# Copyright (C) 2005-2011 Canonical Ltd
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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

# TODO: Some kind of command-line display of revision properties:
# perhaps show them in log -v and allow them as options to the commit command.


from .lazy_import import lazy_import
lazy_import(globals(), """
from breezy import bugtracker
""")
from . import (
    errors,
    osutils,
    )

NULL_REVISION = b"null:"
CURRENT_REVISION = b"current:"


class Revision(object):
    """Single revision on a branch.

    Revisions may know their revision_hash, but only once they've been
    written out.  This is not stored because you cannot write the hash
    into the file it describes.

    After bzr 0.0.5 revisions are allowed to have multiple parents.

    parent_ids
        List of parent revision_ids

    properties
        Dictionary of revision properties.  These are attached to the
        revision as extra metadata.  The name must be a single
        word; the value can be an arbitrary string.
    """

    def __init__(self, revision_id, properties=None, **args):
        self.revision_id = revision_id
        if properties is None:
            self.properties = {}
        else:
            self.properties = properties
            self._check_properties()
        self.committer = None
        self.parent_ids = []
        self.parent_sha1s = []
        """Not used anymore - legacy from for 4."""
        self.__dict__.update(args)

    def __repr__(self):
        return "<Revision id %s>" % self.revision_id

    def __eq__(self, other):
        if not isinstance(other, Revision):
            return False
        return (
            self.inventory_sha1 == other.inventory_sha1
            and self.revision_id == other.revision_id
            and self.timestamp == other.timestamp
            and self.message == other.message
            and self.timezone == other.timezone
            and self.committer == other.committer
            and self.properties == other.properties
            and self.parent_ids == other.parent_ids)

    def __ne__(self, other):
        return not self.__eq__(other)

    def _check_properties(self):
        """Verify that all revision properties are OK."""
        for name, value in self.properties.items():
            # GZ 2017-06-10: What sort of string are properties exactly?
            not_text = not isinstance(name, str)
            if not_text or osutils.contains_whitespace(name):
                raise ValueError("invalid property name %r" % name)
            if not isinstance(value, (str, bytes)):
                raise ValueError("invalid property value %r for %r" %
                                 (value, name))

    def get_history(self, repository):
        """Return the canonical line-of-history for this revision.

        If ghosts are present this may differ in result from a ghost-free
        repository.
        """
        current_revision = self
        reversed_result = []
        while current_revision is not None:
            reversed_result.append(current_revision.revision_id)
            if not len(current_revision.parent_ids):
                reversed_result.append(None)
                current_revision = None
            else:
                next_revision_id = current_revision.parent_ids[0]
                current_revision = repository.get_revision(next_revision_id)
        reversed_result.reverse()
        return reversed_result

    def get_summary(self):
        """Get the first line of the log message for this revision.

        Return an empty string if message is None.
        """
        if self.message:
            return self.message.lstrip().split('\n', 1)[0]
        else:
            return ''

    def get_apparent_authors(self):
        """Return the apparent authors of this revision.

        If the revision properties contain the names of the authors,
        return them. Otherwise return the committer name.

        The return value will be a list containing at least one element.
        """
        authors = self.properties.get('authors', None)
        if authors is None:
            author = self.properties.get('author', self.committer)
            if author is None:
                return []
            return [author]
        else:
            return authors.split("\n")

    def iter_bugs(self):
        """Iterate over the bugs associated with this revision."""
        bug_property = self.properties.get('bugs', None)
        if bug_property is None:
            return iter([])
        return bugtracker.decode_bug_urls(bug_property)


def iter_ancestors(revision_id, revision_source, only_present=False):
    ancestors = (revision_id,)
    distance = 0
    while len(ancestors) > 0:
        new_ancestors = []
        for ancestor in ancestors:
            if not only_present:
                yield ancestor, distance
            try:
                revision = revision_source.get_revision(ancestor)
            except errors.NoSuchRevision as e:
                if e.revision == revision_id:
                    raise
                else:
                    continue
            if only_present:
                yield ancestor, distance
            new_ancestors.extend(revision.parent_ids)
        ancestors = new_ancestors
        distance += 1


def find_present_ancestors(revision_id, revision_source):
    """Return the ancestors of a revision present in a branch.

    It's possible that a branch won't have the complete ancestry of
    one of its revisions.

    """
    found_ancestors = {}
    anc_iter = enumerate(iter_ancestors(revision_id, revision_source,
                                        only_present=True))
    for anc_order, (anc_id, anc_distance) in anc_iter:
        if anc_id not in found_ancestors:
            found_ancestors[anc_id] = (anc_order, anc_distance)
    return found_ancestors


def __get_closest(intersection):
    intersection.sort()
    matches = []
    for entry in intersection:
        if entry[0] == intersection[0][0]:
            matches.append(entry[2])
    return matches


def is_reserved_id(revision_id):
    """Determine whether a revision id is reserved

    :return: True if the revision is reserved, False otherwise
    """
    return isinstance(revision_id, bytes) and revision_id.endswith(b':')


def check_not_reserved_id(revision_id):
    """Raise ReservedId if the supplied revision_id is reserved"""
    if is_reserved_id(revision_id):
        raise errors.ReservedId(revision_id)


def ensure_null(revision_id):
    """Ensure only NULL_REVISION is used to represent the null revision"""
    if revision_id is None:
        raise ValueError(
            'NULL_REVISION should be used for the null'
            ' revision instead of None.')
    return revision_id


def is_null(revision_id):
    if revision_id is None:
        raise ValueError('NULL_REVISION should be used for the null'
                         ' revision instead of None.')
    return (revision_id == NULL_REVISION)
