#!/usr/bin/python2
#
# Copyright 2019 Google Inc.
#
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.


from __future__ import print_function
import StringIO
import argparse
import os
import sys


parser = argparse.ArgumentParser()
parser.add_argument('-n', '--dry-run', action='store_true',
                    help='Just check there is nothing to rewrite.')
parser.add_argument('sources', nargs='*',
                    help='Source files to rewrite, or all if empty.')
args = parser.parse_args()

roots = [
    'bench',
    'dm',
    'docs',
    'example',
    'experimental',
    'fuzz',
    'gm',
    'include',
    'modules',
    'platform_tools/android/apps',
    'samplecode',
    'src',
    'tests',
    'third_party/etc1',
    'third_party/gif',
    'tools'
  ]

# Don't count our local Vulkan headers as Skia headers;
# we don't want #include <vulkan/vulkan_foo.h> rewritten to point to them.
# Nor do we care about things in node_modules, used by *Kits.
ignorelist = ['include/third_party/vulkan', 'node_modules']

assert '/' in [os.sep, os.altsep]
def fix_path(p):
  return p.replace(os.sep, os.altsep) if os.altsep else p

# Map short name -> absolute path for all Skia headers.
headers = {}
for root in roots:
  for path, _, files in os.walk(root):
    if not any(snippet in fix_path(path) for snippet in ignorelist):
      for file_name in files:
        if file_name.endswith('.h'):
          if file_name in headers:
            message = ('Header filename is used more than once!\n- ' + path + '/' + file_name +
                       '\n- ' + headers[file_name])
            assert file_name not in headers, message
          headers[file_name] = os.path.abspath(os.path.join(path, file_name))

def to_rewrite():
  if args.sources:
    for path in args.sources:
      yield path
  else:
    for root in roots:
      for path, _, files in os.walk(root):
        for file_name in files:
          yield os.path.join(path, file_name)

# Rewrite any #includes relative to Skia's top-level directory.
need_rewriting = []
for file_path in to_rewrite():
  if ('/generated/' in file_path or
      'tests/sksl/' in file_path or
      'third_party/skcms' in file_path):
    continue
  if (file_path.endswith('.h') or
      file_path.endswith('.c') or
      file_path.endswith('.m') or
      file_path.endswith('.mm') or
      file_path.endswith('.inc') or
      file_path.endswith('.fp') or
      file_path.endswith('.cc') or
      file_path.endswith('.cpp')):
    # Read the whole file into memory.
    lines = open(file_path).readlines()

    # Write it back out again line by line with substitutions for #includes.
    output = StringIO.StringIO() if args.dry_run else open(file_path, 'wb')

    includes = []
    for line in lines:
      parts = line.replace('<', '"').replace('>', '"').split('"')
      if (len(parts) == 3
          and '#' in parts[0]
          and 'include' in parts[0]
          and os.path.basename(parts[1]) in headers):
        header = fix_path(os.path.relpath(headers[os.path.basename(parts[1])], '.'))
        includes.append(parts[0] + '"%s"' % header + parts[2])
      else:
        for inc in sorted(includes):
          output.write(inc.strip('\n') + '\n')
        includes = []
        output.write(line.strip('\n') + '\n')

    if args.dry_run and output.getvalue() != open(file_path).read():
      need_rewriting.append(file_path)
      rc = 1
    output.close()

if need_rewriting:
  print('Some files need rewritten #includes:')
  for path in need_rewriting:
    print('\t' + path)
  print('To do this automatically, run')
  print('python tools/rewrite_includes.py ' + ' '.join(need_rewriting))
  sys.exit(1)