# Copyright (c) 2014 The Chromium Embedded Framework Authors. All rights
# reserved. Use of this source code is governed by a BSD-style license that
# can be found in the LICENSE file.

from __future__ import absolute_import
import os
from file_util import *
import sys

# script directory.
script_dir = os.path.dirname(__file__)

# CEF root directory.
cef_dir = os.path.abspath(os.path.join(script_dir, os.pardir))


def get_files_for_variable(cmake_path, variables, variable):
  """ Returns the path values associated with |variable| and relative to the
        |cmake_path| directory. """
  if not variable in variables:
    raise Exception('Variable %s does not exist' % variable)

  # Cmake file directory.
  cmake_dirname = os.path.dirname(cmake_path) + '/'

  # Return path values relative to the cmake file directory.
  # Example 1:
  #   cmake file   = "/path/to/libcef_dll/CMakeLists.txt"
  #   include path = "/path/to/libcef_dll/wrapper/cef_browser_info_map.h"
  #   return path  = "wrapper/cef_browser_info_map.h"
  # Example 2:
  #   cmake file   = "/path/to/libcef_dll/CMakeLists.txt"
  #   include path = "/path/to/include/internal/cef_export.h"
  #   return path  = "../include/internal/cef_export.h"
  new_paths = []
  paths = variables[variable]
  for path in paths:
    abspath = os.path.join(cef_dir, path)
    newpath = normalize_path(os.path.relpath(abspath, cmake_dirname))
    new_paths.append(newpath)
  return new_paths


def format_cmake_set(name, values):
  result = 'set(%s\n' % name
  for value in values:
    result += '  %s\n' % value
  return result + '  )\n'


def format_cmake_group(cmake_path, name, files, platform_sep, append_macro):
  platforms = {}
  common = []

  # Folder will be the cmake parent directory name combined with the path to
  # first file in the files list.
  # Example 1:
  #   cmake file   = "/path/to/libcef_dll/CMakeLists.txt"
  #   include path = "wrapper/cef_browser_info_map.h"
  #   folder       = "libcef_dll\\\\wrapper"
  # Example 2:
  #   cmake file   = "/path/to/libcef_dll/CMakeLists.txt"
  #   include path = "../include/internal/cef_export.h"
  #   folder       = "include\\\\internal"
  folder = os.path.basename(os.path.dirname(cmake_path))
  folder = os.path.dirname(os.path.normpath(os.path.join(folder, files[0])))
  folder = normalize_path(folder).replace('/', '\\\\\\\\')

  # Group the files by platform.
  for file in files:
    parts = file.split(platform_sep)
    file = parts[0]
    if len(parts) > 1:
      # Add the file under the platform.
      platform = parts[1]
      if not platform in platforms:
        platforms[platform] = []
      platforms[platform].append(file)
    else:
      common.append(file)

  result = ''
  if len(common) > 0:
    result += format_cmake_set(name, common)

  if len(platforms) > 0:
    keys = sorted(platforms.keys())
    for key in keys:
      result += format_cmake_set(name + '_' + key, platforms[key])
    result += '%s(%s)\n' % (append_macro, name)

  result += 'source_group(%s FILES ${%s})\n\n' % (folder, name)
  return result


def format_cmake_library(name, group_names):
  result = 'add_library(%s\n' % name
  for group in group_names:
    result += '  ${%s}\n' % group
  return result + '  )\n\n'


def process_cmake_template_segment(segment, segment_ct, cmake_path, variables):
  prefix = None
  library = None
  set = None
  includes = []
  suffix = '_SRCS'  # Appended to each group name before the platform name.
  platform_sep = ':'  # Used to separate value from platform name.
  append_macro = 'APPEND_PLATFORM_SOURCES'  # CMake macro name.

