# Copyright 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import itertools
import re

from recipe_engine import recipe_api

class GitApi(recipe_api.RecipeApi):
  _GIT_HASH_RE = re.compile('[0-9a-f]{40}', re.IGNORECASE)

  def __call__(self, *args, **kwargs):
    """Return a git command step."""
    name = kwargs.pop('name', 'git ' + args[0])

    infra_step = kwargs.pop('infra_step', True)
    git_cmd = ['git']

    if kwargs.pop('add_retry', False) and not self.m.runtime.is_luci:
      # On LUCI, the `git` binary is a go wrapper which already implements all
      # the git-retry logic.
      git_cmd += ['retry']

    options = kwargs.pop('git_config_options', {})
    for k, v in sorted(options.iteritems()):
      git_cmd.extend(['-c', '%s=%s' % (k, v)])
    can_fail_build = kwargs.pop('can_fail_build', True)
    try:
      with self.m.context(cwd=(self.m.context.cwd or self.m.path['checkout'])):
        return self.m.step(name, git_cmd + list(args), infra_step=infra_step,
                           **kwargs)
    except self.m.step.StepFailure as f:
      if can_fail_build:
        raise
      else:
        return f.result

  def fetch_tags(self, remote_name=None, **kwargs):
    """Fetches all tags from the remote."""
    kwargs.setdefault('name', 'git fetch tags')
    remote_name = remote_name or 'origin'
    return self('fetch', remote_name, '--tags', **kwargs)

  def cat_file_at_commit(self, file_path, commit_hash, remote_name=None,
                         **kwargs):
    """Outputs the contents of a file at a given revision."""
    self.fetch_tags(remote_name=remote_name, **kwargs)
    kwargs.setdefault('name', 'git cat-file %s:%s' % (commit_hash, file_path))
    return self('cat-file', 'blob', '%s:%s' % (commit_hash, file_path),
                **kwargs)

  def count_objects(self, previous_result=None, can_fail_build=False, **kwargs):
    """Returns `git count-objects` result as a dict.

    Args:
      previous_result (dict): the result of previous count_objects call.
        If passed, delta is reported in the log and step text.
      can_fail_build (bool): if True, may fail the build and/or raise an
        exception. Defaults to False.

    Returns:
      A dict of count-object values, or None if count-object run failed.
    """
    if previous_result:
      assert isinstance(previous_result, dict)
      assert all(isinstance(v, long) for v in previous_result.itervalues())
      assert 'size' in previous_result
      assert 'size-pack' in previous_result

    step_result = None
    try:
      step_result = self(
          'count-objects', '-v', stdout=self.m.raw_io.output(),
          can_fail_build=can_fail_build, **kwargs)

      if not step_result.stdout:
        return None

      result = {}
      for line in step_result.stdout.splitlines():
        name, value = line.split(':', 1)
        result[name] = long(value.strip())

      def results_to_text(results):
        return ['  %s: %s' % (k, v) for k, v in results.iteritems()]

      step_result.presentation.logs['result'] = results_to_text(result)

      if previous_result:
        delta = {
            key: value - previous_result[key]
            for key, value in result.iteritems()
            if key in previous_result}
        step_result.presentation.logs['delta'] = (
            ['before:'] + results_to_text(previous_result) +
            ['', 'after:'] + results_to_text(result) +
            ['', 'delta:'] + results_to_text(delta)
        )

        size_delta = (
            result['size'] + result['size-pack']
            - previous_result['size'] - previous_result['size-pack'])
        # size_delta is in KiB.
        step_result.presentation.step_text = (
            'size delta: %+.2f MiB' % (size_delta / 1024.0))

      return result
    except Exception as ex:
      if step_result:
        step_result.presentation.logs['exception'] = ['%r' % ex]
        step_result.presentation.status = self.m.step.WARNING
      if can_fail_build:
        raise recipe_api.InfraFailure('count-objects failed: %s' % ex)
      return None

  def checkout(self, url, ref=None, dir_path=None, recursive=False,
               submodules=True, submodule_update_force=False,
               keep_paths=None, step_suffix=None,
               curl_trace_file=None, can_fail_build=True,
               set_got_revision=False, remote_name=None,
               display_fetch_size=None, file_name=None,
               submodule_update_recursive=True,
               use_git_cache=False, progress=True, tags=False):
    """Performs a full git checkout and returns sha1 of checked out revision.

