# stack.py - code related to stack workflow

#

# 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.i18n import _

from mercurial import (

    destutil,

    context,

    error,

    node,

    phases,

    obsolete,

    util,

)

from .evolvebits import (

    _singlesuccessor,

    MultipleSuccessorsError,

    builddependencies,

)

short = node.short

# TODO: compat

if not util.safehasattr(context.basectx, 'orphan'):

    context.basectx.orphan = context.basectx.unstable

if not util.safehasattr(context.basectx, 'isunstable'):

    context.basectx.isunstable = context.basectx.troubled

def _stackcandidates(repo):

    """build the smaller set of revs that might be part of a stack.

    The intend is to build something more efficient than what revsets do in

    this area.

    """

    phasecache = repo._phasecache

    if not phasecache._phasesets:

        return repo.revs('(not public()) - obsolete()')

    if any(s is None for s in phasecache._phasesets):

        return repo.revs('(not public()) - obsolete()')

    result = set()

    for s in phasecache._phasesets[phases.draft:]:

        result |= s

    result -= obsolete.getrevs(repo, 'obsolete')

    return result

class stack(object):

    """object represent a stack and common logic associated to it."""

    def __init__(self, repo, branch=None, topic=None):

        self._repo = repo

        self.branch = branch

        self.topic = topic

        self.behinderror = None

        subset = _stackcandidates(repo)

        if topic is not None and branch is not None:

            raise error.ProgrammingError('both branch and topic specified (not defined yet)')

        elif topic is not None:

            trevs = repo.revs("%ld and topic(%s)", subset, topic)

        elif branch is not None:

            trevs = repo.revs("%ld and branch(%s) - topic()", subset, branch)

        else:

            raise error.ProgrammingError('neither branch and topic specified (not defined yet)')

        self._revs = trevs

    def __iter__(self):

        return iter(self.revs)

    def __getitem__(self, index):

        return self.revs[index]

    def index(self, item):

        return self.revs.index(item)

    @util.propertycache

    def _dependencies(self):

        deps, rdeps = builddependencies(self._repo, self._revs)

        repo = self._repo

        srcpfunc = repo.changelog.parentrevs

        ### post process to skip over possible gaps in the stack

        #

        # For example in the following situation, we need to detect that "t3"

        # indirectly depends on t2.

        #

        #  o t3

        #  |

        #  o other

        #  |

        #  o t2

        #  |

        #  o t1

        pmap = {}

        def pfuncrev(repo, rev):

            """a special "parent func" that also consider successors"""

            parents = pmap.get(rev)

            if parents is None:

                parents = [repo[_singlesuccessor(repo, repo[p])].rev()

                           for p in srcpfunc(rev) if 0 <= p]

                pmap[rev] = parents

            return parents

        revs = self._revs

        stackrevs = set(self._revs)

        for root in [r for r in revs if not deps[r]]:

            seen = set()

            stack = [root]

            while stack:

                current = stack.pop()

                for p in pfuncrev(repo, current):

                    if p in seen:

                        continue

                    seen.add(p)

                    if p in stackrevs:

                        rdeps[p].add(root)

                        deps[root].add(p)

                    elif phases.public < repo[p].phase():

                        # traverse only if we did not found a proper candidate

                        stack.append(p)

        return deps, rdeps

    @util.propertycache

    def revs(self):

        # some duplication/change from _orderrevs because we use a post

        # processed dependency graph.

        # Step 1: compute relation of revision with each other

        dependencies, rdependencies = self._dependencies

        dependencies = dependencies.copy()

        rdependencies = rdependencies.copy()

        # Step 2: Build the ordering

        # Remove the revisions with no dependency(A) and add them to the ordering.

        # Removing these revisions leads to new revisions with no dependency (the

        # one depending on A) that we can remove from the dependency graph and add

        # to the ordering. We progress in a similar fashion until the ordering is

        # built

        solvablerevs = [r for r in sorted(dependencies.keys())

                        if not dependencies[r]]

        revs = []

        while solvablerevs:

            rev = solvablerevs.pop()

            for dependent in rdependencies[rev]:

                dependencies[dependent].remove(rev)

                if not dependencies[dependent]:

                    solvablerevs.append(dependent)

            del dependencies[rev]

            revs.append(rev)

        revs.extend(sorted(dependencies))

        # step 3: add t0

        if revs:

            pt1 = self._repo[revs[0]].p1()

        else:

            pt1 = self._repo['.']

        if pt1.obsolete():

            pt1 = self._repo[_singlesuccessor(self._repo, pt1)]

        revs.insert(0, pt1.rev())

        return revs

    @util.propertycache

    def changesetcount(self):

        return len(self._revs)

    @util.propertycache

    def troubledcount(self):

        return len([r for r in self._revs if self._repo[r].isunstable()])

    @util.propertycache

    def heads(self):

        revs = self.revs[1:]

        deps, rdeps = self._dependencies

        return [r for r in revs if not rdeps[r]]

    @util.propertycache

    def behindcount(self):

        revs = self.revs[1:]

        deps, rdeps = self._dependencies

        if revs:

            minroot = [min(r for r in revs if not deps[r])]

            try:

                dest = destutil.destmerge(self._repo, action='rebase',

                                          sourceset=minroot,

                                          onheadcheck=False)

                return len(self._repo.revs("only(%d, %ld)", dest, minroot))

            except error.NoMergeDestAbort:

                return 0

            except error.ManyMergeDestAbort as exc:

                # XXX we should make it easier for upstream to provide the information

                self.behinderror = str(exc).split('-', 1)[0].rstrip()

                return -1

        return 0

    @util.propertycache

    def branches(self):

        branches = sorted(set(self._repo[r].branch() for r in self._revs))

        if not branches:

            branches = set([self._repo[None].branch()])

        return branches

def labelsgen(prefix, labelssuffix):

    """ Takes a label prefix and a list of suffixes. Returns a string of the prefix

    formatted with each suffix separated with a space.

