<?php

declare(strict_types=1);

namespace App\Form\Service\Abstract;

use App\Form\Model\BookingDtoInterface;
use App\Form\Service\Contract\FieldOptionsProviderInterface;

/**
 * Abstract base class for field options providers.
 *
 * This class contains common field options generation logic shared between
 * different field options provider implementations. It provides the core
 * functionality for managing field option providers and generating dynamic
 * field configurations.
 */
abstract class AbstractFieldOptionsProvider implements FieldOptionsProviderInterface
{
    /** @var array<string, callable> Field option providers indexed by field name */
    protected array $fieldOptionProviders = [];

    public function __construct()
    {
        $this->registerFieldOptionProviders();
    }

    /**
     * Retrieves form field options for a specified dynamic field.
     *
     * This method looks up the appropriate option provider for the field
     * and executes it with the current booking and participant context to
     * generate dynamic field options.
     *
     * The returned array contains Symfony form field options that will be
     * used when building the form field. These options are merged with any
     * static options defined in the form type.
     *
     * @param string              $fieldName        The name of the field to configure
     * @param BookingDtoInterface $bookingDto       The current booking data for context (create or edit)
     * @param int                 $participantIndex The index of the participant being configured
     *
     * @return array<string, mixed> Symfony form field options, or empty array if field not supported
     */
    public function getFieldOptions(string $fieldName, BookingDtoInterface $bookingDto, int $participantIndex): array
    {
        // Check if we have a provider for this field
        if (!isset($this->fieldOptionProviders[$fieldName])) {
            return [];
        }

        // Execute the provider with current context to generate dynamic options
        return $this->fieldOptionProviders[$fieldName]($bookingDto, $participantIndex);
    }

    /**
     * Checks whether a field has option provider support.
     *
     * This method allows form builders to determine if a field can be
     * dynamically configured by this service. It's useful for deciding
     * whether to use static field options or dynamic configuration.
     *
     * @param string $fieldName The name of the field to check
     *
     * @return bool True if the field has registered option providers, false otherwise
     */
    public function hasFieldOptions(string $fieldName): bool
    {
        return isset($this->fieldOptionProviders[$fieldName]);
    }

    /**
     * Registers field option providers during service initialization.
     *
     * This method must be implemented by concrete classes to define their
     * specific field option providers. Each provider is a callable that
     * receives the booking DTO and participant index and returns appropriate
     * Symfony form field options.
     *
     * Example implementation:
     *
     * protected function registerFieldOptionProviders(): void
     * {
     *     $this->fieldOptionProviders['fieldName'] = fn($bookingDto, $participantIndex) => [
     *         'label' => 'Field Label',
     *         'choices' => $this->generateChoicesFor($bookingDto, $participantIndex),
     *     ];
     * }
     */
    abstract protected function registerFieldOptionProviders(): void;
}