#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2019 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# pylint: disable=global-statement

"""Creates the arguments for the patch manager for LLVM."""

from __future__ import print_function

import argparse
import os

from failure_modes import FailureModes
import chroot
import get_llvm_hash
import patch_manager
import subprocess_helpers

# If set to `True`, then the contents of `stdout` after executing a command will
# be displayed to the terminal.
verbose = False


def GetCommandLineArgs():
  """Parses the commandline for the optional commandline arguments.

  Returns:
    An argument parser object that contains all the commandline arguments.
  """

  # Default path to the chroot if a path is not specified.
  cros_root = os.path.expanduser('~')
  cros_root = os.path.join(cros_root, 'chromiumos')

  # Create parser and add optional command-line arguments.
  parser = argparse.ArgumentParser(description='Patch management for packages.')

  # Add argument for a specific chroot path.
  parser.add_argument(
      '--chroot_path',
      type=patch_manager.is_directory,
      default=cros_root,
      help='the absolute path to the chroot (default: %(default)s)')

  # Add argument for which packages to manage their patches.
  parser.add_argument(
      '--packages',
      required=False,
      nargs='+',
      default=['sys-devel/llvm'],
      help='the packages to manage their patches (default: %(default)s)')

  # Add argument for whether to display command contents to `stdout`.
  parser.add_argument(
      '--verbose',
      action='store_true',
      help='display contents of a command to the terminal '
      '(default: %(default)s)')

  # Add argument for the LLVM version to use for patch management.
  parser.add_argument(
      '--llvm_version',
      type=int,
      help='the LLVM version to use for patch management. Alternatively, you '
      'can pass "google3" or "google3-unstable". (Default: "google3")')

  # Add argument for the mode of the patch management when handling patches.
  parser.add_argument(
      '--failure_mode',
      default=FailureModes.FAIL.value,
      choices=[FailureModes.FAIL.value, FailureModes.CONTINUE.value,
               FailureModes.DISABLE_PATCHES.value,
               FailureModes.REMOVE_PATCHES.value],
      help='the mode of the patch manager when handling failed patches ' \
          '(default: %(default)s)')

  # Add argument for the patch metadata file in $FILESDIR of LLVM.
  parser.add_argument(
      '--patch_metadata_file',
      default='PATCHES.json',
      help='the .json file in $FILESDIR that has all the patches and their '
      'metadata if applicable (default: %(default)s)')

  # Parse the command line.
  args_output = parser.parse_args()

  global verbose

  verbose = args_output.verbose

  unique_packages = list(set(args_output.packages))

  # Duplicate packages were passed into the command line
  if len(unique_packages) != len(args_output.packages):
    raise ValueError('Duplicate packages were passed in: %s' % ' '.join(
        args_output.packages))

  args_output.packages = unique_packages

  return args_output


def GetPathToFilesDirectory(chroot_path, package):
  """Gets the absolute path to $FILESDIR of the package.

  Args:
    chroot_path: The absolute path to the chroot.
    package: The package to find its absolute path to $FILESDIR.

  Returns:
    The  absolute path to $FILESDIR.

  Raises:
    ValueError: An invalid chroot path has been provided.
  """

  if not os.path.isdir(chroot_path):
    raise ValueError('Invalid chroot provided: %s' % chroot_path)

  # Get the absolute chroot path to the ebuild.
  chroot_ebuild_path = subprocess_helpers.ChrootRunCommand(
      chroot_path, ['equery', 'w', package], verbose=verbose)

  # Get the absolute chroot path to $FILESDIR's parent directory.
  filesdir_parent_path = os.path.dirname(chroot_ebuild_path.strip())

  # Get the relative path to $FILESDIR's parent directory.
  rel_path = _GetRelativePathOfChrootPath(filesdir_parent_path)

  # Construct the absolute path to the package's 'files' directory.
  return os.path.join(chroot_path, rel_path, 'files/')


def _GetRelativePathOfChrootPath(chroot_path):
  """Gets the relative path of the chroot path passed in.

  Args:
    chroot_path: The chroot path to get its relative path.

  Returns:
    The relative path after '/mnt/host/source/'.

