# frozen_string_literal: true

# @private
class StatsD::Instrument::MetricExpectation
  attr_accessor :times, :type, :name, :value, :sample_rate, :tags
  attr_reader :ignore_tags

  def initialize(options = {})
    if options[:type]
      @type = options[:type]
    else
      raise ArgumentError, "Metric :type is required."
    end

    if options[:name]
      @name = options[:name]
    else
      raise ArgumentError, "Metric :name is required."
    end

    if options[:times]
      @times = options[:times]
    else
      raise ArgumentError, "Metric :times is required."
    end

    @name = StatsD.prefix ? "#{StatsD.prefix}.#{@name}" : @name unless options[:no_prefix]
    @tags = StatsD::Instrument::Metric.normalize_tags(options[:tags])
    @sample_rate = options[:sample_rate]
    @value = options[:value]
    @ignore_tags = StatsD::Instrument::Metric.normalize_tags(options[:ignore_tags])
  end

  def matches(actual_metric)
    return false if sample_rate && sample_rate != actual_metric.sample_rate
    return false if value && value != actual_metric.value

    if tags

      expected_tags = Set.new(tags)
      actual_tags = Set.new(actual_metric.tags)

      if ignore_tags
        ignored_tags = Set.new(ignore_tags) - expected_tags
        actual_tags -= ignored_tags

        if ignore_tags.is_a?(Array)
          actual_tags.delete_if { |key| ignore_tags.include?(key.split(":").first) }
        end
      end

      return expected_tags.subset?(actual_tags)
    end
    true
  end

  def default_value
    1 if type == :c
  end

  TYPES = {
    c: 'increment',
    ms: 'measure',
    g: 'gauge',
    h: 'histogram',
    d: 'distribution',
    kv: 'key/value',
    s: 'set',
  }

  def to_s
    str = +"#{TYPES[type]} #{name}:#{value}"
    str << " @#{sample_rate}" if sample_rate != 1.0
    str << " " << tags.map { |t| "##{t}" }.join(' ') if tags
    str << " times:#{times}" if times > 1
    str
  end

  def inspect
    "#<StatsD::Instrument::MetricExpectation #{self}>"
  end
end