"""FBPACK format definitions and structures.

This module defines the data structures used for parsing and creating FBPACK
(FastBoot PacK) images, including PackEntry and PackHeader.
"""
import collections
from typing import List

from google3.third_party.devsite.androidsource.en.docs.core.architecture.bootloader.tools.pixel.fw_unpack import packedstruct


OrderedDict = collections.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.PackedStruct):
  """Pack entry info."""

  _FIELDS = OrderedDict([
      ('type', 'I'),
      ('name', '36s'),
      ('product', '40s'),
      ('offset', 'Q'),
      ('size', 'Q'),
      ('slotted', 'I'),
      ('crc32', 'I'),
  ])
  type: int
  name: bytes
  product: bytes
  offset: int
  size: int
  slotted: int
  crc32: int
  filepath: str
  filename: str

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


class PackHeader(packedstruct.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'),
  ])
  magic: int
  version: int
  header_size: int
  entry_header_size: int
  platform: bytes
  pack_version: bytes
  slot_type: int
  data_align: int
  total_entries: int
  total_size: int
  name: str
  entries: List[PackEntry]

  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().__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)
    self.name = ''
    self.entries = []