<?php
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

class QEPW_Viewer {
    public static function init() {
        add_shortcode( 'qepw_pdf_viewer', [ self::class, 'render_pdf_viewer' ] );
        add_action( 'wp_enqueue_scripts', [ self::class, 'conditionally_enqueue_assets' ] );
        add_filter( 'media_send_to_editor', [ self::class, 'replace_pdf_with_shortcode' ], 10, 3 );
        
       
        add_action( 'enqueue_block_editor_assets', [ self::class, 'enqueue_block_editor_assets' ] );
    }

    public static function enqueue_block_editor_assets() {
        
        wp_enqueue_script(
            'qepw-gutenberg-block',
            QEPW_PLUGIN_URL . 'assets/js/block.js',  
            [ 'wp-blocks', 'wp-element', 'wp-editor', 'wp-components' ],
            QEPW_VERSION,
            true
        );

        
        wp_enqueue_style(
            'qepw-gutenberg-block-style',
            QEPW_PLUGIN_URL . 'assets/css/block.css',
            [],
            QEPW_VERSION
        );
    }

    public static function conditionally_enqueue_assets() {
        if ( ! is_singular() ) {
            return;
        }

        global $post;
        if ( has_shortcode( $post->post_content, 'qepw_pdf_viewer' ) ) {
            wp_register_style(
                'qepw-viewer-css',
                QEPW_PLUGIN_URL . 'assets/css/viewer.css',
                [],
                QEPW_VERSION
            );
            wp_enqueue_style( 'qepw-viewer-css' );

            wp_register_script(
                'qepw-pdfjs-lib',
                QEPW_PLUGIN_URL . 'assets/js/pdfjs/pdf.min.js',
                [],
                QEPW_VERSION,
                true
            );
            wp_enqueue_script( 'qepw-pdfjs-lib' );

            wp_register_script(
                'qepw-viewer-js',
                QEPW_PLUGIN_URL . 'assets/js/viewer.jquery.js',
                [ 'jquery', 'qepw-pdfjs-lib' ],
                QEPW_VERSION,
                true
            );

            wp_localize_script(
                'qepw-viewer-js',
                'qepwViewerConfig',
                [
                    'workerSrc' => esc_url( QEPW_PLUGIN_URL . 'assets/js/pdfjs/pdf.worker.min.js' ),
                ]
            );

            wp_enqueue_script( 'qepw-viewer-js' );

            $pdf_width = intval( get_option( 'qepw_width', 800 ) );
            add_action( 'wp_head', function () use ( $pdf_width ) {
                echo '<style>.pdf-viewer { max-width: ' . esc_attr( $pdf_width ) . 'px; margin: 0 auto; }</style>';
            });
        }
    }

    public static function render_pdf_viewer( $atts ) {
        $atts = shortcode_atts(
            [ 'file' => '' ],
            $atts,
            'qepw_pdf_viewer'
        );
        $file_url = esc_url( $atts['file'] );
        $show_download_button = get_option( 'qepw_download_button', true );

        if ( empty( $file_url ) ) {
            return '<p style="color: red;">No PDF file provided.</p>';
        }

        $file_size = '';
        if ( filter_var( $file_url, FILTER_VALIDATE_URL ) ) {
            $file_headers = @get_headers( $file_url, 1 );
            if ( isset( $file_headers['Content-Length'] ) ) {
                $file_size = size_format( $file_headers['Content-Length'], 2 );
            }
        }

        ob_start(); ?>
        <div class="pdf-viewer" data-pdf-url="<?php echo esc_url( $file_url ); ?>">
            <canvas class="pdf-canvas"></canvas>
            <div class="pdf-controls">
                <button class="prev-page">Previous Page</button>
                <span class="page-info"></span>
                <button class="next-page">Next Page</button>
                <?php if ( $show_download_button ) : ?>
                    <button class="download-pdf">
                        <a href="<?php echo esc_url( $file_url ); ?>" download>
                            <?php
                            echo esc_html( sprintf(
                                'Download (%s)',
                                $file_size ? esc_html( $file_size ) : 'Unknown size'
                            ) );
                            ?>
                        </a>
                    </button>
                <?php endif; ?>
            </div>
        </div>
        <?php
        return ob_get_clean();
    }

    public static function replace_pdf_with_shortcode( $html, $id, $attachment ) {
        $mime = get_post_mime_type( $id );
        if ( $mime === 'application/pdf' ) {
            $file_url = wp_get_attachment_url( $id );
            $html = sprintf( '[qepw_pdf_viewer file="%s"]', esc_url( $file_url ) );
        }
        return $html;
    }
}