# __init__.py - topic extension
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""support for topic branches

Topic branches are lightweight branches which disappear when changes are
finalized (move to the public phase).

Compared to bookmark, topic is reference carried by each changesets of the
series instead of just the single head revision.  Topic are quite similar to
the way named branch work, except they eventualy fade away when the changeset
becomes part of the immutable history. Changeset can belong to both a topic and
a named branch, but as long as it is mutable, its topic identity will prevail.
As a result, default destination for 'update', 'merge', etc...  will take topic
into account. When a topic is active these operations will only consider other
changesets on that topic (and, in some occurence, bare changeset on same
branch).  When no topic is active, changeset with topic will be ignored and
only bare one on the same branch will be taken in account.

There is currently two commands to be used with that extension: 'topics' and
'stack'.

The 'hg topics' command is used to set the current topic, change and list
existing one. 'hg topics --verbose' will list various information related to
each topic.

The 'stack' will show you information about the stack of commit belonging to
your current topic.

Topic is offering you aliases reference to changeset in your current topic
stack as 't#'. For example, 't1' refers to the root of your stack, 't2' to the
second commits, etc. The 'hg stack' command show these number.

Push behavior will change a bit with topic. When pushing to a publishing
repository the changesets will turn public and the topic data on them will fade
away. The logic regarding pushing new heads will behave has before, ignore any
topic related data. When pushing to a non-publishing repository (supporting
topic), the head checking will be done taking topic data into account.
Push will complain about multiple heads on a branch if you push multiple heads
with no topic information on them (or multiple public heads). But pushing a new
topic will not requires any specific flag. However, pushing multiple heads on a
topic will be met with the usual warning.

The 'evolve' extension takes 'topic' into account. 'hg evolve --all'
will evolve all changesets in the active topic. In addition, by default. 'hg
next' and 'hg prev' will stick to the current topic.

Be aware that this extension is still an experiment, commands and other features
are likely to be change/adjusted/dropped over time as we refine the concept.
"""

from __future__ import absolute_import

import re

from mercurial.i18n import _
from mercurial import (
    branchmap,
    cmdutil,
    commands,
    context,
    error,
    extensions,
    localrepo,
    lock,
    merge,
    namespaces,
    node,
    obsolete,
    patch,
    phases,
    registrar,
    util,
)

from . import (
    constants,
    revset as topicrevset,
    destination,
    stack,
    topicmap,
    discovery,
)

if util.safehasattr(registrar, 'command'):
    commandfunc = registrar.command
else: # compat with hg < 4.3
    commandfunc = cmdutil.command

cmdtable = {}
command = commandfunc(cmdtable)
colortable = {'topic.active': 'green',
              'topic.list.troubledcount': 'red',
              'topic.list.headcount.multiple': 'yellow',
              'topic.list.behindcount': 'cyan',
              'topic.list.behinderror': 'red',
              'topic.stack.index': 'yellow',
              'topic.stack.index.base': 'none dim',
              'topic.stack.desc.base': 'none dim',
              'topic.stack.state.base': 'dim',
              'topic.stack.state.clean': 'green',
              'topic.stack.index.current': 'cyan',       # random pick
              'topic.stack.state.current': 'cyan bold',  # random pick
              'topic.stack.desc.current': 'cyan',        # random pick
              'topic.stack.state.unstable': 'red',
              'topic.stack.summary.behindcount': 'cyan',
              'topic.stack.summary.behinderror': 'red',
              'topic.stack.summary.headcount.multiple': 'yellow',
              # default color to help log output and thg
              # (first pick I could think off, update as needed
              'log.topic': 'green_background',
              'topic.active': 'green',
             }

testedwith = '4.0.2 4.1.3 4.2'

def _contexttopic(self):
    return self.extra().get(constants.extrakey, '')
context.basectx.topic = _contexttopic

topicrev = re.compile(r'^t\d+$')

def _namemap(repo, name):
    if topicrev.match(name):
        idx = int(name[1:])
        topic = repo.currenttopic
        if not topic:
            raise error.Abort(_('cannot resolve "%s": no active topic') % name)
        revs = list(stack.getstack(repo, topic))
        try:
            r = revs[idx - 1]
        except IndexError:
            msg = _('cannot resolve "%s": topic "%s" has only %d changesets')
            raise error.Abort(msg % (name, topic, len(revs)))
        return [repo[r].node()]
    if name not in repo.topics:
        return []
    return [ctx.node() for ctx in
            repo.set('not public() and extra(topic, %s)', name)]

