# Module dedicated to host history rewriting commands
#
# Copyright 2017 Octobus <contact@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

# Status: Stabilization of the API in progress
#
#   The final set of command should go into core.

from __future__ import absolute_import

import random

from mercurial import (
    bookmarks as bookmarksmod,
    cmdutil,
    commands,
    context,
    copies,
    error,
    hg,
    lock as lockmod,
    node,
    obsolete,
    phases,
    scmutil,
    util,
)

from mercurial.i18n import _

from . import (
    compat,
    exthelper,
    rewriteutil,
    utility,
)

eh = exthelper.exthelper()

walkopts = commands.walkopts
commitopts = commands.commitopts
commitopts2 = commands.commitopts2
mergetoolopts = commands.mergetoolopts

# option added by evolve

def _resolveoptions(ui, opts):
    """modify commit options dict to handle related options

    For now, all it does is figure out the commit date: respect -D unless
    -d was supplied.
    """
    # N.B. this is extremely similar to setupheaderopts() in mq.py
    if not opts.get('date') and opts.get('current_date'):
        opts['date'] = '%d %d' % util.makedate()
    if not opts.get('user') and opts.get('current_user'):
        opts['user'] = ui.username()

commitopts3 = [
    ('D', 'current-date', None,
     _('record the current date as commit date')),
    ('U', 'current-user', None,
     _('record the current user as committer')),
]

interactiveopt = [['i', 'interactive', None, _('use interactive mode')]]

@eh.command(
    'amend|refresh',
    [('A', 'addremove', None,
      _('mark new/missing files as added/removed before committing')),
     ('a', 'all', False, _("match all files")),
     ('e', 'edit', False, _('invoke editor on commit messages')),
     ('', 'extract', False, _('extract changes from the commit to the working copy')),
     ('', 'close-branch', None,
      _('mark a branch as closed, hiding it from the branch list')),
     ('s', 'secret', None, _('use the secret phase for committing')),
    ] + walkopts + commitopts + commitopts2 + commitopts3 + interactiveopt,
    _('[OPTION]... [FILE]...'))
def amend(ui, repo, *pats, **opts):
    """combine a changeset with updates and replace it with a new one

    Commits a new changeset incorporating both the changes to the given files
    and all the changes from the current parent changeset into the repository.

    See :hg:`commit` for details about committing changes.

    If you don't specify -m, the parent's message will be reused.

    If --extra is specified, the behavior of `hg amend` is reversed: Changes
    to selected files in the checked out revision appear again as uncommitted
    changed in the working directory.

    Returns 0 on success, 1 if nothing changed.
    """
    opts = opts.copy()
    if opts.get('extract'):
        if opts.pop('interactive', False):
            msg = _('not support for --interactive with --extract yet')
            raise error.Abort(msg)
        return uncommit(ui, repo, *pats, **opts)
    else:
        if opts.pop('all', False):
            # add an include for all
            include = list(opts.get('include'))
            include.append('re:.*')
        edit = opts.pop('edit', False)
        log = opts.get('logfile')
        opts['amend'] = True
        if not (edit or opts['message'] or log):
            opts['message'] = repo['.'].description()
        _resolveoptions(ui, opts)
        _alias, commitcmd = cmdutil.findcmd('commit', commands.table)
        try:
            wlock = repo.wlock()
            lock = repo.lock()
            rewriteutil.precheck(repo, [repo['.'].rev()], action='amend')
            return commitcmd[0](ui, repo, *pats, **opts)
        finally:
            lockmod.release(lock, wlock)

def _touchedbetween(repo, source, dest, match=None):
    touched = set()
    for files in repo.status(source, dest, match=match)[:3]:
        touched.update(files)
    return touched

