require 'sugar-high/numeric'
require 'sugar-high/string'

module GeoUnits
  module DmsConverter
    include NumericCheckExt

    def parse_dms dms_str  
      # check for signed decimal degrees without NSEW, if so return it directly
      return dms_str if is_numeric?(dms_str)

      # strip off any sign or compass dir'n & split out separate d/m/s
      dms = dms_str.strip.gsub(/^-/,'').gsub(/[NSEW]$/i,'').split(/[^0-9.,]+/).map(&:strip).map(&:to_f)
      return nil if dms.empty?

      # and convert to decimal degrees...
      deg = case dms.length      
      when 3 # interpret 3-part result as d/m/s
         dms[0]/1 + dms[1]/60 + dms[2]/3600
      when 2 # interpret 2-part result as d/m
        dms[0]/1 + dms[1]/60        
      when 1 # just d (possibly decimal) or non-separated dddmmss        
        d = dms[0];
        # check for fixed-width unseparated format eg 0033709W
        d = "0#{d}" if (/[NS]/i.match(dms_str)) # - normalise N/S to 3-digit degrees
        d = "#{d.slice(0,3)/1}#{deg.slice(3,5)/60}#{deg.slice(5)/3600}" if (/[0-9]{7}/.match(deg)) 
        d
      else
        nil
      end
      return nil if !deg
      deg = (deg * -1) if (/^-|[WS]$/i.match(dms_str.strip)) # take '-', west and south as -ve
      deg.to_f
    end

    # Convert decimal degrees to deg/min/sec format
    #  - degree, prime, double-prime symbols are added, but sign is discarded, though no compass
    #    direction is added
    # 
    # 
    # @param   {Number} deg: Degrees
    # @param   {String} [format=dms]: Return value as 'd', 'dm', 'dms'
    # @param   {Number} [dp=0|2|4]: No of decimal places to use - default 0 for dms, 2 for dm, 4 for d
    # @returns {String} deg formatted as deg/min/secs according to specified format
    # @throws  {TypeError} deg is an object, perhaps DOM object without .value?

    def to_dms deg, format = :dms, dp = nil 
      deg = begin
        deg.to_f
      rescue
        nil
      end
      return nil if !deg # give up here if we can't make a number from deg   

      # default values
      format ||= :dms
      dp = if dp.nil?
        case format.to_sym
        when :d 
          4
        when :dm 
          2
        else
          0 # default
        end
      end
      dp ||= 0

      deg = deg.abs # (unsigned result ready for appending compass dir'n)

      case format
      when :d
        d = deg.round(dp)       # round degrees
        ds = "0#{d}" if (d <100)    # pad with leading zeros
        ds = "0#{ds}" if (d <10) 
        dms = ds.to_s.concat("\u00B0")  # add º symbol
      when :dm            
        min = (deg*60).round(dp)   # convert degrees to minutes & round
        d = d.to_i
        d = (min / 60).floor          # get component deg/min
        m = (min % 60).round(dp)   # pad with trailing zeros
        ds = d
        ms = m
        ds = "0#{d}" if (d<100)        # pad with leading zeros
        ds = "0#{d}" if (d<10)
        ms = "0#{m}" if (m<10)               
        dms = ds.to_s.concat("\u00B0", ms, "\u2032") # add º, ' symbols
      when :dms
        sec = (deg * 3600).round   # convert degrees to seconds & round
        d = (sec / 3600).floor          # get component deg/min/sec
        m = ((sec / 60) % 60).floor
        s = (sec % 60).round(dp)     # pad with trailing zeros
        ds = d
        ms = m
        ss = s
        ds = "0#{d}" if (d < 100)          # pad with leading zeros
        ds = "0#{ds}" if (d < 10) 
        ms = "0#{m}" if (m < 10) 
        ss = "0#{s}" if (s < 10) 
        dms = ds.to_s.concat("\u00B0", ms, "\u2032", ss, "\u2033")  # add º, ', " symbols
      end
      return dms
    end
    
    extend self
  end
end