# Copyright 2016 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.

"""Presubmit script for ui/accessibility."""

import os, re, json

AX_MOJOM = 'ui/accessibility/ax_enums.mojom'
AUTOMATION_IDL = 'extensions/common/api/automation.idl'

AX_JS_FILE = 'chrome/browser/resources/accessibility/accessibility.js'
AX_MODE_HEADER = 'ui/accessibility/ax_mode.h'

def InitialLowerCamelCase(unix_name):
  words = unix_name.split('_')
  return words[0] + ''.join(word.capitalize() for word in words[1:])

def CamelToLowerHacker(str):
  out = ''
  for i in range(len(str)):
    if str[i] >= 'A' and str[i] <= 'Z' and out:
      out += '_'
    out += str[i]
  return out.lower()

# Given a full path to an IDL or MOJOM file containing enum definitions,
# parse the file for enums and return a dict mapping the enum name
# to a list of values for that enum.
def GetEnumsFromFile(fullpath):
  enum_name = None
  enums = {}
  for line in open(fullpath).readlines():
    # Strip out comments
    line = re.sub('//.*', '', line)

    # Look for lines of the form "enum ENUM_NAME {" and get the enum_name
    m = re.search('enum ([\w]+) {', line)
    if m:
      enum_name = m.group(1)
      continue

    # Look for a "}" character signifying the end of an enum
    if line.find('}') >= 0:
      enum_name = None
      continue

    if not enum_name:
      continue

    # If we're inside an enum definition, add the first string consisting of
    # alphanumerics plus underscore ("\w") to the list of values for that enum.
    m = re.search('([\w]+)', line)
    if m:
      enums.setdefault(enum_name, [])
      enum_value = m.group(1)
      if (enum_value[0] == 'k' and
          enum_value[1] == enum_value[1].upper()):
        enum_value = CamelToLowerHacker(enum_value[1:])
      if enum_value == 'none' or enum_value == 'last':
        continue
      if enum_value == 'active_descendant_changed':
        enum_value = 'activedescendantchanged'
      enums[enum_name].append(enum_value)

  return enums

def CheckMatchingEnum(ax_enums,
                      ax_enum_name,
                      automation_enums,
                      automation_enum_name,
                      errs,
                      output_api,
                      strict_ordering=False):
  if ax_enum_name not in ax_enums:
    errs.append(output_api.PresubmitError(
        'Expected %s to have an enum named %s' % (AX_MOJOM, ax_enum_name)))
    return
  if automation_enum_name not in automation_enums:
    errs.append(output_api.PresubmitError(
        'Expected %s to have an enum named %s' % (
            AUTOMATION_IDL, automation_enum_name)))
    return
  src = ax_enums[ax_enum_name]
  dst = automation_enums[automation_enum_name]
  if strict_ordering and len(src) != len(dst):
    errs.append(output_api.PresubmitError(
        'Expected %s to have the same number of items as %s' % (
            automation_enum_name, ax_enum_name)))
    return

  if strict_ordering:
    for index, value in enumerate(src):
      lower_value = InitialLowerCamelCase(value)
      if lower_value != dst[index]:
        errs.append(output_api.PresubmitError(
            ('At index %s in enums, unexpected ordering around %s.%s ' +
            'and %s.%s in %s and %s') % (
                index, ax_enum_name, lower_value,
                automation_enum_name, dst[index],
                AX_MOJOM, AUTOMATION_IDL)))
        return
    return

  for value in src:
    lower_value = InitialLowerCamelCase(value)
    if lower_value in dst:
      dst.remove(lower_value)  # Any remaining at end are extra and a mismatch.
    else:
      errs.append(output_api.PresubmitError(
          'Found %s.%s in %s, but did not find %s.%s in %s' % (
              ax_enum_name, value, AX_MOJOM,
              automation_enum_name, InitialLowerCamelCase(value),
              AUTOMATION_IDL)))
  #  Should be no remaining items
  for value in dst:
      errs.append(output_api.PresubmitError(
          'Found %s.%s in %s, but did not find %s.%s in %s' % (
              automation_enum_name, value, AUTOMATION_IDL,
              ax_enum_name, InitialLowerCamelCase(value),
              AX_MOJOM)))

def CheckEnumsMatch(input_api, output_api):
  repo_root = input_api.change.RepositoryRoot()
  ax_enums = GetEnumsFromFile(os.path.join(repo_root, AX_MOJOM))
  automation_enums = GetEnumsFromFile(os.path.join(repo_root, AUTOMATION_IDL))