def _commitfiltered(repo, ctx, match, target=None, message=None, user=None,
                    date=None):
    """Recommit ctx with changed files not in match. Return the new
    node identifier, or None if nothing changed.
    """
    base = ctx.p1()
    if target is None:
        target = base
    # ctx
    initialfiles = _touchedbetween(repo, base, ctx)
    if base == target:
        affected = set(f for f in initialfiles if match(f))
        newcontent = set()
    else:
        affected = _touchedbetween(repo, target, ctx, match=match)
        newcontent = _touchedbetween(repo, target, base, match=match)
    # The commit touchs all existing files
    # + all file that needs a new content
    # - the file affected bny uncommit with the same content than base.
    files = (initialfiles - affected) | newcontent
    if not newcontent and files == initialfiles:
        return None

    # Filter copies
    copied = copies.pathcopies(target, ctx)
    copied = dict((dst, src) for dst, src in copied.iteritems()
                  if dst in files)

    def filectxfn(repo, memctx, path, contentctx=ctx, redirect=newcontent):
        if path in redirect:
            return filectxfn(repo, memctx, path, contentctx=target, redirect=())
        if path not in contentctx:
            return None
        fctx = contentctx[path]
        flags = fctx.flags()
        mctx = context.memfilectx(repo, fctx.path(), fctx.data(),
                                  islink='l' in flags,
                                  isexec='x' in flags,
                                  copied=copied.get(path))
        return mctx

    if message is None:
        message = ctx.description()
    if not user:
        user = ctx.user()
    if not date:
        date = ctx.date()
    new = context.memctx(repo,
                         parents=[base.node(), node.nullid],
                         text=message,
                         files=files,
                         filectxfn=filectxfn,
                         user=user,
                         date=date,
                         extra=ctx.extra())
    # commitctx always create a new revision, no need to check
    newid = repo.commitctx(new)
    return newid

def _uncommitdirstate(repo, oldctx, match):
    """Fix the dirstate after switching the working directory from
    oldctx to a copy of oldctx not containing changed files matched by
    match.
    """
    ctx = repo['.']
    ds = repo.dirstate
    copies = dict(ds.copies())
    m, a, r = repo.status(oldctx.p1(), oldctx, match=match)[:3]
    for f in m:
        if ds[f] == 'r':
            # modified + removed -> removed
            continue
        ds.normallookup(f)

    for f in a:
        if ds[f] == 'r':
            # added + removed -> unknown
            ds.drop(f)
        elif ds[f] != 'a':
            ds.add(f)

    for f in r:
        if ds[f] == 'a':
            # removed + added -> normal
            ds.normallookup(f)
        elif ds[f] != 'r':
            ds.remove(f)

    # Merge old parent and old working dir copies
    oldcopies = {}
    for f in (m + a):
        src = oldctx[f].renamed()
        if src:
            oldcopies[f] = src[0]
    oldcopies.update(copies)
    copies = dict((dst, oldcopies.get(src, src))
                  for dst, src in oldcopies.iteritems())
    # Adjust the dirstate copies
    for dst, src in copies.iteritems():
        if (src not in ctx or dst in ctx or ds[dst] != 'a'):
            src = None
        ds.copy(src, dst)

@eh.command(
    '^uncommit',
    [('a', 'all', None, _('uncommit all changes when no arguments given')),
     ('r', 'rev', '', _('revert commit content to REV instead')),
     ] + commands.walkopts + commitopts + commitopts2 + commitopts3,
    _('[OPTION]... [NAME]'))
def uncommit(ui, repo, *pats, **opts):
    """move changes from parent revision to working directory

    Changes to selected files in the checked out revision appear again as
    uncommitted changed in the working directory. A new revision
    without the selected changes is created, becomes the checked out
    revision, and obsoletes the previous one.

    The --include option specifies patterns to uncommit.
    The --exclude option specifies patterns to keep in the commit.

    The --rev argument let you change the commit file to a content of another
    revision. It still does not change the content of your file in the working
    directory.

