<?php

namespace RoosterLMS\Community;

use RoosterLMS\Content\ObjectType;
use RoosterLMS\Data\Db;
use RoosterLMS\Domain\Services;
use RoosterLMS\Privacy\UserTable;

defined( 'ABSPATH' ) || exit;

final class Privacy {

	public const ID = 'rooster-lms-waitlist';

	private static array $pending = array();

	public static function register(): void {
		add_filter( 'rooster_lms_user_data_tables', array( self::class, 'registry' ) );
		add_action( 'rooster_lms_user_purging', array( self::class, 'purging' ), 10, 1 );
		add_filter( 'wp_privacy_personal_data_exporters', array( self::class, 'exporters' ) );
		add_filter( 'wp_privacy_personal_data_erasers', array( self::class, 'erasers' ), 9 );
		add_action( 'before_delete_post', array( self::class, 'before_delete' ), 10, 1 );
		add_action( 'deleted_post', array( self::class, 'deleted' ), 30, 1 );
	}

	public static function registry( $tables ) {
		if ( ! is_array( $tables ) ) {
			return $tables;
		}
		$label   = __( 'Rooster LMS: questions, reviews and saved courses', 'rooster-lms' );
		$entries = array(
			new UserTable(
				'discussions',
				'user_id',
				'community',
				$label,
				array(
					'course_id'  => __( 'Course', 'rooster-lms' ),
					'unit_id'    => __( 'Lesson', 'rooster-lms' ),
					'parent_id'  => __( 'Reply to (0 = a question)', 'rooster-lms' ),
					'body'       => __( 'Text', 'rooster-lms' ),
					'state'      => __( 'State (1 visible, 2 awaiting approval, 3 hidden, 4 in the trash)', 'rooster-lms' ),
					'lang'       => __( 'Language', 'rooster-lms' ),
					'created_at' => __( 'Written', 'rooster-lms' ),
					'updated_at' => __( 'Last changed', 'rooster-lms' ),
				),
				'id'
			),
			new UserTable(
				'course_reviews',
				'user_id',
				'community',
				$label,
				array(
					'course_id'  => __( 'Course', 'rooster-lms' ),
					'rating'     => __( 'Rating (1 to 5)', 'rooster-lms' ),
					'title'      => __( 'Title', 'rooster-lms' ),
					'body'       => __( 'Text', 'rooster-lms' ),
					'state'      => __( 'State (1 awaiting approval, 2 approved, 3 rejected, 4 in the trash)', 'rooster-lms' ),
					'lang'       => __( 'Language', 'rooster-lms' ),
					'reply'      => __( 'Reply', 'rooster-lms' ),
					'created_at' => __( 'Written', 'rooster-lms' ),
					'updated_at' => __( 'Last changed', 'rooster-lms' ),
				),
				'id'
			),
			new UserTable(
				'course_waitlist',
				'user_id',
				'community',
				$label,
				array(
					'course_id'    => __( 'Waiting list of the course', 'rooster-lms' ),
					'email'        => __( 'E-mail', 'rooster-lms' ),
					'confirmed_at' => __( 'Confirmed', 'rooster-lms' ),
					'notified_at'  => __( 'Told that it opened', 'rooster-lms' ),
				),
				'id'
			),
			new UserTable(
				'wishlists',
				'user_id',
				'community',
				$label,
				array(
					'course_id'  => __( 'Saved course', 'rooster-lms' ),
					'created_at' => __( 'Saved', 'rooster-lms' ),
				),
				'course_id'
			),
		);
		$last = end( $tables );
		if ( $last instanceof UserTable && 'people' === $last->table ) {
			array_splice( $tables, count( $tables ) - 1, 0, $entries );
			return $tables;
		}
		return array_merge( $tables, $entries );
	}

	public static function purging( $user_id ): void {
		$user_id = (int) $user_id;
		if ( $user_id <= 0 ) {
			return;
		}
		Services::discussions()->delete_user( $user_id );
		Services::reviews()->delete_user( $user_id );
	}

