# 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 commits"""

from mercurial import extensions, util, cmdutil, commands, error, bundlerepo
from mercurial import hg, changegroup, exchange
from mercurial.extensions import wrapfunction
from hgext import pager
from mercurial.node import hex, nullrev, nullid, short
from mercurial.i18n import _
import errno, os, re, glob, time

pager.attended.append('backups')

cmdtable = {}
command = cmdutil.command(cmdtable)
testedwith = 'internal'
msgwithevolve = """Evolve is enabled so no commit should be stripped unless you
explicitely called hg strip. hg backups will show you the stripped commits.
If you are trying to recover a commit hidden from a previous command, use hg 
reflog to get its sha1 and you will be able to access it directly without 
recovering a backup."""

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

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

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

    --verbose will print the entire commit message and the bundle path for that
    backup.
    '''
    try:
        if extensions.find('evolve'):
            # Warn evolve users that they probably don't want to use backups
            # but reflog instead
            ui.warn(msgwithevolve)
    except KeyError:
        pass
    backuppath = repo.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:
        ui.status("Recover commits using: hg backups --recover <commit hash>\n", label="status.removed")

    for backup in backups:
        # Much of this is copied from the hg incoming logic
        source = os.path.relpath(backup, os.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:
            ui.status("\nwarning: unable to open bundle %s - missing parent rev %s\n" %
                (source, short(ex.name)))
            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:
                    lock = repo.lock()
                    try:
                        if recovernode in other:
                            ui.status("Unbundling %s\n" % (recovernode))
                            f = hg.openpath(ui, source)
                            gen = exchange.readbundle(ui, f, source)
                            modheads = changegroup.addchangegroup(repo, gen, 'unbundle', 'bundle:' + source)
                            break
                    finally:
                        lock.release()
                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'] = "{label('status.modified', node|short)} {desc|firstline}\n"
                    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()