    Return 0 if changed files are uncommitted.
    """

    _resolveoptions(ui, opts) # process commitopts3
    wlock = lock = tr = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()
        wctx = repo[None]
        if len(wctx.parents()) <= 0:
            raise error.Abort(_("cannot uncommit null changeset"))
        if len(wctx.parents()) > 1:
            raise error.Abort(_("cannot uncommit while merging"))
        old = repo['.']
        rewriteutil.precheck(repo, [repo['.'].rev()], action='uncommit')
        if len(old.parents()) > 1:
            raise error.Abort(_("cannot uncommit merge changeset"))
        oldphase = old.phase()

        rev = None
        if opts.get('rev'):
            rev = scmutil.revsingle(repo, opts.get('rev'))
            ctx = repo[None]
            if ctx.p1() == rev or ctx.p2() == rev:
                raise error.Abort(_("cannot uncommit to parent changeset"))

        onahead = old.rev() in repo.changelog.headrevs()
        disallowunstable = not obsolete.isenabled(repo,
                                                  obsolete.allowunstableopt)
        if disallowunstable and not onahead:
            raise error.Abort(_("cannot uncommit in the middle of a stack"))

        # Recommit the filtered changeset
        tr = repo.transaction('uncommit')
        updatebookmarks = rewriteutil.bookmarksupdater(repo, old.node(), tr)
        newid = None
        includeorexclude = opts.get('include') or opts.get('exclude')
        if (pats or includeorexclude or opts.get('all')):
            match = scmutil.match(old, pats, opts)
            if not (opts['message'] or opts['logfile']):
                opts['message'] = old.description()
            message = cmdutil.logmessage(ui, opts)
            newid = _commitfiltered(repo, old, match, target=rev,
                                    message=message, user=opts.get('user'),
                                    date=opts.get('date'))
        if newid is None:
            raise error.Abort(_('nothing to uncommit'),
                              hint=_("use --all to uncommit all files"))
        # Move local changes on filtered changeset
        obsolete.createmarkers(repo, [(old, (repo[newid],))])
        phases.retractboundary(repo, tr, oldphase, [newid])
        with repo.dirstate.parentchange():
            repo.dirstate.setparents(newid, node.nullid)
            _uncommitdirstate(repo, old, match)
        updatebookmarks(newid)
        if not repo[newid].files():
            ui.warn(_("new changeset is empty\n"))
            ui.status(_("(use 'hg prune .' to remove it)\n"))
        tr.close()
    finally:
        lockmod.release(tr, lock, wlock)

@eh.command(
    '^fold|squash',
    [('r', 'rev', [], _("revision to fold")),
     ('', 'exact', None, _("only fold specified revisions")),
     ('', 'from', None, _("fold revisions linearly to working copy parent"))
    ] + commitopts + commitopts2 + commitopts3,
    _('hg fold [OPTION]... [-r] REV'))
def fold(ui, repo, *revs, **opts):
    """fold multiple revisions into a single one

    With --from, folds all the revisions linearly between the given revisions
    and the parent of the working directory.

    With --exact, folds only the specified revisions while ignoring the
    parent of the working directory. In this case, the given revisions must
    form a linear unbroken chain.

    .. container:: verbose

     Some examples:

     - Fold the current revision with its parent::

         hg fold --from .^

     - Fold all draft revisions with working directory parent::

         hg fold --from 'draft()'

       See :hg:`help phases` for more about draft revisions and
       :hg:`help revsets` for more about the `draft()` keyword

