<?php


namespace Vizyt\Privacy;

defined( 'ABSPATH' ) || exit;
// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Vizyt's own tables ({prefix}vizyt_*); exports and erasures must see the current data.

use Vizyt\Models\BookingEvent;
use Vizyt\Models\Customer;

/**
 * WordPress personal data tools (Tools → Export / Erase Personal Data) for
 * Vizyt customers, found by email.
 *
 * Export: the customer row(s) (with tags, notes and date of birth), their
 * bookings (service, specialist, times, status, price, note) and the
 * bookings' history. Erase: Customer::anonymise() — the customer is
 * anonymised and hidden from the admin lists, and the cancel reasons and
 * booking notes (the widget stores the customer's own comment there) are
 * cleared; the bookings themselves stay (statistics, revenue, the
 * specialists' calendars). Deleting a customer with bookings in the admin
 * does the same.
 */
final class PersonalData {

    /** Bookings per exporter page (each with its history). */
    const PER_PAGE = 50;

    public static function register(): void {
        add_filter( 'wp_privacy_personal_data_exporters', [ self::class, 'exporters' ] );
        add_filter( 'wp_privacy_personal_data_erasers', [ self::class, 'erasers' ] );
    }

    public static function exporters( $exporters ): array {
        $exporters          = (array) $exporters;
        $exporters['vizyt'] = [
            'exporter_friendly_name' => __( 'Vizyt bookings', 'vizyt' ),
            'callback'               => [ self::class, 'export' ],
        ];
        return $exporters;
    }

    public static function erasers( $erasers ): array {
        $erasers          = (array) $erasers;
        $erasers['vizyt'] = [
            'eraser_friendly_name' => __( 'Vizyt bookings', 'vizyt' ),
            'callback'             => [ self::class, 'erase' ],
        ];
        return $erasers;
    }

    /**
     * @return array{data: array<int, array{group_id: string, group_label: string, group_description: string, item_id: string, data: array<int, array{name: string, value: string}>}>, done: bool}
     */
    public static function export( $email, $page = 1 ): array {
        global $wpdb;

        $page      = max( 1, (int) $page );
        $customers = self::customers( (string) $email );
        if ( ! $customers ) {
            return [ 'data' => [], 'done' => true ];
        }

        $data = [];

        if ( 1 === $page ) {
            foreach ( $customers as $customer ) {
                $data[] = self::item( 'vizyt-customer', __( 'Booking customer', 'vizyt' ), __( 'Your details as the business keeps them for bookings.', 'vizyt' ), 'vizyt-customer-' . (int) $customer->id, [
                    __( 'First name', 'vizyt' )    => $customer->first_name,
                    __( 'Last name', 'vizyt' )     => $customer->last_name,
                    __( 'Email', 'vizyt' )         => $customer->email,
                    __( 'Phone', 'vizyt' )         => $customer->phone,
                    __( 'Date of birth', 'vizyt' ) => $customer->date_of_birth,
                    __( 'Notes', 'vizyt' )         => $customer->notes,
                    __( 'Tags', 'vizyt' )          => implode( ', ', Customer::tagList( $customer->tags ) ),
                    __( 'Created', 'vizyt' )       => $customer->created_at,
                ] );
            }
        }

        $ids      = array_map( static fn( $c ) => (int) $c->id, $customers );
        $bookings = (array) $wpdb->get_results(
            $wpdb->prepare(
                "SELECT b.*, s.name AS service_name, st.name AS staff_name
                   FROM {$wpdb->prefix}vizyt_bookings b
                   LEFT JOIN {$wpdb->prefix}vizyt_services s ON s.id = b.service_id
                   LEFT JOIN {$wpdb->prefix}vizyt_staff st ON st.id = b.staff_id
                  WHERE b.customer_id IN (" . implode( ',', array_fill( 0, count( $ids ), '%d' ) ) . ')
                  ORDER BY b.id ASC
                  LIMIT %d OFFSET %d',
                array_merge( $ids, [ self::PER_PAGE, ( $page - 1 ) * self::PER_PAGE ] )
            )
        );

