<?php

declare(strict_types=1);

namespace App\Form\Service\Abstract;

use App\Form\Model\BookingDto;
use App\Form\Service\Contract\FieldConditionInterface;
use App\Form\Service\Contract\FieldStateProviderInterface;
use App\Form\Service\Trait\FormTraversalTrait;

/**
 * Abstract base class for field state providers.
 *
 * This class contains common field state evaluation logic shared between
 * different field state provider implementations. It provides the core
 * functionality for evaluating field conditions and applying state modifications.
 */
abstract class AbstractFieldStateProvider implements FieldStateProviderInterface
{
    use FormTraversalTrait;

    /** @var array<string, array<string, FieldConditionInterface>> Field state conditions indexed by field name and state type */
    protected array $fieldStateConditions = [];

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

    /**
     * Determines whether a field should be included in the form at all.
     *
     * Fields with 'hidden' state conditions should not be added to the form
     * rather than being hidden with CSS. This method evaluates the hidden
     * condition independently to allow early field exclusion.
     *
     * @param string               $fieldName        The name of the field to evaluate
     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
     * @param int                  $participantIndex The index of the participant being evaluated
     * @param array<string, mixed> $formData         Current form data for condition evaluation
     *
     * @return bool True if the field should be included in the form, false if it should be excluded
     */
    public function shouldIncludeField(string $fieldName, BookingDto $bookingDto, int $participantIndex, array $formData = []): bool
    {
        if (false === isset($this->fieldStateConditions[$fieldName]['hidden'])) {
            return true; // No hidden condition means field should be included
        }

        $hiddenCondition = $this->fieldStateConditions[$fieldName]['hidden'];

        return !$hiddenCondition->evaluate($bookingDto, $participantIndex, $formData);
    }

    /**
     * Calculates the dynamic state for a specified field.
     *
     * Evaluates all configured conditions for a field and returns the appropriate
     * state modifications. State conditions are organized by state type (readonly,
     * disabled, etc.) and evaluated independently.
     *
     * Note: This method no longer handles 'hidden' state as fields should be
     * excluded from the form entirely rather than hidden with CSS.
     *
     * @param string               $fieldName        The name of the field to evaluate
     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
     * @param int                  $participantIndex The index of the participant being evaluated
     * @param array<string, mixed> $formData         Current form data for condition evaluation
     *
     * @return array<string, mixed> Symfony form field options for state modifications
     */
    public function getFieldState(string $fieldName, BookingDto $bookingDto, int $participantIndex, array $formData = []): array
    {
        if (false === isset($this->fieldStateConditions[$fieldName])) {
            return [];
        }

        $stateModifications = [];
        $attributes = [];

        foreach ($this->fieldStateConditions[$fieldName] as $stateType => $condition) {
            if ($condition->evaluate($bookingDto, $participantIndex, $formData)) {
                switch ($stateType) {
                    case 'readonly':
                        $attributes['readonly'] = true;
                        break;
                    case 'disabled':
                        $stateModifications['disabled'] = true;
                        break;
                    case 'required':
                        $stateModifications['required'] = true;
                        break;
                }
            }
        }

        if (false === empty($attributes)) {
            $stateModifications['attr'] = $attributes;
        }

        return $stateModifications;
    }

    /**
     * Checks whether a field has state conditions configured.
     *
     * @param string $fieldName The name of the field to check
     *
     * @return bool True if the field has state conditions configured
     */
    public function hasStateConditions(string $fieldName): bool
    {
        return isset($this->fieldStateConditions[$fieldName]) && !empty($this->fieldStateConditions[$fieldName]);
    }

    /**
     * Returns field names that trigger state re-evaluation for a given field.
     *
     * @param string $fieldName The name of the field to get dependencies for
     *
     * @return string[] Array of field names that affect the specified field's state
     */
    public function getFieldStateDependencies(string $fieldName): array
    {
        if (!isset($this->fieldStateConditions[$fieldName])) {
            return [];
        }

        $dependencies = [];

        foreach ($this->fieldStateConditions[$fieldName] as $condition) {
            $dependencies = array_merge($dependencies, $condition->getDependentFields());
        }

        return array_unique($dependencies);
    }

    /**
     * Calculates field states for all configured fields at once.
     *
     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
     * @param int                  $participantIndex The index of the participant being evaluated
     * @param array<string, mixed> $formData         Current form data for condition evaluation
     *
     * @return array<string, array<string, mixed>> Field states indexed by field name
     */
    public function getAllFieldStates(BookingDto $bookingDto, int $participantIndex, array $formData = []): array
    {
        $allStates = [];

        foreach (array_keys($this->fieldStateConditions) as $fieldName) {
            $fieldState = $this->getFieldState($fieldName, $bookingDto, $participantIndex, $formData);
            if (!empty($fieldState)) {
                $allStates[$fieldName] = $fieldState;
            }
        }

        return $allStates;
    }

    /**
     * Registers field state conditions during service initialization.
     *
     * This method must be implemented by concrete classes to define their
     * specific field state conditions.
     */
    abstract protected function registerFieldStateConditions(): void;
}