     - Fold revisions between 3 and 6 with the working directory parent::

         hg fold --from 3::6

     - Fold revisions 3 and 4::

        hg fold "3 + 4" --exact

     - Only fold revisions linearly between foo and @::

         hg fold foo::@ --exact
    """
    _resolveoptions(ui, opts)
    revs = list(revs)
    revs.extend(opts['rev'])
    if not revs:
        raise error.Abort(_('no revisions specified'))

    revs = scmutil.revrange(repo, revs)

    if opts['from'] and opts['exact']:
        raise error.Abort(_('cannot use both --from and --exact'))
    elif opts['from']:
        # Try to extend given revision starting from the working directory
        extrevs = repo.revs('(%ld::.) or (.::%ld)', revs, revs)
        discardedrevs = [r for r in revs if r not in extrevs]
        if discardedrevs:
            msg = _("cannot fold non-linear revisions")
            hint = _("given revisions are unrelated to parent of working"
                     " directory")
            raise error.Abort(msg, hint=hint)
        revs = extrevs
    elif opts['exact']:
        # Nothing to do; "revs" is already set correctly
        pass
    else:
        raise error.Abort(_('must specify either --from or --exact'))

    if not revs:
        raise error.Abort(_('specified revisions evaluate to an empty set'),
                          hint=_('use different revision arguments'))
    elif len(revs) == 1:
        ui.write_err(_('single revision specified, nothing to fold\n'))
        return 1

    wlock = lock = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()

        root, head = rewriteutil.foldcheck(repo, revs)

        tr = repo.transaction('fold')
        try:
            commitopts = opts.copy()
            allctx = [repo[r] for r in revs]
            targetphase = max(c.phase() for c in allctx)

            if commitopts.get('message') or commitopts.get('logfile'):
                commitopts['edit'] = False
            else:
                msgs = ["HG: This is a fold of %d changesets." % len(allctx)]
                msgs += ["HG: Commit message of changeset %s.\n\n%s\n" %
                         (c.rev(), c.description()) for c in allctx]
                commitopts['message'] = "\n".join(msgs)
                commitopts['edit'] = True

            newid, unusedvariable = rewriteutil.rewrite(repo, root, allctx,
                                                        head,
                                                        [root.p1().node(),
                                                         root.p2().node()],
                                                        commitopts=commitopts)
            phases.retractboundary(repo, tr, targetphase, [newid])
            obsolete.createmarkers(repo, [(ctx, (repo[newid],))
                                   for ctx in allctx])
            tr.close()
        finally:
            tr.release()
        ui.status('%i changesets folded\n' % len(revs))
        if repo['.'].rev() in revs:
            hg.update(repo, newid)
    finally:
        lockmod.release(lock, wlock)

@eh.command(
    '^metaedit',
    [('r', 'rev', [], _("revision to edit")),
     ('', 'fold', None, _("also fold specified revisions into one")),
    ] + commitopts + commitopts2 + commitopts3,
    _('hg metaedit [OPTION]... [-r] [REV]'))
def metaedit(ui, repo, *revs, **opts):
    """edit commit information

    Edits the commit information for the specified revisions. By default, edits
    commit information for the working directory parent.

    With --fold, also folds multiple revisions into one if necessary. In this
    case, the given revisions must form a linear unbroken chain.

    .. container:: verbose

     Some examples:

     - Edit the commit message for the working directory parent::

         hg metaedit

     - Change the username for the working directory parent::

         hg metaedit --user 'New User <new-email@example.com>'

     - Combine all draft revisions that are ancestors of foo but not of @ into
       one::

         hg metaedit --fold 'draft() and only(foo,@)'

       See :hg:`help phases` for more about draft revisions, and
       :hg:`help revsets` for more about the `draft()` and `only()` keywords.
    """
    _resolveoptions(ui, opts)
    revs = list(revs)
    revs.extend(opts['rev'])
    if not revs:
        if opts['fold']:
            raise error.Abort(_('revisions must be specified with --fold'))
        revs = ['.']

