<?php
/**
 * Per-post SEO overrides shared by the SEO, Robots, Breadcrumbs and Schema
 * modules.
 *
 * Every value here is optional: an empty override means "inherit the global
 * setting". Keeping the resolution in one place is what stops the head output,
 * the sitemap and the social preview from disagreeing with each other.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite\Support;

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

use WP_Post;

final class PostSeo {

	public const CANONICAL   = '_airanksuite_canonical';
	public const CRUMB_TITLE = '_airanksuite_breadcrumb_title';
	public const PREVIEWS    = '_airanksuite_previews';
	public const SOCIAL      = '_airanksuite_social';

	/**
	 * Allowed values for the three Google preview directives.
	 *
	 * @return array<string, array<int, string>>
	 */
	public static function preview_options(): array {
		return array(
			'max_snippet'       => array( '', '-1', '0', '50', '100', '160', '200' ),
			'max_image_preview' => array( '', 'none', 'standard', 'large' ),
			'max_video_preview' => array( '', '-1', '0', '15', '30' ),
		);
	}

	/**
	 * Canonical URL for a post: override if valid, permalink otherwise.
	 */
	public static function canonical( WP_Post $post ): string {
		$custom = trim( (string) get_post_meta( $post->ID, self::CANONICAL, true ) );
		if ( '' !== $custom ) {
			$url = esc_url_raw( $custom );
			// Refuse anything that is not http(s) — a javascript: canonical would
			// otherwise land in the head of every visitor's page.
			if ( '' !== $url && in_array( (string) wp_parse_url( $url, PHP_URL_SCHEME ), array( 'http', 'https' ), true ) ) {
				return $url;
			}
		}
		return (string) get_permalink( $post );
	}

	/**
	 * Breadcrumb label: override, then the SEO title, then the post title.
	 */
	public static function breadcrumb_title( WP_Post $post ): string {
		$custom = trim( (string) get_post_meta( $post->ID, self::CRUMB_TITLE, true ) );
		if ( '' !== $custom ) {
			return $custom;
		}
		return (string) get_the_title( $post );
	}

	/**
	 * Per-post preview directive overrides.
	 *
	 * @return array<string, string> Only keys with a non-empty override.
	 */
	public static function previews( int $post_id ): array {
		$stored = get_post_meta( $post_id, self::PREVIEWS, true );
		$out    = array();
		if ( ! is_array( $stored ) ) {
			return $out;
		}
		foreach ( self::preview_options() as $key => $allowed ) {
			$value = isset( $stored[ $key ] ) ? (string) $stored[ $key ] : '';
			if ( '' !== $value && in_array( $value, $allowed, true ) ) {
				$out[ $key ] = $value;
			}
		}
		return $out;
	}

	/**
	 * Sanitize and store preview overrides.
	 *
	 * @param array<string, mixed> $input Raw input.
	 */
	public static function save_previews( int $post_id, array $input ): void {
		$clean = array();
		foreach ( self::preview_options() as $key => $allowed ) {
			$value = isset( $input[ $key ] ) ? (string) $input[ $key ] : '';
			if ( in_array( $value, $allowed, true ) && '' !== $value ) {
				$clean[ $key ] = $value;
			}
		}
		if ( empty( $clean ) ) {
			delete_post_meta( $post_id, self::PREVIEWS );
			return;
		}
		update_post_meta( $post_id, self::PREVIEWS, $clean );
	}

	/**
	 * Social override fields.
	 *
	 * @return array<int, string>
	 */
	public static function social_keys(): array {
		return array( 'og_title', 'og_desc', 'og_image', 'tw_title', 'tw_desc', 'tw_image', 'tw_card' );
	}

	/**
	 * Raw stored social overrides, always shaped with every key.
	 *
	 * @return array<string, string>
	 */
	public static function social( int $post_id ): array {
		$stored = get_post_meta( $post_id, self::SOCIAL, true );
		$out    = array();
		foreach ( self::social_keys() as $key ) {
			$out[ $key ] = is_array( $stored ) && isset( $stored[ $key ] ) ? (string) $stored[ $key ] : '';
		}
		return $out;
	}

