# -*- coding: utf-8 -*-
# Copyright 2018 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Android utility.

Terminology used in this module:
  "product-variant" is sometimes called "target" and sometimes "flavor".
  I prefer to use "flavor" in the code because
    - "target" is too general
    - sometimes, it is not in the form of "product-variant", for example,
      "cts_arm_64"
"""

from __future__ import print_function
import json
import logging
import os
import tempfile
import urllib.request

from bisect_kit import cli
from bisect_kit import codechange
from bisect_kit import errors
from bisect_kit import git_util
from bisect_kit import repo_util
from bisect_kit import util

logger = logging.getLogger(__name__)

ANDROID_URL_BASE = ('https://android-build.googleplex.com/'
                    'builds/branch/{branch}')
BUILD_IDS_BETWEEN_URL_TEMPLATE = (
    ANDROID_URL_BASE + '/build-ids/between/{end}/{start}')
BUILD_INFO_URL_TEMPLATE = ANDROID_URL_BASE + '/builds?id={build_id}'


def is_android_build_id(s):
  """Is an Android build id."""
  # Build ID is always a number
  return s.isdigit()


def argtype_android_build_id(s):
  if not is_android_build_id(s):
    msg = 'invalid android build id (%s)' % s
    raise cli.ArgTypeError(msg, '9876543')
  return s


def fetch_android_build_data(url):
  """Fetches file from android build server.

  Args:
    url: URL to fetch

  Returns:
    file content (str). None if failed.
  """
  # Fetching android build data directly will fail without authentication.
  # Following code is just serving as demo purpose. You should modify or hook
  # it with your own implementation.
  logger.warning('fetch_android_build_data need to be hooked')
  try:
    return urllib.request.urlopen(url).read().decode('utf8')
  except urllib.request.URLError as e:
    logger.exception('failed to fetch "%s"', url)
    raise errors.ExternalError(str(e))


def is_good_build(branch, flavor, build_id):
  """Determine a build_id was succeeded.

  Args:
    branch: The Android branch from which to retrieve the builds.
    flavor: Target name of the Android image in question.
        E.g. "cheets_x86-userdebug" or "cheets_arm-user".
    build_id: Android build id

  Returns:
    True if the given build was successful.
  """

  url = BUILD_INFO_URL_TEMPLATE.format(branch=branch, build_id=build_id)
  build = json.loads(fetch_android_build_data(url))
  for target in build[0]['targets']:
    if target['target']['name'] == flavor and target.get('successful'):
      return True
  return False


def get_build_ids_between(branch, flavor, start, end):
  """Returns a list of build IDs.

  Args:
    branch: The Android branch from which to retrieve the builds.
    flavor: Target name of the Android image in question.
        E.g. "cheets_x86-userdebug" or "cheets_arm-user".
    start: The starting point build ID. (inclusive)
    end: The ending point build ID. (inclusive)

  Returns:
    A list of build IDs. (str)
  """
  # Do not remove this argument because our internal implementation need it.
  del flavor  # not used

  # TODO(kcwu): remove pagination hack after b/68239878 fixed
  build_id_set = set()
  tmp_end = end
  while True:
    url = BUILD_IDS_BETWEEN_URL_TEMPLATE.format(
        branch=branch, start=start, end=tmp_end)
    query_result = json.loads(fetch_android_build_data(url))
    found_new = set(int(x) for x in query_result['ids']) - build_id_set
    if not found_new:
      break
    build_id_set.update(found_new)
    tmp_end = min(build_id_set)

  logger.debug('Found %d builds in the range.', len(build_id_set))

  return [str(bid) for bid in sorted(build_id_set)]


def lunch(android_root, flavor, *args, **kwargs):
  """Helper to run commands with Android lunch env.

  Args:
    android_root: root path of Android tree
    flavor: lunch flavor
    args: command to run
    kwargs: extra arguments passed to util.Popen
  """
  util.check_call('./android_lunch_helper.sh', android_root, flavor, *args,
                  **kwargs)


def fetch_artifact(flavor, build_id, filename, dest):
  """Fetches Android build artifact.