  Raises:
    ValueError: The prefix of 'chroot_path' did not match '/mnt/host/source/'.
  """

  chroot_prefix = '/mnt/host/source/'

  if not chroot_path.startswith(chroot_prefix):
    raise ValueError('Invalid prefix for the chroot path: %s' % chroot_path)

  return chroot_path[len(chroot_prefix):]


def _CheckPatchMetadataPath(patch_metadata_path):
  """Checks that the patch metadata path is valid.

  Args:
    patch_metadata_path: The absolute path to the .json file that has the
    patches and their metadata.

  Raises:
    ValueError: The file does not exist or the file does not end in '.json'.
  """

  if not os.path.isfile(patch_metadata_path):
    raise ValueError('Invalid file provided: %s' % patch_metadata_path)

  if not patch_metadata_path.endswith('.json'):
    raise ValueError('File does not end in ".json": %s' % patch_metadata_path)


def _MoveSrcTreeHEADToGitHash(src_path, git_hash):
  """Moves HEAD to 'git_hash'."""

  move_head_cmd = ['git', '-C', src_path, 'checkout', git_hash]

  subprocess_helpers.ExecCommandAndCaptureOutput(move_head_cmd, verbose=verbose)


def UpdatePackagesPatchMetadataFile(chroot_path, svn_version,
                                    patch_metadata_file, packages, mode):
  """Updates the packages metadata file.

  Args:
    chroot_path: The absolute path to the chroot.
    svn_version: The version to use for patch management.
    patch_metadata_file: The patch metadta file where all the patches and
    their metadata are.
    packages: All the packages to update their patch metadata file.
    mode: The mode for the patch manager to use when an applicable patch
    fails to apply.
      Ex: 'FailureModes.FAIL'

  Returns:
    A dictionary where the key is the package name and the value is a dictionary
    that has information on the patches.
  """

  # A dictionary where the key is the package name and the value is a dictionary
  # that has information on the patches.
  package_info = {}

  llvm_hash = get_llvm_hash.LLVMHash()

  with llvm_hash.CreateTempDirectory() as temp_dir:
    with get_llvm_hash.CreateTempLLVMRepo(temp_dir) as src_path:
      # Ensure that 'svn_version' exists in the chromiumum mirror of LLVM by
      # finding its corresponding git hash.
      git_hash = get_llvm_hash.GetGitHashFrom(src_path, svn_version)

      # Git hash of 'svn_version' exists, so move the source tree's HEAD to
      # 'git_hash' via `git checkout`.
      _MoveSrcTreeHEADToGitHash(src_path, git_hash)

      for cur_package in packages:
        # Get the absolute path to $FILESDIR of the package.
        filesdir_path = GetPathToFilesDirectory(chroot_path, cur_package)

        # Construct the absolute path to the patch metadata file where all the
        # patches and their metadata are.
        patch_metadata_path = os.path.join(filesdir_path, patch_metadata_file)

        # Make sure the patch metadata path is valid.
        _CheckPatchMetadataPath(patch_metadata_path)

        patch_manager.CleanSrcTree(src_path)

        # Get the patch results for the current package.
        patches_info = patch_manager.HandlePatches(
            svn_version, patch_metadata_path, filesdir_path, src_path, mode)

        package_info[cur_package] = patches_info._asdict()

  return package_info


def main():
  """Updates the patch metadata file of each package if possible.

  Raises:
    AssertionError: The script was run inside the chroot.
  """

  chroot.VerifyOutsideChroot()

  args_output = GetCommandLineArgs()

  # Get the google3 LLVM version if a LLVM version was not provided.
  llvm_version = args_output.llvm_version
  if llvm_version in ('', 'google3', 'google3-unstable'):
    llvm_version = get_llvm_hash.GetGoogle3LLVMVersion(
        stable=llvm_version != 'google3-unstable')

  UpdatePackagesPatchMetadataFile(args_output.chroot_path, llvm_version,
                                  args_output.patch_metadata_file,
                                  args_output.packages,
                                  FailureModes(args_output.failure_mode))

  # Only 'disable_patches' and 'remove_patches' can potentially modify the patch
  # metadata file.
  if args_output.failure_mode == FailureModes.DISABLE_PATCHES.value or \
      args_output.failure_mode == FailureModes.REMOVE_PATCHES.value:
    print('The patch file %s has been modified for the packages:' %
          args_output.patch_metadata_file)
    print('\n'.join(args_output.packages))
  else:
    print('Applicable patches in %s applied successfully.' %
          args_output.patch_metadata_file)


if __name__ == '__main__':
  main()