class CaseLogCsv
  CSV_FIELDS_TO_OMIT = %w[hhmemb net_income_value_check sale_or_letting first_time_property_let_as_social_housing renttype needstype postcode_known is_la_inferred totchild totelder totadult net_income_known is_carehome previous_la_known is_previous_la_inferred age1_known age2_known age3_known age4_known age5_known age6_known age7_known age8_known letting_allocation_unknown details_known_2 details_known_3 details_known_4 details_known_5 details_known_6 details_known_7 details_known_8 rent_type wrent wscharge wpschrge wsupchrg wtcharge wtshortfall rent_value_check old_form_id old_id retirement_value_check tshortfall_known pregnancy_value_check hhtype new_old vacdays].freeze

  def initialize(all, user, attribute_names)
    @all = all
    @user = user
    @attribute_names = attribute_names
  end

  def to_csv
    CSV.generate(headers: true) do |csv|
      attributes = csv_attributes(@user)
      csv << attributes

      @all.find_each do |record|
        csv << attributes.map do |att|
          record.form.get_question(att, record)&.label_from_value(record.send(att)) || label_from_value(record.send(att))
        end
      end
    end
  end

  def label_from_value(value)
    return "Yes" if value == true
    return "No" if value == false

    value
  end

  def csv_attributes(user)
    attributes = @attribute_names + %w[unittype_sh]
    attributes = replace_csv_id_fields_with_names(attributes)

    attributes = order_csv_attributes(attributes)

    user.present? && !user.support? ? attributes - CSV_FIELDS_TO_OMIT : attributes
  end

  def replace_csv_id_fields_with_names(initial_attributes)
    attributes = initial_attributes.clone
    { "managing_organisation_id": "managing_organisation_name", "owning_organisation_id": "owning_organisation_name", "created_by_id": "created_by_name" }.each { |current, new_attribute| attributes[attributes.index(current.to_s)] = new_attribute }
    attributes
  end

  def order_csv_attributes(initial_attributes)
    attributes = initial_attributes.clone
    downloaded_form_years = @all.map(&:collection_start_year).uniq.compact

    downloaded_form_fields = downloaded_form_years.count == 1 && downloaded_form_years[0].present? ? FormHandler.instance.get_form("#{downloaded_form_years[0]}_#{downloaded_form_years[0] + 1}").questions : FormHandler.instance.forms.first.second.questions
    ordered_default_form_questions = move_checkbox_answer_options(downloaded_form_fields)

    attributes = (ordered_default_form_questions & attributes) + (attributes - ordered_default_form_questions)
    attributes = move_metadata_fields_to_front(attributes)
    attributes = move_is_inferred_fields(attributes)
    move_scheme_fields_to_back(attributes)
  end

  def move_checkbox_answer_options(form_questions)
    checkboxes = form_questions.filter { |question| question.type == "checkbox" }.map { |question| { "#{question.id}": question.answer_options.keys } }
    attributes = form_questions.map(&:id).uniq

    checkboxes.each do |checkbox_question|
      checkbox_question.values[0].each do |answer_option|
        attributes.insert(attributes.find_index(checkbox_question.keys[0].to_s), answer_option)
      end
    end
    attributes
  end

  def move_metadata_fields_to_front(attributes)
    metadata_fields = %w[managing_organisation_name owning_organisation_name is_dpo created_by_name updated_at created_at status id]
    move_csv_attributes(attributes, metadata_fields, 0)
  end

  def move_is_inferred_fields(initial_attributes)
    attributes = initial_attributes.clone
    { is_la_inferred: "la", is_previous_la_inferred: "prevloc" }.each do |field, inferred_field|
      attributes.delete(field.to_s)
      attributes.insert(attributes.find_index(inferred_field), field.to_s)
    end
    attributes
  end

  def move_scheme_fields_to_back(attributes)
    move_csv_attributes(attributes, %w[scheme_id location_id], -1)
  end

  def move_csv_attributes(initial_attributes, fields_to_move, index)
    attributes = initial_attributes.clone
    fields_to_move.each do |field|
      attributes.delete(field)
      attributes.insert(index, field)
    end
    attributes
  end
end