#!/usr/bin/env python
#
# Copyright (C) 2018 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.
#
"""A tool for checking that a manifest agrees with the build system."""

from __future__ import print_function

import argparse
import json
import re
import subprocess
import sys
from xml.dom import minidom

from manifest import android_ns
from manifest import get_children_with_tag
from manifest import parse_manifest
from manifest import write_xml


class ManifestMismatchError(Exception):
    pass


def parse_args():
    """Parse commandline arguments."""

    parser = argparse.ArgumentParser()
    parser.add_argument(
        '--uses-library',
        dest='uses_libraries',
        action='append',
        help='specify uses-library entries known to the build system')
    parser.add_argument(
        '--optional-uses-library',
        dest='optional_uses_libraries',
        action='append',
        help='specify uses-library entries known to the build system with '
        'required:false'
    )
    parser.add_argument(
        '--enforce-uses-libraries',
        dest='enforce_uses_libraries',
        action='store_true',
        help='check the uses-library entries known to the build system against '
        'the manifest'
    )
    parser.add_argument(
        '--enforce-uses-libraries-relax',
        dest='enforce_uses_libraries_relax',
        action='store_true',
        help='do not fail immediately, just save the error message to file')
    parser.add_argument(
        '--enforce-uses-libraries-status',
        dest='enforce_uses_libraries_status',
        help='output file to store check status (error message)')
    parser.add_argument(
        '--extract-target-sdk-version',
        dest='extract_target_sdk_version',
        action='store_true',
        help='print the targetSdkVersion from the manifest')
    parser.add_argument(
        '--dexpreopt-config',
        dest='dexpreopt_configs',
        action='append',
        help='a paths to a dexpreopt.config of some library')
    parser.add_argument('--aapt', dest='aapt', help='path to aapt executable')
    parser.add_argument(
        '--output', '-o', dest='output', help='output AndroidManifest.xml file')
    parser.add_argument('input', help='input AndroidManifest.xml file')
    return parser.parse_args()


def enforce_uses_libraries(manifest, required, optional, relax, is_apk, path):
    """Verify that the <uses-library> tags in the manifest match those provided

  by the build system.

  Args:
    manifest: manifest (either parsed XML or aapt dump of APK)
    required: required libs known to the build system
    optional: optional libs known to the build system
    relax:    if true, suppress error on mismatch and just write it to file
    is_apk:   if the manifest comes from an APK or an XML file
    """
    if is_apk:
        manifest_required, manifest_optional, tags = extract_uses_libs_apk(
            manifest)
    else:
        manifest_required, manifest_optional, tags = extract_uses_libs_xml(
            manifest)

    # Trim namespace component. Normally Soong does that automatically when it
    # handles module names specified in Android.bp properties. However not all
    # <uses-library> entries in the manifest correspond to real modules: some of
    # the optional libraries may be missing at build time. Therefor this script
    # accepts raw module names as spelled in Android.bp/Amdroid.mk and trims the
    # optional namespace part manually.
    required = trim_namespace_parts(required)
    optional = trim_namespace_parts(optional)

    if manifest_required == required and manifest_optional == optional:
        return None

    #pylint: disable=line-too-long
    errmsg = ''.join([
        'mismatch in the <uses-library> tags between the build system and the '
        'manifest:\n',
        '\t- required libraries in build system: [%s]\n' % ', '.join(required),
        '\t                 vs. in the manifest: [%s]\n' %
        ', '.join(manifest_required),
        '\t- optional libraries in build system: [%s]\n' % ', '.join(optional),
        '\t                 vs. in the manifest: [%s]\n' %
        ', '.join(manifest_optional),
        '\t- tags in the manifest (%s):\n' % path,
        '\t\t%s\n' % '\t\t'.join(tags),
        'note: the following options are available:\n',
        '\t- to temporarily disable the check on command line, rebuild with ',
        'RELAX_USES_LIBRARY_CHECK=true (this will set compiler filter "verify" ',
        'and disable AOT-compilation in dexpreopt)\n',
        '\t- to temporarily disable the check for the whole product, set ',
        'PRODUCT_BROKEN_VERIFY_USES_LIBRARIES := true in the product makefiles\n',
        '\t- to fix the check, make build system properties coherent with the '
        'manifest\n', '\t- see build/make/Changes.md for details\n'
    ])
    #pylint: enable=line-too-long