    """

    return ' '.join(prefix % suffix for suffix in labelssuffix)

def showstack(ui, repo, branch=None, topic=None, opts=None):

    if opts is None:

        opts = {}

    if topic is not None and branch is not None:

        msg = 'both branch and topic specified [%s]{%s}(not defined yet)'

        msg %= (branch, topic)

        raise error.ProgrammingError(msg)

    elif topic is not None:

        prefix = 't'

        if topic not in repo.topics:

            raise error.Abort(_('cannot resolve "%s": no such topic found') % topic)

    elif branch is not None:

        prefix = 'b'

    else:

        raise error.ProgrammingError('neither branch and topic specified (not defined yet)')

    fm = ui.formatter('topicstack', opts)

    prev = None

    entries = []

    idxmap = {}

    label = 'topic'

    if topic == repo.currenttopic:

        label = 'topic.active'

    data = stackdata(repo, branch=branch, topic=topic)

    empty = False

    if data['changesetcount'] == 0:

        empty = True

    if topic is not None:

        fm.plain(_('### topic: %s')

                 % ui.label(topic, label),

                 label='topic.stack.summary.topic')

        if 1 < data['headcount']:

            fm.plain(' (')

            fm.plain('%d heads' % data['headcount'],

                     label='topic.stack.summary.headcount.multiple')

            fm.plain(')')

        fm.plain('\n')

    fm.plain(_('### target: %s (branch)')

             % '+'.join(data['branches']), # XXX handle multi branches

             label='topic.stack.summary.branches')

    if topic is None:

        if 1 < data['headcount']:

            fm.plain(' (')

            fm.plain('%d heads' % data['headcount'],

                     label='topic.stack.summary.headcount.multiple')

            fm.plain(')')

    else:

        if data['behindcount'] == -1:

            fm.plain(', ')

            fm.plain('ambiguous rebase destination - %s' % data['behinderror'],

                     label='topic.stack.summary.behinderror')

        elif data['behindcount']:

            fm.plain(', ')

            fm.plain('%d behind' % data['behindcount'], label='topic.stack.summary.behindcount')

    fm.plain('\n')

    if empty:

        fm.plain(_("(stack is empty)\n"))

    for idx, r in enumerate(stack(repo, branch=branch, topic=topic), 0):

        ctx = repo[r]

        # special case for t0, b0 as it's hard to plugin into rest of the logic

        if idx == 0:

            # t0, b0 can be None

            if r == -1:

                continue

            entries.append((idx, False, ctx))

            prev = ctx.rev()

            continue

        p1 = ctx.p1()

        p2 = ctx.p2()

        if p1.obsolete():

            try:

                p1 = repo[_singlesuccessor(repo, p1)]

            except MultipleSuccessorsError as e:

                successors = e.successorssets

                if len(successors) > 1:

                    # case of divergence which we don't handle yet

                    raise

                p1 = repo[successors[0][-1]]

        if p2.node() != node.nullid:

            entries.append((idxmap.get(p1.rev()), False, p1))

            entries.append((idxmap.get(p2.rev()), False, p2))

        elif p1.rev() != prev and p1.node() != node.nullid:

            entries.append((idxmap.get(p1.rev()), False, p1))

        entries.append((idx, True, ctx))

        idxmap[ctx.rev()] = idx

        prev = r

    # super crude initial version

    for idx, isentry, ctx in entries[::-1]:

        symbol = None

        states = []

        iscurrentrevision = repo.revs('%d and parents()', ctx.rev())

        if iscurrentrevision:

            states.append('current')

            symbol = '@'

        if ctx.orphan():

            symbol = '$'

            states.append('unstable')

        if not isentry:

            symbol = '^'

            # "base" is kind of a "ghost" entry

            states.append('base')

        # none of the above if statments get executed

        if not symbol:

            symbol = ':'

            states.append('clean')

        states.sort()

        fm.startitem()

        fm.data(isentry=isentry)

        if idx is None:

            fm.plain('  ')

            if ui.verbose:

                fm.plain('              ')

        else:

            fm.write('topic.stack.index', '%s%%d' % prefix, idx,

                     label='topic.stack.index ' + labelsgen('topic.stack.index.%s', states))

            if ui.verbose:

                fm.write('topic.stack.shortnode', '(%s)', short(ctx.node()),

                         label='topic.stack.shortnode ' + labelsgen('topic.stack.shortnode.%s', states))

        fm.write('topic.stack.state.symbol', '%s', symbol,

                 label='topic.stack.state ' + labelsgen('topic.stack.state.%s', states))

        fm.plain(' ')

        fm.write('topic.stack.desc', '%s', ctx.description().splitlines()[0],

                 label='topic.stack.desc ' + labelsgen('topic.stack.desc.%s', states))

        fm.condwrite(states != ['clean'] and idx is not None, 'topic.stack.state',

                     ' (%s)', fm.formatlist(states, 'topic.stack.state'),

                     label='topic.stack.state ' + labelsgen('topic.stack.state.%s', states))

        fm.plain('\n')

    fm.end()

def stackdata(repo, branch=None, topic=None):

    """get various data about a stack

    :changesetcount: number of non-obsolete changesets in the stack

    :troubledcount: number on troubled changesets

    :headcount: number of heads on the topic

    :behindcount: number of changeset on rebase destination

    """

    data = {}