<?php

declare( strict_types=1 );

namespace AcezSeo\Support;

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

/**
 * Detects Advanced Custom Fields at RUNTIME (M49) — by the functions the
 * integration actually calls, never by plugin name/path, so the WP.org
 * "Secure Custom Fields" fork is covered automatically (it ships the same
 * API). Mirrors the SeoPluginDetector/MultilingualPluginDetector doctrine.
 */
final class AcfDetector
{
	public static function is_active(): bool
	{
		return function_exists( 'get_field' ) && function_exists( 'acf_get_field_groups' );
	}

	/** ACF Pro (repeaters/flexible content) — needed by the Pro-side mapping (M30). */
	public static function is_pro(): bool
	{
		return class_exists( 'acf_pro' ) || defined( 'ACF_PRO' ) || ( function_exists( 'acf_is_pro' ) && acf_is_pro() );
	}

	/**
	 * Field name => label for the given post type — text-like and image
	 * fields only by default (the kinds our template variable and OG
	 * fallback can meaningfully resolve). Pass `$types` to narrow this to a
	 * different subset (e.g. Pro's content allowlist wants prose-only:
	 * text/textarea/wysiwyg, not email/url/number/image) without every
	 * caller re-walking ACF's own field-group API itself.
	 *
	 * @param string[]|null $types
	 *
	 * @return array<string, string>
	 */
	public static function field_names( string $post_type, ?array $types = null ): array
	{
		if ( ! self::is_active() || ! function_exists( 'acf_get_fields' ) )
		{
			return array();
		}

		$usable_types = $types ?? array( 'text', 'textarea', 'wysiwyg', 'email', 'url', 'number', 'image' );
		$fields       = array();

		foreach ( (array) acf_get_field_groups( array( 'post_type' => $post_type ) ) as $group )
		{
			foreach ( (array) acf_get_fields( $group ) as $field )
			{
				if ( ! is_array( $field ) )
				{
					continue;
				}

				$name = (string) ( $field['name'] ?? '' );
				$type = (string) ( $field['type'] ?? '' );

				if ( '' !== $name && in_array( $type, $usable_types, true ) )
				{
					$fields[ $name ] = (string) ( $field['label'] ?? $name );
				}
			}
		}

		return $fields;
	}

	/**
	 * Repeater fields for the given post type, each with its own
	 * sub-fields — a repeater's rows aren't scalar (each is
	 * `array<sub_field_name, value>`), so this is deliberately a
	 * separate method from `field_names()` rather than an extra entry
	 * in its `$usable_types` list; mixing the two shapes into one flat
	 * `field => label` map would break every existing scalar caller.
	 * Used by Pro's ACF-repeater → FAQPage/HowTo mapping (M30).
	 *
	 * @return array<string, array{label: string, sub_fields: array<string, string>}>
	 */
	public static function repeater_fields( string $post_type ): array
	{
		if ( ! self::is_active() || ! function_exists( 'acf_get_fields' ) )
		{
			return array();
		}

		$repeaters = array();

		foreach ( (array) acf_get_field_groups( array( 'post_type' => $post_type ) ) as $group )
		{
			foreach ( (array) acf_get_fields( $group ) as $field )
			{
				if ( ! is_array( $field ) || 'repeater' !== ( $field['type'] ?? '' ) )
				{
					continue;
				}

				$name = (string) ( $field['name'] ?? '' );

				if ( '' === $name )
				{
					continue;
				}

				$sub_fields = array();

				foreach ( (array) ( $field['sub_fields'] ?? array() ) as $sub_field )
				{
					if ( ! is_array( $sub_field ) )
					{
						continue;
					}

					$sub_name = (string) ( $sub_field['name'] ?? '' );

					if ( '' !== $sub_name )
					{
						$sub_fields[ $sub_name ] = (string) ( $sub_field['label'] ?? $sub_name );
					}
				}

				$repeaters[ $name ] = array(
					'label'      => (string) ( $field['label'] ?? $name ),
					'sub_fields' => $sub_fields,
				);
			}
		}

		return $repeaters;
	}
}