Class: Groupdate::Series

Inherits:
Object
  • Object
show all
Defined in:
lib/groupdate/series.rb

Instance Method Summary collapse

Constructor Details

#initialize(relation, field, column, time_zone, time_range, week_start) ⇒ Series

Returns a new instance of Series.



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# File 'lib/groupdate/series.rb', line 4

def initialize(relation, field, column, time_zone, time_range, week_start)
  if time_range.is_a?(Range)
    # doesn't matter whether we include the end of a ... range - it will be excluded later
    @relation = relation.where("#{column} >= ? AND #{column} <= ?", time_range.first, time_range.last)
  else
    @relation = relation.where("#{column} IS NOT NULL")
  end
  @field = field
  @time_zone = time_zone
  @time_range = time_range
  @week_start = week_start
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object 



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# File 'lib/groupdate/series.rb', line 84

def method_missing(method, *args, &block)
  # https://github.com/rails/rails/blob/master/activerecord/lib/active_record/relation/calculations.rb
  if ActiveRecord::Calculations.method_defined?(method)
    build_series(@relation.send(method, *args, &block))
  else
    raise NoMethodError, "valid methods are: #{ActiveRecord::Calculations.instance_methods.join(", ")}"
  end
end

Instance Method Details

#build_series(count) ⇒ Object 



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# File 'lib/groupdate/series.rb', line 17

def build_series(count)
  utc = ActiveSupport::TimeZone["UTC"]

  cast_method =
    case @field
    when "day_of_week", "hour_of_day"
      lambda{|k| k.to_i }
    else
      lambda{|k| (k.is_a?(String) ? utc.parse(k) : k.to_time).utc }
    end

  count = Hash[ count.map{|k, v| [cast_method.call(k), v] } ]

  series =
    case @field
    when "day_of_week"
      0..6
    when "hour_of_day"
      0..23
    else
      time_range =
        if @time_range.is_a?(Range)
          @time_range
        else
          # use first and last values
          sorted_keys = count.keys.sort
          sorted_keys.first..sorted_keys.last
        end

      # determine start time
      time = time_range.first.to_time.in_time_zone(@time_zone)
      starts_at =
        case @field
        when "second"
          time.change(:usec => 0)
        when "minute"
          time.change(:sec => 0)
        when "hour"
          time.change(:min => 0)
        when "day"
          time.beginning_of_day
        when "week"
          # same logic as MySQL group
          weekday = (time.wday - 1) % 7
          (time - ((7 - @week_start + weekday) % 7).days).midnight
        when "month"
          time.beginning_of_month
        else # year
          time.beginning_of_year
        end

      series = [starts_at]

      step = 1.send(@field)

      while time_range.cover?(series.last + step)
        series << series.last + step
      end

      series.map{|s| s.to_time.utc }
    end

  Hash[series.map do |k|
    [k, count[k] || 0]
  end]
end