<?php
/**
 * Block Renderer.
 *
 * Injects Bootstrap 5 classes into WordPress core block HTML output
 * on the frontend. Uses WP_HTML_Tag_Processor for safe HTML manipulation.
 *
 * @package WPBootstrap\Block
 * @since   1.1.0
 */

namespace WPBootstrap\Block;

use WP_HTML_Tag_Processor;
use WP_Block;

class BlockRenderer
{
    /**
     * Map of WordPress preset color slugs to Bootstrap button variants.
     */
    private const COLOR_VARIANTS = [
        'primary'   => 'primary',
        'secondary' => 'secondary',
        'success'   => 'success',
        'danger'    => 'danger',
        'warning'   => 'warning',
        'info'      => 'info',
        'light'     => 'light',
        'dark'      => 'dark',
    ];

    /**
     * Register render_block filters for each supported block type.
     */
    public function __construct()
    {
        if ( is_admin() || wp_doing_ajax() ) {
            return;
        }

        if ( defined( 'REST_REQUEST' ) && REST_REQUEST ) {
            return;
        }

        $blocks = $this->getBlockHandlers();

        /**
         * Filters the map of block names to handler method names.
         *
         * Child themes can remove blocks or add new ones.
         *
         * @since 1.1.0
         *
         * @param array $blocks Map of 'core/block-name' => 'methodName'.
         */
        $blocks = apply_filters( 'wp_bootstrap_block_renderer_blocks', $blocks );

        foreach ( $blocks as $blockName => $method ) {
            if ( method_exists( $this, $method ) ) {
                add_filter( "render_block_{$blockName}", [ $this, $method ], 10, 3 );
            }
        }
    }

    /**
     * Get the default map of block names to handler methods.
     *
     * @return array<string, string>
     */
    private function getBlockHandlers(): array
    {
        return [
            'core/table'     => 'renderTable',
            'core/button'    => 'renderButton',
            'core/buttons'   => 'renderButtons',
            'core/image'     => 'renderImage',
            'core/search'    => 'renderSearch',
            'core/quote'     => 'renderQuote',
            'core/pullquote' => 'renderPullquote',
            'core/list'      => 'renderList',
        ];
    }

    /**
     * Add Bootstrap table classes.
     *
     * Injects .table on <table>; adds .table-striped when WP stripes style is active.
     */
    public function renderTable( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( 'table' ) ) {
            return $content;
        }

        $processor->add_class( 'table' );

        $className = $block['attrs']['className'] ?? '';
        if ( str_contains( $className, 'is-style-stripes' ) ) {
            $processor->add_class( 'table-striped' );
        }

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap button classes.
     *
     * Injects .btn + color variant on .wp-block-button__link.
     * Maps WP preset color slugs to Bootstrap btn-{variant} / btn-outline-{variant}.
     */
    public function renderButton( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( [ 'class_name' => 'wp-block-button__link' ] ) ) {
            return $content;
        }

        $processor->add_class( 'btn' );

        $attrs = $block['attrs'] ?? [];

        // Gradient buttons: just .btn, inline style handles the color.
        if ( ! empty( $attrs['gradient'] ) ) {
            return $processor->get_updated_html();
        }

        $className = $attrs['className'] ?? '';
        $isOutline = str_contains( $className, 'is-style-outline' );

        if ( $isOutline ) {
            $colorSlug = $attrs['textColor'] ?? 'primary';
            $variant   = self::COLOR_VARIANTS[ $colorSlug ] ?? 'primary';
            $processor->add_class( 'btn-outline-' . $variant );
        } else {
            $colorSlug = $attrs['backgroundColor'] ?? 'primary';
            $variant   = self::COLOR_VARIANTS[ $colorSlug ] ?? 'primary';
            $processor->add_class( 'btn-' . $variant );
        }

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap flex utilities to button group wrapper.
     */
    public function renderButtons( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( [ 'class_name' => 'wp-block-buttons' ] ) ) {
            return $content;
        }

        $processor->add_class( 'd-flex' );
        $processor->add_class( 'flex-wrap' );
        $processor->add_class( 'gap-2' );

        return $processor->get_updated_html();
    }

    /**
     * Add .img-fluid to block images.
     */
    public function renderImage( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( 'img' ) ) {
            return $content;
        }

        $processor->add_class( 'img-fluid' );

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap form-control and button classes to search block.
     */
    public function renderSearch( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        // Add .input-group to the inner wrapper for seamless input + button.
        if ( $processor->next_tag( [ 'class_name' => 'wp-block-search__inside-wrapper' ] ) ) {
            $processor->add_class( 'input-group' );
        }

        if ( $processor->next_tag( [ 'class_name' => 'wp-block-search__input' ] ) ) {
            $processor->add_class( 'form-control' );
        }

        if ( $processor->next_tag( [ 'class_name' => 'wp-block-search__button' ] ) ) {
            $processor->add_class( 'btn' );
            $processor->add_class( 'btn-primary' );
        }

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap blockquote classes to quote block.
     */
    public function renderQuote( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( 'blockquote' ) ) {
            return $content;
        }

        $processor->add_class( 'blockquote' );

        if ( $processor->next_tag( 'cite' ) ) {
            $processor->add_class( 'blockquote-footer' );
        }

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap blockquote classes to pullquote block.
     */
    public function renderPullquote( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        if ( ! $processor->next_tag( 'blockquote' ) ) {
            return $content;
        }

        $processor->add_class( 'blockquote' );

        if ( $processor->next_tag( 'cite' ) ) {
            $processor->add_class( 'blockquote-footer' );
        }

        return $processor->get_updated_html();
    }

    /**
     * Add Bootstrap list-group classes when list-group style is selected.
     *
     * Only modifies lists with the is-style-list-group block style.
     */
    public function renderList( string $content, array $block, ?WP_Block $instance = null ): string
    {
        if ( empty( $content ) ) {
            return $content;
        }

        $className = $block['attrs']['className'] ?? '';

        if ( ! str_contains( $className, 'is-style-list-group' ) ) {
            return $content;
        }

        $processor = new WP_HTML_Tag_Processor( $content );

        $listTag = ! empty( $block['attrs']['ordered'] ) ? 'ol' : 'ul';
        if ( $processor->next_tag( $listTag ) ) {
            $processor->add_class( 'list-group' );
        }

        while ( $processor->next_tag( 'li' ) ) {
            $processor->add_class( 'list-group-item' );
        }

        return $processor->get_updated_html();
    }
}