# (Be in -*- python -*- mode.)
#
# ====================================================================
# Copyright (c) 2007-2009 CollabNet.  All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution.  The terms
# are also available at http://subversion.tigris.org/license-1.html.
# If newer versions of this license are posted there, you may use a
# newer version instead, at your option.
#
# This software consists of voluntary contributions made by many
# individuals.  For exact contribution history, see the revision
# history and logs, available at http://cvs2svn.tigris.org/.
# ====================================================================

"""Classes for outputting the converted repository to git.

For information about the format allowed by git-fast-import, see:

    http://www.kernel.org/pub/software/scm/git/docs/git-fast-import.html

"""

import bisect
import time

from cvs2svn_lib.common import InternalError
from cvs2svn_lib.log import logger
from cvs2svn_lib.context import Ctx
from cvs2svn_lib.symbol import Trunk
from cvs2svn_lib.symbol import Branch
from cvs2svn_lib.symbol import Tag
from cvs2svn_lib.cvs_item import CVSSymbol
from cvs2svn_lib.dvcs_common import DVCSOutputOption
from cvs2svn_lib.dvcs_common import MirrorUpdater
from cvs2svn_lib.key_generator import KeyGenerator


class GitRevisionWriter(MirrorUpdater):

  def start(self, mirror, f):
    super(GitRevisionWriter, self).start(mirror)
    self.f = f

  def _modify_file(self, cvs_item, post_commit):
    raise NotImplementedError()

  def add_file(self, cvs_rev, post_commit):
    super(GitRevisionWriter, self).add_file(cvs_rev, post_commit)
    self._modify_file(cvs_rev, post_commit)

  def modify_file(self, cvs_rev, post_commit):
    super(GitRevisionWriter, self).modify_file(cvs_rev, post_commit)
    self._modify_file(cvs_rev, post_commit)

  def delete_file(self, cvs_rev, post_commit):
    super(GitRevisionWriter, self).delete_file(cvs_rev, post_commit)
    self.f.write('D %s\n' % (cvs_rev.cvs_file.cvs_path,))

  def branch_file(self, cvs_symbol):
    super(GitRevisionWriter, self).branch_file(cvs_symbol)
    self._modify_file(cvs_symbol, post_commit=False)

  def finish(self):
    super(GitRevisionWriter, self).finish()
    del self.f


class GitRevisionMarkWriter(GitRevisionWriter):
  def _modify_file(self, cvs_item, post_commit):
    if cvs_item.cvs_file.executable:
      mode = '100755'
    else:
      mode = '100644'

    self.f.write(
        'M %s :%d %s\n'
        % (mode, cvs_item.revision_reader_token,
           cvs_item.cvs_file.cvs_path,)
        )


class GitRevisionInlineWriter(GitRevisionWriter):
  def __init__(self, revision_reader):
    self.revision_reader = revision_reader

  def register_artifacts(self, which_pass):
    GitRevisionWriter.register_artifacts(self, which_pass)
    self.revision_reader.register_artifacts(which_pass)

  def start(self, mirror, f):
    GitRevisionWriter.start(self, mirror, f)
    self.revision_reader.start()

  def _modify_file(self, cvs_item, post_commit):
    if cvs_item.cvs_file.executable:
      mode = '100755'
    else:
      mode = '100644'

    self.f.write(
        'M %s inline %s\n'
        % (mode, cvs_item.cvs_file.cvs_path,)
        )

    if isinstance(cvs_item, CVSSymbol):
      cvs_rev = cvs_item.get_cvs_revision_source(Ctx()._cvs_items_db)
    else:
      cvs_rev = cvs_item

    # FIXME: We have to decide what to do about keyword substitution
    # and eol_style here:
    fulltext = self.revision_reader.get_content(cvs_rev)

    self.f.write('data %d\n' % (len(fulltext),))
    self.f.write(fulltext)
    self.f.write('\n')

  def finish(self):
    GitRevisionWriter.finish(self)
    self.revision_reader.finish()


class GitOutputOption(DVCSOutputOption):
  """An OutputOption that outputs to a git-fast-import formatted file.

