# Copyright (c) 2012 Google Inc. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""GYP backend that generates Eclipse CDT settings files.

This backend DOES NOT generate Eclipse CDT projects. Instead, it generates XML
files that can be imported into an Eclipse CDT project. The XML file contains a
list of include paths and symbols (i.e. defines).

Because a full .cproject definition is not created by this generator, it's not
possible to properly define the include dirs and symbols for each file
individually.  Instead, one set of includes/symbols is generated for the entire
project.  This works fairly well (and is a vast improvement in general), but may
still result in a few indexer issues here and there.

This generator has no automated tests, so expect it to be broken.
"""

from xml.sax.saxutils import escape
import os.path
import subprocess
import gyp
import gyp.common
import shlex

generator_wants_static_library_dependencies_adjusted = False

generator_default_variables = {
}

for dirname in ['INTERMEDIATE_DIR', 'PRODUCT_DIR', 'LIB_DIR', 'SHARED_LIB_DIR']:
  # Some gyp steps fail if these are empty(!).
  generator_default_variables[dirname] = 'dir'

for unused in ['RULE_INPUT_PATH', 'RULE_INPUT_ROOT', 'RULE_INPUT_NAME',
               'RULE_INPUT_DIRNAME', 'RULE_INPUT_EXT',
               'EXECUTABLE_PREFIX', 'EXECUTABLE_SUFFIX',
               'STATIC_LIB_PREFIX', 'STATIC_LIB_SUFFIX',
               'SHARED_LIB_PREFIX', 'SHARED_LIB_SUFFIX',
               'CONFIGURATION_NAME']:
  generator_default_variables[unused] = ''

# Include dirs will occasionaly use the SHARED_INTERMEDIATE_DIR variable as
# part of the path when dealing with generated headers.  This value will be
# replaced dynamically for each configuration.
generator_default_variables['SHARED_INTERMEDIATE_DIR'] = \
    '$SHARED_INTERMEDIATES_DIR'


def CalculateVariables(default_variables, params):
  generator_flags = params.get('generator_flags', {})
  for key, val in generator_flags.items():
    default_variables.setdefault(key, val)
  default_variables.setdefault('OS', gyp.common.GetFlavor(params))


def CalculateGeneratorInputInfo(params):
  """Calculate the generator specific info that gets fed to input (called by
  gyp)."""
  generator_flags = params.get('generator_flags', {})
  if generator_flags.get('adjust_static_libraries', False):
    global generator_wants_static_library_dependencies_adjusted
    generator_wants_static_library_dependencies_adjusted = True


def GetAllIncludeDirectories(target_list, target_dicts,
                             shared_intermediates_dir, config_name):
  """Calculate the set of include directories to be used.

  Returns:
    A list including all the include_dir's specified for every target followed
    by any include directories that were added as cflag compiler options.
  """

  gyp_includes_set = set()
  compiler_includes_list = []

  for target_name in target_list:
    target = target_dicts[target_name]
    if config_name in target['configurations']:
      config = target['configurations'][config_name]

      # Look for any include dirs that were explicitly added via cflags. This
      # may be done in gyp files to force certain includes to come at the end.
      # TODO(jgreenwald): Change the gyp files to not abuse cflags for this, and
      # remove this.
      cflags = config['cflags']
      for cflag in cflags:
        include_dir = ''
        if cflag.startswith('-I'):
          include_dir = cflag[2:]
        if include_dir and not include_dir in compiler_includes_list:
          compiler_includes_list.append(include_dir)

      # Find standard gyp include dirs.
      if config.has_key('include_dirs'):
        include_dirs = config['include_dirs']
        for include_dir in include_dirs:
          include_dir = include_dir.replace('$SHARED_INTERMEDIATES_DIR',
                                            shared_intermediates_dir)
          if not os.path.isabs(include_dir):
            base_dir = os.path.dirname(target_name)

            include_dir = base_dir + '/' + include_dir
            include_dir = os.path.abspath(include_dir)

          if not include_dir in gyp_includes_set:
            gyp_includes_set.add(include_dir)


  # Generate a list that has all the include dirs.
  all_includes_list = list(gyp_includes_set)
  all_includes_list.sort()
  for compiler_include in compiler_includes_list:
    if not compiler_include in gyp_includes_set:
      all_includes_list.append(compiler_include)

  # All done.
  return all_includes_list


def GetCompilerPath(target_list, target_dicts, data):
  """Determine a command that can be used to invoke the compiler.

  Returns:
    If this is a gyp project that has explicit make settings, try to determine
    the compiler from that.  Otherwise, see if a compiler was specified via the
    CC_target environment variable.
  """

  # First, see if the compiler is configured in make's settings.
  build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
  make_global_settings_dict = data[build_file].get('make_global_settings', {})
  for key, value in make_global_settings_dict:
    if key in ['CC', 'CXX']:
      return value

  # Check to see if the compiler was specified as an environment variable.
  for key in ['CC_target', 'CC', 'CXX']:
    compiler = os.environ.get(key)
    if compiler:
      return compiler

  return 'gcc'


def GetAllDefines(target_list, target_dicts, data, config_name):
  """Calculate the defines for a project.

