_title', __( 'Accessible title', 'asklet' ), array( __CLASS__, 'field_title' ), self::PAGE, 'asklet_main', array( 'label_for' => 'asklet_title' ) );

		add_settings_section( 'asklet_size', __( 'Size', 'asklet' ), array( __CLASS__, 'section_size' ), self::PAGE );

		add_settings_field( 'asklet_height', __( 'Height', 'asklet' ), array( __CLASS__, 'field_height' ), self::PAGE, 'asklet_size' );
		add_settings_field( 'asklet_max_width', __( 'Maximum width', 'asklet' ), array( __CLASS__, 'field_max_width' ), self::PAGE, 'asklet_size', array( 'label_for' => 'asklet_max_width' ) );
		add_settings_field( 'asklet_align', __( 'Alignment', 'asklet' ), array( __CLASS__, 'field_align' ), self::PAGE, 'asklet_size', array( 'label_for' => 'asklet_align' ) );

		add_settings_section( 'asklet_panel', __( 'Side panel', 'asklet' ), array( __CLASS__, 'section_panel' ), self::PAGE );

		add_settings_field( 'asklet_tab_label', __( 'Tab label', 'asklet' ), array( __CLASS__, 'field_tab_label' ), self::PAGE, 'asklet_panel', array( 'label_for' => 'asklet_tab_label' ) );
		add_settings_field( 'asklet_tab_color', __( 'Tab colour', 'asklet' ), array( __CLASS__, 'field_tab_color' ), self::PAGE, 'asklet_panel', array( 'label_for' => 'asklet_tab_color' ) );
	}

	/**
	 * Sanitizes the submitted settings.
	 *
	 * @param mixed $input Submitted values.
	 * @return array
	 */
	public static function sanitize( $input ) {
		// options.php has already unslashed $input, so it isn't unslashed again here (that would
		// strip backslashes from the title and tab label).
		$input = is_array( $input ) ? $input : array();

		// An empty field clears the key (the widget stops showing). An invalid one keeps the saved key.
		$raw_key  = isset( $input['site_key'] ) && is_string( $input['site_key'] ) ? trim( $input['site_key'] ) : '';
		$site_key = self::extract_site_key( $raw_key );
		if ( '' !== $raw_key && '' === $site_key ) {
			add_settings_error( self::OPTION, 'asklet_site_key', __( 'The site key wasn\'t saved. In Asklet, open your website, click Copy website snippet and copy the Site key, a code like 1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d.', 'asklet' ) );
			$site_key = self::get()['site_key'];
		}

		$allowed_types = array_keys( self::public_post_types() );
		$post_types    = isset( $input['post_types'] ) && is_array( $input['post_types'] )
			? array_values( array_intersect( array_map( 'sanitize_key', array_filter( $input['post_types'], 'is_string' ) ), $allowed_types ) )
			: array();

		$display   = isset( $input['display'] ) && is_string( $input['display'] ) ? sanitize_key( $input['display'] ) : 'after';
		$tab_color = isset( $input['tab_color'] ) && is_string( $input['tab_color'] ) ? sanitize_hex_color( $input['tab_color'] ) : '';

		return array(
			'site_key'    => $site_key,
			'post_types'  => $post_types,
			'display'     => array_key_exists( $display, self::display_values() ) ? $display : 'after',
			'title'       => isset( $input['title'] ) && is_string( $input['title'] ) ? sanitize_text_field( $input['title'] ) : '',
			'tab_label'   => isset( $input['tab_label'] ) && is_string( $input['tab_label'] ) ? sanitize_text_field( $input['tab_label'] ) : '',
			'tab_color'   => $tab_color ? $tab_color : self::DEFAULT_TAB_COLOR,
			'height_mode' => isset( $input['height_mode'] ) && 'fixed' === $input['height_mode'] ? 'fixed' : 'fit',
			'height'      => self::clamp_height( isset( $input['height'] ) ? $input['height'] : null ),
			'max_width'   => self::clamp_width( isset( $input['max_width'] ) ? $input['max_width'] : null ),
			'align'       => isset( $input['align'] ) && 'left' === $input['align'] ? 'left' : 'center',
		);
	}

	/**
	 * Public post types except attachments, keyed by name.
	 *
	 * @return array<string, WP_Post_Type>
	 */
	public static function public_post_types() {
		$types = get_post_types( array( 'public' => true ), 'objects' );
		unset( $types['attachment'] );
		return $types;
	}

	/**
	 * Adds Settings → Asklet.
	 */
	public static function add_page() {
		add_options_page( __( 'Asklet', 'asklet' ), __( 'Asklet', 'asklet' ), 'manage_options', self::PAGE, array( __CLASS__, 'render_page' ) );
	}

