<?php
/**
 * Scribd Shortcode
 *
 * [scribd id=DOCUMENT_ID key=DOCUMENT_KEY mode=MODE]
 * DOCUMENT_ID is an integer (also used as an object_id)
 * DOCUMENT_KEY is an alphanumeric hash ('-' character as well)
 * MODE can be 'list', 'book', 'slide', 'slideshow', or 'tile'
 *
 * [scribd id=39027960 key=key-3kaiwcjqhtipf25m8tw mode=list]
 *
 * @package Jetpack
 */

/**
 * Register Scribd shortcode.
 *
 * @param array $atts Shortcode attributes.
 */
function scribd_shortcode_handler( $atts ) {
	$atts = shortcode_atts(
		array(
			'id'   => 0,
			'key'  => 0,
			'mode' => '',
		),
		$atts,
		'scribd'
	);

	$modes = array( 'list', 'book', 'slide', 'slideshow', 'tile' );

	$atts['id'] = (int) $atts['id'];
	if ( preg_match( '/^[A-Za-z0-9-]+$/', $atts['key'], $m ) ) {
		$atts['key'] = $m[0];

		if ( ! in_array( $atts['mode'], $modes, true ) ) {
			$atts['mode'] = '';
		}

		return scribd_shortcode_markup( $atts );
	} else {
		return '';
	}
}

/**
 * Display the shortcode.
 *
 * @param array $atts Shortcode attributes.
 */
function scribd_shortcode_markup( $atts ) {
	$markup = <<<EOD
<iframe class="scribd_iframe_embed" src="//www.scribd.com/embeds/$atts[id]/content?start_page=1&view_mode=$atts[mode]&access_key=$atts[key]" data-auto-height="true" scrolling="no" id="scribd_$atts[id]" width="100%" height="500" frameborder="0"></iframe>
<div style="font-size:10px;text-align:center;width:100%"><a href="https://www.scribd.com/doc/$atts[id]" target="_blank">View this document on Scribd</a></div>
EOD;

	return $markup;
}
add_shortcode( 'scribd', 'scribd_shortcode_handler' );

/**
 * Scribd supports HTTPS, so use that endpoint to get HTTPS-compatible embeds.
 *
 * @param array $providers Array of oEmbed providers.
 */
function scribd_https_oembed( $providers ) {
	if ( isset( $providers['#https?://(www\.)?scribd\.com/doc/.*#i'] ) ) {
		$providers['#https?://(www\.)?scribd\.com/doc/.*#i'][0] = 'https://www.scribd.com/services/oembed';
	}

	return $providers;
}
add_filter( 'oembed_providers', 'scribd_https_oembed' );