# Copyright 2005, 2006 Benoit Boissinot <benoit.boissinot@ens-lyon.org>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

'''commands to sign and verify changesets'''

from __future__ import absolute_import

import binascii

import os

from mercurial.i18n import _

from mercurial.node import (

    bin,

    hex,

    nullid,

    short,

)

from mercurial import (

    cmdutil,

    error,

    help,

    match,

    pycompat,

    registrar,

)

from mercurial.utils import (

    dateutil,

    procutil,

)

cmdtable = {}

command = registrar.command(cmdtable)

# 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 = b'ships-with-hg-core'

configtable = {}

configitem = registrar.configitem(configtable)

configitem(

    b'gpg',

    b'cmd',

    default=b'gpg',

)

configitem(

    b'gpg',

    b'key',

    default=None,

)

configitem(

    b'gpg',

    b'.*',

    default=None,

    generic=True,

)

# Custom help category

_HELP_CATEGORY = b'gpg'

help.CATEGORY_ORDER.insert(

    help.CATEGORY_ORDER.index(registrar.command.CATEGORY_HELP), _HELP_CATEGORY

)

help.CATEGORY_NAMES[_HELP_CATEGORY] = b'Signing changes (GPG)'

class gpg(object):

    def __init__(self, path, key=None):

        self.path = path

        self.key = (key and b" --local-user \"%s\"" % key) or b""

    def sign(self, data):

        gpgcmd = b"%s --sign --detach-sign%s" % (self.path, self.key)

        return procutil.filter(data, gpgcmd)

    def verify(self, data, sig):

        """ returns of the good and bad signatures"""

        sigfile = datafile = None

        try:

            # create temporary files

            fd, sigfile = pycompat.mkstemp(prefix=b"hg-gpg-", suffix=b".sig")

            fp = os.fdopen(fd, 'wb')

            fp.write(sig)

            fp.close()

            fd, datafile = pycompat.mkstemp(prefix=b"hg-gpg-", suffix=b".txt")

            fp = os.fdopen(fd, 'wb')

            fp.write(data)

            fp.close()

            gpgcmd = (

                b"%s --logger-fd 1 --status-fd 1 --verify \"%s\" \"%s\""

                % (

                    self.path,

                    sigfile,

                    datafile,

                )

            )

            ret = procutil.filter(b"", gpgcmd)

        finally:

            for f in (sigfile, datafile):

                try:

                    if f:

                        os.unlink(f)

                except OSError:

                    pass

        keys = []

        key, fingerprint = None, None

        for l in ret.splitlines():

            # see DETAILS in the gnupg documentation

            # filter the logger output

            if not l.startswith(b"[GNUPG:]"):

                continue

            l = l[9:]

            if l.startswith(b"VALIDSIG"):

                # fingerprint of the primary key

                fingerprint = l.split()[10]

            elif l.startswith(b"ERRSIG"):

                key = l.split(b" ", 3)[:2]

                key.append(b"")

                fingerprint = None

            elif (

                l.startswith(b"GOODSIG")

                or l.startswith(b"EXPSIG")

                or l.startswith(b"EXPKEYSIG")

                or l.startswith(b"BADSIG")

            ):

                if key is not None:

                    keys.append(key + [fingerprint])

                key = l.split(b" ", 2)

                fingerprint = None

        if key is not None:

            keys.append(key + [fingerprint])

        return keys

def newgpg(ui, **opts):

    """create a new gpg instance"""

    gpgpath = ui.config(b"gpg", b"cmd")

    gpgkey = opts.get('key')

    if not gpgkey:

        gpgkey = ui.config(b"gpg", b"key")

    return gpg(gpgpath, gpgkey)

def sigwalk(repo):

    """

    walk over every sigs, yields a couple

    ((node, version, sig), (filename, linenumber))

    """

    def parsefile(fileiter, context):

        ln = 1

        for l in fileiter:

            if not l:

                continue

            yield (l.split(b" ", 2), (context, ln))

            ln += 1

    # read the heads

    fl = repo.file(b".hgsigs")

    for r in reversed(fl.heads()):

        fn = b".hgsigs|%s" % short(r)

        for item in parsefile(fl.read(r).splitlines(), fn):

            yield item

    try:

        # read local signatures

        fn = b"localsigs"

        for item in parsefile(repo.vfs(fn), fn):

            yield item

    except IOError:

        pass

def getkeys(ui, repo, mygpg, sigdata, context):

    """get the keys who signed a data"""

    fn, ln = context

    node, version, sig = sigdata

    prefix = b"%s:%d" % (fn, ln)

    node = bin(node)

    data = node2txt(repo, node, version)

    sig = binascii.a2b_base64(sig)

    keys = mygpg.verify(data, sig)

    validkeys = []

    # warn for expired key and/or sigs

    for key in keys:

        if key[0] == b"ERRSIG":

            ui.write(_(b"%s Unknown key ID \"%s\"\n") % (prefix, key[1]))

            continue

        if key[0] == b"BADSIG":

            ui.write(_(b"%s Bad signature from \"%s\"\n") % (prefix, key[2]))

            continue

        if key[0] == b"EXPSIG":

            ui.write(

                _(b"%s Note: Signature has expired (signed by: \"%s\")\n")

                % (prefix, key[2])