	/**
	 * Adds a Settings link on the Plugins screen.
	 *
	 * @param string[] $links Existing links.
	 * @return string[]
	 */
	public static function action_links( $links ) {
		$url = admin_url( 'options-general.php?page=' . self::PAGE );
		array_unshift( $links, '<a href="' . esc_url( $url ) . '">' . esc_html__( 'Settings', 'asklet' ) . '</a>' );
		return $links;
	}

	/**
	 * Reminds admins on the Plugins screen that nothing shows until a site key is set.
	 */
	public static function missing_key_notice() {
		$screen = get_current_screen();
		if ( ! $screen || 'plugins' !== $screen->id || ! current_user_can( 'manage_options' ) || '' !== self::get()['site_key'] ) {
			return;
		}
		printf(
			'<div class="notice notice-info"><p>%s <a href="%s">%s</a></p></div>',
			esc_html__( 'Asklet is active but has no site key yet, so no survey is shown.', 'asklet' ),
			esc_url( admin_url( 'options-general.php?page=' . self::PAGE ) ),
			esc_html__( 'Add your site key', 'asklet' )
		);
	}

	/**
	 * Renders the settings page.
	 */
	public static function render_page() {
		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}
		$host = wp_parse_url( home_url(), PHP_URL_HOST );
		?>
		<div class="wrap">
			<h1><?php esc_html_e( 'Asklet', 'asklet' ); ?></h1>
			<p>
				<?php esc_html_e( 'Asklet shows a short survey on your posts and picks the survey for each post from its address. You manage questions, paths and results in Asklet, not here.', 'asklet' ); ?>
			</p>
			<div class="notice notice-info inline">
				<p>
					<?php
					printf(
						/* translators: %s: this site's domain, e.g. example.com */
						esc_html__( 'In Asklet, make sure %s is one of your website\'s domains. The survey only loads on the domains listed there.', 'asklet' ),
						'<code>' . esc_html( (string) $host ) . '</code>'
					);
					?>
				</p>
			</div>
			<form action="options.php" method="post">
				<?php
				settings_fields( self::PAGE );
				do_settings_sections( self::PAGE );
				submit_button();
				?>
			</form>
		</div>
		<?php
	}

	/**
	 * Site key field.
	 */
	public static function field_site_key() {
		$settings = self::get();
		// No pattern attribute: the survey link or the whole snippet may be pasted too (sanitize()
		// keeps only the key).
		printf(
			'<input type="text" id="asklet_site_key" name="%s[site_key]" value="%s" class="regular-text code" autocomplete="off" spellcheck="false" placeholder="1a2b3c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d" aria-describedby="asklet_site_key_help" />',
			esc_attr( self::OPTION ),
			esc_attr( $settings['site_key'] )
		);
		printf(
			'<p class="description" id="asklet_site_key_help">%s</p>',
			esc_html__( 'In Asklet, open your website, click Copy website snippet and copy the Site key. Pasting the survey link or the whole snippet works too: only the key is saved.', 'asklet' )
		);
	}

	/**
	 * Post type checkboxes.
	 */
	public static function field_post_types() {
		$settings = self::get();
		echo '<fieldset>';
		foreach ( self::public_post_types() as $name => $type ) {
			printf(
				'<label><input type="checkbox" name="%s[post_types][]" value="%s" %s /> %s</label><br />',
				esc_attr( self::OPTION ),
				esc_attr( $name ),
				checked( in_array( $name, $settings['post_types'], true ), true, false ),
				esc_html( $type->labels->name )
			);
		}
		echo '</fieldset>';
		echo '<p class="description">' . esc_html__( 'Where the survey is added automatically. Any post or page can still choose its own display in its Asklet box, and the Asklet block and [asklet] shortcode work everywhere.', 'asklet' ) . '</p>';
	}

	/**
	 * Display radios.
	 */
	public static function field_display() {
		$settings = self::get();
		echo '<fieldset>';
		foreach ( self::displays() as $value => $label ) {
			printf(
				'<label><input type="radio" name="%s[display]" value="%s" %s /> %s</label><br />',
				esc_attr( self::OPTION ),
				esc_attr( $value ),
				checked( $settings['display'], $value, false ),
				esc_html( $label )
			);
		}
		echo '</fieldset>';
		echo '<p class="description">' . esc_html__( 'The default for every post. Change it for one post in the Asklet box in its sidebar.', 'asklet' ) . '</p>';
	}

	/**
	 * Iframe title field.
	 */
	public static function field_title() {
		$settings = self::get();
		printf(
			'<input type="text" id="asklet_title" name="%s[title]" value="%s" class="regular-text" placeholder="%s" />',
			esc_attr( self::OPTION ),
			esc_attr( $settings['title'] ),
			esc_attr__( 'Article feedback', 'asklet' )
		);
		echo '<p class="description">' . esc_html__( 'Read out by screen readers. Leave it empty to use “Article feedback”.', 'asklet' ) . '</p>';
	}

