# Copyright (C) 2015 The Android Open Source Project
#
# 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.

import os
import multiprocessing
import platform
import re
import sys
import time

import git_command
import git_config
import wrapper

from error import ManifestParseError

NUM_BATCH_RETRIEVE_REVISIONID = 32


def get_gitc_manifest_dir():
  return wrapper.Wrapper().get_gitc_manifest_dir()


def parse_clientdir(gitc_fs_path):
  return wrapper.Wrapper().gitc_parse_clientdir(gitc_fs_path)


def _get_project_revision(args):
  """Worker for _set_project_revisions to lookup one project remote."""
  (i, url, expr) = args
  gitcmd = git_command.GitCommand(
      None, ['ls-remote', url, expr], capture_stdout=True, cwd='/tmp')
  rc = gitcmd.Wait()
  return (i, rc, gitcmd.stdout.split('\t', 1)[0])


def _set_project_revisions(projects):
  """Sets the revisionExpr for a list of projects.

  Because of the limit of open file descriptors allowed, length of projects
  should not be overly large. Recommend calling this function multiple times
  with each call not exceeding NUM_BATCH_RETRIEVE_REVISIONID projects.

  Args:
    projects: List of project objects to set the revionExpr for.
  """
  # Retrieve the commit id for each project based off of it's current
  # revisionExpr and it is not already a commit id.
  with multiprocessing.Pool(NUM_BATCH_RETRIEVE_REVISIONID) as pool:
    results_iter = pool.imap_unordered(
        _get_project_revision,
        ((i, project.remote.url, project.revisionExpr)
         for i, project in enumerate(projects)
         if not git_config.IsId(project.revisionExpr)),
        chunksize=8)
    for (i, rc, revisionExpr) in results_iter:
      project = projects[i]
      if rc:
        print('FATAL: Failed to retrieve revisionExpr for %s' % project.name)
        pool.terminate()
        sys.exit(1)
      if not revisionExpr:
        pool.terminate()
        raise ManifestParseError('Invalid SHA-1 revision project %s (%s)' %
                                 (project.remote.url, project.revisionExpr))
      project.revisionExpr = revisionExpr


def generate_gitc_manifest(gitc_manifest, manifest, paths=None):
  """Generate a manifest for shafsd to use for this GITC client.

  Args:
    gitc_manifest: Current gitc manifest, or None if there isn't one yet.
    manifest: A GitcManifest object loaded with the current repo manifest.
    paths: List of project paths we want to update.
  """

  print('Generating GITC Manifest by fetching revision SHAs for each '
        'project.')
  if paths is None:
    paths = list(manifest.paths.keys())

  groups = [x for x in re.split(r'[,\s]+', manifest.GetGroupsStr()) if x]

  # Convert the paths to projects, and filter them to the matched groups.
  projects = [manifest.paths[p] for p in paths]
  projects = [p for p in projects if p.MatchesGroups(groups)]

  if gitc_manifest is not None:
    for path, proj in manifest.paths.items():
      if not proj.MatchesGroups(groups):
        continue

      if not proj.upstream and not git_config.IsId(proj.revisionExpr):
        proj.upstream = proj.revisionExpr

      if path not in gitc_manifest.paths:
        # Any new projects need their first revision, even if we weren't asked
        # for them.
        projects.append(proj)
      elif path not in paths:
        # And copy revisions from the previous manifest if we're not updating
        # them now.
        gitc_proj = gitc_manifest.paths[path]
        if gitc_proj.old_revision:
          proj.revisionExpr = None
          proj.old_revision = gitc_proj.old_revision
        else:
          proj.revisionExpr = gitc_proj.revisionExpr

  _set_project_revisions(projects)

  if gitc_manifest is not None:
    for path, proj in gitc_manifest.paths.items():
      if proj.old_revision and path in paths:
        # If we updated a project that has been started, keep the old-revision
        # updated.
        repo_proj = manifest.paths[path]
        repo_proj.old_revision = repo_proj.revisionExpr
        repo_proj.revisionExpr = None

  # Convert URLs from relative to absolute.
  for _name, remote in manifest.remotes.items():
    remote.fetchUrl = remote.resolvedFetchUrl

  # Save the manifest.
  save_manifest(manifest)


def save_manifest(manifest, client_dir=None):
  """Save the manifest file in the client_dir.

  Args:
    manifest: Manifest object to save.
    client_dir: Client directory to save the manifest in.
  """
  if not client_dir:
    manifest_file = manifest.manifestFile
  else:
    manifest_file = os.path.join(client_dir, '.manifest')
  with open(manifest_file, 'w') as f:
    manifest.Save(f, groups=manifest.GetGroupsStr())
  # TODO(sbasi/jorg): Come up with a solution to remove the sleep below.
  # Give the GITC filesystem time to register the manifest changes.
  time.sleep(3)