    wlock = lock = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()

        revs = scmutil.revrange(repo, revs)
        if not opts['fold'] and len(revs) > 1:
            # TODO: handle multiple revisions. This is somewhat tricky because
            # if we want to edit a series of commits:
            #
            #   a ---- b ---- c
            #
            # we need to rewrite a first, then directly rewrite b on top of the
            # new a, then rewrite c on top of the new b. So we need to handle
            # revisions in topological order.
            raise error.Abort(_('editing multiple revisions without --fold is '
                                'not currently supported'))

        if opts['fold']:
            root, head = rewriteutil.foldcheck(repo, revs)
        else:
            if repo.revs("%ld and public()", revs):
                raise error.Abort(_('cannot edit commit information for public '
                                    'revisions'))
            newunstable = rewriteutil.disallowednewunstable(repo, revs)
            if newunstable:
                msg = _('cannot edit commit information in the middle'
                        ' of a stack')
                hint = _('%s will become unstable and new unstable changes'
                         ' are not allowed')
                hint %= repo[newunstable.first()]
                raise error.Abort(msg, hint=hint)
            root = head = repo[revs.first()]

        wctx = repo[None]
        p1 = wctx.p1()
        tr = repo.transaction('metaedit')
        newp1 = None
        try:
            commitopts = opts.copy()
            allctx = [repo[r] for r in revs]
            targetphase = max(c.phase() for c in allctx)

            if commitopts.get('message') or commitopts.get('logfile'):
                commitopts['edit'] = False
            else:
                if opts['fold']:
                    msgs = ["HG: This is a fold of %d changesets." % len(allctx)]
                    msgs += ["HG: Commit message of changeset %s.\n\n%s\n" %
                             (c.rev(), c.description()) for c in allctx]
                else:
                    msgs = [head.description()]
                commitopts['message'] = "\n".join(msgs)
                commitopts['edit'] = True

            # TODO: if the author and message are the same, don't create a new
            # hash. Right now we create a new hash because the date can be
            # different.
            newid, created = rewriteutil.rewrite(repo, root, allctx, head,
                                                 [root.p1().node(),
                                                  root.p2().node()],
                                                 commitopts=commitopts)
            if created:
                if p1.rev() in revs:
                    newp1 = newid
                phases.retractboundary(repo, tr, targetphase, [newid])
                obsolete.createmarkers(repo, [(ctx, (repo[newid],))
                                              for ctx in allctx])
            else:
                ui.status(_("nothing changed\n"))
            tr.close()
        finally:
            tr.release()

        if opts['fold']:
            ui.status('%i changesets folded\n' % len(revs))
        if newp1 is not None:
            hg.update(repo, newp1)
    finally:
        lockmod.release(lock, wlock)

metadataopts = [
    ('d', 'date', '',
     _('record the specified date in metadata'), _('DATE')),
    ('u', 'user', '',
     _('record the specified user in metadata'), _('USER')),
]

def _getmetadata(**opts):
    metadata = {}
    date = opts.get('date')
    user = opts.get('user')
    if date:
        metadata['date'] = '%i %i' % util.parsedate(date)
    if user:
        metadata['user'] = user
    return metadata

@eh.command(
    '^prune|obsolete',
    [('n', 'new', [], _("successor changeset (DEPRECATED)")),
     ('s', 'succ', [], _("successor changeset")),
     ('r', 'rev', [], _("revisions to prune")),
     ('k', 'keep', None, _("does not modify working copy during prune")),
     ('', 'biject', False, _("do a 1-1 map between rev and successor ranges")),
     ('', 'fold', False,
      _("record a fold (multiple precursors, one successors)")),
     ('', 'split', False,
      _("record a split (on precursor, multiple successors)")),
     ('B', 'bookmark', [], _("remove revs only reachable from given"
                             " bookmark"))] + metadataopts,
    _('[OPTION] [-r] REV...'))
# XXX -U  --noupdate option to prevent wc update and or bookmarks update ?
def cmdprune(ui, repo, *revs, **opts):
    """hide changesets by marking them obsolete

    Pruned changesets are obsolete with no successors. If they also have no
    descendants, they are hidden (invisible to all commands).

    Non-obsolete descendants of pruned changesets become "unstable". Use :hg:`evolve`
    to handle this situation.

