# Copyright(c) 2017, Intel Corporation

#

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import os

import json

import struct

from metadata import constants

from metadata import metadata

RBF_EXT = ".rbf"

GBS_EXT = ".gbs"

"""

Class GBS for operations related to GBS files

"""

class GBS:

    def __init__(self, gbs_file=None):

        self.guid = ''

        self.metadata_len = 0

        self.gbs_info = ''

        self.rbf = ''

        self.metadata = []

        if gbs_file:

            self.filename = os.path.splitext(os.path.basename(gbs_file))[0]

            self.validate_gbs_file(gbs_file)

    """

    classmethod to create a gbs instance from json and

    rbf file. Used to create a new gbs file

    @return instance of the new GBS object

    """

    @classmethod

    def create_gbs_from_afu_info(cls, rbf_file, afu_json):

        gbs = cls()

        rbf = open(rbf_file, 'rb')

        rbf_content = rbf.read()

        gbs.guid = constants.METADATA_GUID

        gbs.metadata_len = len(afu_json)

        gbs.gbs_info = afu_json

        gbs.rbf = rbf_content

        gbs.metadata = metadata.get_metadata(afu_json)

        gbs.filename = os.path.splitext(os.path.basename(rbf_file))[0]

        return gbs

    """

    Set of get methods to retrieve gbs attributes

    """

    def get_gbs_guid(self):

        return self.guid

    def get_gbs_meta_len(self):

        return self.metadata_len

    def get_gbs_info(self):

        return self.gbs_info

    def get_rbf_val(self):

        return self.rbf

    def get_gbs_metadata(self):

        return self.metadata

    """

    Function to print GBS info to the console

    """

    def print_gbs_info(self):

        if self.gbs_info == '':

            raise Exception("No metadata in GBS file")

        print(json.dumps(self.gbs_info, indent=4))

    """

    Function to write a new rbf file to the filesystem

    """

    def write_rbf(self, rbf_file):

        if not rbf_file:

            rbf_file = self.filename + RBF_EXT

        with open(rbf_file, 'wb') as rbf:

            rbf.write(self.rbf)

        return rbf_file

    """

    Function to write a new gbs file to the filesystem

    """

    def write_gbs(self, gbs_file):

        if not gbs_file:

            gbs_file = self.filename + GBS_EXT

        decoded_bytes = [c if isinstance(c, int) else ord(c)

                         for c in self.get_gbs_metadata()]

        gbs_file_header = bytearray(decoded_bytes)

        with open(gbs_file, 'wb') as gbs:

            gbs.write(gbs_file_header + self.rbf)

        return gbs_file

    """

    Function to update gbs info in an object with input info

    """

    def update_gbs_info(self, gbs_info):

        self.gbs_info = gbs_info

        self.metadata = metadata.get_metadata(self.gbs_info)

    """

    Function to make make sure GBS file conforms to standard

    and polpulate the GBS object with appropriate values

    """

    def validate_gbs_file(self, gbs_file):

        file = open(gbs_file, 'rb')

        gbs = file.read()

        if len(constants.METADATA_GUID) >= len(gbs):

            raise Exception("Invalid GBS file")

        self.guid = gbs[:constants.GUID_LEN]

        if self.guid != constants.METADATA_GUID:

            raise Exception("Unsupported GBS format")

        metadata_index = constants.GUID_LEN + constants.SIZEOF_LEN_FIELD

        metadata_len = struct.unpack(

            "

        self.metadata_len = metadata_len[0]

        if self.metadata_len != 0:

            self.gbs_info = json.loads(

                gbs[metadata_index:(metadata_index + self.metadata_len)])

        rbf_index = metadata_index + metadata_len[0]

        if rbf_index == len(gbs):

            raise Exception("No RBF in GBS file!")

        self.rbf = gbs[rbf_index:]

        self.metadata = metadata.get_metadata(self.gbs_info)