  # Focused state only exists in automation.
  automation_enums['StateType'].remove('focused')
  # Offscreen state only exists in automation.
  automation_enums['StateType'].remove('offscreen')

  errs = []
  CheckMatchingEnum(ax_enums, 'Role', automation_enums, 'RoleType', errs,
                    output_api)
  CheckMatchingEnum(ax_enums, 'State', automation_enums, 'StateType', errs,
                    output_api, strict_ordering=True)
  CheckMatchingEnum(ax_enums, 'Action', automation_enums, 'ActionType', errs,
                    output_api, strict_ordering=True)
  CheckMatchingEnum(ax_enums, 'Event', automation_enums, 'EventType', errs,
                    output_api)
  CheckMatchingEnum(ax_enums, 'NameFrom', automation_enums, 'NameFromType',
                    errs, output_api)
  CheckMatchingEnum(ax_enums, 'Restriction', automation_enums,
                   'Restriction', errs, output_api)
  CheckMatchingEnum(ax_enums, 'DefaultActionVerb', automation_enums,
                   'DefaultActionVerb', errs, output_api)
  return errs

# Given a full path to c++ header, return an array of the first static
# constexpr defined. (Note there can be more than one defined in a C++
# header)
def GetConstexprFromFile(fullpath):
  values = []
  for line in open(fullpath).readlines():
    # Strip out comments
    line = re.sub('//.*', '', line)

    # Look for lines of the form "static constexpr <type> NAME "
    m = re.search('static constexpr [\w]+ ([\w]+)', line)
    if m:
      value = m.group(1)
      # Skip first/last sentinels
      if value == 'kFirstModeFlag' or value == 'kLastModeFlag':
        continue
      values.append(value)

  return values

# Given a full path to js file, return the AXMode consts
# defined
def GetAccessibilityModesFromFile(fullpath):
  values = []
  inside = False
  for line in open(fullpath).readlines():
    # Strip out comments
    line = re.sub('//.*', '', line)

    # Look for the block of code that defines AXMode
    m = re.search('const AXMode = {', line)
    if m:
      inside = True
      continue

    # Look for a "}" character signifying the end of an enum
    if line.find('};') >= 0:
      return values

    if not inside:
      continue

    m = re.search('([\w]+):', line)
    if m:
      values.append(m.group(1))
      continue

    # getters
    m = re.search('get ([\w]+)\(\)', line)
    if m:
      values.append(m.group(1))
  return values

# Make sure that the modes defined in the C++ header match those defined in
# the js file. Note that this doesn't guarantee that the values are the same,
# but does make sure if we add or remove we can signal to the developer that
# they should be aware that this dependency exists.
def CheckModesMatch(input_api, output_api):
  errs = []
  repo_root = input_api.change.RepositoryRoot()

  ax_modes_in_header = GetConstexprFromFile(
    os.path.join(repo_root,AX_MODE_HEADER))
  ax_modes_in_js = GetAccessibilityModesFromFile(
    os.path.join(repo_root, AX_JS_FILE))

  for value in ax_modes_in_header:
    if value not in ax_modes_in_js:
      errs.append(output_api.PresubmitError(
          'Found %s in %s, but did not find %s in %s' % (
              value, AX_MODE_HEADER, value, AX_JS_FILE)))
  return errs

def CheckChangeOnUpload(input_api, output_api):
  errs = []
  for path in input_api.LocalPaths():
    path = path.replace('\\', '/')
    if AX_MOJOM == path:
      errs.extend(CheckEnumsMatch(input_api, output_api))

    if AX_MODE_HEADER == path:
      errs.extend(CheckModesMatch(input_api, output_api))

  return errs

def CheckChangeOnCommit(input_api, output_api):
  errs = []
  for path in input_api.LocalPaths():
    path = path.replace('\\', '/')
    if AX_MOJOM == path:
      errs.extend(CheckEnumsMatch(input_api, output_api))

    if AX_MODE_HEADER == path:
      errs.extend(CheckModesMatch(input_api, output_api))

  return errs