    When you prune the parent of your working copy, Mercurial updates the working
    copy to a non-obsolete parent.

    You can use ``--succ`` to tell Mercurial that a newer version (successor) of the
    pruned changeset exists. Mercurial records successor revisions in obsolescence
    markers.

    You can use the ``--biject`` option to specify a 1-1 mapping (bijection) between
    revisions to pruned (precursor) and successor changesets. This option may be
    removed in a future release (with the functionality provided automatically).

    If you specify multiple revisions in ``--succ``, you are recording a "split" and
    must acknowledge it by passing ``--split``. Similarly, when you prune multiple
    changesets with a single successor, you must pass the ``--fold`` option.
    """
    revs = scmutil.revrange(repo, list(revs) + opts.get('rev'))
    succs = opts['new'] + opts['succ']
    bookmarks = set(opts.get('bookmark'))
    metadata = _getmetadata(**opts)
    biject = opts.get('biject')
    fold = opts.get('fold')
    split = opts.get('split')

    options = [o for o in ('biject', 'fold', 'split') if opts.get(o)]
    if 1 < len(options):
        raise error.Abort(_("can only specify one of %s") % ', '.join(options))

    if bookmarks:
        reachablefrombookmark = rewriteutil.reachablefrombookmark
        repomarks, revs = reachablefrombookmark(repo, revs, bookmarks)
        if not revs:
            # no revisions to prune - delete bookmark immediately
            rewriteutil.deletebookmark(repo, repomarks, bookmarks)

    if not revs:
        raise error.Abort(_('nothing to prune'))

    wlock = lock = tr = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()
        rewriteutil.precheck(repo, revs, 'touch')
        tr = repo.transaction('prune')
        # defines pruned changesets
        precs = []
        revs.sort()
        for p in revs:
            cp = repo[p]
            precs.append(cp)
        if not precs:
            raise error.Abort('nothing to prune')

        # defines successors changesets
        sucs = scmutil.revrange(repo, succs)
        sucs.sort()
        sucs = tuple(repo[n] for n in sucs)
        if not biject and len(sucs) > 1 and len(precs) > 1:
            msg = "Can't use multiple successors for multiple precursors"
            hint = _("use --biject to mark a series as a replacement"
                     " for another")
            raise error.Abort(msg, hint=hint)
        elif biject and len(sucs) != len(precs):
            msg = "Can't use %d successors for %d precursors" \
                % (len(sucs), len(precs))
            raise error.Abort(msg)
        elif (len(precs) == 1 and len(sucs) > 1) and not split:
            msg = "please add --split if you want to do a split"
            raise error.Abort(msg)
        elif len(sucs) == 1 and len(precs) > 1 and not fold:
            msg = "please add --fold if you want to do a fold"
            raise error.Abort(msg)
        elif biject:
            relations = [(p, (s,)) for p, s in zip(precs, sucs)]
        else:
            relations = [(p, sucs) for p in precs]

        wdp = repo['.']

        if len(sucs) == 1 and len(precs) == 1 and wdp in precs:
            # '.' killed, so update to the successor
            newnode = sucs[0]
        else:
            # update to an unkilled parent
            newnode = wdp

            while newnode in precs or newnode.obsolete():
                newnode = newnode.parents()[0]

        if newnode.node() != wdp.node():
            if opts.get('keep', False):
                # This is largely the same as the implementation in
                # strip.stripcmd(). We might want to refactor this somewhere
                # common at some point.

