#!/usr/bin/env python
#
# Copyright 2008 Google Inc.  All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Generate Google Mock classes from base classes.

This program will read in a C++ source file and output the Google Mock
classes for the specified classes.  If no class is specified, all
classes in the source file are emitted.

Usage:
  gmock_class.py header-file.h [ClassName]...

Output is sent to stdout.
"""

import os
import re
import sys

from cpp import ast
from cpp import utils

# Preserve compatibility with Python 2.3.
try:
  _dummy = set
except NameError:
  import sets

  set = sets.Set

_VERSION = (1, 0, 1)  # The version of this script.
# How many spaces to indent.  Can set me with the INDENT environment variable.
_INDENT = 2


def _RenderType(ast_type):
  """Renders the potentially recursively templated type into a string.

  Args:
    ast_type: The AST of the type.

  Returns:
    Rendered string of the type.
  """
  # Add modifiers like 'const'.
  modifiers = ''
  if ast_type.modifiers:
    modifiers = ' '.join(ast_type.modifiers) + ' '
  return_type = modifiers + ast_type.name
  if ast_type.templated_types:
    # Collect template args.
    template_args = []
    for arg in ast_type.templated_types:
      rendered_arg = _RenderType(arg)
      template_args.append(rendered_arg)
    return_type += '<' + ', '.join(template_args) + '>'
  if ast_type.pointer:
    return_type += '*'
  if ast_type.reference:
    return_type += '&'
  return return_type


def _GenerateArg(source):
  """Strips out comments, default arguments, and redundant spaces from a single argument.

  Args:
    source: A string for a single argument.

  Returns:
    Rendered string of the argument.
  """
  # Remove end of line comments before eliminating newlines.
  arg = re.sub(r'//.*', '', source)

  # Remove c-style comments.
  arg = re.sub(r'/\*.*\*/', '', arg)

  # Remove default arguments.
  arg = re.sub(r'=.*', '', arg)

  # Collapse spaces and newlines into a single space.
  arg = re.sub(r'\s+', ' ', arg)
  return arg.strip()


def _EscapeForMacro(s):
  """Escapes a string for use as an argument to a C++ macro."""
  paren_count = 0
  for c in s:
    if c == '(':
      paren_count += 1
    elif c == ')':
      paren_count -= 1
    elif c == ',' and paren_count == 0:
      return '(' + s + ')'
  return s


def _GenerateMethods(output_lines, source, class_node):
  function_type = (
      ast.FUNCTION_VIRTUAL | ast.FUNCTION_PURE_VIRTUAL | ast.FUNCTION_OVERRIDE)
  ctor_or_dtor = ast.FUNCTION_CTOR | ast.FUNCTION_DTOR
  indent = ' ' * _INDENT

  for node in class_node.body:
    # We only care about virtual functions.
    if (isinstance(node, ast.Function) and node.modifiers & function_type and
        not node.modifiers & ctor_or_dtor):
      # Pick out all the elements we need from the original function.
      modifiers = 'override'
      if node.modifiers & ast.FUNCTION_CONST:
        modifiers = 'const, ' + modifiers

      return_type = 'void'
      if node.return_type:
        return_type = _EscapeForMacro(_RenderType(node.return_type))

      args = []
      for p in node.parameters:
        arg = _GenerateArg(source[p.start:p.end])
        args.append(_EscapeForMacro(arg))

      # Create the mock method definition.
      output_lines.extend([
          '%sMOCK_METHOD(%s, %s, (%s), (%s));' %
          (indent, return_type, node.name, ', '.join(args), modifiers)
      ])


def _GenerateMocks(filename, source, ast_list, desired_class_names):
  processed_class_names = set()
  lines = []
  for node in ast_list:
    if (isinstance(node, ast.Class) and node.body and
        # desired_class_names being None means that all classes are selected.
        (not desired_class_names or node.name in desired_class_names)):
      class_name = node.name
      parent_name = class_name
      processed_class_names.add(class_name)
      class_node = node
      # Add namespace before the class.
      if class_node.namespace:
        lines.extend(['namespace %s {' % n for n in class_node.namespace])  # }
        lines.append('')

      # Add template args for templated classes.
      if class_node.templated_types:
        # TODO(paulchang): The AST doesn't preserve template argument order,
        # so we have to make up names here.
        # TODO(paulchang): Handle non-type template arguments (e.g.
        # template<typename T, int N>).
        template_arg_count = len(class_node.templated_types.keys())
        template_args = ['T%d' % n for n in range(template_arg_count)]
        template_decls = ['typename ' + arg for arg in template_args]
        lines.append('template <' + ', '.join(template_decls) + '>')
        parent_name += '<' + ', '.join(template_args) + '>'

      # Add the class prolog.
      lines.append('class Mock%s : public %s {'  # }
                   % (class_name, parent_name))
      lines.append('%spublic:' % (' ' * (_INDENT // 2)))

      # Add all the methods.
      _GenerateMethods(lines, source, class_node)

      # Close the class.
      if lines:
        # If there are no virtual methods, no need for a public label.
        if len(lines) == 2:
          del lines[-1]

        # Only close the class if there really is a class.
        lines.append('};')
        lines.append('')  # Add an extra newline.

      # Close the namespace.
      if class_node.namespace:
        for i in range(len(class_node.namespace) - 1, -1, -1):
          lines.append('}  // namespace %s' % class_node.namespace[i])
        lines.append('')  # Add an extra newline.

  if desired_class_names:
    missing_class_name_list = list(desired_class_names - processed_class_names)
    if missing_class_name_list:
      missing_class_name_list.sort()
      sys.stderr.write('Class(es) not found in %s: %s\n' %
                       (filename, ', '.join(missing_class_name_list)))
  elif not processed_class_names:
    sys.stderr.write('No class found in %s\n' % filename)

  return lines


def main(argv=sys.argv):
  if len(argv) < 2:
    sys.stderr.write('Google Mock Class Generator v%s\n\n' %
                     '.'.join(map(str, _VERSION)))
    sys.stderr.write(__doc__)
    return 1

  global _INDENT
  try:
    _INDENT = int(os.environ['INDENT'])
  except KeyError:
    pass
  except:
    sys.stderr.write('Unable to use indent of %s\n' % os.environ.get('INDENT'))

  filename = argv[1]
  desired_class_names = None  # None means all classes in the source file.
  if len(argv) >= 3:
    desired_class_names = set(argv[2:])
  source = utils.ReadFile(filename)
  if source is None:
    return 1

  builder = ast.BuilderFromSource(source, filename)
  try:
    entire_ast = filter(None, builder.Generate())
  except KeyboardInterrupt:
    return
  except:
    # An error message was already printed since we couldn't parse.
    sys.exit(1)
  else:
    lines = _GenerateMocks(filename, source, entire_ast, desired_class_names)
    sys.stdout.write('\n'.join(lines))


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