# -*- coding: utf-8 -*-
#
# Copyright 2010-2017 The pygit2 contributors
#
# This file is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License, version 2,
# as published by the Free Software Foundation.
#
# In addition to the permissions in the GNU General Public License,
# the authors give you unlimited permission to link the compiled
# version of this file into combinations with other programs,
# and to distribute those combinations without any restriction
# coming from the use of this file.  (The General Public License
# restrictions do apply in other respects; for example, they cover
# modification of the file, and distribution when not linked into
# a combined executable.)
#
# This file is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; see the file COPYING.  If not, write to
# the Free Software Foundation, 51 Franklin Street, Fifth Floor,
# Boston, MA 02110-1301, USA.

# Import from the future
from __future__ import absolute_import

# Import from pygit2
from _pygit2 import Oid
from .errors import check_error, Passthrough
from .ffi import ffi, C
from .refspec import Refspec
from .utils import to_bytes, strarray_to_strings, StrArray


def maybe_string(ptr):
    if not ptr:
        return None

    return ffi.string(ptr).decode()


class TransferProgress(object):
    """Progress downloading and indexing data during a fetch"""

    def __init__(self, tp):

        self.total_objects = tp.total_objects
        """Total number of objects to download"""

        self.indexed_objects = tp.indexed_objects
        """Objects which have been indexed"""

        self.received_objects = tp.received_objects
        """Objects which have been received up to now"""

        self.local_objects = tp.local_objects
        """Local objects which were used to fix the thin pack"""

        self.total_deltas = tp.total_deltas
        """Total number of deltas in the pack"""

        self.indexed_deltas = tp.indexed_deltas
        """Deltas which have been indexed"""

        self.received_bytes = tp.received_bytes
        """"Number of bytes received up to now"""


class RemoteCallbacks(object):
    """Base class for pygit2 remote callbacks.

    Inherit from this class and override the callbacks which you want to use
    in your class, which you can then pass to the network operations.
    """

    def __init__(self, credentials=None, certificate=None):
        """Initialize some callbacks in-line

        Use this constructor to provide credentials and certificate
        callbacks in-line, instead of defining your own class for these ones.

        You can e.g. also pass in one of the credential objects as 'credentials'
        instead of creating a function which returns a hard-coded object.
        """

        if credentials is not None:
            self.credentials = credentials
        if certificate is not None:
            self.certificate = certificate

    def sideband_progress(self, string):
        """
        Progress output callback.  Override this function with your own
        progress reporting function

        Parameters:

        string : str
            Progress output from the remote.
        """

    def credentials(self, url, username_from_url, allowed_types):
        """
        Credentials callback.  If the remote server requires authentication,
        this function will be called and its return value used for
        authentication. Override it if you want to be able to perform
        authentication.

        Returns: credential

        Parameters:

        url : str
            The url of the remote.

        username_from_url : str or None
            Username extracted from the url, if any.

        allowed_types : int
            Credential types supported by the remote.
        """
        raise Passthrough

    def certificate_check(self, certificate, valid, host):
        """
        Certificate callback. Override with your own function to determine
        whether the accept the server's certificate.

        Returns: True to connect, False to abort.

        Parameters:

        certificate : None
            The certificate. It is currently always None while we figure out
            how to represent it cross-platform.

        valid : bool
            Whether the TLS/SSH library thinks the certificate is valid.

        host : str
            The hostname we want to connect to.
        """

        raise Passthrough

    def transfer_progress(self, stats):
        """
        Transfer progress callback. Override with your own function to report
        transfer progress.

        Parameters:

        stats : TransferProgress
            The progress up to now.
        """

    def update_tips(self, refname, old, new):
        """
        Update tips callabck. Override with your own function to report
        reference updates.

        Parameters:

        refname : str
            The name of the reference that's being updated.

        old : Oid
            The reference's old value.

        new : Oid
            The reference's new value.
        """

    def push_update_reference(self, refname, message):
        """
        Push update reference callback. Override with your own function to
        report the remote's acceptace or rejection of reference updates.

        refname : str
            The name of the reference (on the remote).

