# Copyright 2021 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import struct
from packedstruct import PackedStruct
from collections import OrderedDict

FBPACK_MAGIC = 0x4b504246   # "FBPK"  FastBook PacK
FBPACK_VERSION = 2
FBPACK_DEFAULT_DATA_ALIGN = 16

FBPACK_PARTITION_TABLE = 0
FBPACK_PARTITION_DATA = 1
FBPACK_SIDELOAD_DATA = 2


class PackEntry(PackedStruct):
    """Pack entry info."""

    _FIELDS = OrderedDict([
        ('type', 'I'),
        ('name', '36s'),
        ('product', '40s'),
        ('offset', 'Q'),
        ('size', 'Q'),
        ('slotted', 'I'),
        ('crc32', 'I'),
    ])

    def __init__(self, type_=0, name=b'', prod=b'', offset=0, size=0, slotted=0, crc32=0):
        super(PackEntry, self).__init__(type_, name, prod, offset, size, slotted, crc32)


class PackHeader(PackedStruct):
    """ A packed image representation """

    _FIELDS = OrderedDict([
        ('magic', 'I'),
        ('version', 'I'),
        ('header_size', 'I'),
        ('entry_header_size', 'I'),
        ('platform', '16s'),
        ('pack_version', '64s'),
        ('slot_type', 'I'),
        ('data_align', 'I'),
        ('total_entries', 'I'),
        ('total_size', 'I'),
    ])

    def __init__(
            self,
            magic=FBPACK_MAGIC,
            version=FBPACK_VERSION,
            header_size=0,
            entry_header_size=len(PackEntry()),
            platform=b'',
            pack_version=b'',
            slot_type=0,
            data_align=FBPACK_DEFAULT_DATA_ALIGN,
            total_entries=0,
            total_size=0):
        super(PackHeader, self).__init__(
            magic,
            version,
            header_size,
            entry_header_size,
            platform,
            pack_version,
            slot_type,
            data_align,
            total_entries,
            total_size)
        # update header size once we know all fields
        self.header_size = len(self)