# states.py - introduce the state concept for mercurial changeset
#
# Copyright 2011 Pierre-Yves David <pierre-yves.david@ens-lyon.org>
#                Logilab SA        <contact@logilab.fr>
#                Augie Fackler     <durin42@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''introduce the state concept for mercurial changeset

Change can be in the following state:

0 immutable
1 mutable
2 private

name are not fixed yet.
'''
from functools import partial
from mercurial.i18n import _
from mercurial import cmdutil
from mercurial import scmutil
from mercurial import context
from mercurial import revset
from mercurial import templatekw
from mercurial import util
from mercurial import node
from mercurial.node import nullid
from mercurial import discovery
from mercurial import extensions


_NOPULLPUSH=2

STATES = (0, _NOPULLPUSH)
def statename(state):
    return str(STATES)


# util function
#############################
def noderange(repo, revsets):
    return map(repo.changelog.node,
               scmutil.revrange(repo, revsets))

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

def state(ctx):
    return ctx._repo.nodestate(ctx.node())
context.changectx.state = state

# improve template
#############################

def showstate(ctx, **args):
    return ctx.state()

# New revset predicate
#############################

def revsetpublicheads(repo, subset, x):
    args = revset.getargs(x, 0, 0, 'publicheads takes no arguments')
    heads = map(repo.changelog.rev, repo._statesheads[0])
    heads.sort()
    return heads

def extsetup(ui):
    revset.symbols['publicheads'] = revsetpublicheads

REVSETHEADS = {0: 'publicheads()'}

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

def cmdsetstate(ui, repo, state, *changesets):
    """turn private changesets into public ones"""
    #assert repo.ui.configbool('private', 'enable', False)
    state = int(state) #for now
    revs = scmutil.revrange(repo, changesets)
    repo.setstate(state, [repo.changelog.node(rev) for rev in revs])
    return 0

cmdtable = {
    'setstate':  (cmdsetstate,   [], _('state <revset>')),
    }


templatekw.keywords['state'] = showstate






def uisetup(ui):
    def filterprivateout(orig, repo, *args,**kwargs):
        common, heads = orig(repo, *args, **kwargs)
        return common, repo._reducehead(heads)
    def filterprivatein(orig, repo, remote, *args, **kwargs):
        common, anyinc, heads = orig(repo, remote, *args, **kwargs)
        heads = remote._reducehead(heads)
        return common, anyinc, heads

    extensions.wrapfunction(discovery, 'findcommonoutgoing', filterprivateout)
    extensions.wrapfunction(discovery, 'findcommonincoming', filterprivatein)

def reposetup(ui, repo):

    if not repo.local():
        return

    class statefulrepo(repo.__class__):

        def nodestate(self, node):
            rev = self.changelog.rev(node)
            for head in self._publicheads:
                revhead = self.changelog.rev(head)
                if self.changelog.descendant(revhead, rev):
                    return STATES[1]
            return STATES[0]

        @property
        def _publicheads(self):
            if self.ui.configbool('states', 'private', False):
                return self._statesheads[0]
            return self.heads()

        @util.propertycache
        def _statesheads(self):
            return self._readstatesheads()


        def _readstatesheads(self):
            statesheads = {}
            try:
                f = self.opener('publicheads')
                try:
                    heads = sorted([node.bin(n) for n in f.read().split() if n])
                finally:
                    f.close()
            except IOError:
                heads = [nullid]
            statesheads[0] = heads
            return statesheads

        def _writestateshead(self):
            # transaction!
            f = self.opener('publicheads', 'w', atomictemp=True)
            try:
                for h in self._statesheads[0]:
                    f.write(node.hex(h) + '\n')
                f.rename()
            finally:
                f.close()

        def setstate(self, state, nodes):
            """freeze targets changeset and it's ancestors.

            Simplify the list of head."""
            heads = self._statesheads[state]
            olds = heads[:]
            heads.extend(nodes)
            heads[:] = set(heads)
            heads.sort()
            if olds != heads:
                heads[:] = noderange(repo, ["heads(::%s)" % REVSETHEADS[state]])
                heads.sort()
            if olds != heads:
                self._writestateshead()

        def _reducehead(self, candidates):
            selected = set()
            for candidate in candidates:
                rev = self.changelog.rev(candidate)
                ok = True
                for h in self._publicheads:
                    revh = self.changelog.rev(h)
                    if self.changelog.descendant(revh, rev):
                        ok = False
                        selected.add(h)
                if ok:
                    selected.add(candidate)
            return sorted(selected)

    repo.__class__ = statefulrepo