from __future__ import absolute_import

from mercurial import (

    error,

    registrar,

    revset,

    util,

)

from . import (

    destination,

    stack,

)

try:

    mkmatcher = revset._stringmatcher

except AttributeError:

    try:

        from mercurial.utils import stringutil

        mkmatcher = stringutil.stringmatcher

    except (ImportError, AttributeError):

        mkmatcher = util.stringmatcher

revsetpredicate = registrar.revsetpredicate()

def getstringstrict(x, err):

    if x and x[0] == b'string':

        return x[1]

    raise error.ParseError(err)

@revsetpredicate(b'topic([string or set])')

def topicset(repo, subset, x):

    """All changesets with the specified topic or the topics of the given

    changesets. Without the argument, all changesets with any topic specified.

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

    as a regular expression.

    """

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

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

    if not args:

        return (subset & mutable).filter(lambda r: bool(repo[r].topic()))

    try:

        topic = getstringstrict(args[0], b'')

    except error.ParseError:

        # not a string, but another revset

        pass

    else:

        kind, pattern, matcher = mkmatcher(topic)

        if topic.startswith(b'literal:') and pattern not in repo.topics:

            raise error.RepoLookupError(b"topic '%s' does not exist" % pattern)

        def matches(r):

            topic = repo[r].topic()

            if not topic:

                return False

            return matcher(topic)

        return (subset & mutable).filter(matches)

    s = revset.getset(repo, revset.fullreposet(repo), x)

    topics = {repo[r].topic() for r in s}

    topics.discard(b'')

    def matches(r):

        if r in s:

            return True

        topic = repo[r].topic()

        if not topic:

            return False

        return topic in topics

    return (subset & mutable).filter(matches)

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

def ngtipset(repo, subset, x):

    """The untopiced tip.

    Name is horrible so that people change it.

    """

    args = revset.getargs(x, 1, 1, b'ngtip takes one argument')

    # match a specific topic

    branch = revset.getstring(args[0], b'ngtip requires a string')

    if branch == b'.':

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

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

@revsetpredicate(b'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 = b'stack takes no arguments, it works on current topic'

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

    topic = None

    branch = None

    if repo.currenttopic:

        topic = repo.currenttopic

    else:

        branch = repo[None].branch()

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

if util.safehasattr(revset, 'subscriptrelations'):

    def stackrel(repo, subset, x, rel, z, order):

        """This is a revset-flavored implementation of stack aliases.

        The syntax is: rev#stack[n] or rev#s[n]. Plenty of logic is borrowed

        from topic._namemap, but unlike that function, which prefers to abort

        (e.g. when stack index is too high), this returns empty set to be more

        revset-friendly.

        """

        # hg 4.9 provides a number or None, hg 5.0 provides a tuple of tokens

        if isinstance(z, tuple):

            a, b = revset.getintrange(

                z,

                b'relation subscript must be an integer or a range',

                b'relation subscript bounds must be integers',

                None, None)

        else:

            a = b = z

        s = revset.getset(repo, revset.fullreposet(repo), x)

        if not s:

            return revset.baseset()

        def getrange(st, a, b):

            start = 1 if a is None else a

            end = len(st.revs) if b is None else b + 1

            return range(start, end)

        revs = []

        for r in s:

            topic = repo[r].topic()

            if topic:

                st = stack.stack(repo, topic=topic)

            else:

                st = stack.stack(repo, branch=repo[r].branch())

            for n in getrange(st, a, b):

                if abs(n) >= len(st.revs):

                    # also means stack base is not accessible with n < 0, which

                    # is by design

                    continue

                if n == 0 and b != 0 and a != 0:

                    # quirk: we don't want stack base unless specifically asked

                    # for it (at least one of the indices is 0)

                    continue

                rev = st.revs[n]

                if rev == -1 and n == 0:

                    continue

                if rev not in revs:

                    revs.append(rev)

        return subset & revset.baseset(revs)

    revset.subscriptrelations[b'stack'] = stackrel

    revset.subscriptrelations[b's'] = stackrel

    def topicrel(repo, subset, x, *args):

        subset &= topicset(repo, subset, x)

        return revset.generationsrel(repo, subset, x, *args)

    revset.subscriptrelations[b'topic'] = topicrel

    revset.subscriptrelations[b't'] = topicrel