# obsolete.py - introduce the obsolete concept in mercurial.
#
# Copyright 2011 Pierre-Yves David <pierre-yves.david@ens-lyon.org>
#                Logilab SA        <contact@logilab.fr>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from mercurial import util
from mercurial import context
from mercurial import revset
from mercurial import scmutil
from mercurial import extensions
from mercurial import pushkey
from mercurial import discovery
from mercurial import error
from mercurial.node import hex, bin

# Patch changectx
#############################

def obsolete(ctx):
    """is the changeset obsolete by other"""
    if ctx.node()is None:
        return False
    return bool(ctx._repo.obsoletedby(ctx.node()))

context.changectx.obsolete = obsolete

ohidden = context.changectx.hidden
def hidden(ctx):
    # hack to fill hiddenrevs
    # compute hidden (XXX should move elsewhere)
    if not getattr(ctx._repo.changelog, 'hiddeninit', False):
        basicquery = 'obsolete() - (ancestors(not obsolete() or . or bookmark()))'
        for rev in scmutil.revrange(ctx._repo, [basicquery]):
            ctx._repo.changelog.hiddenrevs.add(rev)
        ctx._repo.changelog.hiddeninit = True

    return ohidden(ctx)
context.changectx.hidden = hidden

# revset
#############################

def revsetobsolete(repo, subset, x):
    args = revset.getargs(x, 0, 0, 'publicheads takes no arguments')
    return [r for r in subset if repo[r].obsolete()] # XXX slow

def extsetup(ui):
    revset.symbols["obsolete"] = revsetobsolete

    def filterobsoleteout(orig, repo, remote, *args,**kwargs):
        common, heads = orig(repo, remote, *args, **kwargs)

        # filter obsolete
        heads = set(map(repo.changelog.rev, heads))
        obsoletes = set()
        for obj in repo._obsobjrels:
            try:
                obsoletes.add(repo.changelog.rev(obj))
            except error.LookupError:
                pass # we don't have this node locally

        outgoing = set(repo.changelog.ancestors(*heads))
        outgoing.update(heads)

        selected = outgoing - obsoletes
        heads = sorted(map(repo.changelog.node, selected))

        return common, heads

    extensions.wrapfunction(discovery, 'findcommonoutgoing', filterobsoleteout)
    
    try:
        rebase = extensions.find('rebase')
        if rebase:
            extensions.wrapfunction(rebase, 'concludenode', concludenode)
    except KeyError:
        pass # rebase not found

# Pushkey mechanism for mutable
#########################################

def pushobsolete(repo, key, old, relations):
    assert key == "relations"
    w = repo.wlock()
    try:
        for sub, objs in relations.iteritems():
            for obj in objs:
                repo.addobsolete(sub, obj)
    finally:
        w.release()

def listobsolete(repo):
    return {'relations': repo._obssubrels}

pushkey.register('obsolete', pushobsolete, listobsolete)

# New commands
#############################


def cmddebugobsolete(ui, repo, subject, object):
    """Add an obsolete relation between a too node
    
    The subject is expected to be a newer version of the object"""
    sub = repo[subject]
    obj = repo[object]
    repo.addobsolete(sub.node(), obj.node())
    return 0

cmdtable = {'debugobsolete': (cmddebugobsolete, [], '<subject> <object>')}

def reposetup(ui, repo):

    if not repo.local():
        return

    opull = repo.pull
    opush = repo.push

    class obsoletingrepo(repo.__class__):


        ### Hidden revision support
        @util.propertycache
        def hiddenrevs(self):
            # It's a property because It simpler that to handle the __init__
            revs = set()
            return revs

        ### obsolete storage
        @util.propertycache
        def _obsobjrels(self):
            """{<old-node> -> set(<new-node>)}

            also compute hidden revision"""
            #reverse sub -> objs mapping
            objrels = {}
            for sub, objs in self._obssubrels.iteritems():
                for obj in objs:
                    objrels.setdefault(obj, set()).add(sub)
            return objrels

        @util.propertycache
        def _obssubrels(self):
            """{<new-node> -> set(<old-node>)}"""
            return self._readobsrels()


        ### Disk IO
        def _readobsrels(self):
            """Write obsolete relation on disk"""
            # XXX handle lock
            rels = {}
            try:
                f = self.opener('obsolete-relations')
                try:
                    for line in f:
                        subhex, objhex = line.split()
                        rels.setdefault(bin(subhex), set()).add(bin(objhex))
                finally:
                    f.close()
            except IOError:
                pass
            return rels

        def _writeobsrels(self):
            """Write obsolete relation on disk"""
            # XXX handle lock
            f = self.opener('obsolete-relations', 'w', atomictemp=True)
            try:
                for sub, objs in self._obssubrels.iteritems():
                    for obj in objs:
                        f.write('%s %s\n' % (hex(sub), hex(obj)))
                f.rename()
            finally:
                f.close()

        ### pull // push support

        def pull(self, remote, *args, **kwargs):
            obskey = remote.listkeys('obsolete')
            obsrels = obskey.get('relations', {})
            result = opull(remote, *args, **kwargs)
            for sub, objs in obsrels.iteritems():
                for obj in objs:
                    self.addobsolete(sub, obj)
            return result

        def push(self, remote, *args, **opts):
            obskey = remote.listkeys('obsolete')
            obssupport = 'relations' in obskey
            result = opush(remote, *args, **opts)
            if obssupport:
                remote.pushkey('obsolete', 'relations', {}, self._obssubrels)
            return result


        ### Public method
        def obsoletedby(self, node):
            """return the set of node that make <node> obsolete (obj)"""
            return self._obsobjrels.get(node, set())

        def obsolete(self, node):
            """return the set of node that <node> make obsolete (sub)"""
            return self._obssubrels.get(node, set())

        def addobsolete(self, sub, obj):
            """Add a relation marking that node <sub> is a new version of <obj>"""
            self._obssubrels.setdefault(sub, set()).add(obj)
            self._obsobjrels.setdefault(obj, set()).add(sub)
            try:
                self.changelog.hiddenrevs.add(repo[obj].rev())
            except error.RepoLookupError:
                pass #unknow revision (but keep propagating the data
            self._writeobsrels()

    repo.__class__ = obsoletingrepo


### Other Extension compat
############################

def concludenode(orig, repo, rev, *args, **kwargs):
    newrev = orig(repo, rev, *args, **kwargs)
    oldnode = repo[rev].node()
    newnode = repo[newrev].node()
    repo.addobsolete(newnode, oldnode)
    return newrev