# fbmetaedit.py - improved metaedit functionality
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""extends the existing metaedit functionality

Speeds up metaedit by reusing manifestes and allows to metaedit
multiple commit at once.
"""

from mercurial import (
    cmdutil,
    context,
    error,
    extensions,
    lock as lockmod,
    scmutil,
    obsolete,
)
from mercurial.i18n import _

wrapcommand = extensions.wrapcommand
wrapfunction = extensions.wrapfunction

cmdtable = {}
command = cmdutil.command(cmdtable)

testedwith = 'ships-with-fb-hgext'

def uisetup(ui):
    order = extensions._order
    order.remove('fbmetaedit')
    order.append('fbmetaedit')

def extsetup(ui):
    try:
        evolve = extensions.find('evolve')

        def metarewrite(repo, old, newbases, commitopts):
            """Return (nodeid, created) where nodeid is the identifier of the
            changeset generated by the rewrite process, and created is True if
            nodeid was actually created. If created is False, nodeid
            references a changeset existing before the rewrite call.
            """
            wlock = lock = tr = None
            try:
                wlock = repo.wlock()
                lock = repo.lock()
                tr = repo.transaction('rewrite')
                updatebookmarks = evolve._bookmarksupdater(repo, old.node(), tr)

                message = cmdutil.logmessage(repo.ui, commitopts)
                if not message:
                    message = old.description()

                user = commitopts.get('user') or old.user()
                date = commitopts.get('date') or None # old.date()
                extra = dict(commitopts.get('extra', old.extra()))
                extra['branch'] = old.branch()

                new = context.metadataonlyctx(repo,
                                              old,
                                              parents=newbases,
                                              text=message,
                                              user=user,
                                              date=date,
                                              extra=extra)

                if commitopts.get('edit'):
                    new._text = cmdutil.commitforceeditor(repo, new, [])
                revcount = len(repo)
                newid = repo.commitctx(new)
                new = repo[newid]
                created = len(repo) != revcount
                updatebookmarks(newid)

                tr.close()
                return newid, created
            finally:
                lockmod.release(tr, lock, wlock)

        def _metaedit(orig, ui, repo, *revs, **opts):
            if opts['fold']:
                return orig(ui, repo, *revs, **opts)
            revs = list(revs)
            revs.extend(opts['rev'])
            if not revs:
                revs = ['.']

            wlock = lock = None
            try:
                wlock = repo.wlock()
                lock = repo.lock()

                revs = scmutil.revrange(repo, revs)

                if repo.revs("%ld and public()", revs):
                    raise error.Abort(_('cannot edit commit information for '
                                        'public revisions'))
                wctx = repo[None]
                p1 = wctx.p1()
                tr = repo.transaction('metaedit')
                try:
                    commitopts = opts.copy()
                    allctx = [repo[r] for r in revs]

                    if commitopts.get('message') or commitopts.get('logfile'):
                        commitopts['edit'] = False
                    else:
                        commitopts['edit'] = True

                    replacemap = {}
                    # we need topological order
                    allctx = sorted(allctx, key=lambda c: c.rev())
                    # all descendats that can be safely rewritten
                    newunstable = evolve._disallowednewunstable(repo, revs)
                    newunstablectx = sorted([repo[r] for r in newunstable],
                                            key=lambda c: c.rev())

                    def _rewritesingle(c, _commitopts):
                        if _commitopts.get('edit', False):
                            _commitopts['message'] = \
                                "HG: Commit message of changeset %s\n%s" %\
                                (str(c), c.description())
                        bases = [
                            replacemap.get(c.p1().node(), c.p1().node()),
                            replacemap.get(c.p2().node(), c.p2().node()),
                        ]
                        newid, created = metarewrite(repo, c, bases,
                                                     commitopts=_commitopts)
                        if created:
                            replacemap[c.node()] = newid
                    for c in allctx:
                        _rewritesingle(c, commitopts)
                    for c in newunstablectx:
                        _rewritesingle(c,
                                       {'date': commitopts.get('date') or None})

                    if p1.node() in replacemap:
                        repo.setparents(replacemap[p1.node()])
                    if len(replacemap) > 0:
                        obsolete.createmarkers(
                            repo,
                            [(repo[old], (repo[new],))
                                for old, new in replacemap.iteritems()],
                        )
                        # TODO: set poroper phase boundaries (affects secret
                        # phase only)
                    else:
                        ui.status(_("nothing changed\n"))
                    tr.close()
                finally:
                    tr.release()
            finally:
                lockmod.release(lock, wlock)

        wrapcommand(evolve.cmdtable, 'metaedit', _metaedit)
    except KeyError:
        pass # evolve not found