  Members:

    dump_filename -- (string) the name of the file to which the
        git-fast-import commands for defining revisions will be
        written.

    author_transforms -- a map from CVS author names to git full name
        and email address.  See
        DVCSOutputOption.normalize_author_transforms() for information
        about the form of this parameter.

  """

  name = "Git"

  # The first mark number used for git-fast-import commit marks.  This
  # value needs to be large to avoid conflicts with blob marks.
  _first_commit_mark = 1000000000

  def __init__(
        self, dump_filename, revision_writer,
        author_transforms=None,
        tie_tag_fixup_branches=False,
        ):
    """Constructor.

    DUMP_FILENAME is the name of the file to which the git-fast-import
    commands for defining revisions should be written.  (Please note
    that depending on the style of revision writer, the actual file
    contents might not be written to this file.)

    REVISION_WRITER is a GitRevisionWriter that is used to output
    either the content of revisions or a mark that was previously used
    to label a blob.

    AUTHOR_TRANSFORMS is a map {cvsauthor : (fullname, email)} from
    CVS author names to git full name and email address.  All of the
    contents should either be Unicode strings or 8-bit strings encoded
    as UTF-8.

    TIE_TAG_FIXUP_BRANCHES means whether after finishing with a tag
    fixup branch, it should be psuedo-merged (ancestry linked but no
    content changes) back into its source branch, to dispose of the
    open head.

    """
    DVCSOutputOption.__init__(self)
    self.dump_filename = dump_filename
    self.revision_writer = revision_writer

    self.author_transforms = self.normalize_author_transforms(
        author_transforms
        )

    self.tie_tag_fixup_branches = tie_tag_fixup_branches

    self._mark_generator = KeyGenerator(GitOutputOption._first_commit_mark)

  def register_artifacts(self, which_pass):
    DVCSOutputOption.register_artifacts(self, which_pass)
    self.revision_writer.register_artifacts(which_pass)

  def check_symbols(self, symbol_map):
    # FIXME: What constraints does git impose on symbols?
    pass

  def setup(self, svn_rev_count):
    DVCSOutputOption.setup(self, svn_rev_count)
    self.f = open(self.dump_filename, 'wb')

    # The youngest revnum that has been committed so far:
    self._youngest = 0

    # A map {lod : [(revnum, mark)]} giving each of the revision
    # numbers in which there was a commit to lod, and the mark active
    # at the end of the revnum.
    self._marks = {}

    self.revision_writer.start(self._mirror, self.f)

  def _create_commit_mark(self, lod, revnum):
    mark = self._mark_generator.gen_id()
    self._set_lod_mark(lod, revnum, mark)
    return mark

  def _set_lod_mark(self, lod, revnum, mark):
    """Record MARK as the status of LOD for REVNUM.

    If there is already an entry for REVNUM, overwrite it.  If not,
    append a new entry to the self._marks list for LOD."""

    assert revnum >= self._youngest
    entry = (revnum, mark)
    try:
      modifications = self._marks[lod]
    except KeyError:
      # This LOD hasn't appeared before; create a new list and add the
      # entry:
      self._marks[lod] = [entry]
    else:
      # A record exists, so it necessarily has at least one element:
      if modifications[-1][0] == revnum:
        modifications[-1] = entry
      else:
        modifications.append(entry)
    self._youngest = revnum

  def _get_author(self, svn_commit):
    """Return the author to be used for SVN_COMMIT.

