= form_with url: submit_main_path, multipart: true, class: 'form' do |form|
  - if @submission and @submission.errors.any?
    #error_explanation
      .alert.alert-danger
        %h3= "#{pluralize(@submission.errors.count, "error")} prohibited this user from being saved:"
        %ul
          - @submission.errors.full_messages.each do |msg|
            %li= msg
  .row.mb-2
    .col-sm-2
      = form.label :submission, 'Problem:', class: 'col-form-label'
    .col-sm-10
      = select 'submission', 'problem_id', [[(t 'main.specified_in_header'),'-1']] + @problems.collect {|p| ["[#{p.name}] #{p.full_name}", p.id]}, {:selected => '-1'}, { class: 'select2 form-control', style: "width: 100%" }
  .row.mb-2
    .col-sm-2
      = form.label :file, 'File:', class: 'col-form-label'
    .col-sm-10
      = form.file_field :file, class: 'form-control'
  = form.submit 'Submit', class: 'btn btn-primary'