#! /usr/bin/env python

tclscript = """
 foreach d [concat \
      [list $tcl_library \
            [lindex $tcl_pkgPath 0]] \
      $auto_path \
      [list [file dirname $tcl_library] \
            [file dirname [lindex $tcl_pkgPath 0]] \
            [file dirname [file dirname $tcl_library]] \
            [file dirname [file dirname [lindex $tcl_pkgPath 0]]] \
            [file dirname [file dirname [file dirname $tcl_library]]] \
            [file dirname [file dirname [file dirname [lindex $tcl_pkgPath 0]]]]] \
 ] {
     if {[file exists [file join $d tclConfig.sh]]} {
         puts "[file join $d tclConfig.sh]"
         exit
     }
 }
"""

# determine location of tclConfig.sh

import subprocess
output = subprocess.Popen(["tclsh"], stdin=subprocess.PIPE, stdout=subprocess.PIPE).communicate(input=tclscript)[0]
tclconfigfile = output.strip()

# parse the file to determine the names of the variables it contains

f = file(tclconfigfile)

# default build environment variables that are assumed to already be defined
# note that these are normally given default values in GNU Make, but we're
# not inside make, so we might not have these.
# FIXME: could try importing these from the environment?
d = {
	"CC":"gcc",
	"CFLAGS":"",
	"LDFLAGS":"",
	"AR":"",
	"LIBS":"",
	"VERSION":"",
	"DBGX":""
}

# regular expression used for variable substitution
import re
r = re.compile(r'\$\{([A-Z_0-9]+)\}')

# variable substitution/expansion function
def expand(s,d):
	m = r.search(s)
	#print "MATCHING",s
	if m:
		#print "MATCH!"
		if d.has_key(m.group(1)):
			return expand(s[:m.start()] + d[m.group(1)] + s[m.end():],d)
		else:
			raise RuntimeError("Missing variable '%s'" % m.group(1))
	return s

for l in f:
	ls = l.strip()
	if ls == "" or ls[0]=="#":
		continue
	k,v = ls.split("=",1)
	if len(v) >= 2 and v[0] == "'" and v[len(v)-1] == "'":
		v = v[1:len(v)-1]

	d[k] = expand(v,d)

# output the variable that the user requests

import getopt, sys

def usage(progname):
	print "%s [--cflags] [--libs] [--var=TCL_VAR_NAME] [--vars]" % progname
	print "Output configuration variables for the Tcl script interpreter."
	print "Options:"
	print "\t--cflags           Compiler flags for C code that uses Tcl"
	print "\t--libs             Linker flags for code that uses Tcl"
	print "\t--vars             List all variables defined in tclConfig.sh"
	print "\t--var=VARNAME      Output the value of a specific variable"
	print "\nSee http://ascendwiki.cheme.cmu.edu/Tcl-config for more info."

try:
    opts, args = getopt.getopt(sys.argv[1:], "h",
		["help", "cflags", "libs","var=","vars"]
	)
except getopt.GetoptError, err:
    print str(err)
    usage(sys.argv[0])
    sys.exit(2)

for o, a in opts:
	if o == "-h" or o == "--help":
		usage(sys.argv[0])
		sys.exit()
	elif o == "--cflags":
		print d['TCL_INCLUDE_SPEC']
	elif o == "--libs":
		print d['TCL_LIB_SPEC']
	elif o == "--var":
		if d.has_key(a):
			print d[a]
		else:
			raise RuntimeError("Unknown variable '%s'" % a)
	elif o == "--vars":
		for k in d.keys():
			print k
	else:
		assert False, "unhandled option"