<?php
/**
 * Shared embed logic for the Pepvote block and shortcode.
 *
 * @package Pepvote
 */

defined( 'ABSPATH' ) || exit;

/** Default iframe height in pixels. Matches the Pepvote dashboard embed scripts. */
const PEPVOTE_DEFAULT_HEIGHT = 560;

/** Smallest iframe height in pixels. A shorter frame hides most page content. */
const PEPVOTE_MIN_HEIGHT = 200;

/** Largest fixed iframe height in pixels. Auto height is not limited by this value. */
const PEPVOTE_MAX_HEIGHT = 4000;

/**
 * Returns the Pepvote site that embeds load from, without a trailing slash.
 *
 * Define PEPVOTE_BASE_URL in wp-config.php or use the `pepvote_base_url`
 * filter to point embeds at another Pepvote environment.
 *
 * @return string
 */
function pepvote_get_base_url() {
	$base_url = defined( 'PEPVOTE_BASE_URL' ) ? (string) PEPVOTE_BASE_URL : 'https://pepvote.com';

	/**
	 * Filters the Pepvote site that embeds load from.
	 *
	 * @param string $base_url Pepvote site URL, for example https://pepvote.com.
	 */
	$base_url = (string) apply_filters( 'pepvote_base_url', $base_url );

	return untrailingslashit( esc_url_raw( $base_url ) );
}

/**
 * Returns the public Pepvote pages that can be embedded.
 *
 * The list matches the Embed Scripts sheet in the Pepvote dashboard.
 *
 * @return array<string, array{label: string, path: string, title: string}>
 */
function pepvote_get_embed_pages() {
	return array(
		'voting'                 => array(
			'label' => __( 'Main voting page', 'pepvote' ),
			'path'  => '/voting',
			'title' => __( 'Pepvote voting page', 'pepvote' ),
		),
		'candidate-registration' => array(
			'label' => __( 'Candidate registration', 'pepvote' ),
			'path'  => '/candidate/register',
			'title' => __( 'Pepvote candidate registration', 'pepvote' ),
		),
		'voter-registration'     => array(
			'label' => __( 'Voter registration (elections only)', 'pepvote' ),
			'path'  => '/voter/register',
			'title' => __( 'Pepvote voter registration', 'pepvote' ),
		),
		'ballot'                 => array(
			'label' => __( 'Ballot preview', 'pepvote' ),
			'path'  => '/vote/ballot',
			'title' => __( 'Pepvote ballot preview', 'pepvote' ),
		),
		'cast'                   => array(
			'label' => __( 'Cast votes', 'pepvote' ),
			'path'  => '/vote/cast',
			'title' => __( 'Pepvote cast votes', 'pepvote' ),
		),
		'confirm'                => array(
			'label' => __( 'Confirm votes', 'pepvote' ),
			'path'  => '/vote/confirm',
			'title' => __( 'Pepvote confirm votes', 'pepvote' ),
		),
		'result'                 => array(
			'label' => __( 'Results', 'pepvote' ),
			'path'  => '/vote/result',
			'title' => __( 'Pepvote results', 'pepvote' ),
		),
	);
}

/**
 * Turns a voting event code or a pasted Pepvote link into a clean code.
 *
 * Accepts values such as "ENWPH8799", " enwph8799 ", or
 * "https://pepvote.com/voting?votingEventCode=ENWPH8799".
 *
 * @param mixed $value Raw code or link.
 * @return string The code, or an empty string when the value is not usable.
 */
function pepvote_sanitize_event_code( $value ) {
	if ( ! is_scalar( $value ) ) {
		return '';
	}

	$value = trim( (string) $value );

	if ( false !== strpos( $value, 'votingEventCode=' ) ) {
		$query = wp_parse_url( $value, PHP_URL_QUERY );
		$args  = array();

		wp_parse_str( is_string( $query ) ? $query : '', $args );
		$value = isset( $args['votingEventCode'] ) && is_string( $args['votingEventCode'] ) ? $args['votingEventCode'] : '';
	}

	$code   = strtoupper( (string) preg_replace( '/[^A-Za-z0-9]/', '', $value ) );
	$length = strlen( $code );