  Args:
    flavor: Android build flavor
    build_id: Android build id
    filename: artifact name
    dest: local path to store the fetched artifact
  """
  service_account_args = []
  # These arguments are for bisector service and not required for users of
  # bisect-kit using personal account.
  if os.environ.get('ANDROID_CLOUD_SERVICE_ACCOUNT_EMAIL'):
    assert os.environ.get('ANDROID_CLOUD_SERVICE_ACCOUNT_KEY')
    service_account_args += [
        '--email',
        os.environ.get('ANDROID_CLOUD_SERVICE_ACCOUNT_EMAIL'),
        '--apiary_service_account_private_key_path',
        os.environ.get('ANDROID_CLOUD_SERVICE_ACCOUNT_KEY'),
    ]

  util.check_call('/google/data/ro/projects/android/fetch_artifact', '--target',
                  flavor, '--bid', build_id, filename, dest,
                  *service_account_args)


def fetch_manifest(android_root, flavor, build_id):
  """Fetches Android repo manifest of given build.

  Args:
    android_root: root path of Android tree. Fetched manifest file will be
        stored inside.
    flavor: Android build flavor
    build_id: Android build id

  Returns:
    the local filename of manifest (relative to android_root/.repo/manifests/)
  """
  # Assume manifest is flavor independent, thus not encoded into the file name.
  manifest_name = 'manifest_%s.xml' % build_id
  manifest_path = os.path.join(android_root, '.repo', 'manifests',
                               manifest_name)
  if not os.path.exists(manifest_path):
    fetch_artifact(flavor, build_id, manifest_name, manifest_path)
  return manifest_name


def lookup_build_timestamp(flavor, build_id):
  """Lookup timestamp of Android prebuilt.

  Args:
    flavor: Android build flavor
    build_id: Android build id

  Returns:
    timestamp
  """
  tmp_fn = tempfile.mktemp()
  try:
    fetch_artifact(flavor, build_id, 'BUILD_INFO', tmp_fn)
    with open(tmp_fn) as f:
      data = json.load(f)
    return int(data['sync_start_time'])
  finally:
    if os.path.exists(tmp_fn):
      os.unlink(tmp_fn)


class AndroidSpecManager(codechange.SpecManager):
  """Repo manifest related operations.

  This class fetches and enumerates android manifest files, parses them,
  and sync to disk state according to them.
  """

  def __init__(self, config):
    self.config = config
    self.manifest_dir = os.path.join(self.config['android_root'], '.repo',
                                     'manifests')

  def collect_float_spec(self, old, new, fixed_specs=None):
    del fixed_specs  # unused
    result = []
    path = 'default.xml'

    commits = []
    old_timestamp = lookup_build_timestamp(self.config['flavor'], old)
    new_timestamp = lookup_build_timestamp(self.config['flavor'], new)
    for timestamp, git_rev in git_util.get_history(self.manifest_dir, path):
      if timestamp < old_timestamp:
        commits = []
      commits.append((timestamp, git_rev))
      if timestamp > new_timestamp:
        break

    for timestamp, git_rev in commits:
      result.append(
          codechange.Spec(codechange.SPEC_FLOAT, git_rev, timestamp, path))
    return result

  def collect_fixed_spec(self, old, new):
    result = []
    revlist = get_build_ids_between(self.config['branch'],
                                    self.config['flavor'], int(old), int(new))
    for rev in revlist:
      manifest_name = fetch_manifest(self.config['android_root'],
                                     self.config['flavor'], rev)
      path = os.path.join(self.manifest_dir, manifest_name)
      timestamp = lookup_build_timestamp(self.config['flavor'], rev)
      result.append(
          codechange.Spec(codechange.SPEC_FIXED, rev, timestamp, path))
    return result

  def _load_manifest_content(self, spec):
    if spec.spec_type == codechange.SPEC_FIXED:
      manifest_name = fetch_manifest(self.config['branch'],
                                     self.config['flavor'], spec.name)
      with open(os.path.join(self.manifest_dir, manifest_name)) as f:
        content = f.read()
    else:
      content = git_util.get_file_from_revision(self.manifest_dir, spec.name,
                                                spec.path)
    return content

  def parse_spec(self, spec):
    logging.debug('parse_spec %s', spec.name)
    manifest_content = self._load_manifest_content(spec)
    parser = repo_util.ManifestParser(self.manifest_dir)
    root = parser.parse_single_xml(manifest_content, allow_include=False)
    spec.entries = parser.process_parsed_result(root)
    if spec.spec_type == codechange.SPEC_FIXED:
      if not spec.is_static():
        raise ValueError('fixed spec %r has unexpected floating entries' %
                         spec.name)

  def sync_disk_state(self, rev):
    manifest_name = fetch_manifest(self.config['android_root'],
                                   self.config['flavor'], rev)
    repo_util.sync(
        self.config['android_root'],
        manifest_name=manifest_name,
        current_branch=True)