# show.py - Extension implementing `hg show`

#

# Copyright 2017 Gregory Szorc <gregory.szorc@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.

"""unified command to show various repository information (EXPERIMENTAL)

This extension provides the :hg:`show` command, which provides a central

command for displaying commonly-accessed repository data and views of that

data.

The following config options can influence operation.

``commands``

------------

``show.aliasprefix``

   List of strings that will register aliases for views. e.g. ``s`` will

   effectively set config options ``alias.s<view> = show <view>`` for all

   views. i.e. `hg swork` would execute `hg show work`.

   Aliases that would conflict with existing registrations will not be

   performed.

"""

from __future__ import absolute_import

from mercurial.i18n import _

from mercurial.node import nullrev

from mercurial import (

    cmdutil,

    commands,

    destutil,

    error,

    formatter,

    graphmod,

    phases,

    pycompat,

    registrar,

    revset,

    revsetlang,

)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for

# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should

# be specifying the version(s) of Mercurial they are tested with, or

# leave the attribute unspecified.

testedwith = 'ships-with-hg-core'

cmdtable = {}

command = registrar.command(cmdtable)

revsetpredicate = registrar.revsetpredicate()

class showcmdfunc(registrar._funcregistrarbase):

    """Register a function to be invoked for an `hg show <thing>`."""

    # Used by _formatdoc().

    _docformat = '%s -- %s'

    def _extrasetup(self, name, func, fmtopic=None, csettopic=None):

        """Called with decorator arguments to register a show view.

        ``name`` is the sub-command name.

        ``func`` is the function being decorated.

        ``fmtopic`` is the topic in the style that will be rendered for

        this view.

        ``csettopic`` is the topic in the style to be used for a changeset

        printer.

        If ``fmtopic`` is specified, the view function will receive a

        formatter instance. If ``csettopic`` is specified, the view

        function will receive a changeset printer.

        """

        func._fmtopic = fmtopic

        func._csettopic = csettopic

showview = showcmdfunc()

@command('show', [

    # TODO: Switch this template flag to use cmdutil.formatteropts if

    # 'hg show' becomes stable before --template/-T is stable. For now,

    # we are putting it here without the '(EXPERIMENTAL)' flag because it

    # is an important part of the 'hg show' user experience and the entire

    # 'hg show' experience is experimental.

    ('T', 'template', '', ('display with template'), _('TEMPLATE')),

    ], _('VIEW'))

def show(ui, repo, view=None, template=None):

    """show various repository information

    A requested view of repository data is displayed.

    If no view is requested, the list of available views is shown and the

    command aborts.

    .. note::

       There are no backwards compatibility guarantees for the output of this

       command. Output may change in any future Mercurial release.

       Consumers wanting stable command output should specify a template via

       ``-T/--template``.

    List of available views:

    """

    if ui.plain() and not template:

        hint = _('invoke with -T/--template to control output format')

        raise error.Abort(_('must specify a template in plain mode'), hint=hint)

    views = showview._table

    if not view:

        ui.pager('show')

        # TODO consider using formatter here so available views can be

        # rendered to custom format.

        ui.write(_('available views:\n'))

        ui.write('\n')

        for name, func in sorted(views.items()):

            ui.write(('%s\n') % func.__doc__)

        ui.write('\n')

        raise error.Abort(_('no view requested'),

                          hint=_('use "hg show VIEW" to choose a view'))

    # TODO use same logic as dispatch to perform prefix matching.

    if view not in views:

        raise error.Abort(_('unknown view: %s') % view,

                          hint=_('run "hg show" to see available views'))

    template = template or 'show'

    fn = views[view]

    ui.pager('show')

    if fn._fmtopic:

        fmtopic = 'show%s' % fn._fmtopic

        with ui.formatter(fmtopic, {'template': template}) as fm:

            return fn(ui, repo, fm)

    elif fn._csettopic:

        ref = 'show%s' % fn._csettopic

        spec = formatter.lookuptemplate(ui, ref, template)

        displayer = cmdutil.changeset_templater(ui, repo, spec, buffered=True)

        return fn(ui, repo, displayer)

    else:

        return fn(ui, repo)

@showview('bookmarks', fmtopic='bookmarks')

def showbookmarks(ui, repo, fm):

    """bookmarks and their associated changeset"""

    marks = repo._bookmarks

    if not len(marks):

        # This is a bit hacky. Ideally, templates would have a way to

        # specify an empty output, but we shouldn't corrupt JSON while

        # waiting for this functionality.

        if not isinstance(fm, formatter.jsonformatter):

            ui.write(_('(no bookmarks set)\n'))

        return

    active = repo._activebookmark

    longestname = max(len(b) for b in marks)

    for bm, node in sorted(marks.items()):

        fm.startitem()

        fm.context(ctx=repo[node])

        fm.write('bookmark', '%s', bm)

        fm.write('node', fm.hexfunc(node), fm.hexfunc(node))

        fm.data(active=bm == active,

                longestbookmarklen=longestname,

@showview('stack', csettopic='stack')

def showstack(ui, repo, displayer):

    """current line of work"""

    wdirctx = repo['.']

    if wdirctx.rev() == nullrev:

        raise error.Abort(_('stack view only available when there is a '

                            'working directory'))

    if wdirctx.phase() == phases.public:

        ui.write(_('(empty stack; working directory parent is a published '

                   'changeset)\n'))

        return

    # TODO extract "find stack" into a function to facilitate

    # customization and reuse.

    baserev = destutil.stackbase(ui, repo)

    basectx = None

    if baserev is None:

        baserev = wdirctx.rev()

        stackrevs = {wdirctx.rev()}

    else:

        stackrevs = set(repo.revs('%d::.', baserev))

    ctx = repo[baserev]

    if ctx.p1().rev() != nullrev:

        basectx = ctx.p1()

