Class: Medjool::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/medjool/parser.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(context = {}) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/medjool/parser.rb', line 8

def initialize(context = {})
  @context = context
end

Instance Attribute Details

#context ⇒ Object (readonly)

Returns the value of attribute context.



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# File 'lib/medjool/parser.rb', line 6

def context
  @context
end

Instance Method Details

#is_date_range?(text) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/medjool/parser.rb', line 12

def is_date_range?(text)
  Medjool::DATE_RANGE_MATCHER.match(text.strip).present?
end

#parse(text, update_now = true) ⇒ Object 



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# File 'lib/medjool/parser.rb', line 53

def parse(text, update_now = true)
  if Medjool::DATE_MATCHER.match(text)
    # Let's do an aggressive strip of any whitespace at the start and end, including crazy unicodeness
    # that the standard 'strip' would miss
    text = text.gsub(/^[^a-zA-Z0-9]*/, "").gsub(/[^a-zA-Z0-9]*$/, "")

    if /^[0-9]$/.match(text)
      # Handle lone integers
      text = "#{text}st"
    end

    begin
      base_date = Date.parse(text)
    rescue ArgumentError => e
      # If Date.parse is used on the string "31st" during
      # a month with only 30 days, it will explode
      if Medjool::END_OF_MONTH_MATCHER.match(text)
        # This is a little bit hacky, but switch to a date that will definitely work
        base_date = Date.parse("#{text} January")
      else
        return nil
      end
    end

    should_determine_ambiguity = false
    if @context[:now]
      should_determine_ambiguity = true
    else
      # In the absence of context, always fall back on the default guess
      guess_date = base_date

      # Only exception for that is the special case where it's currently December,
      # and "January" *obviouly* should mean January NEXT year not THIS year
      if Date.today.month == 12 && guess_date < 10.months.ago          
        should_determine_ambiguity = true
        @context[:now] = Date.today
      end
    end

    if should_determine_ambiguity
      # Determine the ambiguity level for this data
      ambiguity = determine_ambiguity(text)

      now = @context[:now].to_date

      case ambiguity
        when :none
          return base_date

        when :weekly
          # Pick the nearest week that meets the context
          guess_date = now + (base_date.wday - now.wday).days - 1.week

          while guess_date < now
            guess_date += 1.week
          end
        when :monthly
          # Pick the nearest month where the provided day of the month meets the context
          y = now.year
          m = now.month - 1
          guess_date = nil

          while guess_date.nil? || guess_date < now
            m += 1
            if m > 12
              m = 1
              y += 1
            end
            begin
              guess_date = Date.new(y, m, base_date.day)
            rescue ArgumentError
              # This might happen e.g. 31st Feb,
              # so just carry on to the next month
              next
            end
          end

        when :yearly
          # Skip ahead a year at a time unless we meet the context
          guess_date = Date.new(now.year, base_date.month, base_date.day)
          while guess_date < now
            guess_date += 1.year
          end

      end
    end

    @context[:now] = guess_date if update_now
    return guess_date
  else
    return nil
  end
end

#parse_date_range(text) ⇒ Object 



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# File 'lib/medjool/parser.rb', line 16

def parse_date_range(text)
  if bits = Medjool::DATE_RANGE_MATCHER.match(text.strip)
    if bits[1].present?
      prefix = bits[1].strip.sub(/:$/, '')
    else
      prefix = nil
    end

    if bits[52]
      # October
      if month_start = self.parse(text.strip, update_now = false)
        month_end = month_start.end_of_month
        return Medjool::DateRange.new(month_start, month_end, prefix)
      end
    elsif bits[3]
      # 12-15 Oct
      # Start is 12 Oct
      end_month = bits[17]
      start_month = bits[6] || end_month
      range_start = self.parse("#{bits[4]} #{start_month}", update_now = false)
      # End is 15 Oct
      range_end = self.parse("#{bits[16]} #{end_month}", update_now = false)
      return Medjool::DateRange.new(range_start, range_end, prefix)
    elsif bits[29]
      # Oct 12-15
      # Start is 12 Oct
      end_month = bits[41]
      start_month = bits[29] || end_month

      range_start = self.parse("#{bits[39]} #{start_month}", update_now = false)
      # End is 15 Oct
      range_end = self.parse("#{bits[51]} #{end_month}", update_now = false)
      return Medjool::DateRange.new(range_start, range_end, prefix)
    end
  end
end