# objectspec.py -- Object specification
# Copyright (C) 2014 Jelmer Vernooij <jelmer@samba.org>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2
# of the License or (at your option) a later version of the License.
#
# This program 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; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA  02110-1301, USA.

"""Object specification."""


def to_bytes(text):
    if getattr(text, "encode", None) is not None:
        text = text.encode('ascii')
    return text


def parse_object(repo, objectish):
    """Parse a string referring to an object.

    :param repo: A `Repo` object
    :param objectish: A string referring to an object
    :return: A git object
    :raise KeyError: If the object can not be found
    """
    objectish = to_bytes(objectish)
    return repo[objectish]


def parse_ref(container, refspec):
    """Parse a string referring to a reference.

    :param container: A RefsContainer object
    :param refspec: A string referring to a ref
    :return: A ref
    :raise KeyError: If the ref can not be found
    """
    refspec = to_bytes(refspec)
    for ref in [refspec, b"refs/heads/" + refspec]:
        if ref in container:
            return ref
    else:
        raise KeyError(refspec)


def parse_reftuple(lh_container, rh_container, refspec):
    """Parse a reftuple spec.

    :param lh_container: A RefsContainer object
    :param hh_container: A RefsContainer object
    :param refspec: A string
    :return: A tuple with left and right ref
    :raise KeyError: If one of the refs can not be found
    """
    if refspec.startswith(b"+"):
        force = True
        refspec = refspec[1:]
    else:
        force = False
    refspec = to_bytes(refspec)
    if b":" in refspec:
        (lh, rh) = refspec.split(b":")
    else:
        lh = rh = refspec
    if rh == b"":
        lh = None
    else:
        lh = parse_ref(lh_container, lh)
    if rh == b"":
        rh = None
    else:
        try:
            rh = parse_ref(rh_container, rh)
        except KeyError:
            # TODO: check force?
            if not b"/" in rh:
                rh = b"refs/heads/" + rh
    return (lh, rh, force)


def parse_reftuples(lh_container, rh_container, refspecs):
    """Parse a list of reftuple specs to a list of reftuples.

    :param lh_container: A RefsContainer object
    :param hh_container: A RefsContainer object
    :param refspecs: A list of refspecs or a string
    :return: A list of refs
    :raise KeyError: If one of the refs can not be found
    """
    if not isinstance(refspecs, list):
        refspecs = [refspecs]
    ret = []
    # TODO: Support * in refspecs
    for refspec in refspecs:
        ret.append(parse_reftuple(lh_container, rh_container, refspec))
    return ret


def parse_refs(container, refspecs):
    """Parse a list of refspecs to a list of refs.

    :param container: A RefsContainer object
    :param refspecs: A list of refspecs or a string
    :return: A list of refs
    :raise KeyError: If one of the refs can not be found
    """
    # TODO: Support * in refspecs
    if not isinstance(refspecs, list):
        refspecs = [refspecs]
    ret = []
    for refspec in refspecs:
        ret.append(parse_ref(container, refspec))
    return ret


def parse_commit_range(repo, committishs):
    """Parse a string referring to a range of commits.

    :param repo: A `Repo` object
    :param committishs: A string referring to a range of commits.
    :return: An iterator over `Commit` objects
    :raise KeyError: When the reference commits can not be found
    :raise ValueError: If the range can not be parsed
    """
    committishs = to_bytes(committishs)
    return iter([repo[committishs]])


def parse_commit(repo, committish):
    """Parse a string referring to a single commit.

    :param repo: A` Repo` object
    :param commitish: A string referring to a single commit.
    :return: A Commit object
    :raise KeyError: When the reference commits can not be found
    :raise ValueError: If the range can not be parsed
    """
    committish = to_bytes(committish)
    return repo[committish] # For now..