<?php
namespace AdvancedAddons\Tools;

use AdvancedAddons\AI_Service;
use AdvancedAddons\Block_Updater;
use AdvancedAddons\HtmlToBlocks;
use AdvancedAddons\Tool;
use WP_Error;

/**
 * Convert Tailwind HTML to blocks and replace the currently selected blocks.
 */
class Replace_Selected_Blocks_Tool implements Tool {

	/**
	 * @var AI_Service
	 */
	private $ai_service;

	public function __construct( AI_Service $ai_service ) {
		$this->ai_service = $ai_service;
	}

	public function name(): string {
		return 'replace_selected_blocks';
	}

	public function description(): string {
		return 'Convert HTML or WordPress block markup into WordPress blocks and replace the currently selected blocks in the editor. ' .
			'Use this when the user asks to change, update, restyle, or edit the selected section. ' .
			'Provide either raw html/block markup or a description and the content will be generated for you. ' .
			"Set block_type to 'native' when generating dynamic or native WordPress content such as blog posts, navigation, post content, archives, or search forms.";
	}

	public function input_schema(): array {
		return array(
			'type'       => 'object',
			'properties' => array(
				'html' => array(
					'type'        => 'string',
					'description' => 'Tailwind CSS HTML or serialized WordPress block markup to convert and use as the replacement.',
				),
				'description' => array(
					'type'        => 'string',
					'description' => 'Description of the replacement section to generate. Use this if you do not have ready HTML/block markup.',
				),
				'block_type' => array(
					'type'        => 'string',
					'enum'        => array( 'tailwind', 'native' ),
					'default'     => 'tailwind',
					'description' => "Use 'native' for dynamic or native WordPress blocks (blog posts, navigation, post content, archives, search). Use 'tailwind' (default) for static sections, hero areas, cards, buttons, and custom layouts.",
				),
			),
		);
	}

	public function execute( array $input, array $context = array() ): array {
		$content = $this->prepare_content( $input, $context );

		if ( is_wp_error( $content ) ) {
			return array(
				'type'    => 'error',
				'message' => $content->get_error_message(),
			);
		}

		$blocks = HtmlToBlocks::convert( $content );
		if ( empty( $blocks ) ) {
			return array(
				'type'    => 'error',
				'message' => sprintf(
					/* translators: %s: received HTML snippet */
					__( 'Could not convert HTML to blocks. Received: %s', 'advanced-animation' ),
					mb_strimwidth( $content, 0, 200, '...' )
				),
			);
		}

		$stage_result = 'chat' !== ( $context['request_source'] ?? '' );
		$selection = $context['selection'] ?? null;
		if ( is_array( $selection ) && empty( $selection['post_id'] ) ) {
			$selection['post_id'] = intval( $context['post_id'] ?? 0 );
		}
		$result = Block_Updater::replace_selection(
			$blocks,
			$context['page_content'] ?? null,
			$stage_result,
			$selection
		);

		if ( is_wp_error( $result ) ) {
			return array(
				'type'    => 'error',
				'message' => $result->get_error_message(),
			);
		}

		return array_merge(
			array(
				'type'   => 'blocks_updated',
				'action' => 'replace',
			),
			$result
		);
	}

	/**
	 * Resolve the content to insert, either from input or by generating it.
	 *
	 * @return string|WP_Error
	 */
	private function prepare_content( array $input, array $context ) {
		$html = $input['html'] ?? '';

		if ( ! empty( $html ) ) {
			return $this->clean_content( $html );
		}

		$description = $input['description'] ?? '';
		if ( empty( $description ) ) {
			return new WP_Error( 'missing_input', __( 'No html or description provided.', 'advanced-animation' ) );
		}

		$block_type = $input['block_type'] ?? 'tailwind';
		$preference = $context['block_type_preference'] ?? 'auto';
		if ( in_array( $preference, array( 'tailwind', 'native' ), true ) ) {
			$block_type = $preference;
		}
		$post_id    = intval( $context['post_id'] ?? 0 ) ?: null;
		if ( 'native' === $block_type ) {
			$generated = $this->ai_service->generate_native_blocks( $description, $context['selection'] ?? null, $post_id );
		} else {
			$generated = $this->ai_service->generate_html( $description, $context['selection'] ?? null, $post_id );
		}

		if ( is_wp_error( $generated ) ) {
			return $generated;
		}

		return $this->clean_content( $generated );
	}

	/**
	 * Strip markdown fences and other wrapping that breaks conversion.
	 */
	private function clean_content( string $content ): string {
		$content = trim( $content );

		// Strip markdown fences.
		if ( preg_match( '/^```[^\r\n]*\R([\s\S]*?)```$/', $content, $matches ) ) {
			$content = trim( $matches[1] );
		}

		// Extract serialized native block markup from explanatory model text.
		$native_start = stripos( $content, '<!-- wp:' );
		if ( false !== $native_start ) {
			$content = substr( $content, $native_start );
			$native_end = strrpos( $content, '-->' );
			if ( false !== $native_end ) {
				return trim( substr( $content, 0, $native_end + 3 ) );
			}
		}

		// Extract body contents if a full document is returned.
		if ( preg_match( '/<body[^>]*>(.*?)<\/body>/s', $content, $matches ) ) {
			$content = trim( $matches[1] );
		}

		return $content;
	}
}