#!/usr/bin/env python
# Copyright 2015 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import subprocess
import sys
import os

SRC_ROOT = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

def get_out_dir(args):
    if args.target_os is not None:
        target_dir = [args.target_os]
    else:
        target_dir = ['host']

    target_dir.append(args.runtime_mode)

    if args.simulator:
        target_dir.append('sim')

    if args.unoptimized:
        target_dir.append('unopt')

    if args.android_cpu != 'arm':
        target_dir.append(args.android_cpu)

    return os.path.join('out', '_'.join(target_dir))

def to_command_line(gn_args):
    def merge(key, value):
        if type(value) is bool:
            return '%s=%s' % (key, 'true' if value else 'false')
        return '%s="%s"' % (key, value)
    return [merge(x, y) for x, y in gn_args.iteritems()]

def to_gn_args(args):
    if args.simulator:
        if args.target_os == 'android':
            raise Exception('--simulator is not supported on Android')
        elif args.target_os == 'ios':
            if args.runtime_mode != 'debug':
                raise Exception('iOS simulator only supports the debug runtime mode')

    gn_args = {}

    gn_args['is_debug'] = args.unoptimized
    gn_args['is_clang'] = args.clang and args.target_os not in ['android']

    ios_target_cpu = 'arm64'

    aot = args.runtime_mode != 'debug'
    if args.target_os == 'android':
        gn_args['target_os'] = 'android'
    elif args.target_os == 'ios':
        gn_args['target_os'] = 'ios'
        gn_args['ios_deployment_target'] = '7.0'
        gn_args['use_ios_simulator'] = args.simulator
        if args.simulator:
          gn_args['use_libjpeg_turbo'] = False
        else:
          # Always use AOT on iOS devices until the interpreter stabilizes
          aot = True
    else:
      gn_args['use_system_harfbuzz'] = False
      aot = False

    if args.runtime_mode == 'debug':
        gn_args['dart_runtime_mode'] = 'develop'
    else:
        gn_args['dart_runtime_mode'] = args.runtime_mode

    if args.target_os == 'android':
        gn_args['target_cpu'] = args.android_cpu
    elif args.target_os == 'ios':
        if args.simulator:
            gn_args['target_cpu'] = 'x64'
        else:
            gn_args['target_cpu'] = 'arm64'

    gn_args['flutter_aot'] = aot
    if aot:
        gn_args['dart_target_arch'] = gn_args['target_cpu']

    # On iOS Devices, use the Dart bytecode interpreter so we don't incur
    # snapshotting and linking costs of the precompiler during development.
    # We can still use the JIT on the simulator though.
    use_dbc = args.target_os == 'ios' and not args.simulator and args.runtime_mode == 'debug'
    gn_args['dart_experimental_interpreter'] = use_dbc

    gn_args['flutter_runtime_mode'] = args.runtime_mode

    if args.target_sysroot:
      gn_args['target_sysroot'] = args.target_sysroot

    if args.toolchain_prefix:
      gn_args['toolchain_prefix'] = args.toolchain_prefix

    goma_dir = os.environ.get('GOMA_DIR')
    goma_home_dir = os.path.join(os.getenv('HOME', ''), 'goma')
    if args.goma and goma_dir:
      gn_args['use_goma'] = True
      gn_args['goma_dir'] = goma_dir
    elif args.goma and os.path.exists(goma_home_dir):
      gn_args['use_goma'] = True
      gn_args['goma_dir'] = goma_home_dir
    else:
      gn_args['use_goma'] = False
      gn_args['goma_dir'] = None

    gn_args['use_glfw'] = args.use_glfw

    return gn_args

def parse_args(args):
  args = args[1:]
  parser = argparse.ArgumentParser(description='A script run` gn gen`.')

  parser.add_argument('--unoptimized', default=False, action='store_true')

  parser.add_argument('--runtime-mode', type=str, choices=['debug', 'profile', 'release'], default='debug')

  parser.add_argument('--target-os', type=str, choices=['android', 'ios'])
  parser.add_argument('--android', dest='target_os', action='store_const', const='android')
  parser.add_argument('--android-cpu', type=str, choices=['arm', 'x64', 'x86'], default='arm')
  parser.add_argument('--ios', dest='target_os', action='store_const', const='ios')
  parser.add_argument('--simulator', action='store_true', default=False)

  parser.add_argument('--goma', default=True, action='store_true')
  parser.add_argument('--no-goma', dest='goma', action='store_false')

  parser.add_argument('--clang', default=True, action='store_true')
  parser.add_argument('--no-clang', dest='clang', action='store_false')

  parser.add_argument('--target-sysroot', type=str)
  parser.add_argument('--toolchain-prefix', type=str)

  parser.add_argument('--use-glfw', action='store_true', default=False)

  return parser.parse_args(args)

def main(argv):
  args = parse_args(argv)

  if sys.platform.startswith(('cygwin', 'win')):
    subdir = 'win'
  elif sys.platform == 'darwin':
    subdir = 'mac'
  elif sys.platform.startswith('linux'):
     subdir = 'linux64'
  else:
    raise Error('Unknown platform: ' + sys.platform)

  command = [
    '%s/buildtools/%s/gn' % (SRC_ROOT, subdir),
    'gen',
    '--check'
  ]
  gn_args = to_command_line(to_gn_args(args))
  out_dir = get_out_dir(args)
  print "gn gen --check in %s" % out_dir
  command.append(out_dir)
  command.append('--args=%s' % ' '.join(gn_args))
  return subprocess.call(command, cwd=SRC_ROOT)


if __name__ == '__main__':
    sys.exit(main(sys.argv))