        messsage : str
            Rejection message from the remote. If None, the update was accepted.
        """

    def _fill_fetch_options(self, fetch_opts):
        fetch_opts.callbacks.sideband_progress = self._sideband_progress_cb
        fetch_opts.callbacks.transfer_progress = self._transfer_progress_cb
        fetch_opts.callbacks.update_tips = self._update_tips_cb
        fetch_opts.callbacks.credentials = self._credentials_cb
        fetch_opts.callbacks.certificate_check = self._certificate_cb
        # We need to make sure that this handle stays alive
        self._self_handle = ffi.new_handle(self)
        fetch_opts.callbacks.payload = self._self_handle

        self._stored_exception = None

    def _fill_push_options(self, push_opts):
        push_opts.callbacks.sideband_progress = self._sideband_progress_cb
        push_opts.callbacks.transfer_progress = self._transfer_progress_cb
        push_opts.callbacks.update_tips = self._update_tips_cb
        push_opts.callbacks.credentials = self._credentials_cb
        push_opts.callbacks.certificate_check = self._certificate_cb
        push_opts.callbacks.push_update_reference = self._push_update_reference_cb
        # We need to make sure that this handle stays alive
        self._self_handle = ffi.new_handle(self)
        push_opts.callbacks.payload = self._self_handle

    # These functions exist to be called by the git_remote as
    # callbacks. They proxy the call to whatever the user set

    @ffi.callback('git_transfer_progress_cb')
    def _transfer_progress_cb(stats_ptr, data):
        self = ffi.from_handle(data)

        transfer_progress = getattr(self, 'transfer_progress', None)
        if not transfer_progress:
            return 0

        try:
            transfer_progress(TransferProgress(stats_ptr))
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

    @ffi.callback('git_transport_message_cb')
    def _sideband_progress_cb(string, length, data):
        self = ffi.from_handle(data)

        progress = getattr(self, 'progress', None)
        if not progress:
            return 0

        try:
            s = ffi.string(string, length).decode()
            progress(s)
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

    @ffi.callback('int (*update_tips)(const char *refname, const git_oid *a,'
                  'const git_oid *b, void *data)')
    def _update_tips_cb(refname, a, b, data):
        self = ffi.from_handle(data)

        update_tips = getattr(self, 'update_tips', None)
        if not update_tips:
            return 0

        try:
            s = maybe_string(refname)
            a = Oid(raw=bytes(ffi.buffer(a)[:]))
            b = Oid(raw=bytes(ffi.buffer(b)[:]))

            update_tips(s, a, b)
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

    @ffi.callback("int (*push_update_reference)(const char *ref, const char *msg, void *data)")
    def _push_update_reference_cb(ref, msg, data):
        self = ffi.from_handle(data)

        push_update_reference = getattr(self, 'push_update_reference', None)
        if not push_update_reference:
            return 0

        try:
            refname = ffi.string(ref)
            message = maybe_string(msg)
            push_update_reference(refname, message)
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

    @ffi.callback('int (*credentials)(git_cred **cred, const char *url,'
                  'const char *username_from_url, unsigned int allowed_types,'
                  'void *data)')
    def _credentials_cb(cred_out, url, username, allowed, data):
        self = ffi.from_handle(data)

        credentials = getattr(self, 'credentials', None)
        if not credentials:
            return 0

        try:
            ccred = get_credentials(credentials, url, username, allowed)
            cred_out[0] = ccred[0]
        except Passthrough as e:
            return C.GIT_PASSTHROUGH
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

    @ffi.callback('int (*git_transport_certificate_check_cb)'
                  '(git_cert *cert, int valid, const char *host, void *payload)')
    def _certificate_cb(cert_i, valid, host, data):
        self = ffi.from_handle(data)

        # We want to simulate what should happen if libgit2 supported pass-through for
        # this callback. For SSH, 'valid' is always False, because it doesn't look
        # at known_hosts, but we do want to let it through in order to do what libgit2 would
        # if the callback were not set.
        try:
            is_ssh = cert_i.cert_type == C.GIT_CERT_HOSTKEY_LIBSSH2

            certificate_check = getattr(self, 'certificate_check', None)
            if not certificate_check:
                raise Passthrough

            # python's parsing is deep in the libraries and assumes an OpenSSL-owned cert
            val = certificate_check(None, bool(valid), ffi.string(host))
            if not val:
                return C.GIT_ECERTIFICATE
        except Passthrough as e:
            if is_ssh:
                return 0
            elif valid:
                return 0
            else:
                return C.GIT_ECERTIFICATE
        except Exception as e:
            self._stored_exception = e
            return C.GIT_EUSER

        return 0

class Remote(object):
    def __init__(self, repo, ptr):
        """The constructor is for internal use only"""

        self._repo = repo
        self._remote = ptr
        self._stored_exception = None

    def __del__(self):
        C.git_remote_free(self._remote)

