from __future__ import absolute_import

from mercurial import (

    registrar,

    revset,

    util,

)

from . import (

    constants,

    destination,

    stack,

)

try:

    mkmatcher = revset._stringmatcher

except AttributeError:

    mkmatcher = util.stringmatcher

revsetpredicate = registrar.revsetpredicate()

@revsetpredicate('topic([topic])')

def topicset(repo, subset, x):

    """Specified topic or all changes with any topic specified.

    If `topic` starts with `re:` the remainder of the name is treated

    as a regular expression.

    TODO: make `topic(revset)` work the same as `branch(revset)`.

    """

    args = revset.getargs(x, 0, 1, 'topic takes one or no arguments')

    if args:

        # match a specific topic

        topic = revset.getstring(args[0], 'topic() argument must be a string')

        if topic == '.':

            topic = repo['.'].extra().get('topic', '')

        _kind, _pattern, matcher = mkmatcher(topic)

    else:

        matcher = lambda t: bool(t)

    mutable = revset._notpublic(repo, revset.fullreposet(repo), ())

    rawchange = repo.changelog.changelogrevision

    key = constants.extrakey

    def matchtopic(r):

        topic = rawchange(r).extra.get(key)

        if topic is None:

            return False

        return matcher(topic)

    return (subset & mutable).filter(matchtopic)

@revsetpredicate('ngtip([branch])')

def ngtipset(repo, subset, x):

    """The untopiced tip.

    Name is horrible so that people change it.

    """

    args = revset.getargs(x, 1, 1, 'topic takes one')

    # match a specific topic

    branch = revset.getstring(args[0], 'ngtip() argument must be a string')

    if branch == '.':

        branch = repo['.'].branch()

    return subset & revset.baseset(destination.ngtip(repo, branch))

@revsetpredicate('stack()')

def stackset(repo, subset, x):

    """All relevant changes in the current topic,

    This is roughly equivalent to 'topic(.) - obsolete' with a sorting moving

    unstable changeset after there future parent (as if evolve where already

    run)."""

    err = 'stack() takes no argument, it works on current topic'

    revset.getargs(x, 0, 0, err)

    topic = repo.currenttopic

    topic = None

    branch = None

    if not topic and repo.currenttopic:

        topic = repo.currenttopic

    if not topic:

        branch = repo[None].branch()

    return revset.baseset(stack.stack(repo, branch=branch, topic=topic)[1:]) & subset