    Args:
      url (str): url of remote repo to use as upstream
      ref (str): ref to fetch and check out
      dir_path (Path): optional directory to clone into
      recursive (bool): whether to recursively fetch submodules or not
      submodules (bool): whether to sync and update submodules or not
      submodule_update_force (bool): whether to update submodules with --force
      keep_paths (iterable of strings): paths to ignore during git-clean;
          paths are gitignore-style patterns relative to checkout_path.
      step_suffix (str): suffix to add to a each step name
      curl_trace_file (Path): if not None, dump GIT_CURL_VERBOSE=1 trace to that
          file. Useful for debugging git issue reproducible only on bots. It has
          a side effect of all stderr output of 'git fetch' going to that file.
      can_fail_build (bool): if False, ignore errors during fetch or checkout.
      set_got_revision (bool): if True, resolves HEAD and sets got_revision
          property.
      remote_name (str): name of the git remote to use
      display_fetch_size (bool): if True, run `git count-objects` before and
        after fetch and display delta. Adds two more steps. Defaults to False.
      file_name (str): optional path to a single file to checkout.
      submodule_update_recursive (bool): if True, updates submodules
          recursively.
      use_git_cache (bool): if True, git cache will be used for this checkout.
          WARNING, this is EXPERIMENTAL!!! This wasn't tested with:
           * submodules
           * since origin url is modified
             to a local path, may cause problem with scripts that do
             "git fetch origin" or "git push origin".
           * arbitrary refs such refs/whatever/not-fetched-by-default-to-cache
       progress (bool): wether to show progress for fetch or not
      tags (bool): Also fetch tags.

    Returns: If the checkout was successful, this returns the commit hash of
      the checked-out-repo. Otherwise this returns None.
    """
    retVal = None

    # TODO(robertocn): Break this function and refactor calls to it.
    #     The problem is that there are way too many unrealated use cases for
    #     it, and the function's signature is getting unwieldy and its body
    #     unreadable.
    display_fetch_size = display_fetch_size or False
    if not dir_path:
      dir_path = url.rsplit('/', 1)[-1]
      if dir_path.endswith('.git'):  # ex: https://host/foobar.git
        dir_path = dir_path[:-len('.git')]

      # ex: ssh://host:repo/foobar/.git
      dir_path = dir_path or dir_path.rsplit('/', 1)[-1]

      dir_path = self.m.path['start_dir'].join(dir_path)

    if 'checkout' not in self.m.path:
      self.m.path['checkout'] = dir_path

    git_setup_args = ['--path', dir_path, '--url', url]

    if remote_name:
      git_setup_args += ['--remote', remote_name]
    else:
      remote_name = 'origin'

    step_suffix = '' if step_suffix is  None else ' (%s)' % step_suffix
    self.m.python(
        'git setup%s' % step_suffix,
        self.resource('git_setup.py'),
        git_setup_args)

    # Some of the commands below require depot_tools to be in PATH.
    path = self.m.path.pathsep.join([
        str(self.repo_resource()), '%(PATH)s'])

    with self.m.context(cwd=dir_path):
      if use_git_cache:
        with self.m.context(env={'PATH': path}):
          self('cache', 'populate', '-c',
               self.m.infra_paths.default_git_cache_dir, url,

               name='populate cache',
               can_fail_build=can_fail_build,
               add_retry=True)
          dir_cmd = self(
              'cache', 'exists', '--quiet',
              '--cache-dir', self.m.infra_paths.default_git_cache_dir, url,
              can_fail_build=can_fail_build,
              stdout=self.m.raw_io.output(),
              step_test_data=lambda:
                  self.m.raw_io.test_api.stream_output('mirror_dir'))
          mirror_dir = dir_cmd.stdout.strip()
          self('remote', 'set-url', 'origin', mirror_dir,
               can_fail_build=can_fail_build)

