#!/usr/bin/python3 -B

# Copyright 2017 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.

"""Generates the timezone data files used by Android."""

import argparse
import glob
import os
import re
import subprocess
import sys
import tarfile
import tempfile

sys.path.append('%s/external/icu/tools' % os.environ.get('ANDROID_BUILD_TOP'))
import i18nutil
import icuutil
import tzdatautil

# Unix epoch timestamp in seconds up to which transitions in tzdata will be pregenerated.
pregeneration_upper_bound = 4102444800 # 1 Jan 2100

# Calculate the paths that are referred to by multiple functions.
android_build_top = i18nutil.GetAndroidRootOrDie()
timezone_dir = os.path.realpath('%s/system/timezone' % android_build_top)
i18nutil.CheckDirExists(timezone_dir, 'system/timezone')

android_host_out = i18nutil.GetAndroidHostOutOrDie()

zone_compactor_dir = os.path.realpath('%s/system/timezone/input_tools/android' % android_build_top)
i18nutil.CheckDirExists(zone_compactor_dir, 'system/timezone/input_tools/android')

timezone_input_tools_dir = os.path.realpath('%s/input_tools' % timezone_dir)
timezone_input_data_dir = os.path.realpath('%s/input_data' % timezone_dir)

timezone_output_data_dir = '%s/output_data' % timezone_dir
i18nutil.CheckDirExists(timezone_output_data_dir, 'output_data')

tmp_dir = tempfile.mkdtemp('-tzdata')

def GenerateZicInputFile(extracted_iana_data_dir):
  # Android APIs assume DST means "summer time" so we follow the rearguard format
  # introduced in 2018e.
  zic_input_file_name = 'rearguard.zi'

  # 'NDATA=' is used to remove unnecessary rules files.
  subprocess.check_call(['make', '-C', extracted_iana_data_dir, 'NDATA=', zic_input_file_name])

  zic_input_file = '%s/%s' % (extracted_iana_data_dir, zic_input_file_name)
  if not os.path.exists(zic_input_file):
    print('Could not find %s' % zic_input_file)
    sys.exit(1)
  return zic_input_file


def WriteSetupFile(zic_input_file):
  """Writes the list of zones that ZoneCompactor should process."""
  links = []
  zones = []
  for line in open(zic_input_file):
    fields = line.split()
    if fields:
      line_type = fields[0]
      if line_type == 'Link':
        # Each "Link" line requires the creation of a link from an old tz ID to
        # a new tz ID, and implies the existence of a zone with the old tz ID.
        #
        # IANA terminology:
        # TARGET = the new tz ID, LINK-NAME = the old tz ID
        target = fields[1]
        link_name = fields[2]
        links.append('Link %s %s' % (target, link_name))
        zones.append('Zone %s' % link_name)
      elif line_type == 'Zone':
        # Each "Zone" line indicates the existence of a tz ID.
        #
        # IANA terminology:
        # NAME is the tz ID, other fields like STDOFF, RULES, FORMAT,[UNTIL] are
        # ignored.
        name = fields[1]
        zones.append('Zone %s' % name)

  zone_compactor_setup_file = '%s/setup' % tmp_dir
  setup = open(zone_compactor_setup_file, 'w')

  # Ordering requirement from ZoneCompactor: Links must come first.
  for link in sorted(set(links)):
    setup.write('%s\n' % link)
  for zone in sorted(set(zones)):
    setup.write('%s\n' % zone)
  setup.close()
  return zone_compactor_setup_file


def BuildIcuData(iana_data_tar_file):
  icu_build_dir = '%s/icu' % tmp_dir

  icuutil.PrepareIcuBuild(icu_build_dir)
  icuutil.MakeTzDataFiles(icu_build_dir, iana_data_tar_file)

  # Create ICU system image files.
  icuutil.MakeAndCopyIcuDataFiles(icu_build_dir)

  # Create the ICU's .res time zone files.
  icu_overlay_dir = '%s/icu_overlay' % timezone_output_data_dir
  icuutil.MakeAndCopyIcuTzFiles(icu_build_dir, icu_overlay_dir)

  # There are files in ICU which generation depends on ICU itself,
  # so multiple builds might be needed.
  icuutil.GenerateIcuDataFiles()

  # Copy ICU license file(s)
  icuutil.CopyLicenseFiles(icu_overlay_dir)


def GetIanaVersion(iana_tar_file):
  iana_tar_filename = os.path.basename(iana_tar_file)
  iana_version = re.search('tz(?:data|code)(.+)\\.tar\\.gz', iana_tar_filename).group(1)
  return iana_version


def ExtractTarFile(tar_file, dir):
  print('Extracting %s...' % tar_file)
  if not os.path.exists(dir):
    os.mkdir(dir)
  tar = tarfile.open(tar_file, 'r')
  tar.extractall(dir)


def BuildZic(iana_tools_dir):
  iana_zic_code_tar_file = tzdatautil.GetIanaTarFile(iana_tools_dir, 'tzcode')
  iana_zic_code_version = GetIanaVersion(iana_zic_code_tar_file)
  iana_zic_data_tar_file = tzdatautil.GetIanaTarFile(iana_tools_dir, 'tzdata')
  iana_zic_data_version = GetIanaVersion(iana_zic_data_tar_file)

  print('Found IANA zic release %s/%s in %s/%s ...' \
      % (iana_zic_code_version, iana_zic_data_version, iana_zic_code_tar_file,
         iana_zic_data_tar_file))

  zic_build_dir = '%s/zic' % tmp_dir
  ExtractTarFile(iana_zic_code_tar_file, zic_build_dir)
  ExtractTarFile(iana_zic_data_tar_file, zic_build_dir)

