import contextlib

import hashlib

from mercurial.node import hex, bin, nullid

from mercurial import (

    branchmap,

    changegroup,

    cmdutil,

    encoding,

    error,

    extensions,

    scmutil,

)

def _filename(repo):

    """name of a branchcache file for a given repo or repoview"""

    filename = "cache/topicmap"

    if repo.filtername:

        filename = '%s-%s' % (filename, repo.filtername)

    return filename

oldbranchcache = branchmap.branchcache

def _phaseshash(repo, maxrev):

    revs = set()

    cl = repo.changelog

    fr = cl.filteredrevs

    nm = cl.nodemap

    for roots in repo._phasecache.phaseroots[1:]:

        for n in roots:

            r = nm.get(n)

            if r not in fr and r < maxrev:

                revs.add(r)

    key = nullid

    revs = sorted(revs)

    if revs:

        s = hashlib.sha1()

        for rev in revs:

            s.update('%s;' % rev)

        key = s.digest()

    return key

@contextlib.contextmanager

def usetopicmap(repo):

    """use awful monkey patching to ensure topic map usage

    During the extend of the context block, The topicmap should be used and

    updated instead of the branchmap."""

    oldbranchcache = branchmap.branchcache

    oldfilename = branchmap._filename

    oldread = branchmap.read

    oldcaches = getattr(repo, '_branchcaches', {})

    try:

        branchmap.branchcache = topiccache

        branchmap._filename = _filename

        branchmap.read = readtopicmap

        repo._branchcaches = getattr(repo, '_topiccaches', {})

        yield

        repo._topiccaches = repo._branchcaches

    finally:

        repo._branchcaches = oldcaches

        branchmap.branchcache = oldbranchcache

        branchmap._filename = oldfilename

        branchmap.read = oldread

def cgapply(orig, repo, *args, **kwargs):

    """make sure a topicmap is used when applying a changegroup"""

    with usetopicmap(repo):

        return orig(repo, *args, **kwargs)

def commitstatus(orig, repo, node, branch, bheads=None, opts=None):

    # wrap commit status use the topic branch heads

    ctx = repo[node]

    if ctx.topic() and ctx.branch() == branch:

        bheads = repo.branchheads("%s:%s" % (branch, ctx.topic()))

    return orig(repo, node, branch, bheads=bheads, opts=opts)

class topiccache(oldbranchcache):

    def __init__(self, *args, **kwargs):

        otherbranchcache = branchmap.branchcache

        try:

            # super() call may fail otherwise

            branchmap.branchcache = oldbranchcache

            super(topiccache, self).__init__(*args, **kwargs)

            if self.filteredhash is None:

                self.filteredhash = nullid

            self.phaseshash = nullid

        finally:

            branchmap.branchcache = otherbranchcache

    def copy(self):

        """return an deep copy of the branchcache object"""

        new = topiccache(self, self.tipnode, self.tiprev, self.filteredhash,

                         self._closednodes)

        if self.filteredhash is None:

            self.filteredhash = nullid

        new.phaseshash = self.phaseshash

        return new

    def branchtip(self, branch, topic=''):

        '''Return the tipmost open head on branch head, otherwise return the

        tipmost closed head on branch.

        Raise KeyError for unknown branch.'''

        if topic:

            branch = '%s:%s' % (branch, topic)

        return super(topiccache, self).branchtip(branch)

    def branchheads(self, branch, closed=False, topic=''):

        if topic:

            branch = '%s:%s' % (branch, topic)

        return super(topiccache, self).branchheads(branch, closed=closed)

    def validfor(self, repo):

        """Is the cache content valid regarding a repo

        - False when cached tipnode is unknown or if we detect a strip.

        - True when cache is up to date or a subset of current repo."""