	// Generated codes have 9 characters. The range leaves room for custom codes.
	return ( $length >= 4 && $length <= 32 ) ? $code : '';
}

/**
 * Returns a known page key, or the main voting page for unknown values.
 *
 * @param mixed $page Raw page key.
 * @return string
 */
function pepvote_sanitize_page( $page ) {
	$page  = is_string( $page ) ? sanitize_key( $page ) : '';
	$pages = pepvote_get_embed_pages();

	return isset( $pages[ $page ] ) ? $page : 'voting';
}

/**
 * Clamps a height value to the allowed range.
 *
 * @param mixed $height Raw height.
 * @return int
 */
function pepvote_sanitize_height( $height ) {
	$height = absint( $height );

	if ( 0 === $height ) {
		return PEPVOTE_DEFAULT_HEIGHT;
	}

	return min( PEPVOTE_MAX_HEIGHT, max( PEPVOTE_MIN_HEIGHT, $height ) );
}

/**
 * Builds the public Pepvote URL for a voting event page.
 *
 * @param string $code Sanitized voting event code.
 * @param string $page Sanitized page key.
 * @return string
 */
function pepvote_get_embed_url( $code, $page ) {
	$pages = pepvote_get_embed_pages();
	$page  = pepvote_sanitize_page( $page );

	return add_query_arg(
		array( 'votingEventCode' => rawurlencode( $code ) ),
		pepvote_get_base_url() . $pages[ $page ]['path']
	);
}

/**
 * Registers the small front-end script that resizes embeds to fit their content.
 */
function pepvote_register_scripts() {
	wp_register_script(
		'pepvote-embed',
		plugins_url( 'assets/js/embed.js', PEPVOTE_PLUGIN_FILE ),
		array(),
		PEPVOTE_VERSION,
		array(
			'in_footer' => true,
			'strategy'  => 'defer',
		)
	);
}
add_action( 'init', 'pepvote_register_scripts' );

/**
 * Renders the iframe embed.
 *
 * @param array  $args {
 *     Embed options.
 *
 *     @type string    $code        Voting event code or Pepvote link.
 *     @type string    $page        Page key from pepvote_get_embed_pages().
 *     @type int       $height      Iframe height in pixels. Used as the starting height with auto height.
 *     @type string    $title       Accessible iframe title. Defaults to the page title.
 *     @type bool      $auto_height Whether the iframe grows and shrinks to fit the Pepvote page.
 * }
 * @param string $wrapper_attributes Optional HTML attributes for the wrapper, already escaped.
 * @return string
 */
function pepvote_render_embed( $args, $wrapper_attributes = '' ) {
	$args = wp_parse_args(
		$args,
		array(
			'code'        => '',
			'page'        => 'voting',
			'height'      => PEPVOTE_DEFAULT_HEIGHT,
			'title'       => '',
			'auto_height' => true,
		)
	);

	$code = pepvote_sanitize_event_code( $args['code'] );

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

		return sprintf(
			'<p class="pepvote-embed-notice">%s</p>',
			esc_html__( 'Pepvote: add a valid voting event code to show this embed. Only editors can see this message.', 'pepvote' )
		);
	}

	$pages       = pepvote_get_embed_pages();
	$page        = pepvote_sanitize_page( $args['page'] );
	$height      = pepvote_sanitize_height( $args['height'] );
	$title       = trim( sanitize_text_field( (string) $args['title'] ) );
	$title       = '' !== $title ? $title : $pages[ $page ]['title'];
	$auto_height = filter_var( $args['auto_height'], FILTER_VALIDATE_BOOLEAN );

	if ( $auto_height ) {
		wp_enqueue_script( 'pepvote-embed' );
	}

	if ( '' === $wrapper_attributes ) {
		$wrapper_attributes = 'class="pepvote-embed"';
	}

	return sprintf(
		'<div %1$s><iframe src="%2$s" title="%3$s" width="100%%" height="%4$d" style="border: 0; display: block; width: 100%%;" loading="lazy" allow="clipboard-write; payment"%5$s></iframe></div>',
		$wrapper_attributes,
		esc_url( pepvote_get_embed_url( $code, $page ) ),
		esc_attr( $title ),
		$height,
		$auto_height ? ' data-pepvote-auto-height' : ''
	);
}