  Returns:
    A dict that includes explict defines declared in gyp files along with all of
    the default defines that the compiler uses.
  """

  # Get defines declared in the gyp files.
  all_defines = {}
  for target_name in target_list:
    target = target_dicts[target_name]

    if config_name in target['configurations']:
      config = target['configurations'][config_name]
      for define in config['defines']:
        split_define = define.split('=', 1)
        if len(split_define) == 1:
          split_define.append('1')
        if split_define[0].strip() in all_defines:
          # Already defined
          continue

        all_defines[split_define[0].strip()] = split_define[1].strip()

  # Get default compiler defines (if possible).
  cc_target = GetCompilerPath(target_list, target_dicts, data)
  if cc_target:
    command = shlex.split(cc_target)
    command.extend(['-E', '-dM', '-'])
    cpp_proc = subprocess.Popen(args=command, cwd='.',
                                stdin=subprocess.PIPE, stdout=subprocess.PIPE)
    cpp_output = cpp_proc.communicate()[0]
    cpp_lines = cpp_output.split('\n')
    for cpp_line in cpp_lines:
      if not cpp_line.strip():
        continue
      cpp_line_parts = cpp_line.split(' ', 2)
      key = cpp_line_parts[1]
      if len(cpp_line_parts) >= 3:
        val = cpp_line_parts[2]
      else:
        val = '1'
      all_defines[key] = val

  return all_defines


def WriteIncludePaths(out, eclipse_langs, include_dirs):
  """Write the includes section of a CDT settings export file."""

  out.write('  <section name="org.eclipse.cdt.internal.ui.wizards.' \
            'settingswizards.IncludePaths">\n')
  out.write('    <language name="holder for library settings"></language>\n')
  for lang in eclipse_langs:
    out.write('    <language name="%s">\n' % lang)
    for include_dir in include_dirs:
      out.write('      <includepath workspace_path="false">%s</includepath>\n' %
                include_dir)
    out.write('    </language>\n')
  out.write('  </section>\n')


def WriteMacros(out, eclipse_langs, defines):
  """Write the macros section of a CDT settings export file."""

  out.write('  <section name="org.eclipse.cdt.internal.ui.wizards.' \
            'settingswizards.Macros">\n')
  out.write('    <language name="holder for library settings"></language>\n')
  for lang in eclipse_langs:
    out.write('    <language name="%s">\n' % lang)
    for key in sorted(defines.iterkeys()):
      out.write('      <macro><name>%s</name><value>%s</value></macro>\n' %
                (escape(key), escape(defines[key])))
    out.write('    </language>\n')
  out.write('  </section>\n')


def GenerateOutputForConfig(target_list, target_dicts, data, params,
                            config_name):
  options = params['options']
  generator_flags = params.get('generator_flags', {})

  # build_dir: relative path from source root to our output files.
  # e.g. "out/Debug"
  build_dir = os.path.join(generator_flags.get('output_dir', 'out'),
                           config_name)

  toplevel_build = os.path.join(options.toplevel_dir, build_dir)
  shared_intermediate_dir = os.path.join(toplevel_build, 'obj', 'gen')

  if not os.path.exists(toplevel_build):
    os.makedirs(toplevel_build)
  out = open(os.path.join(toplevel_build, 'eclipse-cdt-settings.xml'), 'w')

  out.write('<?xml version="1.0" encoding="UTF-8"?>\n')
  out.write('<cdtprojectproperties>\n')

  eclipse_langs = ['C++ Source File', 'C Source File', 'Assembly Source File',
                   'GNU C++', 'GNU C', 'Assembly']
  include_dirs = GetAllIncludeDirectories(target_list, target_dicts,
                                          shared_intermediate_dir, config_name)
  WriteIncludePaths(out, eclipse_langs, include_dirs)
  defines = GetAllDefines(target_list, target_dicts, data, config_name)
  WriteMacros(out, eclipse_langs, defines)

  out.write('</cdtprojectproperties>\n')
  out.close()


def GenerateOutput(target_list, target_dicts, data, params):
  """Generate an XML settings file that can be imported into a CDT project."""

  if params['options'].generator_output:
    raise NotImplementedError, "--generator_output not implemented for eclipse"

  user_config = params.get('generator_flags', {}).get('config', None)
  if user_config:
    GenerateOutputForConfig(target_list, target_dicts, data, params,
                            user_config)
  else:
    config_names = target_dicts[target_list[0]]['configurations'].keys()
    for config_name in config_names:
      GenerateOutputForConfig(target_list, target_dicts, data, params,
                              config_name)