      # There are five kinds of refs we can be handed:
      # 0) None. In this case, we default to api.buildbucket.gitiles_commit.ref.
      # 1) A fully qualified branch name, e.g. 'refs/heads/master'.
      #    Chop off 'refs/heads/' and now it matches case (4).
      # 2) A 40-character SHA1 hash.
      # 3) A fully-qualifed arbitrary ref, e.g. 'refs/foo/bar/baz'.
      # 4) A branch name, e.g. 'master'.
      # Note that 'FETCH_HEAD' can be many things (and therefore not a valid
      # checkout target) if many refs are fetched, but we only explicitly fetch
      # one ref here, so this is safe.
      if not ref:                                  # Case 0.
        ref = self.m.buildbucket.gitiles_commit.ref or 'master'

      # If it's a fully-qualified branch name, trim the 'refs/heads/' prefix.
      if ref.startswith('refs/heads/'):            # Case 1.
        ref = ref[len('refs/heads/'):]

      fetch_args = []
      if self._GIT_HASH_RE.match(ref):             # Case 2.
        fetch_remote = remote_name
        fetch_ref = ''
        checkout_ref = ref
      else:                                        # Cases 3 and 4.
        fetch_remote = remote_name
        fetch_ref = ref
        checkout_ref = 'FETCH_HEAD'

      fetch_args = [x for x in (fetch_remote, fetch_ref) if x]
      if recursive:
        fetch_args.append('--recurse-submodules')

      if progress:
        fetch_args.append('--progress')

      fetch_env = {'PATH': path}
      fetch_stderr = None
      if curl_trace_file:
        fetch_env['GIT_CURL_VERBOSE'] = '1'
        fetch_stderr = self.m.raw_io.output(leak_to=curl_trace_file)

      if tags:
        fetch_args.append('--tags')

      fetch_step_name = 'git fetch%s' % step_suffix
      if display_fetch_size:
        count_objects_before_fetch = self.count_objects(
            name='count-objects before %s' % fetch_step_name,
            step_test_data=lambda: self.m.raw_io.test_api.stream_output(
                self.test_api.count_objects_output(1000)))
      with self.m.context(env=fetch_env):
        self('fetch', *fetch_args,
          name=fetch_step_name,
          stderr=fetch_stderr,
          can_fail_build=can_fail_build,
          add_retry=True)
      if display_fetch_size:
        self.count_objects(
            name='count-objects after %s' % fetch_step_name,
            previous_result=count_objects_before_fetch,
            step_test_data=lambda: self.m.raw_io.test_api.stream_output(
                self.test_api.count_objects_output(2000)))

      if file_name:
        self('checkout', '-f', checkout_ref, '--', file_name,
          name='git checkout%s' % step_suffix,
          can_fail_build=can_fail_build)

      else:
        self('checkout', '-f', checkout_ref,
          name='git checkout%s' % step_suffix,
          can_fail_build=can_fail_build)

      rev_parse_step = self('rev-parse', 'HEAD',
                           name='read revision',
                           stdout=self.m.raw_io.output(),
                           can_fail_build=False,
                           step_test_data=lambda:
                              self.m.raw_io.test_api.stream_output('deadbeef'))

      if rev_parse_step.presentation.status == 'SUCCESS':
        sha = rev_parse_step.stdout.strip()
        retVal = sha
        rev_parse_step.presentation.step_text = "<br/>checked out %r<br/>" % sha
        if set_got_revision:
          rev_parse_step.presentation.properties['got_revision'] = sha