    # And relevant descendants.

    branchpointattip = False

    cl = repo.changelog

    for rev in cl.descendants([wdirctx.rev()]):

        ctx = repo[rev]

        # Will only happen if . is public.

        if ctx.phase() == phases.public:

            break

        stackrevs.add(ctx.rev())

        # ctx.children() within a function iterating on descandants

        # potentially has severe performance concerns because revlog.children()

        # iterates over all revisions after ctx's node. However, the number of

        # draft changesets should be a reasonably small number. So even if

        # this is quadratic, the perf impact should be minimal.

        if len(ctx.children()) > 1:

            branchpointattip = True

            break

    stackrevs = list(sorted(stackrevs, reverse=True))

    # Find likely target heads for the current stack. These are likely

    # merge or rebase targets.

    if basectx:

        # TODO make this customizable?

        newheads = set(repo.revs('heads(%d::) - %ld - not public()',

                                 basectx.rev(), stackrevs))

    else:

        newheads = set()

    try:

        cmdutil.findcmd('rebase', commands.table)

        haverebase = True

    except (error.AmbiguousCommand, error.UnknownCommand):

        haverebase = False

    # TODO use templating.

    # TODO consider using graphmod. But it may not be necessary given

    # our simplicity and the customizations required.

    # TODO use proper graph symbols from graphmod

    def shortest(ctx):

        return shortesttmpl.render({'ctx': ctx, 'node': ctx.hex()})

    # We write out new heads to aid in DAG awareness and to help with decision

    # making on how the stack should be reconciled with commits made since the

    # branch point.

    if newheads:

        # Calculate distance from base so we can render the count and so we can

        # sort display order by commit distance.

        revdistance = {}

        for head in newheads:

            # There is some redundancy in DAG traversal here and therefore

            # room to optimize.

            ancestors = cl.ancestors([head], stoprev=basectx.rev())

            revdistance[head] = len(list(ancestors))

        sourcectx = repo[stackrevs[-1]]

        sortedheads = sorted(newheads, key=lambda x: revdistance[x],

                             reverse=True)

        for i, rev in enumerate(sortedheads):

            ctx = repo[rev]

            if i:

                ui.write(': ')

            else:

                ui.write('  ')

            ui.write(('o  '))

            displayer.flush(ctx)

            ui.write('\n')

            if i:

                ui.write(':/')

            else:

                ui.write(' /')

            ui.write('    (')

            ui.write(_('%d commits ahead') % revdistance[rev],

                     label='stack.commitdistance')

            if haverebase:

                # TODO may be able to omit --source in some scenarios

                ui.write('; ')

                ui.write(('hg rebase --source %s --dest %s' % (

                         shortest(sourcectx), shortest(ctx))),

                         label='stack.rebasehint')

            ui.write(')\n')

        ui.write(':\n:    ')

        ui.write(_('(stack head)\n'), label='stack.label')

    if branchpointattip:

        ui.write(' \\ /  ')

        ui.write(_('(multiple children)\n'), label='stack.label')

        ui.write('  |\n')

    for rev in stackrevs:

        ctx = repo[rev]

        symbol = '@' if rev == wdirctx.rev() else 'o'

        if newheads:

            ui.write(': ')

        else:

            ui.write('  ')

        ui.write(symbol, '  ')

        displayer.flush(ctx)

        ui.write('\n')

    # TODO display histedit hint?

    if basectx:

        # Vertically and horizontally separate stack base from parent

        # to reinforce stack boundary.

        if newheads:

            ui.write(':/   ')

        else:

            ui.write(' /   ')

        ui.write(_('(stack base)'), '\n', label='stack.label')

        ui.write(('o  '))

        displayer.flush(basectx)

        ui.write('\n')

@revsetpredicate('_underway([commitage[, headage]])')

def underwayrevset(repo, subset, x):

    args = revset.getargsdict(x, 'underway', 'commitage headage')

    if 'commitage' not in args:

        args['commitage'] = None

    if 'headage' not in args:

        args['headage'] = None

    # We assume callers of this revset add a topographical sort on the

    # result. This means there is no benefit to making the revset lazy

    # since the topographical sort needs to consume all revs.

    #

    # With this in mind, we build up the set manually instead of constructing

    # a complex revset. This enables faster execution.

    # Mutable changesets (non-public) are the most important changesets

    # to return. ``not public()`` will also pull in obsolete changesets if

    # there is a non-obsolete changeset with obsolete ancestors. This is

    # why we exclude obsolete changesets from this query.

    rs = 'not public() and not obsolete()'

    rsargs = []

    if args['commitage']:

        rs += ' and date(%s)'

        rsargs.append(revsetlang.getstring(args['commitage'],

                                           _('commitage requires a string')))

    mutable = repo.revs(rs, *rsargs)

    relevant = revset.baseset(mutable)

    # Add parents of mutable changesets to provide context.

    relevant += repo.revs('parents(%ld)', mutable)

    # We also pull in (public) heads if they a) aren't closing a branch

    # b) are recent.

    rs = 'head() and not closed()'

    rsargs = []

    if args['headage']:

        rs += ' and date(%s)'

        rsargs.append(revsetlang.getstring(args['headage'],

                                           _('headage requires a string')))

    relevant += repo.revs(rs, *rsargs)

    # Add working directory parent.

    wdirrev = repo['.'].rev()

    if wdirrev != nullrev:

        relevant += revset.baseset({wdirrev})

    return subset & relevant

@showview('work', csettopic='work')

def showwork(ui, repo, displayer):

    """changesets that aren't finished"""

    # TODO support date-based limiting when calling revset.

    revs = repo.revs('sort(_underway(), topo)')