def _nodemap(repo, node):
    ctx = repo[node]
    t = ctx.topic()
    if t and ctx.phase() > phases.public:
        return [t]
    return []

def uisetup(ui):
    destination.modsetup(ui)
    topicrevset.modsetup(ui)
    discovery.modsetup(ui)
    topicmap.modsetup(ui)
    setupimportexport(ui)

    extensions.afterloaded('rebase', _fixrebase)

    entry = extensions.wrapcommand(commands.table, 'commit', commitwrap)
    entry[1].append(('t', 'topic', '',
                     _("use specified topic"), _('TOPIC')))

    extensions.wrapfunction(cmdutil, 'buildcommittext', committextwrap)
    extensions.wrapfunction(merge, 'update', mergeupdatewrap)
    cmdutil.summaryhooks.add('topic', summaryhook)


def reposetup(ui, repo):
    if not isinstance(repo, localrepo.localrepository):
        return # this can be a peer in the ssh case (puzzling)

    if repo.ui.config('experimental', 'thg.displaynames', None) is None:
        repo.ui.setconfig('experimental', 'thg.displaynames', 'topics',
                          source='topic-extension')

    class topicrepo(repo.__class__):

        def _restrictcapabilities(self, caps):
            caps = super(topicrepo, self)._restrictcapabilities(caps)
            caps.add('topics')
            return caps

        def commit(self, *args, **kwargs):
            backup = self.ui.backupconfig('ui', 'allowemptycommit')
            try:
                if repo.currenttopic != repo['.'].topic():
                    # bypass the core "nothing changed" logic
                    self.ui.setconfig('ui', 'allowemptycommit', True)
                return super(topicrepo, self).commit(*args, **kwargs)
            finally:
                self.ui.restoreconfig(backup)

        def commitctx(self, ctx, error=None):
            if isinstance(ctx, context.workingcommitctx):
                current = self.currenttopic
                if current:
                    ctx.extra()[constants.extrakey] = current
            if (isinstance(ctx, context.memctx) and
                ctx.extra().get('amend_source') and
                ctx.topic() and
                not self.currenttopic):
                # we are amending and need to remove a topic
                del ctx.extra()[constants.extrakey]
            with topicmap.usetopicmap(self):
                return super(topicrepo, self).commitctx(ctx, error=error)

        @property
        def topics(self):
            if self._topics is not None:
                return self._topics
            topics = set(['', self.currenttopic])
            for c in self.set('not public()'):
                topics.add(c.topic())
            topics.remove('')
            self._topics = topics
            return topics

        @property
        def currenttopic(self):
            return self.vfs.tryread('topic')

        def branchmap(self, topic=True):
            if not topic:
                super(topicrepo, self).branchmap()
            with topicmap.usetopicmap(self):
                branchmap.updatecache(self)
            return self._topiccaches[self.filtername]

        def destroyed(self, *args, **kwargs):
            with topicmap.usetopicmap(self):
                return super(topicrepo, self).destroyed(*args, **kwargs)

        def invalidatevolatilesets(self):
            # XXX we might be able to move this to something invalidated less often
            super(topicrepo, self).invalidatevolatilesets()
            self._topics = None
            if '_topiccaches' in vars(self.unfiltered()):
                self.unfiltered()._topiccaches.clear()

        def peer(self):
            peer = super(topicrepo, self).peer()
            if getattr(peer, '_repo', None) is not None: # localpeer
                class topicpeer(peer.__class__):
                    def branchmap(self):
                        usetopic = not self._repo.publishing()
                        return self._repo.branchmap(topic=usetopic)
                peer.__class__ = topicpeer
            return peer

    repo.__class__ = topicrepo
    repo._topics = None
    if util.safehasattr(repo, 'names'):
        repo.names.addnamespace(namespaces.namespace(
            'topics', 'topic', namemap=_namemap, nodemap=_nodemap,
            listnames=lambda repo: repo.topics))

@command('topics [TOPIC]', [
        ('', 'clear', False, 'clear active topic if any'),
        ('r', 'rev', '', 'revset of existing revisions', _('REV')),
        ('l', 'list', False, 'show the stack of changeset in the topic'),
    ] + commands.formatteropts)
def topics(ui, repo, topic='', clear=False, rev=None, list=False, **opts):
    """View current topic, set current topic, or see all topics.