                # only reset the dirstate for files that would actually change
                # between the working context and uctx
                descendantrevs = repo.revs("%d::." % newnode.rev())
                changedfiles = []
                for rev in descendantrevs:
                    # blindly reset the files, regardless of what actually
                    # changed
                    changedfiles.extend(repo[rev].files())

                # reset files that only changed in the dirstate too
                dirstate = repo.dirstate
                dirchanges = [f for f in dirstate if dirstate[f] != 'n']
                changedfiles.extend(dirchanges)
                repo.dirstate.rebuild(newnode.node(), newnode.manifest(),
                                      changedfiles)
                dirstate.write(tr)
            else:
                bookactive = repo._activebookmark
                # Active bookmark that we don't want to delete (with -B option)
                # we deactivate and move it before the update and reactivate it
                # after
                movebookmark = bookactive and not bookmarks
                if movebookmark:
                    bookmarksmod.deactivate(repo)
                    bmchanges = [(bookactive, newnode.node())]
                    compat.bookmarkapplychanges(repo, tr, bmchanges)
                commands.update(ui, repo, newnode.rev())
                ui.status(_('working directory now at %s\n')
                          % ui.label(str(newnode), 'evolve.node'))
                if movebookmark:
                    bookmarksmod.activate(repo, bookactive)

        # update bookmarks
        if bookmarks:
            rewriteutil.deletebookmark(repo, repomarks, bookmarks)

        # create markers
        obsolete.createmarkers(repo, relations, metadata=metadata)

        # informs that changeset have been pruned
        ui.status(_('%i changesets pruned\n') % len(precs))

        for ctx in repo.unfiltered().set('bookmark() and %ld', precs):
            # used to be:
            #
            #   ldest = list(repo.set('max((::%d) - obsolete())', ctx))
            #   if ldest:
            #      c = ldest[0]
            #
            # but then revset took a lazy arrow in the knee and became much
            # slower. The new forms makes as much sense and a much faster.
            for dest in ctx.ancestors():
                if not dest.obsolete():
                    bookmarksupdater = rewriteutil.bookmarksupdater
                    updatebookmarks = bookmarksupdater(repo, ctx.node(), tr)
                    updatebookmarks(dest.node())
                    break

        tr.close()
    finally:
        lockmod.release(tr, lock, wlock)

@eh.command(
    '^split',
    [('r', 'rev', [], _("revision to split")),
    ] + commitopts + commitopts2 + commitopts3,
    _('hg split [OPTION]... [-r] REV'))
def cmdsplit(ui, repo, *revs, **opts):
    """split a changeset into smaller changesets

    By default, split the current revision by prompting for all its hunks to be
    redistributed into new changesets.

    Use --rev to split a given changeset instead.
    """
    _resolveoptions(ui, opts)
    tr = wlock = lock = None
    newcommits = []

    revarg = (list(revs) + opts.get('rev')) or ['.']
    if len(revarg) != 1:
        msg = _("more than one revset is given")
        hnt = _("use either `hg split <rs>` or `hg split --rev <rs>`, not both")
        raise error.Abort(msg, hint=hnt)

    try:
        wlock = repo.wlock()
        lock = repo.lock()
        rev = scmutil.revsingle(repo, revarg[0])
        cmdutil.bailifchanged(repo)
        rewriteutil.precheck(repo, [rev], action='split')
        tr = repo.transaction('split')
        ctx = repo[rev]

        if len(ctx.parents()) > 1:
            raise error.Abort(_("cannot split merge commits"))
        prev = ctx.p1()
        bmupdate = rewriteutil.bookmarksupdater(repo, ctx.node(), tr)
        bookactive = repo._activebookmark
        if bookactive is not None:
            repo.ui.status(_("(leaving bookmark %s)\n") % repo._activebookmark)
        bookmarksmod.deactivate(repo)

