<?php

defined( 'ABSPATH' ) || exit;

final class AIparently_Classification_Service {
	const META_KEY = '_aiparently_ai_usage';
	const SUPPORTED_POST_TYPES = array( 'post', 'page', 'attachment' );
	const STATUSES = array( 'none', 'assisted', 'generated' );

	private $rules;

	public function __construct( AIparently_Rule_Engine $rules ) {
		$this->rules = $rules;
	}

	public static function sanitize_status( $status ) {
		$status = sanitize_key( (string) $status );
		return in_array( $status, self::STATUSES, true ) ? $status : '';
	}

	public function supports( $post_id ) {
		return in_array( get_post_type( $post_id ), self::SUPPORTED_POST_TYPES, true );
	}

	public function get_status( $post_id ) {
		if ( ! $this->supports( $post_id ) || ! metadata_exists( 'post', $post_id, self::META_KEY ) ) {
			return 'unchecked';
		}

		$status = self::sanitize_status( get_post_meta( $post_id, self::META_KEY, true ) );
		return $status ?: 'unchecked';
	}

	public function set_status( $post_id, $status ) {
		$post_id = absint( $post_id );
		$status  = self::sanitize_status( $status );

		if ( ! $post_id || ! $status || ! $this->supports( $post_id ) ) {
			return new WP_Error( 'aiparently_invalid_classification', __( 'Invalid content or AI status.', 'aiparently' ) );
		}

		$result = update_post_meta( $post_id, self::META_KEY, $status );
		if ( false === $result && $status !== get_post_meta( $post_id, self::META_KEY, true ) ) {
			return new WP_Error( 'aiparently_save_failed', __( 'The AI status could not be saved.', 'aiparently' ) );
		}

		do_action( 'aiparently_classification_changed', $post_id, $status );
		return true;
	}

	public function get_decision( $post_id ) {
		$status = $this->get_status( $post_id );
		return $this->rules->evaluate(
			$status,
			array(
				'post_id'   => absint( $post_id ),
				'post_type' => get_post_type( $post_id ),
			)
		);
	}

	public function check_content( $post_id ) {
		if ( ! $this->supports( $post_id ) ) {
			return new WP_Error( 'aiparently_not_supported', __( 'This content type is not supported.', 'aiparently' ) );
		}

		return array(
			'post_id'        => absint( $post_id ),
			'classification' => $this->get_status( $post_id ),
			'disclosure'     => $this->get_decision( $post_id ),
		);
	}

	public function list_content( $args = array() ) {
		$defaults = array(
			'post_type'      => self::SUPPORTED_POST_TYPES,
			'post_status'    => array( 'publish', 'draft', 'pending', 'private', 'inherit' ),
			'posts_per_page' => 20,
			'paged'          => 1,
			'orderby'        => 'modified',
			'order'          => 'DESC',
			'status'         => '',
		);
		$args   = wp_parse_args( $args, $defaults );
		$status = sanitize_key( (string) $args['status'] );
		unset( $args['status'] );

		if ( 'unchecked' === $status ) {
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- Classification is intentionally stored as post meta and indexed by WordPress.
			$args['meta_query'] = array(
				array( 'key' => self::META_KEY, 'compare' => 'NOT EXISTS' ),
			);
		} elseif ( in_array( $status, self::STATUSES, true ) ) {
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key -- Classification is intentionally stored as post meta and queried through WP_Query.
			$args['meta_key']   = self::META_KEY;
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_value -- Classification is intentionally stored as post meta and queried through WP_Query.
			$args['meta_value'] = $status;
		}

		return new WP_Query( $args );
	}

	public function get_counts( $args = array() ) {
		$counts = array();
		foreach ( array( 'none', 'assisted', 'generated', 'unchecked' ) as $status ) {
			$query = $this->list_content(
				array_merge(
					$args,
					array(
						'status'         => $status,
						'posts_per_page' => 1,
						'fields'         => 'ids',
						'no_found_rows'  => false,
					)
				)
			);
			$counts[ $status ] = (int) $query->found_posts;
		}
		$counts['reviewed'] = $counts['none'] + $counts['assisted'] + $counts['generated'];
		return $counts;
	}
}