    The --verbose version of this command display various information on the state of each topic."""
    if list:
        if clear or rev:
            raise error.Abort(_("cannot use --clear or --rev with --list"))
        if not topic:
            topic = repo.currenttopic
        if not topic:
            raise error.Abort(_('no active topic to list'))
        return stack.showstack(ui, repo, topic, opts)

    if rev:
        if not obsolete.isenabled(repo, obsolete.createmarkersopt):
            raise error.Abort(_('must have obsolete enabled to change topics'))
        if not topic and not clear:
            raise error.Abort('changing topic requires a topic name or --clear')
        if any(not c.mutable() for c in repo.set('%r and public()', rev)):
            raise error.Abort("can't change topic of a public change")
        _changetopics(ui, repo, rev, topic, clear)
    if clear:
        if repo.vfs.exists('topic'):
            repo.vfs.unlink('topic')
        return
    if topic:
        with repo.wlock():
            with repo.vfs.open('topic', 'w') as f:
                f.write(topic)
        return
    _listtopics(ui, repo, opts)

@command('stack [TOPIC]', [] + commands.formatteropts)
def cmdstack(ui, repo, topic='', **opts):
    """list all changesets in a topic and other information

    List the current topic by default."""
    if not topic:
        topic = repo.currenttopic
    if not topic:
        raise error.Abort(_('no active topic to list'))
    return stack.showstack(ui, repo, topic, opts)

def _changetopics(ui, repo, revset, topic, clear):
    rewrote = 0
    needevolve = False
    l = repo.lock()
    txn = repo.transaction('rewrite-topics')
    try:
        newp = None
        oldp = None
        p1 = None
        p2 = None
        for c in repo.set('%r', revset):
            def filectxfn(repo, ctx, path):
                try:
                    return c[path]
                except error.ManifestLookupError:
                    return None
            fixedextra = dict(c.extra())
            ui.debug('old node id is %s\n' % node.hex(c.node()))
            ui.debug('origextra: %r\n' % fixedextra)
            newtopic = None if clear else topic
            oldtopic = fixedextra.get(constants.extrakey, None)
            if oldtopic == newtopic:
                continue
            if clear:
                del fixedextra[constants.extrakey]
            else:
                fixedextra[constants.extrakey] = topic
            if 'amend_source' in fixedextra:
                # TODO: right now the commitctx wrapper in
                # topicrepo overwrites the topic in extra if
                # amend_source is set to support 'hg commit
                # --amend'. Support for amend should be adjusted
                # to not be so invasive.
                del fixedextra['amend_source']
            ui.debug('changing topic of %s from %s to %s\n' % (
                c, oldtopic, newtopic))
            ui.debug('fixedextra: %r\n' % fixedextra)
            # While changing topic of set of linear commits, make sure that
            # we base our commits on new parent rather than old parent which
            # was obsoleted while changing the topic
            if newp and c.p1().node() == oldp:
                p1 = newp
                p2 = c.p2().node()
            elif newp and c.p2().node() == oldp:
                p1 = c.p1().node()
                p2 = newp
            else:
                p1 = c.p1().node()
                p2 = c.p2().node()
            mc = context.memctx(
                repo, (p1, p2), c.description(),
                c.files(), filectxfn,
                user=c.user(), date=c.date(), extra=fixedextra)
            newnode = repo.commitctx(mc)
            oldp = c.node()
            newp = newnode
            ui.debug('new node id is %s\n' % node.hex(newnode))
            needevolve = needevolve or (len(c.children()) > 0)
            obsolete.createmarkers(repo, [(c, (repo[newnode],))])
            rewrote += 1
        txn.close()
    except:
        try:
            txn.abort()
        finally:
            repo.invalidate()
        raise
    finally:
        lock.release(txn, l)
    ui.status('changed topic on %d changes\n' % rewrote)
    if needevolve:
        evolvetarget = 'topic(%s)' % topic if topic else 'not topic()'
        ui.status('please run hg evolve --rev "%s" now\n' % evolvetarget)