    Return the author as a UTF-8 string in the form needed by git
    fast-import; that is, 'name <email>'."""

    cvs_author = svn_commit.get_author()
    return self._map_author(cvs_author)

  def _map_author(self, cvs_author):
    return self.author_transforms.get(cvs_author, "%s <>" % (cvs_author,))

  @staticmethod
  def _get_log_msg(svn_commit):
    return svn_commit.get_log_msg()

  def process_initial_project_commit(self, svn_commit):
    self._mirror.start_commit(svn_commit.revnum)
    self._mirror.end_commit()

  def process_primary_commit(self, svn_commit):
    author = self._get_author(svn_commit)
    log_msg = self._get_log_msg(svn_commit)

    lods = set()
    for cvs_rev in svn_commit.get_cvs_items():
      lods.add(cvs_rev.lod)
    if len(lods) != 1:
      raise InternalError('Commit affects %d LODs' % (len(lods),))
    lod = lods.pop()

    self._mirror.start_commit(svn_commit.revnum)
    if isinstance(lod, Trunk):
      # FIXME: is this correct?:
      self.f.write('commit refs/heads/master\n')
    else:
      self.f.write('commit refs/heads/%s\n' % (lod.name,))
    self.f.write(
        'mark :%d\n'
        % (self._create_commit_mark(lod, svn_commit.revnum),)
        )
    self.f.write(
        'committer %s %d +0000\n' % (author, svn_commit.date,)
        )
    self.f.write('data %d\n' % (len(log_msg),))
    self.f.write('%s\n' % (log_msg,))
    for cvs_rev in svn_commit.get_cvs_items():
      self.revision_writer.process_revision(cvs_rev, post_commit=False)

    self.f.write('\n')
    self._mirror.end_commit()

  def process_post_commit(self, svn_commit):
    author = self._get_author(svn_commit)
    log_msg = self._get_log_msg(svn_commit)

    source_lods = set()
    for cvs_rev in svn_commit.cvs_revs:
      source_lods.add(cvs_rev.lod)
    if len(source_lods) != 1:
      raise InternalError('Commit is from %d LODs' % (len(source_lods),))
    source_lod = source_lods.pop()

    self._mirror.start_commit(svn_commit.revnum)
    # FIXME: is this correct?:
    self.f.write('commit refs/heads/master\n')
    self.f.write(
        'mark :%d\n'
        % (self._create_commit_mark(None, svn_commit.revnum),)
        )
    self.f.write(
        'committer %s %d +0000\n' % (author, svn_commit.date,)
        )
    self.f.write('data %d\n' % (len(log_msg),))
    self.f.write('%s\n' % (log_msg,))
    self.f.write(
        'merge :%d\n'
        % (self._get_source_mark(source_lod, svn_commit.revnum),)
        )
    for cvs_rev in svn_commit.cvs_revs:
      self.revision_writer.process_revision(cvs_rev, post_commit=True)

    self.f.write('\n')
    self._mirror.end_commit()

  def _get_source_mark(self, source_lod, revnum):
    """Return the mark active on SOURCE_LOD at the end of REVNUM."""

    modifications = self._marks[source_lod]
    i = bisect.bisect_left(modifications, (revnum + 1,)) - 1
    (revnum, mark) = modifications[i]
    return mark

  def describe_lod_to_user(self, lod):
    """This needs to make sense to users of the fastimported result."""
    if isinstance(lod, Trunk):
      return 'master'
    else:
      return lod.name

  def _describe_commit(self, svn_commit, lod):
      author = self._map_author(svn_commit.get_author())
      if author.endswith(" <>"):
        author = author[:-3]
      date = time.strftime(
          "%Y-%m-%d %H:%M:%S UTC", time.gmtime(svn_commit.date)
          )
      log_msg = svn_commit.get_log_msg()
      if log_msg.find('\n') != -1:
        log_msg = log_msg[:log_msg.index('\n')]
      return "%s %s %s '%s'" % (
          self.describe_lod_to_user(lod), date, author, log_msg,)

  def _process_symbol_commit(self, svn_commit, git_branch, source_groups):
    author = self._get_author(svn_commit)
    log_msg = self._get_log_msg(svn_commit)

