# rust_macros.py - Generate rust_macros bindings from IDL.
#
# 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/.

"""Generate rust bindings information for the IDL file specified"""

from xpidl import rust, xpidl

derive_method_tmpl = """\
Method {
    name: "%(name)s",
    params: &[%(params)s],
    ret: "%(ret)s",
}"""


def attrAsMethodStruct(iface, m, getter):
    params = [
        'Param { name: "%s", ty: "%s" }' % x
        for x in rust.attributeRawParamList(iface, m, getter)
    ]
    return derive_method_tmpl % {
        "name": rust.attributeNativeName(m, getter),
        "params": ", ".join(params),
        "ret": "::nserror::nsresult",
    }


def methodAsMethodStruct(iface, m):
    params = [
        'Param { name: "%s", ty: "%s" }' % x for x in rust.methodRawParamList(iface, m)
    ]
    return derive_method_tmpl % {
        "name": rust.methodNativeName(m),
        "params": ", ".join(params),
        "ret": rust.methodReturnType(m),
    }


derive_iface_tmpl = """\
Interface {
    name: "%(name)s",
    base: %(base)s,
    methods: %(methods)s,
},
"""


def write_interface(iface, fd):
    if iface.namemap is None:
        raise Exception("Interface was not resolved.")

    assert iface.base or (iface.name == "nsISupports")

    base = 'Some("%s")' % iface.base if iface.base is not None else "None"
    try:
        methods = ""
        for member in iface.members:
            if type(member) == xpidl.Attribute:
                methods += "/* %s */\n" % member.toIDL()
                methods += "%s,\n" % attrAsMethodStruct(iface, member, True)
                if not member.readonly:
                    methods += "%s,\n" % attrAsMethodStruct(iface, member, False)
                methods += "\n"

            elif type(member) == xpidl.Method:
                methods += "/* %s */\n" % member.toIDL()
                methods += "%s,\n\n" % methodAsMethodStruct(iface, member)
        fd.write(
            derive_iface_tmpl
            % {
                "name": iface.name,
                "base": base,
                "methods": "Ok(&[\n%s])" % methods,
            }
        )
    except xpidl.RustNoncompat as reason:
        fd.write(
            derive_iface_tmpl
            % {
                "name": iface.name,
                "base": base,
                "methods": 'Err("%s")' % reason,
            }
        )


header = """\
//
// DO NOT EDIT.  THIS FILE IS GENERATED FROM $SRCDIR/%(relpath)s
//

"""


def print_rust_macros_bindings(idl, fd, relpath):
    fd = rust.AutoIndent(fd)

    fd.write(header % {"relpath": relpath})
    fd.write("{static D: &'static [Interface] = &[\n")

    for p in idl.productions:
        if p.kind == "interface":
            write_interface(p, fd)

    fd.write("]; D}\n")