	/**
	 * Sanitize and store social overrides.
	 *
	 * @param array<string, mixed> $input Raw input.
	 */
	public static function save_social( int $post_id, array $input ): void {
		$clean = array();
		foreach ( self::social_keys() as $key ) {
			$value = isset( $input[ $key ] ) ? (string) $input[ $key ] : '';
			if ( '' === trim( $value ) ) {
				continue;
			}
			if ( 'og_image' === $key || 'tw_image' === $key ) {
				$clean[ $key ] = esc_url_raw( $value );
				continue;
			}
			if ( 'tw_card' === $key ) {
				$clean[ $key ] = in_array( $value, array( 'summary', 'summary_large_image' ), true ) ? $value : '';
				continue;
			}
			$clean[ $key ] = sanitize_text_field( $value );
		}
		$clean = array_filter( $clean, static fn( $v ) => '' !== $v );
		if ( empty( $clean ) ) {
			delete_post_meta( $post_id, self::SOCIAL );
			return;
		}
		update_post_meta( $post_id, self::SOCIAL, $clean );
	}

	/**
	 * The social card exactly as Facebook, LinkedIn and X will render it —
	 * used both for the head output and for the editor preview, so what the
	 * customer sees in the preview is byte-for-byte what ships.
	 *
	 * @param string $fallback_title Resolved document title.
	 * @param string $fallback_desc  Resolved meta description.
	 * @return array<string, string>
	 */
	public static function social_card( WP_Post $post, string $fallback_title, string $fallback_desc ): array {
		$stored = self::social( $post->ID );
		// Fallback chain: per-post override → featured image (full size, so
		// crawlers get the real resolution) → site-wide default share image.
		$thumb = (string) get_the_post_thumbnail_url( $post, 'full' );
		if ( '' === $thumb && class_exists( \AiRankSuite\Modules\Social\SocialModule::class ) ) {
			$thumb = \AiRankSuite\Modules\Social\SocialModule::default_image();
		}

		$og_image = '' !== $stored['og_image'] ? $stored['og_image'] : $thumb;
		$tw_image = '' !== $stored['tw_image'] ? $stored['tw_image'] : $og_image;

		$card = $stored['tw_card'];
		if ( '' === $card ) {
			$card = '' !== $tw_image ? 'summary_large_image' : 'summary';
		}

		$meta    = class_exists( \AiRankSuite\Modules\Social\SocialModule::class )
			? \AiRankSuite\Modules\Social\SocialModule::image_meta( $og_image )
			: null;
		$warning = '';
		if ( '' === $og_image ) {
			$warning = 'none';
		} elseif ( null !== $meta && ( $meta['width'] < 600 || $meta['height'] < 315 ) ) {
			$warning = 'too_small'; // Below Facebook's minimum — link previews degrade.
		} elseif ( null !== $meta && ( $meta['width'] < 1200 || $meta['height'] < 630 ) ) {
			$warning = 'small'; // Renders, but blurry on high-DPI feeds.
		}

		return array(
			'og_title'   => '' !== $stored['og_title'] ? $stored['og_title'] : $fallback_title,
			'og_desc'    => '' !== $stored['og_desc'] ? $stored['og_desc'] : $fallback_desc,
			'og_image'   => $og_image,
			'tw_title'   => '' !== $stored['tw_title'] ? $stored['tw_title'] : ( '' !== $stored['og_title'] ? $stored['og_title'] : $fallback_title ),
			'tw_desc'    => '' !== $stored['tw_desc'] ? $stored['tw_desc'] : ( '' !== $stored['og_desc'] ? $stored['og_desc'] : $fallback_desc ),
			'tw_image'   => $tw_image,
			'tw_card'    => $card,
			'image_meta' => $meta,
			'image_warn' => $warning,
		);
	}
}