<?php
/**
 * Per-post translation orchestrator. Translates title, content, excerpt, then
 * inserts a new draft post linked to the source via post meta.
 *
 * @package AdaraTranslate
 */

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

final class Adara_Translate_Translator {

	public const META_LANGUAGE  = '_adara_language';
	public const META_SOURCE_ID = '_adara_source_id';

	/**
	 * Translate a post and create a draft duplicate.
	 *
	 * @return array|WP_Error On success: { translation_id, edit_link, language }.
	 */
	public static function translate_post( int $post_id, string $target_lang, ?string $source_lang = null ) {
		$post = get_post( $post_id );
		if ( ! $post ) {
			return new WP_Error(
				'adara_post_not_found',
				__( 'Post not found.', 'adara-translate' ),
				[ 'status' => 404 ]
			);
		}

		$existing = self::find_existing_translation( $post_id, $target_lang );
		if ( null !== $existing ) {
			return new WP_Error(
				'adara_translation_exists',
				__( 'A translation already exists for this language.', 'adara-translate' ),
				[
					'status'         => 409,
					'translation_id' => $existing,
					'edit_link'      => get_edit_post_link( $existing, 'raw' ),
				]
			);
		}

		$title_result = Adara_Translate_Client::translate( $post->post_title, $target_lang, $source_lang );
		if ( is_wp_error( $title_result ) ) {
			return $title_result;
		}

		$content_translated = Adara_Translate_Block_Translator::translate_content(
			$post->post_content,
			$target_lang,
			$source_lang
		);
		if ( is_wp_error( $content_translated ) ) {
			return $content_translated;
		}

		$excerpt_translated = '';
		if ( '' !== $post->post_excerpt ) {
			$excerpt_result = Adara_Translate_Client::translate( $post->post_excerpt, $target_lang, $source_lang );
			if ( is_wp_error( $excerpt_result ) ) {
				return $excerpt_result;
			}
			$excerpt_translated = (string) $excerpt_result['translatedText'];
		}

		$new_post_id = wp_insert_post(
			[
				'post_title'   => (string) $title_result['translatedText'],
				'post_content' => (string) $content_translated,
				'post_excerpt' => $excerpt_translated,
				'post_status'  => 'draft',
				'post_type'    => $post->post_type,
				'post_author'  => get_current_user_id(),
			],
			true
		);

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

		update_post_meta( (int) $new_post_id, self::META_LANGUAGE, sanitize_key( $target_lang ) );
		update_post_meta( (int) $new_post_id, self::META_SOURCE_ID, $post_id );

		return [
			'translation_id' => (int) $new_post_id,
			'edit_link'      => get_edit_post_link( $new_post_id, 'raw' ),
			'language'       => $target_lang,
		];
	}

	public static function find_existing_translation( int $source_id, string $target_lang ) : ?int {
		$query = new WP_Query(
			[
				'post_type'      => 'any',
				'post_status'    => [ 'draft', 'pending', 'private', 'publish', 'future' ],
				'posts_per_page' => 1,
				'fields'         => 'ids',
				'no_found_rows'  => true,
				'meta_query'     => [
					'relation' => 'AND',
					[ 'key' => self::META_SOURCE_ID, 'value' => $source_id ],
					[ 'key' => self::META_LANGUAGE,  'value' => sanitize_key( $target_lang ) ],
				],
			]
		);
		$ids = $query->posts;
		return ! empty( $ids ) ? (int) $ids[0] : null;
	}
}