# backups.py
#
# Copyright 2013 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.
"""display recently made backups to recover stripped changesets

This extension allows the listing and restoring of strip backups.

By default, this will display a warning if you have obsolescence marker creation
enabled (since most hg installations use either strip or markers, but not both).
To disable that warning, set ``backups.warnobsolescence`` to False.
"""

from mercurial import cmdutil, commands, error, bundlerepo
from mercurial import hg, exchange, obsolete, registrar
from mercurial import bundle2, registrar
from mercurial import lock as lockmod
from mercurial import pycompat
from hgext import pager
from mercurial.node import nullid, short
from mercurial.i18n import _
import os, glob, time

pager.attended.append('backups')

cmdtable = {}
command = registrar.command(cmdtable)
testedwith = 'ships-with-fb-hgext'
msgwithcreatermarkers = """Marker creation is enabled so no changeset should be
stripped unless you explicitly called hg strip. hg backups will show you the
stripped changesets. If you are trying to recover a changeset hidden from a
previous command, use hg journal to get its sha1 and you will be able to access
it directly without recovering a backup.\n\n"""
verbosetemplate = "{label('status.modified', node|short)} {desc|firstline}\n"

@command('^backups', [
    ('', 'recover', '',
     'brings the specified changeset back into the repository')
    ] + commands.logopts, _('hg backups [--recover HASH]'))
def backups(ui, repo, *pats, **opts):
    '''lists the changesets available in backup bundles

    Without any arguments, this command prints a list of the changesets in each
    backup bundle.

    --recover takes a changeset hash and unbundles the first bundle that
    contains that hash, which puts that changeset back in your repository.

    --verbose will print the entire commit message and the bundle path for that
    backup.
    '''
    supportsmarkers = obsolete.isenabled(repo, obsolete.createmarkersopt)
    if supportsmarkers and ui.configbool('backups', 'warnobsolescence', True):
        # Warn users of obsolescence markers that they probably don't want to
        # use backups but reflog instead
        ui.warn(msgwithcreatermarkers)
    backuppath = repo.vfs.join("strip-backup")
    backups = filter(os.path.isfile, glob.glob(backuppath + "/*.hg"))
    backups.sort(key=lambda x: os.path.getmtime(x), reverse=True)

    opts['bundle'] = ''
    opts['force'] = None

    def display(other, chlist, displayer):
        limit = cmdutil.loglimit(opts)
        if opts.get('newest_first'):
            chlist.reverse()
        count = 0
        for n in chlist:
            if limit is not None and count >= limit:
                break
            parents = [p for p in other.changelog.parents(n) if p != nullid]
            if opts.get('no_merges') and len(parents) == 2:
                continue
            count += 1
            displayer.show(other[n])

    recovernode = opts.get('recover')
    if recovernode:
        if recovernode in repo:
            ui.warn(_("%s already exists in the repo\n") % recovernode)
            return
    else:
        msg = _('Recover changesets using: hg backups --recover '
                '<changeset hash>\n\nAvailable backup changesets:')
        ui.status(msg, label="status.removed")

    for backup in backups:
        # Much of this is copied from the hg incoming logic
        source = os.path.relpath(backup, pycompat.getcwd())
        source = ui.expandpath(source)
        source, branches = hg.parseurl(source, opts.get('branch'))
        try:
            other = hg.peer(repo, opts, source)
        except error.LookupError as ex:
            msg = _("\nwarning: unable to open bundle %s") % source
            hint = _("\n(missing parent rev %s)\n") % short(ex.name)
            ui.warn(msg)
            ui.warn(hint)
            continue
        revs, checkout = hg.addbranchrevs(repo, other, branches,
                                          opts.get('rev'))

        if revs:
            revs = [other.lookup(rev) for rev in revs]

        quiet = ui.quiet
        try:
            ui.quiet = True
            other, chlist, cleanupfn = bundlerepo.getremotechanges(ui, repo,
                                        other, revs, opts["bundle"],
                                        opts["force"])
        except error.LookupError:
            continue
        finally:
            ui.quiet = quiet

        try:
            if chlist:
                if recovernode:
                    tr = lock = None
                    try:
                        lock = repo.lock()
                        if recovernode in other:
                            ui.status(_("Unbundling %s\n") % (recovernode))
                            f = hg.openpath(ui, source)
                            gen = exchange.readbundle(ui, f, source)
                            tr = repo.transaction("unbundle")
                            if not isinstance(gen, bundle2.unbundle20):
                                gen.apply(repo, 'unbundle', 'bundle:' + source)
                            if isinstance(gen, bundle2.unbundle20):
                                bundle2.applybundle(repo, gen, tr,
                                                    source='unbundle',
                                                    url='bundle:' + source)
                            tr.close()
                            break
                    finally:
                        lockmod.release(lock, tr)
                else:
                    backupdate = os.path.getmtime(source)
                    backupdate = time.strftime('%a %H:%M, %Y-%m-%d',
                                                time.localtime(backupdate))
                    ui.status("\n%s\n" % (backupdate.ljust(50)))
                    if not ui.verbose:
                        opts['template'] = verbosetemplate
                    else:
                        ui.status("%s%s\n" % ("bundle:".ljust(13), source))
                    displayer = cmdutil.show_changeset(ui, other, opts, False)
                    display(other, chlist, displayer)
                    displayer.close()
        finally:
            cleanupfn()