      clean_args = list(itertools.chain(
          *[('-e', path) for path in keep_paths or []]))

      self('clean', '-f', '-d', '-x', *clean_args,
        name='git clean%s' % step_suffix,
        can_fail_build=can_fail_build)

      if submodules:
        self('submodule', 'sync',
          name='submodule sync%s' % step_suffix,
          can_fail_build=can_fail_build)
        submodule_update = ['submodule', 'update', '--init']
        if submodule_update_recursive:
          submodule_update.append('--recursive')
        if submodule_update_force:
          submodule_update.append('--force')
        self(*submodule_update,
          name='submodule update%s' % step_suffix,
          can_fail_build=can_fail_build)

    return retVal

  def get_timestamp(self, commit='HEAD', test_data=None, **kwargs):
    """Find and return the timestamp of the given commit."""
    step_test_data = None
    if test_data is not None:
      step_test_data = lambda: self.m.raw_io.test_api.stream_output(test_data)
    return self('show', commit, '--format=%at', '-s',
                stdout=self.m.raw_io.output(),
                step_test_data=step_test_data).stdout.rstrip()

  def rebase(self, name_prefix, branch, dir_path, remote_name=None,
             **kwargs):
    """Run rebase HEAD onto branch
    Args:
    name_prefix (str): a prefix used for the step names
    branch (str): a branch name or a hash to rebase onto
    dir_path (Path): directory to clone into
    remote_name (str): the remote name to rebase from if not origin
    """
    remote_name = remote_name or 'origin'
    with self.m.context(cwd=dir_path):
      try:
        self('rebase', '%s/master' % remote_name,
             name="%s rebase" % name_prefix, **kwargs)
      except self.m.step.StepFailure:
        self('rebase', '--abort', name='%s rebase abort' % name_prefix,
             **kwargs)
        raise

  def config_get(self, prop_name, **kwargs):
    """Returns: (str) The Git config output, or None if no output was generated.

    Args:
      prop_name: (str) The name of the config property to query.
      kwargs: Forwarded to '__call__'.
    """
    kwargs['name'] = kwargs.get('name', 'git config %s' % (prop_name,))
    result = self('config', '--get', prop_name, stdout=self.m.raw_io.output(),
                  **kwargs)

    value = result.stdout
    if value:
      value = value.strip()
      result.presentation.step_text = value
    return value

  def get_remote_url(self, remote_name=None, **kwargs):
    """Returns: (str) The URL of the remote Git repository, or None.

    Args:
      remote_name: (str) The name of the remote to query, defaults to 'origin'.
      kwargs: Forwarded to '__call__'.
    """
    remote_name = remote_name or 'origin'
    return self.config_get('remote.%s.url' % (remote_name,), **kwargs)

  def bundle_create(self, bundle_path, rev_list_args=None, **kwargs):
    """Run 'git bundle create' on a Git repository.

    Args:
      bundle_path (Path): The path of the output bundle.
      refs (list): The list of refs to include in the bundle. If None, all
          refs in the Git checkout will be bundled.
      kwargs: Forwarded to '__call__'.
    """
    if not rev_list_args:
      rev_list_args = ['--all']
    self('bundle', 'create', bundle_path, *rev_list_args, **kwargs)

  def new_branch(self, branch, name=None, upstream=None, **kwargs):
    """Runs git new-branch on a Git repository, to be used before git cl upload.

    Args:
      branch (str): new branch name, which must not yet exist.
      name (str): step name.
      upstream (str): to origin/master.
      kwargs: Forwarded to '__call__'.
    """
    env = self.m.context.env
    env['PATH'] = self.m.path.pathsep.join([
        str(self.repo_resource()), '%(PATH)s'])
    args = ['new-branch', branch]
    if upstream:
      args.extend(['--upstream', upstream])
    if not name:
      name = 'git new-branch %s' % branch
    with self.m.context(env=env):
      return self(*args, name=name, **kwargs)