gistfile1.txt

  def calculate_cached_attributes
    # TODO OPTIMIZE
    clocks.sort_by!(&:datetime)

    self.started_at = clocks.first.datetime

    # assign finished_at if shift is finished and check that there isn't one finish clock
    if clocks.last.activity == :finish && clocks.first != clocks.last
      self.finished_at = clocks.last.datetime
    else
      self.finished_at = nil
    end

    following_clock = nil
    shift_duration = 0

    clocks.reverse.each do |clock|
      if following_clock
        clock.duration = following_clock.datetime - clock.datetime
      else
        clock.duration = 0
      end

      shift_duration += clock.duration unless clock.activity == :break
      following_clock = clock
    end

    self.duration = shift_duration
  end

gistfile2.txt

Employee starts "work" at "Job A" at "7am" (creates new shift and a work clock)
Employee starts "travel" from "Job A" at "8am" (adds a travel clock to shift)
Employee starts "work" at "Job B" at "9am" (adds a work clock to shift)
Employee finishes "work" at "Job B" at "3pm" (adds a finish clock to shift)

models

=> Shift(id: integer, job_id: integer, duration: integer, created_at: datetime, updated_at: datetime, employee_id: integer, started_at: datetime, finished_at: datetime)

=> Clock(id: integer, shift_id: integer, activity: string, datetime: datetime, status: string, created_at: datetime, updated_at: datetime, origin: string, duration: integer, job_id: integer)

=> Job(id: integer, company_id: integer, name: string, customer: string, created_at: datetime, updated_at: datetime, active: boolean)

=> Employee(id: integer, user_id: integer, company_id: integer, role_id: integer, number: integer, created_at: datetime, updated_at: datetime, active: boolean)

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