  # zic
  print('Building zic...')
  # VERSION_DEPS= is to stop the build process looking for files that might not
  # be present across different versions.
  subprocess.check_call(['make', '-C', zic_build_dir, 'zic'])

  zic_binary_file = '%s/zic' % zic_build_dir
  if not os.path.exists(zic_binary_file):
    print('Could not find %s' % zic_binary_file)
    sys.exit(1)
  return zic_binary_file


def BuildTzdata(zic_binary_file, extracted_iana_data_dir, iana_data_version):
  print('Generating zic input file...')
  zic_input_file = GenerateZicInputFile(extracted_iana_data_dir)

  print('Calling zic...')
  zic_output_dir = '%s/data' % tmp_dir
  os.mkdir(zic_output_dir)
  # -R specifies upper bound for generated transitions.
  zic_cmd = [zic_binary_file, '-b', 'slim', '-R', f'@{pregeneration_upper_bound}', '-d', zic_output_dir, zic_input_file]
  subprocess.check_call(zic_cmd)

  # ZoneCompactor
  zone_compactor_setup_file = WriteSetupFile(zic_input_file)

  print('Calling ZoneCompactor to update tzdata to %s...' % iana_data_version)

  tzdatautil.InvokeSoong(android_build_top, ['zone_compactor'])

  # Create args for ZoneCompactor
  header_string = 'tzdata%s' % iana_data_version

  print('Executing ZoneCompactor...')
  command = '%s/bin/zone_compactor' % android_host_out
  iana_output_data_dir = '%s/iana' % timezone_output_data_dir
  subprocess.check_call([command, zone_compactor_setup_file, zic_output_dir, iana_output_data_dir,
                         header_string])


def BuildTzlookupAndTzIds(iana_data_dir):
  countryzones_source_file = '%s/android/countryzones.txt' % timezone_input_data_dir
  tzlookup_dest_file = '%s/android/tzlookup.xml' % timezone_output_data_dir
  tzids_dest_file = '%s/android/tzids.prototxt' % timezone_output_data_dir

  print('Calling TzLookupGenerator to create tzlookup.xml / tzids.prototxt...')
  tzdatautil.InvokeSoong(android_build_top, ['tzlookup_generator'])

  zone_tab_file = '%s/zone.tab' % iana_data_dir
  command = '%s/bin/tzlookup_generator' % android_host_out
  subprocess.check_call([command, countryzones_source_file, zone_tab_file, tzlookup_dest_file,
                         tzids_dest_file])


def BuildTelephonylookup():
  telephonylookup_source_file = '%s/android/telephonylookup.txt' % timezone_input_data_dir
  telephonylookup_dest_file = '%s/android/telephonylookup.xml' % timezone_output_data_dir

  print('Calling TelephonyLookupGenerator to create telephonylookup.xml...')
  tzdatautil.InvokeSoong(android_build_top, ['telephonylookup_generator'])

  command = '%s/bin/telephonylookup_generator' % android_host_out
  subprocess.check_call([command, telephonylookup_source_file, telephonylookup_dest_file])


def CreateTzVersion(iana_data_version, android_revision, output_version_file):
  create_tz_version_script = '%s/input_tools/version/create-tz_version.py' % timezone_dir

  subprocess.check_call([create_tz_version_script,
      '-iana_version', iana_data_version,
      '-revision', str(android_revision),
      '-output_version_file', output_version_file])

def UpdateTestFiles():
  testing_data_dir = '%s/testing/data' % timezone_dir
  update_test_files_script = '%s/create-test-data.sh' % testing_data_dir
  subprocess.check_call([update_test_files_script], cwd=testing_data_dir)


# Run from any directory, with no special setup required.
# In the rare case when tzdata has to be updated, but under the same version,
# pass "-revision" argument.
# See http://www.iana.org/time-zones/ for more about the source of this data.
def main():
  parser = argparse.ArgumentParser()
  parser.add_argument('-revision', type=int, default=1,
      help='Revision of current the IANA version, default = 1')

  args = parser.parse_args()
  android_revision = args.revision

  print('Source data file structure: %s' % timezone_input_data_dir)
  print('Source tools file structure: %s' % timezone_input_tools_dir)
  print('Intermediate / working dir: %s' % tmp_dir)
  print('Output data file structure: %s' % timezone_output_data_dir)

  iana_input_data_dir = '%s/iana' % timezone_input_data_dir
  iana_data_tar_file = tzdatautil.GetIanaTarFile(iana_input_data_dir, 'tzdata')
  iana_data_version = GetIanaVersion(iana_data_tar_file)
  print('IANA time zone data release %s in %s ...' % (iana_data_version, iana_data_tar_file))

  icu_dir = icuutil.icuDir()
  print('Found icu in %s ...' % icu_dir)

  BuildIcuData(iana_data_tar_file)

  iana_tools_dir = '%s/iana' % timezone_input_tools_dir
  zic_binary_file = BuildZic(iana_tools_dir)

  iana_data_dir = '%s/iana_data' % tmp_dir
  ExtractTarFile(iana_data_tar_file, iana_data_dir)
  BuildTzdata(zic_binary_file, iana_data_dir, iana_data_version)

  BuildTzlookupAndTzIds(iana_data_dir)

  BuildTelephonylookup()

  # Create a version file from the output from prior stages.
  output_version_file = '%s/version/tz_version' % timezone_output_data_dir
  CreateTzVersion(iana_data_version, android_revision, output_version_file)

  # Update test versions of data files too.
  UpdateTestFiles()

  print('Look in %s and %s for new files' % (timezone_output_data_dir, icu_dir))
  sys.exit(0)


if __name__ == '__main__':
  main()