module NSWTopo::ArcGIS::Renderer

def classify(*fields, where: @where)
  raise TooManyFieldsError unless fields.size <= 3
  raise NoGeometryError, "ArcGIS layer does not support spatial filtering: #{@name}" if @geometry
  types = fields.map do |name|
    @layer["fields"].find do |field|
      field["name"] == name
    end&.fetch("type")
  end
  counts, values = 2.times do |repeat|
    counts, values = %w[| ~ ^ #].find do |delimiter|
      classification_def = { type: "uniqueValueDef", uniqueValueFields: fields.take(repeat) + fields, fieldDelimiter: delimiter }
      unique_values = get_json("#{@id}/generateRenderer", where: join_clauses(*where), classificationDef: classification_def.to_json).fetch("uniqueValueInfos")
      values = unique_values.map do |info|
        info["value"].split(delimiter).map(&:strip)
      end
      next unless values.all? do |values|
        values.length == fields.length + repeat
      end
      repeat.times { values.each(&:shift) }
      counts = unique_values.map do |info|
        info["count"]
      end
      break counts, values
    end
    raise "couldn't delimit values" unless values
    next if 0 == repeat && fields.one? && (counts.all?(1) || counts.all?(0))
    break counts, values
  end
  values.map do |values|
    values.zip(types).map do |value, type|
      case
      when value == "<Null>" then nil
      when value == "" then nil
      when type == "esriFieldTypeOID" then Integer(value)
      when type == "esriFieldTypeInteger" then Integer(value)
      when type == "esriFieldTypeSmallInteger" then Integer(value)
      when type == "esriFieldTypeDouble" then Float(value)
      when type == "esriFieldTypeSingle" then Float(value)
      when type == "esriFieldTypeString" then String(value)
      when type == "esriFieldTypeGUID" then String(value)
      when type == "esriFieldTypeDate"
        begin
          Time.strptime(value, "%m/%d/%Y %l:%M:%S %p").to_i * 1000
        rescue ArgumentError
        end
      end
    rescue ArgumentError
      raise "could not interpret #{value.inspect} as #{type}"
    end.then do |values|
      fields.zip values
    end.to_h
  end.zip counts
end