    if not relax:
        raise ManifestMismatchError(errmsg)

    return errmsg


MODULE_NAMESPACE = re.compile('^//[^:]+:')


def trim_namespace_parts(modules):
    """Trim the namespace part of each module, if present.

    Leave only the name.
    """

    trimmed = []
    for module in modules:
        trimmed.append(MODULE_NAMESPACE.sub('', module))
    return trimmed


def extract_uses_libs_apk(badging):
    """Extract <uses-library> tags from the manifest of an APK."""

    pattern = re.compile("^uses-library(-not-required)?:'(.*)'$", re.MULTILINE)

    required = []
    optional = []
    lines = []
    for match in re.finditer(pattern, badging):
        lines.append(match.group(0))
        libname = match.group(2)
        if match.group(1) is None:
            required.append(libname)
        else:
            optional.append(libname)

    required = first_unique_elements(required)
    optional = first_unique_elements(optional)
    tags = first_unique_elements(lines)
    return required, optional, tags


def extract_uses_libs_xml(xml): #pylint: disable=inconsistent-return-statements
    """Extract <uses-library> tags from the manifest."""

    manifest = parse_manifest(xml)
    elems = get_children_with_tag(manifest, 'application')
    application = elems[0] if len(elems) == 1 else None
    if len(elems) > 1: #pylint: disable=no-else-raise
        raise RuntimeError('found multiple <application> tags')
    elif not elems:
        if uses_libraries or optional_uses_libraries: #pylint: disable=undefined-variable
            raise ManifestMismatchError('no <application> tag found')
        return

    libs = get_children_with_tag(application, 'uses-library')

    required = [uses_library_name(x) for x in libs if uses_library_required(x)]
    optional = [
        uses_library_name(x) for x in libs if not uses_library_required(x)
    ]

    # render <uses-library> tags as XML for a pretty error message
    tags = []
    for lib in libs:
        tags.append(lib.toprettyxml())

    required = first_unique_elements(required)
    optional = first_unique_elements(optional)
    tags = first_unique_elements(tags)
    return required, optional, tags


def first_unique_elements(l):
    result = []
    for x in l:
        if x not in result:
            result.append(x)
    return result


def uses_library_name(lib):
    """Extract the name attribute of a uses-library tag.

  Args:
    lib: a <uses-library> tag.
    """
    name = lib.getAttributeNodeNS(android_ns, 'name')
    return name.value if name is not None else ''


def uses_library_required(lib):
    """Extract the required attribute of a uses-library tag.

  Args:
    lib: a <uses-library> tag.
    """
    required = lib.getAttributeNodeNS(android_ns, 'required')
    return (required.value == 'true') if required is not None else True


def extract_target_sdk_version(manifest, is_apk=False):
    """Returns the targetSdkVersion from the manifest.

  Args:
    manifest: manifest (either parsed XML or aapt dump of APK)
    is_apk:   if the manifest comes from an APK or an XML file
    """
    if is_apk: #pylint: disable=no-else-return
        return extract_target_sdk_version_apk(manifest)
    else:
        return extract_target_sdk_version_xml(manifest)


def extract_target_sdk_version_apk(badging):
    """Extract targetSdkVersion tags from the manifest of an APK."""

    pattern = re.compile("^targetSdkVersion?:'(.*)'$", re.MULTILINE)

    for match in re.finditer(pattern, badging):
        return match.group(1)

    raise RuntimeError('cannot find targetSdkVersion in the manifest')


def extract_target_sdk_version_xml(xml):
    """Extract targetSdkVersion tags from the manifest."""

