# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.

import sys
import string
import argparse
import subprocess
import buildconfig
from mozbuild import shellutil

# Generates a line of WebIDL with the given spelling of the property name
# (whether camelCase, _underscorePrefixed, etc.) and the given array of
# extended attributes.
def generateLine(propName, extendedAttrs):
    return "  [%s] attribute DOMString %s;\n" % (", ".join(extendedAttrs),
                                                 propName)
def generate(output, idlFilename, preprocessorHeader):
    cpp = shellutil.split(buildconfig.substs['CPP'])
    cpp += shellutil.split(buildconfig.substs['ACDEFINES'])
    cpp.append(preprocessorHeader)
    preprocessed = subprocess.check_output(cpp)

    propList = eval(preprocessed)
    props = ""
    for [name, prop, id, flags, pref, proptype] in propList:
        if "CSS_PROPERTY_INTERNAL" in flags:
            continue
        # Unfortunately, even some of the getters here are fallible
        # (e.g. on nsComputedDOMStyle).
        extendedAttrs = ["Throws", "TreatNullAs=EmptyString"]
        if pref is not "":
            extendedAttrs.append('Pref="%s"' % pref)

        # webkit properties get a capitalized "WebkitFoo" accessor (added here)
        # as well as a camelcase "webkitFoo" accessor (added next).
        if (prop.startswith("Webkit")):
            props += generateLine(prop, extendedAttrs)

        # Generate a line with camelCase spelling of property-name (or capitalized,
        # for Moz-prefixed properties):
        if not prop.startswith("Moz"):
            prop = prop[0].lower() + prop[1:]
        props += generateLine(prop, extendedAttrs)

        # Per spec, what's actually supposed to happen here is that we're supposed
        # to have properties for:
        #
        # 1) Each supported CSS property name, camelCased.
        # 2) Each supported name that contains or starts with dashes,
        #    without any changes to the name.
        # 3) cssFloat
        #
        # Note that "float" will cause a property called "float" to exist due to (1)
        # in that list.
        #
        # In practice, cssFloat is the only case in which "name" doesn't contain
        # "-" but also doesn't match "prop".  So the above generatePropLine() call
        # covered (3) and all of (1) except "float".  If we now output attributes
        # for all the cases where "name" doesn't match "prop", that will cover
        # "float" and (2).
        if prop != name:
            extendedAttrs.append('BinaryName="%s"' % prop)
            # Throw in a '_' before the attribute name, because some of these
            # property names collide with IDL reserved words.
            props += generateLine("_" + name, extendedAttrs)


    idlFile = open(idlFilename, "r")
    idlTemplate = idlFile.read()
    idlFile.close()

    output.write("/* THIS IS AN AUTOGENERATED FILE.  DO NOT EDIT */\n\n" +
                 string.Template(idlTemplate).substitute({"props": props}) + '\n')

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('idlFilename', help='IDL property file template')
    parser.add_argument('preprocessorHeader', help='Header file to pass through the preprocessor')
    args = parser.parse_args()
    generate(sys.stdout, args.idlFilename, args.preprocessorHeader)

if __name__ == '__main__':
    main()