# verify.py - verify Mercurial revisions
#
# Copyright 2014 Facebook.
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import stat

from mercurial import command
from mercurial import error
from mercurial import util as hgutil
from mercurial.node import hex, bin, nullid
from mercurial.i18n import _
from mercurial import scmutil

from dulwich import diff_tree
from dulwich.objects import Commit, S_IFGITLINK

def verify(ui, repo, **opts):
    '''verify that a Mercurial rev matches the corresponding Git rev

    Given a Mercurial revision that has a corresponding Git revision in the map,
    this attempts to answer whether that revision has the same contents as the
    corresponding Git revision.

    '''
    hgctx = scmutil.revsingle(repo, opts.get('rev'), '.')

    handler = repo.githandler

    gitsha = handler.map_git_get(hgctx.hex())
    if not gitsha:
        # TODO deal better with commits in the middle of octopus merges
        raise hgutil.Abort(_('no git commit found for rev %s') % hgctx,
                           hint=_('if this is an octopus merge, verify against the last rev'))

    try:
        gitcommit = handler.git.get_object(gitsha)
    except KeyError:
        raise hgutil.Abort(_('git equivalent %s for rev %s not found!') %
                           (gitsha, hgctx))
    if not isinstance(gitcommit, Commit):
        raise hgutil.Abort(_('git equivalent %s for rev %s is not a commit!') %
                           (gitsha, hgctx))

    ui.status(_('verifying rev %s against git commit %s\n') % (hgctx, gitsha))
    failed = False

    # TODO check commit message and other metadata

    dirkind = stat.S_IFDIR

    hgfiles = set(hgctx)
    # TODO deal with submodules
    hgfiles.discard('.hgsubstate')
    hgfiles.discard('.hgsub')
    gitfiles = set()

    i = 0
    for gitfile, dummy in diff_tree.walk_trees(handler.git.object_store,
                                               gitcommit.tree, None):
        if gitfile.mode == dirkind:
            continue
        # TODO deal with submodules
        if (gitfile.mode == S_IFGITLINK or gitfile.path == '.hgsubstate'
            or gitfile.path == '.hgsub'):
            continue
        ui.progress('verify', i, total=len(hgfiles))
        i += 1
        gitfiles.add(gitfile.path)

        try:
            fctx = hgctx[gitfile.path]
        except error.LookupError:
            # we'll deal with this at the end
            continue

        hgflags = fctx.flags()
        gitflags = handler.convert_git_int_mode(gitfile.mode)
        if hgflags != gitflags:
            ui.write(_("file has different flags: %s (hg '%s', git '%s')\n") %
                     (gitfile.path, hgflags, gitflags))
            failed = True
        if fctx.data() != handler.git[gitfile.sha].data:
            ui.write(_('difference in: %s\n') % gitfile.path)
            failed = True

    ui.progress('verify', None, total=len(hgfiles))

    if hgfiles != gitfiles:
        failed = True
        missing = gitfiles - hgfiles
        for f in sorted(missing):
            ui.write(_('file found in git but not hg: %s\n') % f)
        unexpected = hgfiles - gitfiles
        for f in sorted(unexpected):
            ui.write(_('file found in hg but not git: %s\n') % f)

    if failed:
        return 1
    else:
        return 0