# ISO <<Class>> UnitsOfMeasure
# writer output in XML

# History:
# 	Stan Smith 2014-12-03 original script

require 'class_baseUnit'
require 'class_conventionalUnit'
require 'class_derivedUnit'
require 'class_definitionUnit'

class UnitsOfMeasure

	def initialize(xml)
		@xml = xml
	end

	def writeUnits(unit)

		# define empty containers here to save lines of code
		# for base units
		hBase = {}
		hBase[:identifier] = ''
		hBase[:codeSpace] = 'http://www.bipm.org/en/si/'
		hBase[:name] = ''
		hBase[:catalogSymbol] = ''
		hBase[:unitsSystem] = 'base unit'

		# for conventional units
		hConvent = {}
		hConvent[:identifier] = ''
		hConvent[:codeSpace] = 'http://www.bipm.org/en/si/'
		hConvent[:name] = ''
		hConvent[:catalogSymbol] = ''
		hConvent[:preferredUnit] = ''
		hConvent[:factor] = nil
		hConvent[:a] = nil
		hConvent[:b] = nil
		hConvent[:c] = nil
		hConvent[:d] = nil

		# for derived units
		hDerived = {}
		hDerived[:identifier] = ''
		hDerived[:codeSpace] = ''
		hDerived[:name] = ''
		hDerived[:remarks] = ''
		hDerived[:catalogSymbol] = ''
		hDerived[:derivationUnitTerm] = nil

		# find matching units of measure
		case unit

			# angular degrees
			when 'deg', 'degree', 'degrees'
				hBase[:identifier] = 'degree'
				hBase[:codeSpace] = 'urn:ogc:def:uom:1.0'
				hBase[:name] = 'degree of arc'
				hBase[:catalogSymbol] = 'deg'
				hBase[:unitsSystem] = 'http://www.opengis.net/def/uom/OGC/1.0/degree'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'm', 'meter', 'meters', 'metre'
				hBase[:identifier] = 'meter'
				hBase[:name] = 'meter'
				hBase[:catalogSymbol] = 'm'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'kg', 'kilogram', 'kilograms'
				hBase[:identifier] = 'kilogram'
				hBase[:name] = 'kilogram'
				hBase[:catalogSymbol] = 'kg'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 's', 'second', 'seconds'
				hBase[:identifier] = 'second'
				hBase[:name] = 'second'
				hBase[:catalogSymbol] = 'd'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'A', 'ampere', 'amperes'
				hBase[:identifier] = 'ampere'
				hBase[:name] = 'ampere'
				hBase[:catalogSymbol] = 'A'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'K', 'kelvin'
				hBase[:identifier] = 'kelvin'
				hBase[:name] = 'kelvin'
				hBase[:catalogSymbol] = 'K'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'mol', 'mole', 'moles'
				hBase[:identifier] = 'mole'
				hBase[:name] = 'mole'
				hBase[:catalogSymbol] = 'mol'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'cd', 'candela', 'candelas'
				hBase[:identifier] = 'candela'
				hBase[:name] = 'candela'
				hBase[:catalogSymbol] = 'cd'

				baseClass = BaseUnit.new(@xml)
				baseClass.writeXML(hBase)

			when 'ft', 'foot', 'feet'
				hConvent[:identifier] = 'meter'
				hConvent[:name] = 'foot'
				hConvent[:catalogSymbol] = 'ft'
				hConvent[:preferredUnit] = 'meter'
				hConvent[:factor] = 3.280839

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'in', 'inch', 'inches'
				hConvent[:identifier] = 'meter'
				hConvent[:name] = 'inch'
				hConvent[:catalogSymbol] = 'in'
				hConvent[:preferredUnit] = 'meter'
				hConvent[:factor] = 0.0254

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'mm', 'millimeter', 'millimeters'
				hConvent[:identifier] = 'meter'
				hConvent[:name] = 'millimeter'
				hConvent[:catalogSymbol] = 'mm'
				hConvent[:preferredUnit] = 'meter'
				hConvent[:factor] = 0.001

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'degC', 'centigrade', 'degreesC', 'Celsius'
				hConvent[:identifier] = 'kelvin'
				hConvent[:name] = 'degree Celsius'
				hConvent[:catalogSymbol] = 'degC'
				hConvent[:preferredUnit] = 'kelvin'
				hConvent[:a] = 273.16
				hConvent[:b] = 1
				hConvent[:c] = 1
				hConvent[:d] = 0

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'degF', 'degreesF', 'Fahrenheit'
				hConvent[:identifier] = 'kelvin'
				hConvent[:name] = 'degree Fahrenheit'
				hConvent[:catalogSymbol] = 'degF'
				hConvent[:preferredUnit] = 'kelvin'
				hConvent[:a] = 2298.44
				hConvent[:b] = 5
				hConvent[:c] = 9
				hConvent[:d] = 0

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'mph', 'miles per hour'
				hConvent[:identifier] = 'mi/h'
				hConvent[:name] = 'miles per hour'
				hConvent[:catalogSymbol] = 'mph'
				hConvent[:preferredUnit] = 'm/s'
				hConvent[:a] = 0
				hConvent[:b] = 1609.344
				hConvent[:c] = 0
				hConvent[:d] = 3600.0

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'kph', 'kilometers per hour'
				hConvent[:identifier] = 'k/h'
				hConvent[:name] = 'kilometers per hour'
				hConvent[:catalogSymbol] = 'kph'
				hConvent[:preferredUnit] = 'm/s'
				hConvent[:a] = 0
				hConvent[:b] = 1000
				hConvent[:c] = 0
				hConvent[:d] = 3600

				convClass = ConventionalUnit.new(@xml)
				convClass.writeXML(hConvent)

			when 'density'
				hDerived = {}
				hDerived[:identifier] = 'kg/m^3'
				hDerived[:name] = 'kilograms per cubic meter'
				hDerived[:remarks] = 'volumetric mass density'
				hDerived[:catalogSymbol] = 'p'
				unitTerms = []
				unitTerms << { 'uom' => 'kg', 'exponent' => '1' }
				unitTerms << { 'uom' => 'm', 'exponent' => '-3' }
				hDerived[:derivationUnitTerm] = unitTerms

				dervClass = DerivedUnit.new(@xml)
				dervClass.writeXML(hDerived)

			else
				defnClass = UnitDefinition.new(@xml)
				defnClass.writeXML(unit)

		end
	end

end