#/usr/bin/env python

#Copyright (c) 2009 Richard Ward
#
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#
#The above copyright notice and this permission notice shall be included in
#all copies or substantial portions of the Software.
#
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
#THE SOFTWARE.

#This script downloads the latest opengl spec files from kronos, processes
#them and generates Go files.

import urllib,re,sys

def usage():
	sys.stderr.write("Usage: dlspec.py packagename [/path/to/desired/directory]\n")
	sys.exit(1)

if len(sys.argv)<2 or len(sys.argv)>3:
	usage()

PACKAGENAME=sys.argv[1]

PATHNAME="."
if len(sys.argv)==3:
	PATHNAME=sys.argv[2]
	if not os.path.exists(PATHNAME) or not os.path.isdir(PATHNAME):
		usage()
PATHNAME=PATHNAME+"/"

def getSpecFile(name,ext="spec"):
	url=urllib.urlopen("http://www.opengl.org/registry/api/"+name+"."+ext)
	if url.getcode() is not 200:
		raise IOError("Could not download specifications")
	return url.readlines()

#how the regex works:
#you must read it in parralell with the spec.
#The enums are on lines composed as follows:
#whitespace IDENTIFIERwhich_may_have_underscores_lowercase_and_digits whitespace = whitespace NUMBER
#the number may be a hex number. It may even be a previous constant in some cases.
parserRegex=re.compile("[ \t]+([A-Z0-9_]+)+[\t ]*=[\t ]*([0-9A-Z_a-gx]+)")
def parseEnumFile(name):
	lines=getSpecFile(name)
	f=file(PATHNAME+name+".go","w")
	f.write('package '+PACKAGENAME+'\n\n')
	f.write('//THIS FILE IS AUTOMATICALLY GENERATED BY dlspec.py.\n')
	f.write('//DO NOT ALTER THIS FILE MANUALLY!\n\n')
	f.write('const (\n')
	enums={}
	lineno=0;
	for line in lines:
		lineno=lineno+1
		match=parserRegex.match(line)
		if match is not None:
			enum=match.expand("\\1")
			if not enums.has_key(enum):
				f.write(match.expand("\tGL_\\1 = \\2;\n"))
			enums[enum]=None
	f.write(')\n')
	f.close();



parseEnumFile("enum")