    manifest = parse_manifest(xml)

    # Get or insert the uses-sdk element
    uses_sdk = get_children_with_tag(manifest, 'uses-sdk')
    if len(uses_sdk) > 1: #pylint: disable=no-else-raise
        raise RuntimeError('found multiple uses-sdk elements')
    elif len(uses_sdk) == 0:
        raise RuntimeError('missing uses-sdk element')

    uses_sdk = uses_sdk[0]

    min_attr = uses_sdk.getAttributeNodeNS(android_ns, 'minSdkVersion')
    if min_attr is None:
        raise RuntimeError('minSdkVersion is not specified')

    target_attr = uses_sdk.getAttributeNodeNS(android_ns, 'targetSdkVersion')
    if target_attr is None:
        target_attr = min_attr

    return target_attr.value


def load_dexpreopt_configs(configs):
    """Load dexpreopt.config files and map module names to library names."""
    module_to_libname = {}

    if configs is None:
        configs = []

    for config in configs:
        with open(config, 'r') as f:
            contents = json.load(f)
        module_to_libname[contents['Name']] = contents['ProvidesUsesLibrary']

    return module_to_libname


def translate_libnames(modules, module_to_libname):
    """Translate module names into library names using the mapping."""
    if modules is None:
        modules = []

    libnames = []
    for name in modules:
        if name in module_to_libname:
            name = module_to_libname[name]
        libnames.append(name)

    return libnames


def main():
    """Program entry point."""
    try:
        args = parse_args()

        # The input can be either an XML manifest or an APK, they are parsed and
        # processed in different ways.
        is_apk = args.input.endswith('.apk')
        if is_apk:
            aapt = args.aapt if args.aapt is not None else 'aapt'
            manifest = subprocess.check_output(
                [aapt, 'dump', 'badging', args.input])
        else:
            manifest = minidom.parse(args.input)

        if args.enforce_uses_libraries:
            # Load dexpreopt.config files and build a mapping from module
            # names to library names. This is necessary because build system
            # addresses libraries by their module name (`uses_libs`,
            # `optional_uses_libs`, `LOCAL_USES_LIBRARIES`,
            # `LOCAL_OPTIONAL_LIBRARY_NAMES` all contain module names), while
            # the manifest addresses libraries by their name.
            mod_to_lib = load_dexpreopt_configs(args.dexpreopt_configs)
            required = translate_libnames(args.uses_libraries, mod_to_lib)
            optional = translate_libnames(args.optional_uses_libraries,
                                          mod_to_lib)

            # Check if the <uses-library> lists in the build system agree with
            # those in the manifest. Raise an exception on mismatch, unless the
            # script was passed a special parameter to suppress exceptions.
            errmsg = enforce_uses_libraries(manifest, required, optional,
                                            args.enforce_uses_libraries_relax,
                                            is_apk, args.input)

            # Create a status file that is empty on success, or contains an
            # error message on failure. When exceptions are suppressed,
            # dexpreopt command command will check file size to determine if
            # the check has failed.
            if args.enforce_uses_libraries_status:
                with open(args.enforce_uses_libraries_status, 'w') as f:
                    if errmsg is not None:
                        f.write('%s\n' % errmsg)

        if args.extract_target_sdk_version:
            try:
                print(extract_target_sdk_version(manifest, is_apk))
            except: #pylint: disable=bare-except
                # Failed; don't crash, return "any" SDK version. This will
                # result in dexpreopt not adding any compatibility libraries.
                print(10000)

        if args.output:
            # XML output is supposed to be written only when this script is
            # invoked with XML input manifest, not with an APK.
            if is_apk:
                raise RuntimeError('cannot save APK manifest as XML')

            with open(args.output, 'wb') as f:
                write_xml(f, manifest)

    # pylint: disable=broad-except
    except Exception as err:
        print('error: ' + str(err), file=sys.stderr)
        sys.exit(-1)


if __name__ == '__main__':
    main()