#!/usr/bin/env python3
# Copyright 2024 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.
"""A script gets the information needed by lDE language services.

Expected to run it at repository root,  where top DEP, .gn etc exists.
Not intended to run by user.
See go/reqs-for-peep
"""

import argparse
import os
import re
import subprocess
import sys

def _gn_lines(output_dir, path):
    """
    Generator function that returns args.gn lines one at a time, following
    import directives as needed.
    """
    import_re = re.compile(r'\s*import\("(.*)"\)')
    with open(path, encoding="utf-8") as f:
        for line in f:
            match = import_re.match(line)
            if match:
                raw_import_path = match.groups()[0]
                if raw_import_path[:2] == "//":
                    import_path = os.path.normpath(
                        os.path.join(output_dir, "..", "..",
                                     raw_import_path[2:]))
                else:
                    import_path = os.path.normpath(
                        os.path.join(os.path.dirname(path), raw_import_path))
                for import_line in _gn_lines(output_dir, import_path):
                    yield import_line
            else:
                yield line


def _use_reclient(outdir):
  use_remoteexec = False
  use_reclient = None
  args_gn = os.path.join(outdir, 'args.gn')
  if not os.path.exists(args_gn):
    return False
  for line in _gn_lines(outdir, args_gn):
    line_without_comment = line.split('#')[0]
    m = re.match(r"(^|\s*)use_remoteexec\s*=\s*(true|false)\s*$",
                 line_without_comment)
    if m:
      use_remoteexec = m.group(2) == 'true'
      continue
    m = re.match(r"(^|\s*)use_reclient\s*=\s*(true|false)\s*$",
                 line_without_comment)
    if m:
      use_reclient = m.group(2) == 'true'
  if use_reclient == None:
      use_reclient = use_remoteexec
  return use_reclient


def main():
  parser = argparse.ArgumentParser()
  parser.add_argument('source', nargs='+',
    help=('The source file being analyzed.'
          'Multiple source arguments can be passed in order to batch '
          'process if desired.'))
  parser.add_argument('--perform-build', action='store_true',
    help=('If specified, actually build the target, including any generated '
          'prerequisite files. '
          'If --perform-build is not passed, the contents of '
          'the GeneratedFile results will only be returned if a build has '
          'been previously completed, and may be stale.'))
  parser.add_argument('--out-dir',
    help=('Output directory, containing args.gn, which specifies the build '
          'configuration.'))
  options = parser.parse_args()

  this_dir = os.path.dirname(__file__)
  repo_root = os.path.join(this_dir, '..', '..')

  targets = []
  for source in options.source:
    # source is repo root (cwd) relative,
    # but siso uses out dir relative target.
    target = os.path.relpath(source, start=options.out_dir) + "^"
    targets.append(target)

  if _use_reclient(options.out_dir):
    # b/335795623 ide_query compiler_arguments contain non-compiler arguments
    sys.stderr.write(
        'ide_query won\'t work well with "use_reclient=true"\n'
        'Set "use_reclient=false" in args.gn.\n')
    sys.exit(1)
  if options.perform_build:
    args = ['siso', 'ninja']
    # use `-k=0` to build generated files as much as possible.
    args.extend([
        '-k=0',
        '--prepare',
        '-C',
        options.out_dir,
    ])
    args.extend(targets)
    env = os.environ.copy()
    env['SISO_EXPERIMENTS'] = 'no-fast-deps,prepare-header-only'
    with subprocess.Popen(
        args,
        cwd=repo_root,
        env=env,
        stderr=subprocess.STDOUT,
        stdout=subprocess.PIPE,
        universal_newlines=True
    ) as p:
      for line in p.stdout:
          print(line, end='', file=sys.stderr)
      # loop ends when program finishes, but must wait else returncode is None.
      p.wait()
      if p.returncode != 0:
        # TODO: report error in IdeAnalysis.Status?
        sys.stderr.write('build failed with %d\n' % p.returncode)
        # even if build fails, it should report ideanalysis back.

  args = ['siso', 'query', 'ideanalysis', '-C', options.out_dir]
  args.extend(targets)
  subprocess.run(args, cwd=repo_root, check=True)

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