        # This is copy paste of mercurial.branchmap.branchcache.validfor in

        # 69077c65919d With a small changes to the cache key handling to

        # include phase information that impact the topic cache.

        #

        # All code changes should be flagged on site.

        try:

            if (self.tipnode == repo.changelog.node(self.tiprev)):

                fh = scmutil.filteredhash(repo, self.tiprev)

                if fh is None:

                    fh = nullid

                if ((self.filteredhash == fh)

                    and (self.phaseshash == _phaseshash(repo, self.tiprev))):

                    return True

            return False

        except IndexError:

            return False

    def write(self, repo):

        # This is copy paste of mercurial.branchmap.branchcache.write in

        # 69077c65919d With a small changes to the cache key handling to

        # include phase information that impact the topic cache.

        #

        # All code changes should be flagged on site.

        try:

            f = repo.vfs(_filename(repo), "w", atomictemp=True)

            cachekey = [hex(self.tipnode), str(self.tiprev)]

            # [CHANGE] we need a hash in all cases

            assert self.filteredhash is not None

            cachekey.append(hex(self.filteredhash))

            cachekey.append(hex(self.phaseshash))

            f.write(" ".join(cachekey) + '\n')

            nodecount = 0

            for label, nodes in sorted(self.iteritems()):

                for node in nodes:

                    nodecount += 1

                    if node in self._closednodes:

                        state = 'c'

                    else:

                        state = 'o'

                    f.write("%s %s %s\n" % (hex(node), state,

                                            encoding.fromlocal(label)))

            f.close()

            repo.ui.log('branchcache',

                        'wrote %s branch cache with %d labels and %d nodes\n',

                        repo.filtername, len(self), nodecount)

        except (IOError, OSError, error.Abort) as inst:

            repo.ui.debug("couldn't write branch cache: %s\n" % inst)

            # Abort may be raise by read only opener

            pass

    def update(self, repo, revgen):

        """Given a branchhead cache, self, that may have extra nodes or be

        missing heads, and a generator of nodes that are strictly a superset of

        heads missing, this function updates self to be correct.

        """

        oldgetbranchinfo = repo.revbranchcache().branchinfo

        try:

            def branchinfo(r):

                info = oldgetbranchinfo(r)

                topic = ''

                ctx = repo[r]

                if ctx.mutable():

                    topic = ctx.topic()

                branch = info[0]

                if topic:

                    branch = '%s:%s' % (branch, topic)

                return (branch, info[1])

            repo.revbranchcache().branchinfo = branchinfo

            super(topiccache, self).update(repo, revgen)

            if self.filteredhash is None:

                self.filteredhash = nullid

            self.phaseshash = _phaseshash(repo, self.tiprev)

        finally:

            repo.revbranchcache().branchinfo = oldgetbranchinfo

def readtopicmap(repo):

    # This is copy paste of mercurial.branchmap.read in 69077c65919d

    # With a small changes to the cache key handling to include phase

    # information that impact the topic cache.

    #

    # All code changes should be flagged on site.

    try:

        f = repo.vfs(_filename(repo))

        lines = f.read().split('\n')

        f.close()

    except (IOError, OSError):

        return None

    try:

        cachekey = lines.pop(0).split(" ", 2)

        last, lrev = cachekey[:2]

        last, lrev = bin(last), int(lrev)

        filteredhash = bin(cachekey[2]) # [CHANGE] unconditional filteredhash

        partial = topiccache(tipnode=last, tiprev=lrev,

                             filteredhash=filteredhash)

        partial.phaseshash = bin(cachekey[3]) # [CHANGE] read phaseshash

        if not partial.validfor(repo):

            # invalidate the cache

            raise ValueError('tip differs')

        cl = repo.changelog

        for l in lines:

            if not l:

                continue

            node, state, label = l.split(" ", 2)

            if state not in 'oc':

                raise ValueError('invalid branch state')

            label = encoding.tolocal(label.strip())

            node = bin(node)

            if not cl.hasnode(node):

                raise ValueError('node %s does not exist' % hex(node))

            partial.setdefault(label, []).append(node)

            if state == 'c':

                partial._closednodes.add(node)

    except KeyboardInterrupt:

        raise

    except Exception as inst:

        if repo.ui.debugflag:

            msg = 'invalid branchheads cache'

            if repo.filtername is not None:

                msg += ' (%s)' % repo.filtername

            msg += ': %s\n'

            repo.ui.debug(msg % inst)

        partial = None

    return partial

def modsetup(ui):

    """call at uisetup time to install various wrappings"""

    extensions.wrapfunction(changegroup.cg1unpacker, 'apply', cgapply)

    extensions.wrapfunction(cmdutil, 'commitstatus', commitstatus)