TimeSeries (trend.rb)

Calculates directional trend from current and previous values, returning color-coded indicators, percentage changes, and JSON-serialized data for time-series visualization.

class TimeSeries::Trend
  include ActiveModel::Validations

  attr_reader :current, :previous, :favorable_direction

  validate :values_must_be_of_same_type, :values_must_be_of_known_type

  def initialize(current:, previous:, series: nil, favorable_direction: nil)
    @current = current
    @previous = previous
    @series = series
    @favorable_direction = get_favorable_direction(favorable_direction)

    validate!
  end

  def direction
    if previous.nil? || current == previous
      "flat"
    elsif current && current > previous
      "up"
    else
      "down"
    end.inquiry
  end

  def color
    case direction
    when "up"
      favorable_direction.down? ? red_hex : green_hex
    when "down"
      favorable_direction.down? ? green_hex : red_hex
    else
      gray_hex
    end
 

... (truncated -- full source via MCP)