<?php

namespace App\Traits;

use InvalidArgumentException;

/**
 * Custom state machine trait for Eloquent models.
 * Replacement for spatie/laravel-model-states (incompatible with Laravel 13).
 *
 * Usage:
 *   1. Define a PHP enum for your states
 *   2. Use this trait on your model
 *   3. Implement `getStateMachineConfig()` returning state field + allowed transitions
 */
trait HasStateMachine
{
    /**
     * Get the state machine configuration.
     * Override in your model.
     *
     * @return array{field: string, transitions: array<string, string[]>}
     */
    abstract protected static function stateMachineConfig(): array;

    public function getStateField(): string
    {
        return static::stateMachineConfig()['field'];
    }

    public function getCurrentState(): string
    {
        $field = $this->getStateField();
        return $this->{$field};
    }

    public function canTransitionTo(string $newState): bool
    {
        $config = static::stateMachineConfig();
        $currentState = $this->getCurrentState();
        $transitions = $config['transitions'] ?? [];

        if (!isset($transitions[$currentState])) {
            return false;
        }

        return in_array($newState, $transitions[$currentState], true);
    }

    public function transitionTo(string $newState): static
    {
        if (!$this->canTransitionTo($newState)) {
            $currentState = $this->getCurrentState();
            $field = $this->getStateField();
            throw new InvalidArgumentException(
                "Cannot transition '{$field}' from '{$currentState}' to '{$newState}'."
            );
        }

        $field = $this->getStateField();
        $oldState = $this->getCurrentState();

        $this->{$field} = $newState;
        $this->save();

        // Fire an event for the transition
        $modelName = class_basename(static::class);
        event("{$modelName}StateChanged", [
            'model' => $this,
            'field' => $field,
            'from' => $oldState,
            'to' => $newState,
        ]);

        return $this;
    }

    public function getAllowedTransitions(): array
    {
        $config = static::stateMachineConfig();
        $currentState = $this->getCurrentState();
        return $config['transitions'][$currentState] ?? [];
    }
}