<?php

namespace WPZaraz\Embeds;

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

use WPZaraz\Support\Options;

/**
 * Instagram posts rendered by the Zaraz Instagram tool.
 *
 * Outputs <instagram-post> placeholders, which Zaraz replaces with the post on Cloudflare, so the
 * visitor's browser loads no Instagram script and Instagram sets no cookies. Works through the
 * [zbridge_instagram url="..."] shortcode and by pasting an Instagram post or reel link on its
 * own line (or into an Embed block).
 */
class InstagramEmbeds {

    /**
     * Instagram post, reel and IGTV links.
     */
    public const URL_PATTERN = '#^https?://(?:www\.)?instagram\.com/(p|reel|tv)/([A-Za-z0-9_-]+)/?(?:[?\#].*)?$#i';

    /**
     * Registers the shortcode and the pasted-link handler when Instagram embeds are enabled.
     */
    public function register(): void {
        if (!Options::get('instagram_embeds', false)) {
            return;
        }

        add_shortcode('zbridge_instagram', [$this, 'shortcode']);
        wp_embed_register_handler('zbridge_instagram', self::URL_PATTERN, [$this, 'embedHandler']);
    }

    /**
     * [zbridge_instagram url="https://www.instagram.com/p/..." captions="true"]
     *
     * @param array|string $atts
     * @return string
     */
    public function shortcode($atts): string {
        $rawAtts = (array) $atts;
        $atts = shortcode_atts(['url' => '', 'captions' => 'false'], $rawAtts, 'zbridge_instagram');
        $url = (string) $atts['url'];

        // If 'url' was corrupted (e.g. nested quotes from pasting an HTML <a> tag),
        // recover the Instagram URL from any attribute fragment.
        if (self::canonicalUrl($url) === '') {
            foreach ($rawAtts as $val) {
                if (is_string($val) && preg_match('#https?://(?:www\.)?instagram\.com/(?:p|reel|tv)/[A-Za-z0-9_-]+#i', $val, $match)) {
                    $url = $match[0];
                    break;
                }
            }
        }

        return $this->render($url, filter_var($atts['captions'], FILTER_VALIDATE_BOOLEAN));
    }

    /**
     * Embed handler for pasted Instagram links.
     *
     * @param array  $matches
     * @param array  $attr
     * @param string $url
     * @param array  $rawattr
     * @return string
     */
    public function embedHandler($matches, $attr, $url, $rawattr): string {
        return $this->render((string) $url, false);
    }

    /**
     * The Zaraz placeholder, with a plain link inside for when Zaraz does not render the post.
     *
     * @param string $url
     * @param bool   $captions
     * @return string
     */
    public function render(string $url, bool $captions): string {
        $postUrl = self::canonicalUrl($url);
        if ($postUrl === '') {
            return '';
        }

        return sprintf(
            '<instagram-post post-url="%1$s" captions="%2$s"><a href="%1$s" target="_blank" rel="noopener">%3$s</a></instagram-post>',
            esc_url($postUrl),
            $captions ? 'true' : 'false',
            esc_html__('View this post on Instagram', 'zbridge')
        );
    }

    /**
     * https://www.instagram.com/{p|reel|tv}/{id}/ — the Zaraz component appends "embed/" to it.
     *
     * @param string $url
     * @return string Empty when the URL is not an Instagram post.
     */
    public static function canonicalUrl(string $url): string {
        $url = trim(html_entity_decode(wp_strip_all_tags($url), ENT_QUOTES, 'UTF-8'));
        if (!preg_match(self::URL_PATTERN, $url, $m)) {
            if (preg_match('#https?://(?:www\.)?instagram\.com/(p|reel|tv)/([A-Za-z0-9_-]+)#i', $url, $m)) {
                return 'https://www.instagram.com/' . strtolower($m[1]) . '/' . $m[2] . '/';
            }
            return '';
        }
        return 'https://www.instagram.com/' . strtolower($m[1]) . '/' . $m[2] . '/';
    }
}