<?php

declare(strict_types=1);

namespace Sarcio\WordPress;

/**
 * The UI side: the Sarcio widget script, carrying `data-sarcio-key` and
 * `data-sarcio-api` exactly as every other Sarcio integration does. Once it
 * loads it owns the rest — the in-page reporter, fetching active DOM patches,
 * subscribing to the delivery WebSocket, and verifying each signed manifest
 * against the tenant's published key. None of that needs PHP, so the UI side
 * works whether or not the sidecar and shim are installed.
 *
 * What WordPress adds is an audience: a site's visitors are the public, so the
 * reporter defaults to users who can `edit_posts` rather than to everyone.
 */
final class Widget
{
    public const HANDLE = 'sarcio';

    /**
     * html2canvas, which the widget uses to take a report's screenshot, ships
     * with the plugin. Loaded ahead of the widget, both deferred, so the widget
     * finds it on `window` and never fetches its own copy from a CDN.
     */
    public const SCREENSHOT_HANDLE = 'sarcio-html2canvas';

    public const SCREENSHOT_VERSION = '1.4.1';

    public function register(): void
    {
        add_action('wp_enqueue_scripts', [$this, 'enqueue']);
        add_action('admin_enqueue_scripts', [$this, 'enqueueAdmin']);
        add_action('login_enqueue_scripts', [$this, 'enqueue']);
        add_filter('script_loader_tag', [$this, 'filterTag'], 10, 2);
    }

    /**
     * Add the widget's data attributes (and `defer`) to its own script tag.
     * WordPress has no API for arbitrary script attributes below 6.3, and even
     * there `wp_script_attributes` only covers strategies — so the tag filter is
     * the portable way to do this.
     */
    public function filterTag(string $tag, string $handle): string
    {
        if ($handle === self::SCREENSHOT_HANDLE) {
            return str_contains($tag, ' defer') ? $tag : str_replace(' src=', ' defer src=', $tag);
        }
        if ($handle !== self::HANDLE) {
            return $tag;
        }
        $attributes = sprintf(
            ' data-sarcio-key="%s" data-sarcio-api="%s"',
            esc_attr((string) Options::get('site_key')),
            esc_attr(Options::apiUrl()),
        );
        foreach (Launcher::attributes() as $name => $value) {
            $attributes .= sprintf(' %s="%s"', esc_attr(sanitize_key($name)), esc_attr($value));
        }
        if (!str_contains($tag, ' defer')) {
            $attributes .= ' defer';
        }
        return str_replace(' src=', $attributes . ' src=', $tag);
    }

    public function enqueue(): void
    {
        if (!$this->shouldLoad()) {
            return;
        }
        $deps = [];
        if (self::assetsAreServed()) {
            $script = defined('SCRIPT_DEBUG') && SCRIPT_DEBUG ? 'html2canvas.js' : 'html2canvas.min.js';
            wp_register_script(
                self::SCREENSHOT_HANDLE,
                plugins_url('assets/vendor/html2canvas/' . $script, SARCIO_WP_FILE),
                [],
                self::SCREENSHOT_VERSION,
                false,
            );
            $deps[] = self::SCREENSHOT_HANDLE;
        }
        wp_enqueue_script(self::HANDLE, Options::widgetSrc(), $deps, null, false); // phpcs:ignore WordPress.WP.EnqueuedResourceParameters.MissingVersion -- cache-busted by the control plane
    }

    /**
     * Whether the plugin's own files are reachable over the web: true for a
     * normal install under wp-content/plugins or mu-plugins. A Composer install
     * elsewhere (a vendor directory outside the web root) has no URL for its
     * assets, so the bundled screenshot library is skipped and the widget loads
     * its own copy instead.
     */
    public static function assetsAreServed(?string $pluginFile = null): bool
    {
        $dir = wp_normalize_path(dirname($pluginFile ?? SARCIO_WP_FILE));
        foreach (['WP_PLUGIN_DIR', 'WPMU_PLUGIN_DIR'] as $constant) {
            if (defined($constant) && str_starts_with($dir . '/', trailingslashit(wp_normalize_path((string) constant($constant))))) {
                return true;
            }
        }
        return false;
    }

    public function enqueueAdmin(): void
    {
        if (!Options::get('widget_in_admin')) {
            return;
        }
        $this->enqueue();
    }

    /**
     * Whether this pageview gets the reporter. Filterable with
     * `sarcio_load_widget` for anything the three built-in audiences don't
     * express (a staging host, a query flag, a specific post type).
     */
    public function shouldLoad(): bool
    {
        $configured = Options::get('widget_enabled')
            && (string) Options::get('site_key') !== ''
            && Options::widgetSrc() !== '';

        $allowed = $configured && match ((string) Options::get('widget_audience')) {
            'everyone' => true,
            'logged_in' => is_user_logged_in(),
            default => current_user_can((string) Options::get('widget_capability')),
        };

        return (bool) apply_filters('sarcio_load_widget', $allowed);
    }
}