#!/usr/bin/env python3
# Converts Google's protobuf python definitions of TREZOR wire messages
# to plain-python objects as used in TREZOR Core and python-trezor

import sys
import importlib
import os
import argparse

from google.protobuf.internal.enum_type_wrapper import EnumTypeWrapper


def import_pb2(name):
    return importlib.import_module("pb2.%s_pb2" % name)


def process_type(t, cls, msg_id, indexfile, is_upy):
    print("  * type %s" % t)

    imports = []
    out = ["", "", "class %s(p.MessageType):" % t, ]

    if cls.DESCRIPTOR.fields_by_name:
        out.append("    FIELDS = {")
    elif msg_id is None:
        out.append("    pass")

    for v in sorted(cls.DESCRIPTOR.fields_by_name.values(), key=lambda x: x.number):
        number = v.number
        fieldname = v.name
        type = None
        repeated = v.label == 3
        required = v.label == 2

        # print v.has_default_value, v.default_value

        if v.type in (4, 13, 14):
            # TYPE_UINT64 = 4
            # TYPE_UINT32 = 13
            # TYPE_ENUM = 14
            type = 'p.UVarintType'

        elif v.type in (17,):
            # TYPE_SINT32 = 17
            type = 'p.Sint32Type'

        elif v.type == 9:
            # TYPE_STRING = 9
            type = 'p.UnicodeType'

        elif v.type == 8:
            # TYPE_BOOL = 8
            type = 'p.BoolType'

        elif v.type == 12:
            # TYPE_BYTES = 12
            type = 'p.BytesType'

        elif v.type == 11:
            # TYPE_MESSAGE = 1
            type = v.message_type.name
            imports.append("from .%s import %s" %
                           (v.message_type.name, v.message_type.name))

        else:
            raise Exception("Unknown field type %s for field %s" %
                            (v.type, fieldname))

        if required:
            comment = '  # required'
        elif v.has_default_value:
            comment = '  # default=%s' % repr(v.default_value)
        else:
            comment = ''

        if repeated:
            flags = 'p.FLAG_REPEATED'
        else:
            flags = '0'

        out.append("        %d: ('%s', %s, %s),%s" %
                   (number, fieldname, type, flags, comment))

        # print fieldname, number, type, repeated, comment
        # print v.__dict__
        # print v.CPPTYPE_STRING
        # print v.LABEL_REPEATED
        # print v.enum_type
        # v.has_default_value, v.default_value
        # v.label == 3 # repeated
        # print v.number

    if cls.DESCRIPTOR.fields_by_name:
        out.append("    }")

    if msg_id is not None:
        out.append("    MESSAGE_WIRE_TYPE = %d" % msg_id)
        if indexfile is not None:
            if is_upy:
                indexfile.write("%s = const(%d)\n" % (t, msg_id))
            else:
                indexfile.write("%s = %d\n" % (t, msg_id))

    # Remove duplicate imports
    imports = list(set(imports))

    if is_upy:
        imports = ['import protobuf as p'] + imports
    else:
        imports = ['from __future__ import absolute_import',
                   'from .. import protobuf as p'] + imports


    return imports + out


def process_enum(t, cls, is_upy):
    out = []

    if is_upy:
        out += ("from micropython import const", "")

    print("  * enum %s" % t)

    for k, v in cls.items():
        # Remove type name from the beginning of the constant
        # For example "PinMatrixRequestType_Current" -> "Current"
        if k.startswith("%s_" % t):
            k = k.replace("%s_" % t, '')

        # If type ends with *Type, but constant use type name without *Type, remove it too :)
        # For example "ButtonRequestType & ButtonRequest_Other" => "Other"
        if t.endswith("Type") and k.startswith("%s_" % t.replace("Type", '')):
            k = k.replace("%s_" % t.replace("Type", ''), '')

        if is_upy:
            out.append("%s = const(%s)" % (k, v))
        else:
            out.append("%s = %s" % (k, v))

    return out


def find_msg_type(msg_types, t):
    for k, v in msg_types:
        msg_name = k.replace('MessageType_', '')
        if msg_name == t:
            return v


def process_module(mod, genpath, indexfile, modlist, is_upy):

    print("Processing module %s" % mod.__name__)
    types = dict([(name, cls)
                  for name, cls in mod.__dict__.items() if isinstance(cls, type)])

    msg_types = import_pb2('messages').MessageType.items()

    for t, cls in sorted(types.items()):
        # Find message type for given class
        msg_id = find_msg_type(msg_types, t)

        out = process_type(t, cls, msg_id, indexfile, is_upy)

        write_to_file(genpath, t, out)
        if modlist:
            modlist.write("from .%s import *\n" % t)

    enums = dict([(name, cls) for name, cls in mod.__dict__.items()
                  if isinstance(cls, EnumTypeWrapper)])

    for t, cls in enums.items():
        out = process_enum(t, cls, is_upy)
        write_to_file(genpath, t, out)
        if modlist:
            modlist.write("from . import %s\n" % t)


def write_to_file(genpath, t, out):
    # Write generated sourcecode to given file
    f = open(os.path.join(genpath, "%s.py" % t), 'w')
    out = ["# Automatically generated by pb2py"] + out

    data = "\n".join(out) + "\n"

    f.write(data)
    f.close()


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('modulename', type=import_pb2, help="Name of module to generate")
    parser.add_argument('genpath', type=str, help="Directory for generated source code")
    parser.add_argument('-i', '--indexfile', type=argparse.FileType('a'), help="Generate index file of wire types")
    parser.add_argument('-l', '--modlist', type=argparse.FileType('a'), help="Generate list of modules")
    parser.add_argument('-p', '--protopath', type=str, help="Path to search for pregenerated Google's python sources")
    parser.add_argument('-m', '--micropython', action='store_true', help="Use micropython-favoured source code")
    args = parser.parse_args()

    if args.protopath:
        sys.path.append(args.protopath)

    process_module(args.modulename, args.genpath, args.indexfile, args.modlist, args.micropython)