# Copyright 2017 Google Inc. All Rights Reserved.
#
# 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.
"""Code that's shared between multiple security policies subcommands."""

from __future__ import absolute_import
from __future__ import unicode_literals
import base64
import json

from googlecloudsdk.calliope import exceptions
from googlecloudsdk.core import yaml
from googlecloudsdk.core.resource import resource_printer


def SecurityPolicyFromFile(input_file, messages, file_format):
  """Returns the security policy read from the given file.

  Args:
    input_file: file, A file with a security policy config.
    messages: messages, The set of available messages.
    file_format: string, the format of the file to read from

  Returns:
    A security policy resource.
  """

  if file_format == 'yaml':
    parsed_security_policy = yaml.load(input_file)
  else:
    try:
      parsed_security_policy = json.load(input_file)
    except ValueError as e:
      raise exceptions.BadFileException('Error parsing JSON: {0}'.format(
          str(e)))

  security_policy = messages.SecurityPolicy()
  if 'description' in parsed_security_policy:
    security_policy.description = parsed_security_policy['description']
  if 'fingerprint' in parsed_security_policy:
    security_policy.fingerprint = base64.urlsafe_b64decode(
        parsed_security_policy['fingerprint'].encode('ascii'))

  rules = []
  for rule in parsed_security_policy['rules']:
    security_policy_rule = messages.SecurityPolicyRule()
    security_policy_rule.action = rule['action']
    if 'description' in rule:
      security_policy_rule.description = rule['description']
    match = messages.SecurityPolicyRuleMatcher()
    if 'srcIpRanges' in rule['match']:
      match.srcIpRanges = rule['match']['srcIpRanges']
    if 'versionedExpr' in rule['match']:
      match.versionedExpr = ConvertToEnum(rule['match']['versionedExpr'],
                                          messages)
    if 'config' in rule['match']:
      if 'srcIpRanges' in rule['match']['config']:
        match.config = messages.SecurityPolicyRuleMatcherConfig(
            srcIpRanges=rule['match']['config']['srcIpRanges'])
    security_policy_rule.match = match
    security_policy_rule.priority = rule['priority']
    if 'preview' in rule:
      security_policy_rule.preview = rule['preview']
    rules.append(security_policy_rule)

  security_policy.rules = rules

  return security_policy


def ConvertToEnum(versioned_expr, messages):
  """Converts a string version of a versioned expr to the enum representation.

  Args:
    versioned_expr: string, string version of versioned expr to convert.
    messages: messages, The set of available messages.

  Returns:
    A versioned expression enum.
  """
  return messages.SecurityPolicyRuleMatcher.VersionedExprValueValuesEnum(
      versioned_expr)


def WriteToFile(output_file, security_policy, file_format):
  """Writes the given security policy in the given format to the given file.

  Args:
    output_file: file, File into which the security policy should be written.
    security_policy: resource, SecurityPolicy to be written out.
    file_format: string, the format of the file to write to.
  """
  resource_printer.Print(
      security_policy, print_format=file_format, out=output_file)
