module ForestLiana
  class OperatorDateIntervalParser
    PERIODS = {
      yesterday: { duration: 1, period: 'day' },
      lastWeek: { duration: 1, period: 'week' },
      last2Weeks: { duration: 2, period: 'week' },
      lastMonth: { duration: 1, period: 'month' },
      last3Months: { duration: 3, period: 'month' },
      lastYear: { duration: 1, period: 'year' }
    }

    PERIODS_FROM_NOW = 'fromNow'
    PERIODS_TODAY = 'today'
    PERIODS_LAST_X_DAYS = /^last(\d+)days$/

    def initialize(value)
      @value = value
    end

    def is_interval_date_value
      return false if @value.nil?
      return true if PERIODS[@value.to_sym]
      return true if [PERIODS_FROM_NOW, PERIODS_TODAY].include? @value

      match = PERIODS_LAST_X_DAYS.match(@value)
      return true if match && match[1]

      false
    end

    def has_previous_interval
      return false if @value.nil?
      return true if PERIODS[@value.to_sym]
      return true if PERIODS_TODAY == @value

      match = PERIODS_LAST_X_DAYS.match(@value)
      return true if match && match[1]

      false
    end

    def get_interval_date_filter
      return nil unless is_interval_date_value()

      return ">= '#{Time.now}'" if @value == PERIODS_FROM_NOW

      if @value == PERIODS_TODAY
        return "BETWEEN '#{Time.now.beginning_of_day}' AND " +
          "'#{Time.now.end_of_day}'"
      end

      match = PERIODS_LAST_X_DAYS.match(@value)
      if match && match[1]
        return "BETWEEN '#{Integer(match[1]).day.ago.beginning_of_day}'" +
          " AND '#{1.day.ago.end_of_day}'"
      end

      duration = PERIODS[@value.to_sym][:duration]
      period = PERIODS[@value.to_sym][:period]

      from = duration.send(period).ago.send("beginning_of_#{period}")
      to = 1.send(period).ago.send("end_of_#{period}")
      "BETWEEN '#{from}' AND '#{to}'"
    end

    def get_interval_date_filter_for_previous_interval
      return nil unless has_previous_interval()

      if @value == PERIODS_TODAY
        return "BETWEEN '#{1.day.ago.beginning_of_day}' AND " +
          "'#{1.day.ago.end_of_day}'"
      end

      match = PERIODS_LAST_X_DAYS.match(@value)
      if match && match[1]
        return "BETWEEN '#{Integer(match[1] * 2).day.ago.beginning_of_day}'" +
          " AND '#{Integer(match[1]).day.ago.end_of_day}'"
      end

      duration = PERIODS[@value.to_sym][:duration]
      period = PERIODS[@value.to_sym][:period]

      from = (duration * 2).send(period).ago.send("beginning_of_#{period}")
      to = (1 + duration).send(period).ago.send("end_of_#{period}")
      "BETWEEN '#{from}' AND '#{to}'"
    end
  end
end