        # Prepare the working directory
        rewriteutil.presplitupdate(repo, ui, prev, ctx)

        def haschanges():
            modified, added, removed, deleted = repo.status()[:4]
            return modified or added or removed or deleted
        msg = ("HG: This is the original pre-split commit message. "
               "Edit it as appropriate.\n\n")
        msg += ctx.description()
        opts['message'] = msg
        opts['edit'] = True
        if not opts['user']:
            opts['user'] = ctx.user()
        while haschanges():
            pats = ()
            cmdutil.dorecord(ui, repo, commands.commit, 'commit', False,
                             cmdutil.recordfilter, *pats, **opts)
            # TODO: Does no seem like the best way to do this
            # We should make dorecord return the newly created commit
            newcommits.append(repo['.'])
            if haschanges():
                if ui.prompt('Done splitting? [yN]', default='n') == 'y':
                    commands.commit(ui, repo, **opts)
                    newcommits.append(repo['.'])
                    break
            else:
                ui.status(_("no more change to split\n"))

        if newcommits:
            tip = repo[newcommits[-1]]
            bmupdate(tip.node())
            if bookactive is not None:
                bookmarksmod.activate(repo, bookactive)
            obsolete.createmarkers(repo, [(repo[rev], newcommits)])
        tr.close()
    finally:
        lockmod.release(tr, lock, wlock)

@eh.command(
    '^touch',
    [('r', 'rev', [], 'revision to update'),
     ('D', 'duplicate', False,
      'do not mark the new revision as successor of the old one'),
     ('A', 'allowdivergence', False,
      'mark the new revision as successor of the old one potentially creating '
      'divergence')],
    # allow to choose the seed ?
    _('[-r] revs'))
def touch(ui, repo, *revs, **opts):
    """create successors that are identical to their predecessors except
    for the changeset ID

    This is used to "resurrect" changesets
    """
    duplicate = opts['duplicate']
    allowdivergence = opts['allowdivergence']
    revs = list(revs)
    revs.extend(opts['rev'])
    if not revs:
        revs = ['.']
    revs = scmutil.revrange(repo, revs)
    if not revs:
        ui.write_err('no revision to touch\n')
        return 1
    if not duplicate:
        rewriteutil.precheck(repo, revs, touch)
    tmpl = utility.shorttemplate
    displayer = cmdutil.show_changeset(ui, repo, {'template': tmpl})
    wlock = lock = tr = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()
        tr = repo.transaction('touch')
        revs.sort() # ensure parent are run first
        newmapping = {}
        for r in revs:
            ctx = repo[r]
            extra = ctx.extra().copy()
            extra['__touch-noise__'] = random.randint(0, 0xffffffff)
            # search for touched parent
            p1 = ctx.p1().node()
            p2 = ctx.p2().node()
            p1 = newmapping.get(p1, p1)
            p2 = newmapping.get(p2, p2)

            if not (duplicate or allowdivergence):
                # The user hasn't yet decided what to do with the revived
                # cset, let's ask
                sset = compat.successorssets(repo, ctx.node())
                nodivergencerisk = (len(sset) == 0 or
                                    (len(sset) == 1 and
                                     len(sset[0]) == 1 and
                                     repo[sset[0][0]].rev() == ctx.rev()
                                    ))
                if nodivergencerisk:
                    duplicate = False
                else:
                    displayer.show(ctx)
                    index = ui.promptchoice(
                        _("reviving this changeset will create divergence"
                          " unless you make a duplicate.\n(a)llow divergence or"
                          " (d)uplicate the changeset? $$ &Allowdivergence $$ "
                          "&Duplicate"), 0)
                    choice = ['allowdivergence', 'duplicate'][index]
                    if choice == 'allowdivergence':
                        duplicate = False
                    else:
                        duplicate = True

            extradict = {'extra': extra}
            new, unusedvariable = rewriteutil.rewrite(repo, ctx, [], ctx,
                                                      [p1, p2],
                                                      commitopts=extradict)
            # store touched version to help potential children
            newmapping[ctx.node()] = new

            if not duplicate:
                obsolete.createmarkers(repo, [(ctx, (repo[new],))])
            phases.retractboundary(repo, tr, ctx.phase(), [new])
            if ctx in repo[None].parents():
                with repo.dirstate.parentchange():
                    repo.dirstate.setparents(new, node.nullid)
        tr.close()
    finally:
        lockmod.release(tr, lock, wlock)