# frozen_string_literal: true

require "govuk_design_system_formbuilder"

module Koi
  module Form
    module Elements
      module FileElement
        extend ActiveSupport::Concern

        using GOVUKDesignSystemFormBuilder::PrefixableArray

        include GOVUKDesignSystemFormBuilder::Traits::Error
        include GOVUKDesignSystemFormBuilder::Traits::Hint
        include GOVUKDesignSystemFormBuilder::Traits::Label
        include GOVUKDesignSystemFormBuilder::Traits::Supplemental
        include GOVUKDesignSystemFormBuilder::Traits::HTMLAttributes
        include GOVUKDesignSystemFormBuilder::Traits::HTMLClasses
        include ActionDispatch::Routing::RouteSet::MountedHelpers

        def html
          GOVUKDesignSystemFormBuilder::Containers::FormGroup.new(
            *bound,
            **default_form_group_options(**@form_group),
          ).html do
            safe_join([label_element, preview, hint_element, error_element, file, destroy_element,
                       supplemental_content])
          end
        end

        protected

        def stimulus_controller_actions
          <<~ACTIONS.gsub(/\s+/, " ").freeze
            dragover->#{stimulus_controller}#dragover
            dragenter->#{stimulus_controller}#dragenter
            dragleave->#{stimulus_controller}#dragleave
            drop->#{stimulus_controller}#drop
          ACTIONS
        end

        def stimulus_controller
          nil
        end

        def file
          previous_input = @builder.hidden_field(@attribute_name, id: nil, value: value.signed_id) if attached?
          file_input     = @builder.file_field(@attribute_name, attributes(@html_attributes))

          safe_join([previous_input, file_input])
        end

        def destroy_element
          return if @html_attributes[:optional].blank?

          @builder.fields_for(:"#{@attribute_name}_attachment") do |form|
            form.hidden_field :_destroy, value: false, data: { "#{stimulus_controller}_target" => "destroy" }
          end
        end

        def destroy_element_trigger
          return if @html_attributes[:optional].blank?

          content_tag(:button, "", class: "file-destroy", data: { action: "#{stimulus_controller}#setDestroy" })
        end

        def preview
          ""
        end

        def preview_url
          preview? ? main_app.url_for(value) : ""
        end

        def preview?
          attached?
        end

        def attached?
          value&.attached? && value.blob.persisted?
        end

        def value
          @builder.object.send(@attribute_name)
        end

        def file_input_options
          default_file_input_options = options

          add_option(default_file_input_options, :accept, @mime_types.join(","))
          add_option(default_file_input_options, :data, :action, "change->#{stimulus_controller}#onUpload")

          default_file_input_options
        end

        def options
          {
            id:    field_id(link_errors: true),
            class: classes,
            aria:  { describedby: combine_references(hint_id, error_id, supplemental_id) },
          }
        end

        def classes
          build_classes(%(file-upload), %(file-upload--error) => has_errors?).prefix(brand)
        end

        def default_form_group_options(**form_group_options)
          add_option(form_group_options, :class, "govuk-form-group #{form_group_class}")
          add_option(form_group_options, :data, :controller, stimulus_controller)
          add_option(form_group_options, :data, :action, stimulus_controller_actions)
          add_option(form_group_options, :data, :"#{stimulus_controller}_mime_types_value",
                     @mime_types.to_json)

          form_group_options
        end

        def add_option(options, key, *path)
          if path.length > 1
            add_option(options[key] ||= {}, *path)
          else
            options[key] = [options[key], *path].compact.join(" ")
          end
        end
      end
    end
  end
end