module Text
  def oxford_comma
    if length <= 1 then self.join(", ")
    elsif length == 2 then "#{self[0]} and #{self[1]}"
    else
      "#{self[0...-1].join(", ")}, and #{self[-1]}"
    end
  end

  def is_numeric(x)
    x.to_f.to_s == x
  end

  def year_s_to_year(y)
    y = y.to_i
    y += 2000 if y < 100
    y
  end

  def date_to_time(d)
    case d
    when Numeric then Time.new(d)
    when /([a-zA-Z]+)\.? +([0-9]+)/ then
      month, yr = $1, $2
      Time.new(yr, idx_of_month(month))
    when /([0-9]+)\/([0-9]+)/
      Time.new(year_s_to_year($2), $1.to_i)
    else raise "Unknown Date Format '#{d}'"
    end
  end

  def to_date(d)
    case d
      when /([0-9]+)\/([0-9]+)/ then
        m, y = $1.to_i, $2.to_i
        y = 2000+y if y < 100;
        Time.new(y, m)
      else raise "Invalid date string #{self}"
    end
  end

  def duration(r)
    if not r["start"].nil?
      # { "start" : x, "end" : y }
      # or
      # { "start" : x } (with y implicitly assigned the string 'present')
      # formatted as "x -- y"

      "#{r["start"]} -- #{if r["end"].nil? then "present" else r["end"] end}"
    elsif not r["years"].nil?
      # { "years" : [ y1, y2, y3, y5, ... ] }
      # formatted as y1, y2, y3, y5, ... 
      # Adjacent years are coalesced: e.g., y1-y3, y5, ...

      buffer = []
      r["years"].each do |y|
        y = y.to_i
        prev = 
        if buffer.empty? or buffer[-1][1] != (y-1)
          buffer.push([y,y])
        else
          buffer[-1][1] = y
        end
      end
      buffer.map { |s,e| if s == e then s.to_s else "#{s} -- #{e}" end }.join(", ")
    else
      raise "Invalid time range : #{r}"
    end
  end

  def idx_of_month(m)
    case m
    when "Jan", "January" then 1
    when "Feb", "February" then 2
    when "Mar", "March" then 3
    when "Apr", "April" then 4
    when "May" then 5
    when "Jun", "June" then 6
    when "Jul", "July" then 7
    when "Aug", "August" then 8
    when "Sep", "Sept", "September" then 9
    when "Oct", "October" then 10
    when "Nov", "November" then 11
    when "Dec", "December" then 12
    else raise "Unknown Month '#{m}'"
    end
  end

  def duration_is_since?(r, year)
    if not r["start"].nil?
      return true if r["end"].nil?
      return date_to_time(r["end"]).year >= year
    elsif not r["years"].nil?
      return r["years"].map {|y|y.to_i}.max >= year
    elsif not r["year"].nil? 
      return r["year"].to_i >= year
    elsif not r["date"].nil?
      extracted_year = 
        case r["date"]
        when /[a-z]+\. (\d\d\d\d)/ then $1
        else raise "Invalid date format: #{r["date"]}"
        end
      return extracted_year.to_i >= year      
    else 
      raise "Invalid time range : #{r}"
    end
  end
  
  def format_money(k)
    if k.is_a? String
      return k
    elsif k.is_a? Numeric
      rest, curr = k.divmod(1000)
      ret = sprintf(rest > 0 ? "%03d" : "%.2f", curr)
      while(rest > 0) do
        rest, curr = rest.divmod(1000)
        ret = sprintf(rest > 0 ? "%03d" : "%d", curr)+","+ret
      end
      return "$#{ret}"
    else 
      raise "Invalid Currency Value: #{k}"
    end
  end
  
  def address_line_1(addr)
    raise "Missing Street in Address: #{addr}" if addr["street"].nil?
    addr["street"]
  end
  
  def address_line_2(addr)
    case addr["country"]
      when "USA", nil
        raise "Missing City in Address: #{addr}" if addr["city"].nil?
        raise "Missing State in Address: #{addr}" if addr["state"].nil?
        raise "Missing Zip Code in Address: #{addr}" if addr["zip"].nil?
        "#{addr["city"]}, #{addr["state"]} #{addr["zip"]}"
      else
        raise "Unknown Country '#{addr["country"]}' in Address: #{addr}"
    end
  end

  def split_name(name)
    parts = name.split(/ +/)
    [
      parts[0...-1].join(" "), # first name(s)
      parts[-1]                # last name
    ]
  end
end