# 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 argparse
import runpy
import string
import sys

# 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 [LegacyNullToEmptyString] UTF8String %s;\n" % (
        ", ".join(extendedAttrs),
        propName,
    )


def generate(output, idlFilename, dataFile):
    propList = runpy.run_path(dataFile)["data"]
    props = ""
    for p in propList:
        if "Internal" in p.flags:
            continue

        # Skip properties which aren't valid in style rules.
        if "Style" not in p.rules:
            continue

        # Unfortunately, even some of the getters here are fallible
        # (e.g. on nsComputedDOMStyle).
        extendedAttrs = [
            "CEReactions",
            "Throws",
            "SetterNeedsSubjectPrincipal=NonSystem",
        ]

        if p.pref != "":
            # BackdropFilter is a special case where we want WebIDL to check
            # a function instead of checking the pref directly.
            if p.method == "BackdropFilter":
                extendedAttrs.append('Func="nsCSSProps::IsBackdropFilterAvailable"')
            else:
                extendedAttrs.append('Pref="%s"' % p.pref)

        prop = p.method

        # webkit properties get a camelcase "webkitFoo" accessor
        # as well as a capitalized "WebkitFoo" alias (added here).
        if prop.startswith("Webkit"):
            extendedAttrs.append('BindingAlias="%s"' % prop)

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

        # 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 generateLine() call will
        # cover (3) and all of (1) except "float".  If we now add an alias
        # for all the cases where "name" doesn't match "prop", that will cover
        # "float" and (2).
        if prop != p.name:
            extendedAttrs.append('BindingAlias="%s"' % p.name)

        props += generateLine(prop, 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()