    # There are two distinct cases we need to care for here:
    #  1. initial creation of a LOD
    #  2. fixup of an existing LOD to include more files, because the LOD in
    #     CVS was created piecemeal over time, with intervening commits

    # We look at _marks here, but self._mirror._get_lod_history(lod).exists()
    # might be technically more correct (though _get_lod_history is currently
    # underscore-private)
    is_initial_lod_creation = svn_commit.symbol not in self._marks

    # Create the mark, only after the check above
    mark = self._create_commit_mark(svn_commit.symbol, svn_commit.revnum)

    if is_initial_lod_creation:
      # Get the primary parent
      p_source_revnum, p_source_lod, p_cvs_symbols = source_groups[0]
      try:
        p_source_node = self._mirror.get_old_lod_directory(
            p_source_lod, p_source_revnum
            )
      except KeyError:
        raise InternalError('Source %r does not exist' % (p_source_lod,))
      cvs_files_to_delete = set(self._get_all_files(p_source_node))

      for (source_revnum, source_lod, cvs_symbols,) in source_groups:
        for cvs_symbol in cvs_symbols:
          cvs_files_to_delete.discard(cvs_symbol.cvs_file)

    # Write a trailer to the log message which describes the cherrypicks that
    # make up this symbol creation.
    log_msg += "\n"
    if is_initial_lod_creation:
      log_msg += "\nSprout from %s" % (
          self._describe_commit(
              Ctx()._persistence_manager.get_svn_commit(p_source_revnum),
              p_source_lod
              ),
          )
    for (source_revnum, source_lod, cvs_symbols,) \
            in source_groups[(is_initial_lod_creation and 1 or 0):]:
      log_msg += "\nCherrypick from %s:" % (
          self._describe_commit(
              Ctx()._persistence_manager.get_svn_commit(source_revnum),
              source_lod
              ),
          )
      for cvs_path in sorted(
            cvs_symbol.cvs_file.cvs_path for cvs_symbol in cvs_symbols
            ):
        log_msg += "\n    %s" % (cvs_path,)
    if is_initial_lod_creation:
      if cvs_files_to_delete:
        log_msg += "\nDelete:"
        for cvs_path in sorted(
              cvs_file.cvs_path for cvs_file in cvs_files_to_delete
              ):
          log_msg += "\n    %s" % (cvs_path,)

    self.f.write('commit %s\n' % (git_branch,))
    self.f.write('mark :%d\n' % (mark,))
    self.f.write('committer %s %d +0000\n' % (author, svn_commit.date,))
    self.f.write('data %d\n' % (len(log_msg),))
    self.f.write('%s\n' % (log_msg,))

    # Only record actual DVCS ancestry for the primary sprout parent,
    # all the rest are effectively cherrypicks.
    if is_initial_lod_creation:
      self.f.write(
          'from :%d\n'
          % (self._get_source_mark(p_source_lod, p_source_revnum),)
          )

    for (source_revnum, source_lod, cvs_symbols,) in source_groups:
      for cvs_symbol in cvs_symbols:
        self.revision_writer.branch_file(cvs_symbol)

    if is_initial_lod_creation:
      for cvs_file in cvs_files_to_delete:
        self.f.write('D %s\n' % (cvs_file.cvs_path,))

    self.f.write('\n')
    return mark

  def process_branch_commit(self, svn_commit):
    self._mirror.start_commit(svn_commit.revnum)

    source_groups = self._get_source_groups(svn_commit)
    if self._is_simple_copy(svn_commit, source_groups):
      (source_revnum, source_lod, cvs_symbols) = source_groups[0]
      logger.debug(
          '%s will be created via a simple copy from %s:r%d'
          % (svn_commit.symbol, source_lod, source_revnum,)
          )
      mark = self._get_source_mark(source_lod, source_revnum)
      self._set_symbol(svn_commit.symbol, mark)
      self._mirror.copy_lod(source_lod, svn_commit.symbol, source_revnum)
      self._set_lod_mark(svn_commit.symbol, svn_commit.revnum, mark)
    else:
      logger.debug(
          '%s will be created via fixup commit(s)' % (svn_commit.symbol,)
          )
      self._process_symbol_commit(
          svn_commit, 'refs/heads/%s' % (svn_commit.symbol.name,),
          source_groups,
          )

