module Exportable

def attach_export_file
  file_path = generate_excel
  filename = file_path&.split('/')&.last
  export_file.attach(io: File.open(file_path), filename:)
rescue StandardError => e
  failed!
  raise e
end

def create_workbook(cm_model, records, file_path)
  flattened_records = records.map { |record| CmAdmin::Utils.flatten_hash(record) }
  columns = exportable_columns(cm_model).select do |column|
    flattened_records.first.keys.include?(column.field_name.to_s)
  end
  size_arr = []
  columns.size.times { size_arr << 22 }
  xl = Axlsx::Package.new
  xl.workbook.add_worksheet do |sheet|
    sheet.add_row columns&.map(&:header), b: true
    flattened_records.each do |record|
      sheet.add_row(columns.map { |column| record[column.field_name.to_s] })
    end
    sheet.column_widths(*size_arr)
  end
  xl.serialize(file_path)
end

def exportable_columns(klass, action_name: :index)
  klass.available_fields[action_name].select(&:exportable)
end

def fetch_ar_object(model_object, id)
  return model_object.friendly.find(id) if model_object.respond_to?(:friendly)
  model_object.find(id)
end

def format_records(records, model, selected_column_names, parent_model:, action_name: :index)
  deserialized_columns = CmAdmin::Utils.deserialize_csv_columns(selected_column_names, :as_json_params)
  main_model = parent_model || model
  available_fields = main_model.available_fields[action_name.to_sym]
  # This includes isn't recursve, a full solution should be recursive
  records_arr = []
  records.includes(deserialized_columns[:include].keys).find_each do |record|
    record_hash = record.as_json({ only: selected_column_names.map(&:to_sym) })
    selected_column_names.each do |column_name|
      break unless available_fields.map(&:field_name).include?(column_name.to_sym)
      column = CmAdmin::Models::Column.find_by(model, :index, { name: column_name.to_sym })
      record_hash[column.field_name] = if column.field_type == :custom
                                         send(column.helper_method, record, column.field_name).to_s
                                       else
                                         record.send(column.field_name).to_s
                                       end
    end
    records_arr << record_hash
  end
  records_arr
end

def generate_excel
  params = self.params.with_indifferent_access
  klass_name = params[:class_name]
  associated_klass_name = params[:associated_class_name]
  action_name = params[:action_name] || 'index'
  model = CmAdmin::Model.find_by({ name: klass_name })
  klass = klass_name.constantize
  current_action = CmAdmin::Models::Action.find_by(model, name: action_name)
  if associated_klass_name.present? && params[:parent_id].present?
    scoped_model = "CmAdmin::#{model.name}Policy#{action_name.classify}Scope".constantize.new(Current.user, klass).resolve
    parent_model = model
    model = CmAdmin::Model.find_by({ name: associated_klass_name })
    parent_record = fetch_ar_object(scoped_model, params[:parent_id])
    child_records = parent_record.send(params[:child_records])
  end
  selected_column_names = params[:columns] || []
  records = if associated_klass_name.present?
              child_records
            else
              "CmAdmin::#{klass_name}Policy::Scope".constantize.new(Current.user, klass).resolve
            end
  records.includes(current_action.eager_load_associations) if current_action.eager_load_associations.present?
  filter_params = JSON.parse(params[:filters] || '{}')
  filtered_data = CmAdmin::Models::Filter.filtered_data(filter_params, records, model.filters)
  formatted_data = format_records(filtered_data, model, selected_column_names, parent_model:, action_name:)
  file_path = "#{Rails.root}/tmp/#{model.name}_data_#{DateTime.now.strftime('%Y-%m-%d_%H-%M-%S')}.xlsx"
  create_workbook(model, formatted_data, file_path)
  file_path
end