def _listtopics(ui, repo, opts):
    fm = ui.formatter('bookmarks', opts)
    activetopic = repo.currenttopic
    namemask = '%s'
    if repo.topics and ui.verbose:
        maxwidth = max(len(t) for t in repo.topics)
        namemask = '%%-%is' % maxwidth
    for topic in sorted(repo.topics):
        fm.startitem()
        marker = ' '
        label = 'topic'
        active = (topic == activetopic)
        if active:
            marker = '*'
            label = 'topic.active'
        if not ui.quiet:
            # registering the active data is made explicitly later
            fm.plain(' %s ' % marker, label=label)
        fm.write('topic', namemask, topic, label=label)
        fm.data(active=active)
        if ui.verbose:
            # XXX we should include the data even when not verbose
            data = stack.stackdata(repo, topic)
            fm.plain(' (')
            fm.write('branches+', 'on branch: %s',
                     '+'.join(data['branches']), # XXX use list directly after 4.0 is released
                     label='topic.list.branches')
            fm.plain(', ')
            fm.write('changesetcount', '%d changesets', data['changesetcount'],
                     label='topic.list.changesetcount')
            if data['troubledcount']:
                fm.plain(', ')
                fm.write('troubledcount', '%d troubled',
                         data['troubledcount'],
                         label='topic.list.troubledcount')
            if 1 < data['headcount']:
                fm.plain(', ')
                fm.write('headcount', '%d heads',
                         data['headcount'],
                         label='topic.list.headcount.multiple')
            if 0 < data['behindcount']:
                fm.plain(', ')
                fm.write('behindcount', '%d behind',
                         data['behindcount'],
                         label='topic.list.behindcount')
            elif -1 == data['behindcount']:
                fm.plain(', ')
                fm.write('behinderror', '%s',
                         _('ambiguous destination'),
                         label='topic.list.behinderror')
            fm.plain(')')
        fm.plain('\n')
    fm.end()

def summaryhook(ui, repo):
    t = repo.currenttopic
    if not t:
        return
    # i18n: column positioning for "hg summary"
    ui.write(_("topic:  %s\n") % ui.label(t, 'topic.active'))

def commitwrap(orig, ui, repo, *args, **opts):
    with repo.wlock():
        if opts.get('topic'):
            t = opts['topic']
            with repo.vfs.open('topic', 'w') as f:
                f.write(t)
        return orig(ui, repo, *args, **opts)

def committextwrap(orig, repo, ctx, subs, extramsg):
    ret = orig(repo, ctx, subs, extramsg)
    t = repo.currenttopic
    if t:
        ret = ret.replace("\nHG: branch",
                          "\nHG: topic '%s'\nHG: branch" % t)
    return ret

def mergeupdatewrap(orig, repo, node, branchmerge, force, *args, **kwargs):
    matcher = kwargs.get('matcher')
    partial = not (matcher is None or matcher.always())
    wlock = repo.wlock()
    try:
        ret = orig(repo, node, branchmerge, force, *args, **kwargs)
        if not partial and not branchmerge:
            ot = repo.currenttopic
            t = ''
            pctx = repo[node]
            if pctx.phase() > phases.public:
                t = pctx.topic()
            with repo.vfs.open('topic', 'w') as f:
                f.write(t)
            if t and t != ot:
                repo.ui.status(_("switching to topic %s\n") % t)
        return ret
    finally:
        wlock.release()

def _fixrebase(loaded):
    if not loaded:
        return

    def savetopic(ctx, extra):
        if ctx.topic():
            extra[constants.extrakey] = ctx.topic()

    def newmakeextrafn(orig, copiers):
        return orig(copiers + [savetopic])

    try:
        rebase = extensions.find("rebase")
        extensions.wrapfunction(rebase, '_makeextrafn', newmakeextrafn)
    except KeyError:
        pass

## preserve topic during import/export

def _exporttopic(seq, ctx):
    topic = ctx.topic()
    if topic:
        return 'EXP-Topic %s' % topic
    return None

def _importtopic(repo, patchdata, extra, opts):
    if 'topic' in patchdata:
        extra['topic'] = patchdata['topic']

def setupimportexport(ui):
    """run at ui setup time to install import/export logic"""
    cmdutil.extraexport.append('topic')
    cmdutil.extraexportmap['topic'] = _exporttopic
    cmdutil.extrapreimport.append('topic')
    cmdutil.extrapreimportmap['topic'] = _importtopic
    patch.patchheadermap.append(('EXP-Topic', 'topic'))