<?php
/**
 * Block-based FAQ and HowTo detection.
 *
 * Reads Gutenberg blocks from post content and extracts structured Q/A pairs
 * and step lists from Yoast and Rank Math's FAQ/HowTo blocks.
 *
 * Free tier is deliberately block-only. HTML/DOM extraction (Elementor
 * accordions, generic Q/A patterns) is intentionally excluded — that's the
 * kind of heuristic-heavy work that belongs in a paid tier where support
 * costs can carry it.
 *
 * @package SchemaMonsterFree
 */

namespace SchemaMonsterFree;

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

/**
 * Deterministic block-level detection helpers.
 */
final class Detection {

	/**
	 * Extract FAQ items from Yoast and Rank Math FAQ blocks.
	 *
	 * @param string $content Post content (raw, unmodified).
	 * @return array<int,array{question:string,answer:string}>
	 */
	public static function extract_faq_items( string $content ): array {
		if ( '' === trim( $content ) || ! function_exists( 'parse_blocks' ) ) {
			return array();
		}

		$blocks = parse_blocks( $content );
		if ( ! is_array( $blocks ) ) {
			return array();
		}

		$stack = $blocks;
		$out   = array();

		while ( ! empty( $stack ) ) {
			$block = array_shift( $stack );
			$name  = (string) ( $block['blockName'] ?? '' );
			$attrs = (array) ( $block['attrs'] ?? array() );

			// Yoast: one block per question.
			if ( 'yoast/faq-question' === $name ) {
				$q = trim( (string) ( $attrs['question'] ?? '' ) );
				$a = trim( (string) ( $attrs['answer'] ?? '' ) );
				if ( '' !== $q && '' !== $a ) {
					$out[] = array(
						'question' => wp_strip_all_tags( $q ),
						'answer'   => wp_strip_all_tags( $a ),
					);
				}
			}

			// Rank Math: questions list on container block.
			if ( 'rank-math/faq-block' === $name && ! empty( $attrs['questions'] ) && is_array( $attrs['questions'] ) ) {
				foreach ( $attrs['questions'] as $qa ) {
					if ( ! is_array( $qa ) ) {
						continue;
					}
					$q = trim( (string) ( $qa['title'] ?? '' ) );
					$a = trim( (string) ( $qa['content'] ?? '' ) );
					if ( '' !== $q && '' !== $a ) {
						$out[] = array(
							'question' => wp_strip_all_tags( $q ),
							'answer'   => wp_strip_all_tags( $a ),
						);
					}
				}
			}

			// Recurse into inner blocks.
			if ( ! empty( $block['innerBlocks'] ) && is_array( $block['innerBlocks'] ) ) {
				foreach ( $block['innerBlocks'] as $inner ) {
					$stack[] = $inner;
				}
			}
		}

		return $out;
	}

	/**
	 * Extract HowTo steps from Yoast and Rank Math HowTo blocks.
	 *
	 * @param string $content Post content (raw, unmodified).
	 * @return array<int,array{name:string,text:string}>
	 */
	public static function extract_howto_steps( string $content ): array {
		if ( '' === trim( $content ) || ! function_exists( 'parse_blocks' ) ) {
			return array();
		}

		$blocks = parse_blocks( $content );
		if ( ! is_array( $blocks ) ) {
			return array();
		}

		$stack = $blocks;
		$out   = array();

		while ( ! empty( $stack ) ) {
			$block = array_shift( $stack );
			$name  = (string) ( $block['blockName'] ?? '' );
			$attrs = (array) ( $block['attrs'] ?? array() );

			// Yoast HowTo block: steps carry `text`.
			if ( 'yoast/how-to-block' === $name && ! empty( $attrs['steps'] ) && is_array( $attrs['steps'] ) ) {
				foreach ( $attrs['steps'] as $step ) {
					if ( ! is_array( $step ) ) {
						continue;
					}
					$text = trim( wp_strip_all_tags( (string) ( $step['text'] ?? '' ) ) );
					$name_field = trim( wp_strip_all_tags( (string) ( $step['name'] ?? '' ) ) );
					if ( '' !== $text || '' !== $name_field ) {
						$out[] = array(
							'name' => '' !== $name_field ? $name_field : $text,
							'text' => '' !== $text ? $text : $name_field,
						);
					}
				}
			}

			// Rank Math HowTo block: steps carry `description` and `title`.
			if ( 'rank-math/howto-block' === $name && ! empty( $attrs['steps'] ) && is_array( $attrs['steps'] ) ) {
				foreach ( $attrs['steps'] as $step ) {
					if ( ! is_array( $step ) ) {
						continue;
					}
					$text = trim( wp_strip_all_tags( (string) ( $step['description'] ?? '' ) ) );
					$name_field = trim( wp_strip_all_tags( (string) ( $step['title'] ?? '' ) ) );
					if ( '' !== $text || '' !== $name_field ) {
						$out[] = array(
							'name' => '' !== $name_field ? $name_field : $text,
							'text' => '' !== $text ? $text : $name_field,
						);
					}
				}
			}

			if ( ! empty( $block['innerBlocks'] ) && is_array( $block['innerBlocks'] ) ) {
				foreach ( $block['innerBlocks'] as $inner ) {
					$stack[] = $inner;
				}
			}
		}

		return $out;
	}
}