        foreach ( $bookings as $booking ) {
            $data[] = self::item( 'vizyt-bookings', __( 'Bookings', 'vizyt' ), __( 'Appointments booked with the business.', 'vizyt' ), 'vizyt-booking-' . (int) $booking->id, [
                __( 'Booking', 'vizyt' )        => '#' . (int) $booking->id,
                __( 'Service', 'vizyt' )        => $booking->service_name,
                __( 'Specialist', 'vizyt' )     => $booking->staff_name,
                __( 'Start', 'vizyt' )          => $booking->start_datetime,
                __( 'End', 'vizyt' )            => $booking->end_datetime,
                __( 'Status', 'vizyt' )         => $booking->status,
                __( 'Price', 'vizyt' )          => $booking->price . ' ' . $booking->currency,
                __( 'Cancel reason', 'vizyt' )  => $booking->cancel_reason,
                __( 'Notes', 'vizyt' )          => $booking->internal_note,
                __( 'Created', 'vizyt' )        => $booking->created_at,
            ] );
        }

        if ( $bookings ) {
            $booking_ids = array_map( static fn( $b ) => (int) $b->id, $bookings );
            $events      = (array) $wpdb->get_results(
                $wpdb->prepare(
                    'SELECT id, booking_id, type, meta, created_at FROM %i WHERE booking_id IN (' . implode( ',', array_fill( 0, count( $booking_ids ), '%d' ) ) . ') ORDER BY id ASC',
                    array_merge( [ BookingEvent::table() ], $booking_ids )
                )
            );
            foreach ( $events as $event ) {
                $meta    = $event->meta ? json_decode( (string) $event->meta, true ) : [];
                $details = [];
                foreach ( is_array( $meta ) ? $meta : [] as $key => $value ) {
                    $details[] = $key . ': ' . ( is_bool( $value ) ? ( $value ? 'yes' : 'no' ) : (string) $value );
                }
                $data[] = self::item( 'vizyt-booking-history', __( 'Booking history', 'vizyt' ), __( 'What happened to each booking.', 'vizyt' ), 'vizyt-booking-event-' . (int) $event->id, [
                    __( 'Booking', 'vizyt' ) => '#' . (int) $event->booking_id,
                    __( 'Event', 'vizyt' )   => $event->type,
                    __( 'Date', 'vizyt' )    => $event->created_at . ' UTC',
                    __( 'Details', 'vizyt' ) => implode( '; ', $details ),
                ] );
            }
        }

        return [
            'data' => $data,
            'done' => count( $bookings ) < self::PER_PAGE,
        ];
    }

    /**
     * @return array{items_removed: bool, items_retained: bool, messages: string[], done: bool}
     */
    public static function erase( $email, $page = 1 ): array {
        $customers = self::customers( (string) $email );
        if ( ! $customers ) {
            return [ 'items_removed' => false, 'items_retained' => false, 'messages' => [], 'done' => true ];
        }

        $kept   = 0;
        $erased = 0;
        $failed = 0;
        foreach ( $customers as $customer ) {
            $result = Customer::anonymise( (int) $customer->id );
            if ( false === $result ) {
                ++$failed; // rolled back: this customer is unchanged
                continue;
            }
            ++$erased;
            $kept += $result;
        }

        $messages = [];
        if ( $kept > 0 ) {
            $messages[] = __( 'Vizyt bookings were kept without personal details, for the business statistics.', 'vizyt' );
        }
        if ( $failed > 0 ) {
            $messages[] = __( 'Some Vizyt customer details could not be erased because of a database error. Nothing was changed for them; try again.', 'vizyt' );
        }

        return [
            'items_removed'  => $erased > 0,
            'items_retained' => $kept > 0 || $failed > 0,
            'messages'       => $messages,
            'done'           => true,
        ];
    }

    /**
     * Customer rows with this email (several rows may share one).
     *
     * @return object[]
     */
    private static function customers( string $email ): array {
        global $wpdb;

        $email = sanitize_email( $email );
        if ( '' === $email ) {
            return [];
        }

        return (array) $wpdb->get_results(
            $wpdb->prepare( "SELECT * FROM {$wpdb->prefix}vizyt_customers WHERE email = %s ORDER BY id ASC", $email )
        );
    }

    /**
     * One exporter item; empty values are left out.
     *
     * @param array<string, mixed> $fields label => value
     */
    private static function item( string $group, string $label, string $description, string $item_id, array $fields ): array {
        $data = [];
        foreach ( $fields as $name => $value ) {
            if ( null !== $value && '' !== (string) $value ) {
                $data[] = [ 'name' => (string) $name, 'value' => (string) $value ];
            }
        }

        return [
            'group_id'          => $group,
            'group_label'       => $label,
            'group_description' => $description,
            'item_id'           => $item_id,
            'data'              => $data,
        ];
    }
}