require "spec_helper"

describe Tabs::Metrics::Counter do

  include Tabs::Storage

  let(:metric) { Tabs.create_metric("foo", "counter") }
  let(:now) { Time.utc(2000, 1, 1, 0, 0) }

  describe "incrementing stats" do

    before { Timecop.freeze(now) }

    it "increments the value for the expected periods" do
      metric.increment
      time = Time.utc(now.year, now.month, now.day, now.hour)
      stats = metric.stats(((now - 2.hours)..(now + 4.hours)), :hour)
      expect(stats).to include({ "timestamp" => time, "count" => 1 })
    end

    it "applys the increment to the specified timestamp if one is supplied" do
      time = Time.utc(now.year, now.month, now.day, now.hour) - 2.hours
      metric.increment(time)
      stats = metric.stats(((now - 3.hours)..now), :hour)
      expect(stats).to include({ "timestamp" => time, "count" => 1 })
    end

    it "raises ResolutionMissingError if unregistered resolution requested" do
      time = Time.utc(now.year, now.month, now.day, now.hour) - 2.hours
      metric.increment(time)
      Tabs::Resolution.unregister(:hour)
      expect { metric.stats(((now - 3.hours)..now), :hour) }.to raise_error(Tabs::ResolutionMissingError)
    end

  end

  describe "total count" do

    it "is incremented every time regardless of resolution" do
      30.times { metric.increment }
      expect(metric.total).to eq(30)
    end

  end

  describe "retrieving stats" do

    before do
      Timecop.freeze(now)
    end

    after do
      Timecop.return
    end

    def create_span(time_unit)
      metric.increment
      Timecop.freeze(now + 1.send(time_unit))
      metric.increment
      Timecop.freeze(now + 3.send(time_unit))
      metric.increment
      Timecop.freeze(now + 6.send(time_unit))
      metric.increment
      metric.increment
      Timecop.freeze(now)
    end

    it "returns the expected results for an minutely metric" do
      create_span(:minute)
      stats = metric.stats(now..(now + 7.minutes), :minute)
      expect(stats).to include({ "timestamp" => (now + 3.minutes), "count" => 1 })
      expect(stats).to include({ "timestamp" => (now + 6.minutes), "count" => 2 })
    end

    it "returns the expected results for an hourly metric" do
      create_span(:hours)
      stats = metric.stats(now..(now + 7.hours), :hour)
      expect(stats).to include({ "timestamp" => (now + 3.hours), "count" => 1 })
      expect(stats).to include({ "timestamp" => (now + 6.hours), "count" => 2 })
    end

    it "returns the expected results for a daily metric" do
      create_span(:days)
      stats = metric.stats(now..(now + 7.days), :day)
      expect(stats).to include({ "timestamp" => (now + 3.days), "count" => 1 })
      expect(stats).to include({ "timestamp" => (now + 6.days), "count" => 2 })
    end

    it "returns the expected results for a monthly metric" do
      create_span(:months)
      stats = metric.stats(now..(now + 7.months), :month)
      expect(stats).to include({ "timestamp" => (now + 3.months), "count" => 1 })
      expect(stats).to include({ "timestamp" => (now + 6.months), "count" => 2 })
    end

    it "returns the expected results for a yearly metric" do
      create_span(:years)
      stats = metric.stats(now..(now + 7.years), :year)
      expect(stats).to include({ "timestamp" => (now + 3.years), "count" => 1 })
      expect(stats).to include({ "timestamp" => (now + 6.years), "count" => 2 })
    end

    it "returns zeros for time periods which do not have any events" do
      create_span(:days)
      stats = metric.stats(now..(now + 7.days), :day)
      expect(stats.detect{|s| s["timestamp"] == (now + 2.day)}["count"]).to eq(0)
    end

    context "for weekly metrics" do

      let(:period) do
        (now - 2.days)..((now + 7.weeks) + 2.days)
      end

      it "returns the expected results for a weekly metric" do
        create_span(:weeks)
        stats = metric.stats(period, :week)
        expect(stats.detect{|s| s["timestamp"] == (now + 1.week).beginning_of_week}["count"]).to eq(1)
        expect(stats).to include({ "timestamp" => (now + 3.weeks).beginning_of_week, "count" => 1 })
        expect(stats).to include({ "timestamp" => (now + 6.weeks).beginning_of_week, "count" => 2 })
      end

      it "normalizes the period to the first day of the week" do
        create_span(:weeks)
        stats = metric.stats(period, :week)
        expect(stats.first["timestamp"]).to eq(period.first.beginning_of_week)
        expect(stats.last["timestamp"]).to eq(period.last.beginning_of_week)
      end

    end

  end

  describe ".drop!" do

    before do
      3.times { metric.increment }
      expect(exists("stat:counter:foo:total")).to be_true
      @count_keys = (Tabs::Resolution.all.map do |res|
        smembers("stat:counter:foo:keys:#{res}")
      end).flatten
      metric.drop!
    end

    it "deletes the counter total key" do
      expect(exists("stat:counter:foo:total")).to be_false
    end

    it "deletes all resolution count keys" do
      @count_keys.each do |key|
        expect(exists(key)).to be_false
      end
    end

    it "deletes all resolution key collection keys" do
      Tabs::Resolution.all.each do |res|
        expect(exists("stat:counter:foo:keys:#{res}")).to be_false
      end
    end

  end

  describe ".drop_by_resolution!" do
    before do
      Timecop.freeze(now)
      2.times { metric.increment }
      metric.drop_by_resolution!(:minute)
    end

    it "deletes all metrics for a resolution" do
      stats = metric.stats((now - 1.minute)..(now + 1.minute), :minute)
      expect(stats.total).to eq(0)
    end
  end

  describe "expiration of counter metrics" do
    let(:expires_setting){ 6.hours }
    let(:now){ Time.utc(2050, 1, 1, 0, 0) }

    before do
      Tabs::Config.set_expirations({ minute: expires_setting })
    end

    after do
      Tabs::Config.reset_expirations
    end

    it "sets an expiration when recording a value" do
      metric.increment(now)
      redis_expire_date = Time.now + Tabs::Storage.ttl(metric.storage_key(:minute, now))
      expire_date = now + expires_setting + Tabs::Resolutions::Minute.to_seconds
      expect(redis_expire_date).to be_within(2.seconds).of(expire_date)
    end
  end

end