<?php

declare(strict_types=1);

namespace App\Form\Service\Condition;

use App\Form\Model\BookingDto;
use App\Form\Service\Contract\FieldConditionInterface;

/**
 * Condition that determines if the first participant's personal data should be read-only.
 *
 * It fires only where participant[0] IS the booking's applicant, which
 * BookingDto::isFirstParticipantApplicant() decides: the booking-level choice in create mode,
 * and anmelder vs. participant[0] person id in edit mode, where internal agency bookings
 * always answer false.
 *
 * Business Rules:
 * - CREATE mode (anonymous user): First participant data is editable (user must fill it in)
 * - CREATE mode (logged-in, participant[0] is the applicant): data is prepopulated, read-only
 * - CREATE mode (applicant does not travel): participant[0] is an ordinary traveller, data is
 *   editable
 * - EDIT mode (participant[0] is the applicant): always read-only
 * - EDIT mode (split booking, or internal agency): participant[0] ≠ applicant, editable here
 *   (PersonalDataMutabilityCondition still applies separately)
 *
 * Non-first participants are never affected by this condition - they return false here
 * but may still be read-only via PersonalDataMutabilityCondition in edit mode.
 */
class FirstParticipantReadOnlyCondition implements FieldConditionInterface
{
    /**
     * Evaluates if personal data fields should be shown as static text for the first participant.
     *
     * @param BookingDto           $bookingDto       The booking data
     * @param int                  $participantIndex The index of the participant being evaluated
     * @param array<string, mixed> $formData         Current form data (unused)
     *
     * @return bool True if fields should be shown as static text (read-only)
     */
    public function evaluate(BookingDto $bookingDto, int $participantIndex, array $formData): bool
    {
        // This condition only applies to the first participant.
        // Non-first participants: return false here, but may still be read-only via PersonalDataMutabilityCondition
        if (0 !== $participantIndex) {
            return false;
        }

        // participant[0] is a traveller in their own right: nothing to protect here.
        if (false === $bookingDto->isFirstParticipantApplicant()) {
            return false;
        }

        if (BookingDto::MODE_CREATE === $bookingDto->getMode()) {
            // Anonymous user (no personId) = must fill in data = editable
            return null !== $bookingDto->getParticipant($participantIndex)?->personId;
        }

        // EDIT mode: participant[0] is the applicant, whose record is owned by the account.
        return true;
    }

    /**
     * Returns field names that this condition depends on.
     *
     * This condition is based on the applicant split and personId, which are set during
     * initialization and don't change during form interaction, so no field dependencies.
     *
     * @return string[] Empty array - no field dependencies
     */
    public function getDependentFields(): array
    {
        return [];
    }

    /**
     * Returns a human-readable description of this condition.
     *
     * @return string Description of the first participant read-only logic
     */
    public function getDescription(): string
    {
        return 'First participant personal data is read-only when they are also the applicant';
    }
}