# pylint: disable=g-direct-third-party-import
# Copyright 2017 The Bazel Authors. 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.
"""AndroidManifest checks for android_instrumentation_test.

Ensures that the targetPackage of the instrumentation APK references
the correct target package name.
"""

import os
import sys

import xml.etree.ElementTree as ET
from third_party.py import gflags

gflags.DEFINE_string("instrumentation_manifest", None,
                     "AndroidManifest.xml of the instrumentation APK")
gflags.DEFINE_string("target_manifest", None,
                     "AndroidManifest.xml of the target APK")
gflags.DEFINE_string("output", None, "Output of the check")

FLAGS = gflags.FLAGS


class ManifestError(Exception):
  """Raised when there is a problem with an AndroidManifest.xml."""


# There might be more than one <instrumentation> tag to use different
# test runners, so we need to extract the targetPackage attribute values
# from all of them and check that they are the same.
def _ExtractTargetPackageToInstrument(xml_content, path):
  """Extract the targetPackage value from the <instrumentation> tag."""

  # https://developer.android.com/guide/topics/manifest/manifest-element.html
  # xmlns:android is the required namespace in an Android manifest.
  tree = ET.ElementTree(ET.fromstring(xml_content))
  package_key = "{http://schemas.android.com/apk/res/android}targetPackage"
  instrumentation_elems = tree.iterfind(
      ".//instrumentation[@{0}]".format(package_key))

  package_names = set(e.attrib[package_key] for e in instrumentation_elems)

  if not package_names:
    raise ManifestError("No <instrumentation> tag containing "
                        "the targetPackage attribute is found in the "
                        "manifest at %s" % path)

  if len(package_names) > 1:
    raise ManifestError(
        "The <instrumentation> tags in the manifest at %s do not "
        "reference the same target package: %s" % (path, list(package_names)))

  return package_names.pop()


def _ExtractTargetPackageName(xml_content, path):
  """Extract the package name value from the root <manifest> tag."""
  tree = ET.ElementTree(ET.fromstring(xml_content))
  root = tree.getroot()
  if "package" in root.attrib:
    return root.attrib["package"]
  else:
    raise ManifestError("The <manifest> tag in the manifest at %s needs to "
                        "specify the package name using the 'package' "
                        "attribute." % path)


def _ValidateManifestPackageNames(instr_manifest_content, instr_manifest_path,
                                  target_manifest_content,
                                  target_manifest_path):
  """Diff the package names and throw a ManifestError if not identical."""
  target_package_to_instrument = _ExtractTargetPackageToInstrument(
      instr_manifest_content, instr_manifest_path)
  target_package_name = _ExtractTargetPackageName(target_manifest_content,
                                                  target_manifest_path)

  if target_package_to_instrument != target_package_name:
    raise ManifestError(
        "The targetPackage specified in the instrumentation manifest at "
        "{instr_manifest_path} ({target_package_to_instrument}) does not match "
        "the package name of the target manifest at {target_manifest_path} "
        "({target_package_name})".format(
            instr_manifest_path=instr_manifest_path,
            target_package_to_instrument=target_package_to_instrument,
            target_manifest_path=target_manifest_path,
            target_package_name=target_package_name))

  return target_package_to_instrument, target_package_name


def main():
  FLAGS(sys.argv)

  instr_manifest_path = FLAGS.instrumentation_manifest
  target_manifest_path = FLAGS.target_manifest
  output_path = FLAGS.output
  dirname = os.path.dirname(output_path)
  if not os.path.exists(dirname):
    os.makedirs(dirname)

  with open(instr_manifest_path, "r") as f:
    instr_manifest = f.read()

  with open(target_manifest_path, "r") as f:
    target_manifest = f.read()

  try:
    package_to_instrument, package_name = _ValidateManifestPackageNames(
        instr_manifest, instr_manifest_path, target_manifest,
        target_manifest_path)
  except ManifestError as e:
    sys.exit(e.message)

  with open(output_path, "w") as f:
    f.write("target_package={0}\n".format(package_to_instrument))
    f.write("package_name={0}\n".format(package_name))


if __name__ == "__main__":
  main()