#!/usr/bin/python3


import argparse
import collections
import json
import os
import subprocess
import sys
import tempfile


class OrderedSet(collections.OrderedDict):

  def add(self, value):
    self[value] = True


def compile_module(module, sources, settings, extras, tmpdir):
  output_file_map = {}
  if settings.whole_module_optimization:
    output_file_map[''] = {
        'object': os.path.join(settings.object_dir, module + '.o'),
        'dependencies': os.path.join(tmpdir, module + '.d'),
    }
  else:
    for source in sources:
      name, _ = os.path.splitext(os.path.basename(source))
      output_file_map[source] = {
          'object': os.path.join(settings.object_dir, name + '.o'),
          'dependencies': os.path.join(tmpdir, name + '.d'),
      }

  for key in ('module_path', 'header_path', 'depfile'):
    path = getattr(settings, key)
    if os.path.exists(path):
      os.unlink(path)
    if key == 'module_path':
      for ext in '.swiftdoc', '.swiftsourceinfo':
        path = os.path.splitext(getattr(settings, key))[0] + ext
        if os.path.exists(path):
          os.unlink(path)
    directory = os.path.dirname(path)
    if not os.path.exists(directory):
      os.makedirs(directory)

  if not os.path.exists(settings.object_dir):
    os.makedirs(settings.object_dir)

  for key in output_file_map:
    path = output_file_map[key]['object']
    if os.path.exists(path):
      os.unlink(path)

  output_file_map_path = os.path.join(tmpdir, module + '.json')
  with open(output_file_map_path, 'w') as output_file_map_file:
    output_file_map_file.write(json.dumps(output_file_map))
    output_file_map_file.flush()

  extra_args = []
  if settings.bridge_header:
    extra_args.extend([
        '-import-objc-header',
        os.path.abspath(settings.bridge_header),
    ])

  if settings.whole_module_optimization:
    extra_args.append('-whole-module-optimization')

  if settings.target:
    extra_args.extend([
        '-target',
        settings.target,
    ])

  if settings.sdk:
    extra_args.extend([
        '-sdk',
        os.path.abspath(settings.sdk),
    ])

  if settings.include_dirs:
    for include_dir in settings.include_dirs:
      extra_args.append('-I' + include_dir)

  process = subprocess.Popen(
      ['swiftc',
       '-parse-as-library',
       '-module-name',
       module,
       '-emit-object',
       '-emit-dependencies',
       '-emit-module',
       '-emit-module-path',
       settings.module_path,
       '-emit-objc-header',
       '-emit-objc-header-path',
       settings.header_path,
       '-output-file-map',
       output_file_map_path,
      ] + extra_args + extras + sources,
      stdout=subprocess.PIPE, stderr=subprocess.PIPE,
      universal_newlines=True)

  stdout, stderr = process.communicate()
  if process.returncode:
    sys.stdout.write(stdout)
    sys.stderr.write(stderr)
    sys.exit(process.returncode)


  depfile_content = collections.OrderedDict()
  for key in output_file_map:
    for line in open(output_file_map[key]['dependencies']):
      output, inputs = line.split(' : ', 2)
      _, ext = os.path.splitext(output)
      if ext == '.o':
        key = output
      else:
        key = os.path.splitext(settings.module_path)[0] + ext
      if key not in depfile_content:
        depfile_content[key] = OrderedSet()
      for path in inputs.split():
        depfile_content[key].add(path)

  with open(settings.depfile, 'w') as depfile:
    for key in depfile_content:
      if not settings.depfile_filter or key in settings.depfile_filter:
        inputs = depfile_content[key]
        depfile.write('%s : %s\n' % (key, ' '.join(inputs)))


def main(args):
  parser = argparse.ArgumentParser(add_help=False)
  parser.add_argument(
      '--module-name',
      help='name of the Swift module')
  parser.add_argument(
      '--include', '-I', action='append', dest='include_dirs',
      help='add directory to header search path')
  parser.add_argument(
      'sources', nargs='+',
      help='Swift source file to compile')
  parser.add_argument(
      '--whole-module-optimization', action='store_true',
      help='enable whole module optimization')
  parser.add_argument(
      '--object-dir', '-o',
      help='path to the generated object files directory')
  parser.add_argument(
      '--module-path', '-m',
      help='path to the generated module file')
  parser.add_argument(
      '--header-path', '-h',
      help='path to the generated header file')
  parser.add_argument(
      '--bridge-header', '-b',
      help='path to the Objective-C bridge header')
  parser.add_argument(
      '--depfile', '-d',
      help='path to the generated depfile')
  parser.add_argument(
      '--depfile-filter', action='append',
      help='limit depfile to those files')
  parser.add_argument(
      '--target', action='store',
      help='generate code for the given target <triple>')
  parser.add_argument(
      '--sdk', action='store',
      help='compile against sdk')

  parsed, extras = parser.parse_known_args(args)
  with tempfile.TemporaryDirectory() as tmpdir:
    compile_module(
        parsed.module_name,
        parsed.sources,
        parsed,
        extras,
        tmpdir)


if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))