    self._mirror.end_commit()

  def _set_symbol(self, symbol, mark):
    if isinstance(symbol, Branch):
      category = 'heads'
    elif isinstance(symbol, Tag):
      category = 'tags'
    else:
      raise InternalError()
    self.f.write('reset refs/%s/%s\n' % (category, symbol.name,))
    self.f.write('from :%d\n' % (mark,))

  def get_tag_fixup_branch_name(self, svn_commit):
    # The branch name to use for the "tag fixup branches".  The
    # git-fast-import documentation suggests using 'TAG_FIXUP'
    # (outside of the refs/heads namespace), but this is currently
    # broken.  Use a name containing '.', which is not allowed in CVS
    # symbols, to avoid conflicts (though of course a conflict could
    # still result if the user requests symbol transformations).
    return 'refs/heads/TAG.FIXUP'

  def process_tag_commit(self, svn_commit):
    # FIXME: For now we create a fixup branch with the same name as
    # the tag, then the tag.  We never delete the fixup branch.
    self._mirror.start_commit(svn_commit.revnum)

    source_groups = self._get_source_groups(svn_commit)
    if self._is_simple_copy(svn_commit, source_groups):
      (source_revnum, source_lod, cvs_symbols) = source_groups[0]
      logger.debug(
          '%s will be created via a simple copy from %s:r%d'
          % (svn_commit.symbol, source_lod, source_revnum,)
          )
      mark = self._get_source_mark(source_lod, source_revnum)
      self._set_symbol(svn_commit.symbol, mark)
      self._mirror.copy_lod(source_lod, svn_commit.symbol, source_revnum)
      self._set_lod_mark(svn_commit.symbol, svn_commit.revnum, mark)
    else:
      logger.debug(
          '%s will be created via a fixup branch' % (svn_commit.symbol,)
          )

      fixup_branch_name = self.get_tag_fixup_branch_name(svn_commit)

      # Create the fixup branch (which might involve making more than
      # one commit):
      mark = self._process_symbol_commit(
          svn_commit, fixup_branch_name, source_groups
          )

      # Store the mark of the last commit to the fixup branch as the
      # value of the tag:
      self._set_symbol(svn_commit.symbol, mark)
      self.f.write('reset %s\n' % (fixup_branch_name,))
      self.f.write('\n')

      if self.tie_tag_fixup_branches:
        source_lod = source_groups[0][1]
        source_lod_git_branch = \
            'refs/heads/%s' % (getattr(source_lod, 'name', 'master'),)

        mark2 = self._create_commit_mark(source_lod, svn_commit.revnum)
        author = self._map_author(Ctx().username)
        log_msg = self._get_log_msg_for_ancestry_tie(svn_commit)

        self.f.write('commit %s\n' % (source_lod_git_branch,))
        self.f.write('mark :%d\n' % (mark2,))
        self.f.write('committer %s %d +0000\n' % (author, svn_commit.date,))
        self.f.write('data %d\n' % (len(log_msg),))
        self.f.write('%s\n' % (log_msg,))

        self.f.write(
            'merge :%d\n'
            % (mark,)
            )

        self.f.write('\n')

    self._mirror.end_commit()

  def _get_log_msg_for_ancestry_tie(self, svn_commit):
    return Ctx().text_wrapper.fill(
        Ctx().tie_tag_ancestry_message % {
            'symbol_name' : svn_commit.symbol.name,
            }
        )

  def cleanup(self):
    DVCSOutputOption.cleanup(self)
    self.revision_writer.finish()
    self.f.close()
    del self.f