#!/usr/bin/env python

import sys
import os

from google.protobuf.internal.enum_type_wrapper import EnumTypeWrapper


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

    imports = ["import protobuf as p", "from micropython import const", ]

    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 == 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:
            indexfile.write("%s = const(%d)\n" % (t, msg_id))

    return imports + out


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

    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", ''), '')

        out.append("%s = const(%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):

    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', globals(), locals(), [
                           'messages_pb2', ]).messages_pb2.MessageType.items()

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

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

        write_to_file(genpath, t, out)

    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)
        write_to_file(genpath, t, out)


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__':
    if len(sys.argv) < 2:
        print("Usage: ./pb2py modulename genpath indexfile")
        sys.exit()

    modulename = sys.argv[1]
    genpath = sys.argv[2]

    if len(sys.argv) > 2:
        indexfile = open(sys.argv[3], 'a')
    else:
        indexfile = None

    # Dynamically load module from argv[1]
    tmp = __import__('pb2', globals(), locals(), ['%s_pb2' % modulename])
    mod = getattr(tmp, "%s_pb2" % modulename)

    process_module(mod, genpath, indexfile)