            )

        elif key[0] == b"EXPKEYSIG":

            ui.write(

                _(b"%s Note: This key has expired (signed by: \"%s\")\n")

                % (prefix, key[2])

            )

        validkeys.append((key[1], key[2], key[3]))

    return validkeys

@command(b"sigs", [], _(b'hg sigs'), helpcategory=_HELP_CATEGORY)

def sigs(ui, repo):

    """list signed changesets"""

    mygpg = newgpg(ui)

    revs = {}

    for data, context in sigwalk(repo):

        node, version, sig = data

        fn, ln = context

        try:

            n = repo.lookup(node)

        except KeyError:

            ui.warn(_(b"%s:%d node does not exist\n") % (fn, ln))

            continue

        r = repo.changelog.rev(n)

        keys = getkeys(ui, repo, mygpg, data, context)

        if not keys:

            continue

        revs.setdefault(r, [])

        revs[r].extend(keys)

    for rev in sorted(revs, reverse=True):

        for k in revs[rev]:

            r = b"%5d:%s" % (rev, hex(repo.changelog.node(rev)))

            ui.write(b"%-30s %s\n" % (keystr(ui, k), r))

@command(b"sigcheck", [], _(b'hg sigcheck REV'), helpcategory=_HELP_CATEGORY)

def sigcheck(ui, repo, rev):

    """verify all the signatures there may be for a particular revision"""

    mygpg = newgpg(ui)

    rev = repo.lookup(rev)

    hexrev = hex(rev)

    keys = []

    for data, context in sigwalk(repo):

        node, version, sig = data

        if node == hexrev:

            k = getkeys(ui, repo, mygpg, data, context)

            if k:

                keys.extend(k)

    if not keys:

        ui.write(_(b"no valid signature for %s\n") % short(rev))

        return

    # print summary

    ui.write(_(b"%s is signed by:\n") % short(rev))

    for key in keys:

        ui.write(b" %s\n" % keystr(ui, key))

def keystr(ui, key):

    """associate a string to a key (username, comment)"""

    keyid, user, fingerprint = key

    comment = ui.config(b"gpg", fingerprint)

    if comment:

        return b"%s (%s)" % (user, comment)

    else:

        return user

@command(

    b"sign",

    [

        (b'l', b'local', None, _(b'make the signature local')),

        (b'f', b'force', None, _(b'sign even if the sigfile is modified')),

        (

            b'',

            b'no-commit',

            None,

            _(b'do not commit the sigfile after signing'),

        ),

        (b'k', b'key', b'', _(b'the key id to sign with'), _(b'ID')),

        (b'm', b'message', b'', _(b'use text as commit message'), _(b'TEXT')),

        (b'e', b'edit', False, _(b'invoke editor on commit messages')),

    ]

    + cmdutil.commitopts2,

    _(b'hg sign [OPTION]... [REV]...'),

    helpcategory=_HELP_CATEGORY,

)

def sign(ui, repo, *revs, **opts):

    """add a signature for the current or given revision

    If no revision is given, the parent of the working directory is used,

    or tip if no revision is checked out.

    The ``gpg.cmd`` config setting can be used to specify the command

    to run. A default key can be specified with ``gpg.key``.

    See :hg:`help dates` for a list of formats valid for -d/--date.

    """

    with repo.wlock():

        return _dosign(ui, repo, *revs, **opts)

def _dosign(ui, repo, *revs, **opts):

    mygpg = newgpg(ui, **opts)

    opts = pycompat.byteskwargs(opts)

    sigver = b"0"

    sigmessage = b""

    date = opts.get(b'date')

    if date:

        opts[b'date'] = dateutil.parsedate(date)

    if revs:

        nodes = [repo.lookup(n) for n in revs]

    else:

        nodes = [node for node in repo.dirstate.parents() if node != nullid]

        if len(nodes) > 1:

            raise error.Abort(

                _(b'uncommitted merge - please provide a specific revision')

            )

        if not nodes:

            nodes = [repo.changelog.tip()]

    for n in nodes:

        hexnode = hex(n)

        ui.write(_(b"signing %d:%s\n") % (repo.changelog.rev(n), short(n)))

        # build data

        data = node2txt(repo, n, sigver)

        sig = mygpg.sign(data)

        if not sig:

            raise error.Abort(_(b"error while signing"))

        sig = binascii.b2a_base64(sig)

        sig = sig.replace(b"\n", b"")

        sigmessage += b"%s %s %s\n" % (hexnode, sigver, sig)

    # write it

    if opts[b'local']:

        repo.vfs.append(b"localsigs", sigmessage)

        return

    if not opts[b"force"]:

        msigs = match.exact([b'.hgsigs'])

        if any(repo.status(match=msigs, unknown=True, ignored=True)):

            raise error.Abort(

                _(b"working copy of .hgsigs is changed "),

                hint=_(b"please commit .hgsigs manually"),

            )

    sigsfile = repo.wvfs(b".hgsigs", b"ab")

    sigsfile.write(sigmessage)

    sigsfile.close()

    if b'.hgsigs' not in repo.dirstate:

        repo[None].add([b".hgsigs"])

    if opts[b"no_commit"]:

        return

    message = opts[b'message']

    if not message:

        # we don't translate commit messages

        message = b"\n".join(

            [b"Added signature for changeset %s" % short(n) for n in nodes]

        )