    @property
    def name(self):
        """Name of the remote"""

        return maybe_string(C.git_remote_name(self._remote))

    @property
    def url(self):
        """Url of the remote"""

        return maybe_string(C.git_remote_url(self._remote))

    @property
    def push_url(self):
        """Push url of the remote"""

        return maybe_string(C.git_remote_pushurl(self._remote))

    def save(self):
        """Save a remote to its repository's configuration."""

        err = C.git_remote_save(self._remote)
        check_error(err)

    def fetch(self, refspecs=None, message=None, callbacks=None, prune=C.GIT_FETCH_PRUNE_UNSPECIFIED):
        """Perform a fetch against this remote. Returns a <TransferProgress>
        object.

        Parameters:

        prune : enum
            Either <GIT_FETCH_PRUNE_UNSPECIFIED>, <GIT_FETCH_PRUNE>, or
            <GIT_FETCH_NO_PRUNE>. The first uses the configuration from the
            repo, the second will remove any remote branch in the local
            repository that does not exist in the remote and the last will
            always keep the remote branches
        """

        fetch_opts = ffi.new('git_fetch_options *')
        err = C.git_fetch_init_options(fetch_opts, C.GIT_FETCH_OPTIONS_VERSION)

        if callbacks is None:
            callbacks = RemoteCallbacks()

        callbacks._fill_fetch_options(fetch_opts)
        fetch_opts.prune = prune

        try:
            with StrArray(refspecs) as arr:
                err = C.git_remote_fetch(self._remote, arr, fetch_opts, to_bytes(message))
                if callbacks._stored_exception:
                    raise callbacks._stored_exception
                check_error(err)
        finally:
            callbacks._self_handle = None

        return TransferProgress(C.git_remote_stats(self._remote))

    @property
    def refspec_count(self):
        """Total number of refspecs in this remote"""

        return C.git_remote_refspec_count(self._remote)

    def get_refspec(self, n):
        """Return the <Refspec> object at the given position."""
        spec = C.git_remote_get_refspec(self._remote, n)
        return Refspec(self, spec)

    @property
    def fetch_refspecs(self):
        """Refspecs that will be used for fetching"""

        specs = ffi.new('git_strarray *')
        err = C.git_remote_get_fetch_refspecs(specs, self._remote)
        check_error(err)

        return strarray_to_strings(specs)

    @property
    def push_refspecs(self):
        """Refspecs that will be used for pushing"""

        specs = ffi.new('git_strarray *')
        err = C.git_remote_get_push_refspecs(specs, self._remote)
        check_error(err)

        return strarray_to_strings(specs)

    def push(self, specs, callbacks=None):
        """
        Push the given refspec to the remote. Raises ``GitError`` on protocol
        error or unpack failure.

        When the remote has a githook installed, that denies the reference this
        function will return successfully. Thus it is stronly recommended to
        install a callback, that implements
        :py:meth:`RemoteCallbacks.push_update_reference` and check the passed
        parameters for successfull operations.

        Parameters:

        specs : [str]
            Push refspecs to use.
        """
        push_opts = ffi.new('git_push_options *')
        err = C.git_push_init_options(push_opts, C.GIT_PUSH_OPTIONS_VERSION)

        if callbacks is None:
            callbacks = RemoteCallbacks()

        callbacks._fill_push_options(push_opts)
        # Build custom callback structure

        try:
            with StrArray(specs) as refspecs:
                err = C.git_remote_push(self._remote, refspecs, push_opts)
                check_error(err)
        finally:
            callbacks._self_handle = None

def get_credentials(fn, url, username, allowed):
    """Call fn and return the credentials object"""

    url_str = maybe_string(url)
    username_str = maybe_string(username)

    creds = fn(url_str, username_str, allowed)

    credential_type = getattr(creds, 'credential_type', None)
    credential_tuple = getattr(creds, 'credential_tuple', None)
    if not credential_type or not credential_tuple:
        raise TypeError("credential does not implement interface")

    cred_type = credential_type

    if not (allowed & cred_type):
        raise TypeError("invalid credential type")

    ccred = ffi.new('git_cred **')
    if cred_type == C.GIT_CREDTYPE_USERPASS_PLAINTEXT:
        name, passwd = credential_tuple
        err = C.git_cred_userpass_plaintext_new(ccred, to_bytes(name),
                                                to_bytes(passwd))