  # Extract values from |segment|. Example |segment| contents:
  #  'prefix': 'cefsimple',
  #  'includes': [
  #    'cefsimple_sources_common',
  #    'cefsimple_sources_win:WINDOWS',
  #    'cefsimple_sources_mac:MACOSX',
  #    'cefsimple_sources_linux:LINUX',
  #  ],
  values = eval('{' + segment + '}', {'__builtins__': None}, None)
  if 'prefix' in values:
    prefix = values['prefix']
  else:
    raise Exception('Missing prefix value in segment %d' % segment_ct)

  if 'library' in values:
    library = values['library']

  if 'set' in values:
    set = values['set']

  if 'append_macro' in values:
    append_macro = values['append_macro']

  if 'includes' in values and len(values['includes']) > 0:
    for include in values['includes']:
      parts = include.strip().split(platform_sep)
      files = get_files_for_variable(cmake_path, variables, parts[0])
      if len(parts) == 2:
        # Append the platform to each file path.
        files = [file + platform_sep + parts[1] for file in files]
      includes.extend(files)
  else:
    raise Exception('Missing includes value in segment %d' % segment_ct)

  # Sort the file paths alphabetically.
  includes.sort()

  # Group files by path.
  # For example, '../include/base/foo.h' and '../include/base/bar.h' will be
  # grouped as 'PREFIX_INCLUDE_BASE'.
  groups = {}
  for include in includes:
    paths = include.split('/')
    label = prefix
    for path in paths[0:-1]:
      if path == '..':
        continue
      label += '_' + path
    label = label.replace('.', '_').upper()
    if not label in groups:
      groups[label] = []
    groups[label].append(include)

  # Create the output results.
  result = ''

  keys = sorted(groups.keys())
  for key in keys:
    # Add a group of files that share the same path.
    result += format_cmake_group(cmake_path, key + suffix, groups[key], \
                                 platform_sep, append_macro)

  if not library is None:
    # Add the library declaration if requested.
    result += format_cmake_library(library, [key + suffix for key in keys])

  if not set is None:
    # Add the set declaration if requested.
    result += format_cmake_set(set, \
                               ['${' + key + suffix + '}' for key in keys])

  return result.strip()


def process_cmake_template(input, output, variables, quiet=False):
  """ Reads the |input| template, parses variable substitution sections and
        writes |output|. """
  if not quiet:
    sys.stdout.write('Processing "%s" to "%s"...\n' % (input, output))

  if not os.path.exists(input):
    raise Exception('File %s does not exist' % input)

  cmake_path = normalize_path(os.path.abspath(input))
  template = read_file(cmake_path)

  delim_start = '{{'
  delim_end = '}}'

  # Process the template file, replacing segments delimited by |delim_start|
  # and |delim_end|.
  result = ''
  end = 0
  segment_ct = 0
  while True:
    start = template.find(delim_start, end)
    if start == -1:
      break
    result += template[end:start]
    end = template.find(delim_end, start + len(delim_start))
    if end == -1:
      break
    segment = template[start + len(delim_start):end]
    segment_ct = segment_ct + 1
    result += process_cmake_template_segment(segment, segment_ct, \
                                             cmake_path, variables)
    end += len(delim_end)
  result += template[end:]

  # Only write the output file if the contents have changed.
  changed = True
  if os.path.exists(output):
    existing = read_file(output)
    changed = result != existing
  if changed:
    write_file(output, result)


def read_gypi_variables(source):
  """ Read the |source| gypi file and extract the variables section. """
  path = os.path.join(cef_dir, source + '.gypi')
  if not os.path.exists(path):
    raise Exception('File %s does not exist' % path)
  contents = eval_file(path)
  if not 'variables' in contents:
    raise Exception('File %s does not have a variables section' % path)
  return contents['variables']


# File entry point.
if __name__ == "__main__":
  # Verify that the correct number of command-line arguments are provided.
  if len(sys.argv) != 3:
    sys.stderr.write('Usage: ' + sys.argv[0] + ' <infile> <outfile>')
    sys.exit()

  # Read the gypi files and combine into a single dictionary.
  variables1 = read_gypi_variables('cef_paths')
  variables2 = read_gypi_variables('cef_paths2')
  variables = dict(variables1.items() + variables2.items())

  # Process the cmake template.
  process_cmake_template(sys.argv[1], sys.argv[2], variables)