<?php
namespace Modules\Workflow\Services;
use Illuminate\Contracts\Auth\Authenticatable; use Illuminate\Database\Eloquent\Model; use Illuminate\Support\Facades\DB; use Illuminate\Validation\ValidationException; use Modules\Workflow\Models\WorkflowDefinition; use Modules\Workflow\Models\WorkflowHistory; use Modules\Workflow\Models\WorkflowInstance; use Modules\Workflow\Models\WorkflowTransition;
final class WorkflowManager {
 public function start(Model $subject, WorkflowDefinition $definition, ?Authenticatable $user=null): WorkflowInstance { return DB::transaction(function() use($subject,$definition,$user){ $stage=$definition->stages()->where('is_initial',true)->first() ?? $definition->stages()->firstOrFail(); $instance=WorkflowInstance::updateOrCreate(['subject_type'=>$subject->getMorphClass(),'subject_id'=>$subject->getKey()],['workflow_definition_id'=>$definition->getKey(),'workflow_stage_id'=>$stage->getKey(),'status'=>$stage->is_terminal?'completed':'active','started_by'=>$user?->getAuthIdentifier(),'due_at'=>$stage->due_days?now()->addDays($stage->due_days):null,'completed_at'=>$stage->is_terminal?now():null]); WorkflowHistory::create(['workflow_instance_id'=>$instance->id,'to_stage_id'=>$stage->id,'user_id'=>$user?->getAuthIdentifier(),'action'=>'started']); return $instance->fresh(['definition','stage']); }); }
 public function transition(WorkflowInstance $instance, string $action, ?Authenticatable $user=null, ?string $comment=null): WorkflowInstance { return DB::transaction(function() use($instance,$action,$user,$comment){ $transition=WorkflowTransition::where('workflow_definition_id',$instance->workflow_definition_id)->where('from_stage_id',$instance->workflow_stage_id)->where('action',$action)->first(); if(!$transition) throw ValidationException::withMessages(['action'=>'This transition is not available.']); if($transition->requires_comment && blank($comment)) throw ValidationException::withMessages(['comment'=>'A comment is required.']); if($transition->required_permission && (!$user || !method_exists($user,'can') || !$user->can($transition->required_permission))) abort(403); $target=\Modules\Workflow\Models\WorkflowStage::findOrFail($transition->to_stage_id); $from=$instance->workflow_stage_id; $instance->update(['workflow_stage_id'=>$target->id,'status'=>$target->is_terminal?'completed':'active','due_at'=>$target->due_days?now()->addDays($target->due_days):null,'completed_at'=>$target->is_terminal?now():null]); WorkflowHistory::create(['workflow_instance_id'=>$instance->id,'from_stage_id'=>$from,'to_stage_id'=>$target->id,'user_id'=>$user?->getAuthIdentifier(),'action'=>$action,'comment'=>$comment]); return $instance->fresh(['definition','stage','subject']); }); }
}