	/**
	 * Intro of the Size section.
	 */
	public static function section_size() {
		echo '<p>' . esc_html__( 'For the survey in your posts: inline, the Asklet block and the [asklet] shortcode. A block or shortcode can set its own size. The side panel and slide-in always fit the survey.', 'asklet' ) . '</p>';
	}

	/**
	 * Height: fit to the survey, or a fixed height in px.
	 */
	public static function field_height() {
		$settings = self::get();
		echo '<fieldset><legend class="screen-reader-text">' . esc_html__( 'Height', 'asklet' ) . '</legend>';
		printf(
			'<label><input type="radio" name="%1$s[height_mode]" value="fit" %2$s /> %3$s</label><br />',
			esc_attr( self::OPTION ),
			checked( $settings['height_mode'], 'fit', false ),
			esc_html__( 'Fit to the survey (recommended)', 'asklet' )
		);
		printf(
			'<label><input type="radio" name="%1$s[height_mode]" value="fixed" %2$s /> %3$s</label> <input type="number" id="asklet_height" name="%1$s[height]" value="%4$d" min="%5$d" max="%6$d" step="10" class="small-text" aria-label="%7$s" /> px',
			esc_attr( self::OPTION ),
			checked( $settings['height_mode'], 'fixed', false ),
			esc_html__( 'Fixed height:', 'asklet' ),
			(int) $settings['height'],
			(int) self::MIN_HEIGHT,
			(int) self::MAX_HEIGHT,
			esc_attr__( 'Fixed height in pixels', 'asklet' )
		);
		echo '</fieldset>';
		echo '<p class="description">' . esc_html(
			sprintf(
				/* translators: 1: minimum height, 2: maximum height, in pixels */
				__( 'Fit grows and shrinks with each question, so there is never empty space. A fixed height (%1$d–%2$d px) keeps the box the same size, but can leave space under short questions or scroll inside on long ones.', 'asklet' ),
				self::MIN_HEIGHT,
				self::MAX_HEIGHT
			)
		) . '</p>';
	}

	/**
	 * Maximum width in px; empty for the full column.
	 */
	public static function field_max_width() {
		$settings = self::get();
		printf(
			'<input type="number" id="asklet_max_width" name="%1$s[max_width]" value="%2$s" min="%3$d" max="%4$d" step="10" class="small-text" placeholder="%5$s" /> px',
			esc_attr( self::OPTION ),
			$settings['max_width'] ? (int) $settings['max_width'] : '',
			(int) self::MIN_WIDTH,
			(int) self::MAX_WIDTH,
			esc_attr__( 'Full', 'asklet' )
		);
		echo '<p class="description">' . esc_html__( 'Leave empty to use the full width of the content column. Useful on wide or full-width themes, for example 600.', 'asklet' ) . '</p>';
	}

	/**
	 * Alignment when the survey is narrower than the column.
	 */
	public static function field_align() {
		$settings = self::get();
		printf( '<select id="asklet_align" name="%s[align]">', esc_attr( self::OPTION ) );
		printf( '<option value="center" %s>%s</option>', selected( $settings['align'], 'center', false ), esc_html__( 'Centre', 'asklet' ) );
		printf( '<option value="left" %s>%s</option>', selected( $settings['align'], 'left', false ), esc_html__( 'Left', 'asklet' ) );
		echo '</select>';
		echo '<p class="description">' . esc_html__( 'Used when a maximum width makes the survey narrower than the column.', 'asklet' ) . '</p>';
	}

	/**
	 * Intro of the Side panel section.
	 */
	public static function section_panel() {
		echo '<p>' . esc_html__( 'Used when a post shows the survey as a side panel.', 'asklet' ) . '</p>';
	}

	/**
	 * Side panel tab label field.
	 */
	public static function field_tab_label() {
		$settings = self::get();
		printf(
			'<input type="text" id="asklet_tab_label" name="%s[tab_label]" value="%s" class="regular-text" placeholder="%s" />',
			esc_attr( self::OPTION ),
			esc_attr( $settings['tab_label'] ),
			esc_attr__( 'Feedback', 'asklet' )
		);
		echo '<p class="description">' . esc_html__( 'The text on the tab and at the top of the panel. Leave it empty to use “Feedback”.', 'asklet' ) . '</p>';
	}

	/**
	 * Side panel tab colour field.
	 */
	public static function field_tab_color() {
		$settings = self::get();
		printf(
			'<input type="color" id="asklet_tab_color" name="%s[tab_color]" value="%s" />',
			esc_attr( self::OPTION ),
			esc_attr( $settings['tab_color'] )
		);
		echo '<p class="description">' . esc_html__( 'The tab\'s background. Its text is white, so pick a colour dark enough to read it.', 'asklet' ) . '</p>';
	}
}