    elif cred_type == C.GIT_CREDTYPE_SSH_KEY:
        name, pubkey, privkey, passphrase = credential_tuple
        if pubkey is None and privkey is None:
            err = C.git_cred_ssh_key_from_agent(ccred, to_bytes(name))
        else:
            err = C.git_cred_ssh_key_new(ccred, to_bytes(name),
                                         to_bytes(pubkey), to_bytes(privkey),
                                         to_bytes(passphrase))

    elif cred_type == C.GIT_CREDTYPE_USERNAME:
        name, = credential_tuple
        err = C.git_cred_username_new(ccred, to_bytes(name))

    else:
        raise TypeError("unsupported credential type")

    check_error(err)

    return ccred

class RemoteCollection(object):
    """Collection of configured remotes

    You can use this class to look up and manage the remotes configured
    in a repository.  You can access repositories using index
    access. E.g. to look up the "origin" remote, you can use

    >>> repo.remotes["origin"]
    """

    def __init__(self, repo):
        self._repo = repo;

    def __len__(self):
        names = ffi.new('git_strarray *')

        try:
            err = C.git_remote_list(names, self._repo._repo)
            check_error(err)

            return names.count
        finally:
            C.git_strarray_free(names)

    def __iter__(self):
        names = ffi.new('git_strarray *')

        try:
            err = C.git_remote_list(names, self._repo._repo)
            check_error(err)

            cremote = ffi.new('git_remote **')
            for i in range(names.count):
                err = C.git_remote_lookup(cremote, self._repo._repo, names.strings[i])
                check_error(err)

                yield Remote(self._repo, cremote[0])
        finally:
            C.git_strarray_free(names)

    def __getitem__(self, name):
        if isinstance(name, int):
            return list(self)[name]

        cremote = ffi.new('git_remote **')
        err = C.git_remote_lookup(cremote, self._repo._repo, to_bytes(name))
        check_error(err)

        return Remote(self._repo, cremote[0])

    def create(self, name, url, fetch=None):
        """Create a new remote with the given name and url. Returns a <Remote>
        object.

        If 'fetch' is provided, this fetch refspec will be used instead of the default
        """

        cremote = ffi.new('git_remote **')

        if fetch:
            err = C.git_remote_create_with_fetchspec(cremote, self._repo._repo, to_bytes(name), to_bytes(url), to_bytes(fetch))
        else:
            err = C.git_remote_create(cremote, self._repo._repo, to_bytes(name), to_bytes(url))

        check_error(err)

        return Remote(self._repo, cremote[0])

    def rename(self, name, new_name):
        """Rename a remote in the configuration. The refspecs in standard
        format will be renamed.

        Returns a list of fetch refspecs (list of strings) which were not in
        the standard format and thus could not be remapped.
        """

        if not new_name:
            raise ValueError("Current remote name must be a non-empty string")

        if not new_name:
            raise ValueError("New remote name must be a non-empty string")

        problems = ffi.new('git_strarray *')
        err = C.git_remote_rename(problems, self._repo._repo, to_bytes(name), to_bytes(new_name))
        check_error(err)

        ret = strarray_to_strings(problems)
        C.git_strarray_free(problems)

        return ret

    def delete(self, name):
        """Remove a remote from the configuration

        All remote-tracking branches and configuration settings for the remote will be removed.
        """
        err = C.git_remote_delete(self._repo._repo, to_bytes(name))
        check_error(err)

    def set_url(self, name, url):
        """ Set the URL for a remote
        """
        err = C.git_remote_set_url(self._repo._repo, to_bytes(name), to_bytes(url))
        check_error(err)

    def set_push_url(self, name, url):
        """Set the push-URL for a remote
        """
        err = C.git_remote_set_pushurl(self._repo._repo, to_bytes(name), to_bytes(url))
        check_error(err)

    def add_fetch(self, name, refspec):
        """Add a fetch refspec (str) to the remote
        """

        err = C.git_remote_add_fetch(self._repo._repo, to_bytes(name), to_bytes(refspec))
        check_error(err)

    def add_push(self, name, refspec):
        """Add a push refspec (str) to the remote
        """

        err = C.git_remote_add_push(self._repo._repo, to_bytes(name), to_bytes(refspec))
        check_error(err)
