Create .case alternate.py

#MenuTitle: Create .case alternate
# -*- coding: utf-8 -*-
__doc__="""
Duplicates selected glyphs but as components, giving them .case suffix and the sidebearings. Ideal for making uppercase alternate signs. Modified from Mekkablue's "Create .ssXX glyph from current layer" script.
"""

import GlyphsApp

Font = Glyphs.font
FirstMasterID = Font.masters[0].id
allGlyphNames = [ x.name for x in Font.glyphs ]
selectedLayers = Font.selectedLayers

def findSuffix( glyphName ):
	nameIsFree = False
	duplicateNumber = -1
	
	while nameIsFree is False:
		duplicateNumber += 1
		targetSuffix = ".case.0%.2d" % duplicateNumber
		targetGlyphName = glyphName + targetSuffix
		if allGlyphNames.count( targetGlyphName ) == 0:
			nameIsFree = True
	if targetSuffix == ".case.000":
		targetSuffix = ".case"
	return targetSuffix

	
def process( sourceLayer ):
	# find suffix
	sourceGlyphName = sourceLayer.parent.name
	targetSuffix = findSuffix( sourceGlyphName )
	
	# append suffix, create glyph:
	targetGlyphName = sourceGlyphName + targetSuffix
	targetGlyph = GSGlyph( targetGlyphName )
	Font.glyphs.append( targetGlyph )

	# place component to all layers in the new glyph:
	for thisMaster in Font.masters:
		sourceComponent = GSComponent( sourceGlyphName )
		targetGlyph.layers[thisMaster.id].components.append(sourceComponent)
		targetGlyph.layers[thisMaster.id].setLeftMetricsKeyUI_(sourceGlyphName)
		targetGlyph.layers[thisMaster.id].setRightMetricsKeyUI_(sourceGlyphName)
	print "Created", targetGlyphName 
	
for thisLayer in selectedLayers:
	process( thisLayer )