<?php

declare( strict_types=1 );

namespace AcezSeo\Meta;

use AcezSeo\Data\MetaFields;
use AcezSeo\Data\PostMetaRepositoryInterface;
use AcezSeo\Data\SettingsRepositoryInterface;
use AcezSeo\Support\VariableResolver;

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

/**
 * Resolves the final meta-tag values for a post: custom meta overrides,
 * falling back to per-post-type templates, falling back to WordPress defaults.
 *
 * Each public method is memoized per post ID for the lifetime of this
 * instance (one instance per request) — title()/description() etc. are each
 * called 2-3 times per request (title tag, OG, Twitter Card), so this avoids
 * redundant meta lookups and template resolution within a single page load.
 */
final class MetaResolver
{
	private PostMetaRepositoryInterface $post_meta;
	private SettingsRepositoryInterface $settings;

	/**
	 * @var array<string, mixed>
	 */
	private array $cache = array();

	public function __construct( PostMetaRepositoryInterface $post_meta, SettingsRepositoryInterface $settings )
	{
		$this->post_meta = $post_meta;
		$this->settings  = $settings;
	}

	public function title( \WP_Post $post ): string
	{
		return $this->remember(
			'title:' . $post->ID,
			function () use ( $post ): string
			{
				$custom = (string) $this->post_meta->get( $post->ID, MetaFields::TITLE );

				if ( '' !== $custom )
				{
					return VariableResolver::resolve( $custom, $post );
				}

				$template = (string) $this->settings->get( $post->post_type )['title_template'];

				return '' !== $template ? VariableResolver::resolve( $template, $post ) : '';
			}
		);
	}

	public function description( \WP_Post $post ): string
	{
		return $this->remember(
			'description:' . $post->ID,
			function () use ( $post ): string
			{
				$custom = (string) $this->post_meta->get( $post->ID, MetaFields::DESCRIPTION );

				if ( '' !== $custom )
				{
					return VariableResolver::resolve( $custom, $post );
				}

				$template = (string) $this->settings->get( $post->post_type )['description_template'];
				$resolved = '' !== $template ? VariableResolver::resolve( $template, $post ) : '';

				if ( '' !== $resolved )
				{
					return $resolved;
				}

				return wp_trim_words( wp_strip_all_tags( $post->post_content ), 35 );
			}
		);
	}

	public function canonical( \WP_Post $post ): string
	{
		return $this->remember(
			'canonical:' . $post->ID,
			function () use ( $post ): string
			{
				$custom = (string) $this->post_meta->get( $post->ID, MetaFields::CANONICAL );

				if ( '' !== $custom )
				{
					return $custom;
				}

				$permalink = get_permalink( $post );

				return is_string( $permalink ) ? $permalink : '';
			}
		);
	}

	/**
	 * @return array{index: bool, follow: bool}
	 */
	public function robots( \WP_Post $post ): array
	{
		return $this->remember(
			'robots:' . $post->ID,
			function () use ( $post ): array
			{
				$settings = $this->settings->get( $post->post_type );

				return array(
					'index'  => $this->resolve_robots_flag( $post->ID, MetaFields::ROBOTS_INDEX, (bool) $settings['robots_index'] ),
					'follow' => $this->resolve_robots_flag( $post->ID, MetaFields::ROBOTS_FOLLOW, (bool) $settings['robots_follow'] ),
				);
			}
		);
	}

	public function og_image_url( \WP_Post $post ): string
	{
		return $this->remember(
			'og_image_url:' . $post->ID,
			function () use ( $post ): string
			{
				$image_id = (int) $this->post_meta->get( $post->ID, MetaFields::OG_IMAGE_ID );

				if ( $image_id > 0 )
				{
					$url = wp_get_attachment_image_url( $image_id, 'large' );

					if ( is_string( $url ) )
					{
						return $url;
					}
				}

				// ACF image field configured per content type (M49) — between
				// the post's own OG image and the featured image, so an
				// explicit per-post choice always wins over the ACF value.
				$acf_url = $this->acf_og_image_url( $post );

				if ( '' !== $acf_url )
				{
					return $acf_url;
				}

				if ( has_post_thumbnail( $post ) )
				{
					$url = get_the_post_thumbnail_url( $post, 'large' );

					if ( is_string( $url ) && '' !== $url )
					{
						return $url;
					}
				}

				// Per-content-type default share image (Treści → [typ]).
				$default_id = (int) ( $this->settings->get( $post->post_type )['og_image_id'] ?? 0 );

				if ( $default_id > 0 )
				{
					$url = wp_get_attachment_image_url( $default_id, 'large' );

					if ( is_string( $url ) )
					{
						return $url;
					}
				}

				return '';
			}
		);
	}

	/**
	 * Resolves the per-type "ACF OG image field" setting (M49). ACF image
	 * fields return one of THREE formats depending on the field's Return
	 * Format setting: attachment ID, array (with ID/url), or a bare URL —
	 * all three are handled.
	 */
	private function acf_og_image_url( \WP_Post $post ): string
	{
		$field = trim( (string) ( $this->settings->get( $post->post_type )['og_acf_field'] ?? '' ) );

		if ( '' === $field || ! \AcezSeo\Support\AcfDetector::is_active() )
		{
			return '';
		}

		$value = get_field( $field, $post->ID );

		if ( is_array( $value ) )
		{
			// Prefer a NON-EMPTY attachment ID; an array with ID=0 (or
			// none) falls back to its url entry.
			$value = ! empty( $value['ID'] ) ? $value['ID'] : ( $value['url'] ?? '' );
		}

		if ( is_numeric( $value ) && (int) $value > 0 )
		{
			$url = wp_get_attachment_image_url( (int) $value, 'large' );

			return is_string( $url ) ? $url : '';
		}

		if ( is_string( $value ) && str_starts_with( $value, 'http' ) )
		{
			return esc_url_raw( $value );
		}

		return '';
	}

	public function twitter_card( \WP_Post $post ): string
	{
		return $this->remember(
			'twitter_card:' . $post->ID,
			function () use ( $post ): string
			{
				return (string) $this->post_meta->get( $post->ID, MetaFields::TWITTER_CARD );
			}
		);
	}

	/**
	 * Post-level meta overrides the per-post-type setting, but only when it was
	 * explicitly saved — otherwise the global default for the post type applies.
	 */
	private function resolve_robots_flag( int $post_id, string $meta_key, bool $fallback ): bool
	{
		if ( ! $this->post_meta->has( $post_id, $meta_key ) )
		{
			return $fallback;
		}

		return (bool) $this->post_meta->get( $post_id, $meta_key );
	}

	/**
	 * @return mixed
	 */
	private function remember( string $key, callable $resolve )
	{
		if ( ! array_key_exists( $key, $this->cache ) )
		{
			$this->cache[ $key ] = $resolve();
		}

		return $this->cache[ $key ];
	}
}