	public static function exporters( $exporters ) {
		if ( is_array( $exporters ) ) {
			$exporters[ self::ID ] = array(
				'exporter_friendly_name' => __( 'Rooster LMS: course waiting lists', 'rooster-lms' ),
				'callback'               => array( self::class, 'export' ),
			);
		}
		return $exporters;
	}

	public static function erasers( $erasers ) {
		if ( is_array( $erasers ) ) {
			$erasers[ self::ID ] = array(
				'eraser_friendly_name' => __( 'Rooster LMS: course waiting lists', 'rooster-lms' ),
				'callback'             => array( self::class, 'erase' ),
			);
		}
		return $erasers;
	}

	public static function export( $email, $page = 1 ): array {
		$items = array();
		if ( (int) $page <= 1 ) {
			foreach ( Services::waitlist()->of_email( (string) $email ) as $row ) {
				$items[] = array(
					'group_id'    => self::ID,
					'group_label' => __( 'Rooster LMS: course waiting lists', 'rooster-lms' ),
					'item_id'     => self::ID . '-' . (int) $row['id'],
					'data'        => array(
						array(
							'name'  => __( 'Waiting list of the course', 'rooster-lms' ),
							'value' => Waitlist::course_title( (int) $row['course_id'] ) . ' (#' . (int) $row['course_id'] . ')',
						),
						array(
							'name'  => __( 'E-mail', 'rooster-lms' ),
							'value' => (string) $row['email'],
						),
						array(
							'name'  => __( 'Language', 'rooster-lms' ),
							'value' => (string) $row['lang'],
						),
						array(
							'name'  => __( 'Asked on', 'rooster-lms' ),
							'value' => (string) $row['created_at'],
						),
						array(
							'name'  => __( 'Confirmed', 'rooster-lms' ),
							'value' => (string) ( $row['confirmed_at'] ?? '' ),
						),
						array(
							'name'  => __( 'Told that it opened', 'rooster-lms' ),
							'value' => (string) ( $row['notified_at'] ?? '' ),
						),
					),
				);
			}
		}
		return array(
			'data' => $items,
			'done' => true,
		);
	}

	public static function erase( $email, $page = 1 ): array {
		unset( $page );
		$n = Services::waitlist()->erase_email( (string) $email );
		return array(
			'items_removed'  => $n > 0,
			'items_retained' => false,
			'messages'       => array(),
			'done'           => true,
		);
	}

	public static function before_delete( $post_id ): void {
		$post_id = (int) $post_id;
		if ( $post_id <= 0 ) {
			return;
		}
		$row = Db::row( 'SELECT object_type, object_id FROM %i WHERE post_id = %d AND object_type IN (%d, %d)', Db::table( 'object_posts' ), $post_id, ObjectType::COURSE->value, ObjectType::UNIT->value );
		if ( null !== $row ) {
			self::$pending[ $post_id ] = array( (int) $row['object_type'], (int) $row['object_id'] );
		}
	}

	public static function deleted( $post_id ): void {
		$post_id = (int) $post_id;
		if ( ! isset( self::$pending[ $post_id ] ) ) {
			return;
		}
		list( $type, $id ) = self::$pending[ $post_id ];
		unset( self::$pending[ $post_id ] );
		if ( null !== Db::value( 'SELECT 1 FROM %i WHERE object_type = %d AND object_id = %d LIMIT 1', Db::table( 'object_posts' ), $type, $id ) ) {
			return;
		}
		if ( ObjectType::COURSE->value === $type ) {
			self::course_gone( $id );
		} else {
			Services::discussions()->delete_unit( $id );
		}
	}

	public static function course_gone( int $course_id ): array {
		return array(
			'discussions'     => Services::discussions()->delete_course( $course_id ),
			'course_reviews'  => Services::reviews()->delete_course( $course_id ),
			'course_waitlist' => Services::waitlist()->delete_course( $course_id ),
			'wishlists'       => Services::wishlist()->delete_course( $course_id ),
		);
	}
}