package fr.tiogars.chat.domains.task.services;
   
   import java.io.IOException;
   import java.util.List;
   import java.util.Optional;
   
   import org.springframework.stereotype.Service;
   import org.springframework.transaction.annotation.Transactional;
   
  import fr.tiogars.chat.domains.task.models.Task;
  import fr.tiogars.chat.domains.task.repositories.TaskRepository;
  
  /** Generates a printable PDF for selected active Tasks. */
  @Service
  public class TasksPrintSelectedService {
  
      private final TaskRepository repository;
      private final TaskPdfRenderer renderer;
  
      public TasksPrintSelectedService(TaskRepository repository, TaskPdfRenderer renderer) {
          this.repository = repository;
          this.renderer = renderer;
      }
  
      /**
       * Prints a selection ordered by code without duplicating records.
       *
       * @param ids selected persistent identifiers
       * @return PDF bytes, or empty if any selected record was not found
       * @throws IOException when the PDF cannot be generated
       */
      @Transactional(readOnly = true)
      public Optional<byte[]> printSelected(List<Long> ids) throws IOException {
          if (ids.isEmpty()) {
              throw new IllegalArgumentException("Select at least one Task to print.");
          }
          List<Long> uniqueIds = ids.stream().distinct().toList();
          List<Task> templates = repository.findAllByIdInOrderByCodeAsc(uniqueIds).stream()
                  .map(TaskFindAllService::toRecord)
                  .toList();
          if (templates.size() != uniqueIds.size()) {
              return Optional.empty();
          }
          return Optional.of(renderer.render("Selected Tasks", templates));
      }
  }