# 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, see <http://www.gnu.org/licenses/>.

"""

kallithea.lib.diffs

~~~~~~~~~~~~~~~~~~~

Set of diffing helpers, previously part of vcs

This file was forked by the Kallithea project in July 2014.

Original author and date, and relevant copyright and licensing information is below:

:created_on: Dec 4, 2011

:author: marcink

:copyright: (c) 2013 RhodeCode GmbH, and others.

:license: GPLv3, see LICENSE.md for more details.

"""

import re

import difflib

import logging

from tg.i18n import ugettext as _

from kallithea.lib.vcs.exceptions import VCSError

from kallithea.lib.vcs.nodes import FileNode, SubModuleNode

from kallithea.lib.vcs.backends.base import EmptyChangeset

from kallithea.lib.utils2 import safe_unicode

log = logging.getLogger(__name__)

def _safe_id(idstring):

    """Make a string safe for including in an id attribute.

    The HTML spec says that id attributes 'must begin with

    a letter ([A-Za-z]) and may be followed by any number

    of letters, digits ([0-9]), hyphens ("-"), underscores

    ("_"), colons (":"), and periods (".")'. These regexps

    are slightly over-zealous, in that they remove colons

    and periods unnecessarily.

    Whitespace is transformed into underscores, and then

    anything which is not a hyphen or a character that

    matches \w (alphanumerics and underscore) is removed.

    """

    # Transform all whitespace to underscore

    idstring = re.sub(r'\s', "_", idstring)

    # Remove everything that is not a hyphen or a member of \w

    idstring = re.sub(r'(?!-)\W', "", idstring).lower()

            diff_limit is None or

            (filenode_old.size < diff_limit and filenode_new.size < diff_limit)):

        raw_diff = get_gitdiff(filenode_old, filenode_new,

                                ignore_whitespace=ignore_whitespace,

                                context=line_context)

        diff_processor = DiffProcessor(raw_diff)

        if diff_processor.parsed: # there should be exactly one element, for the specified file

            f = diff_processor.parsed[0]

            op = f['operation']

            a_path = f['old_filename']

        html_diff = as_html(parsed_lines=diff_processor.parsed, enable_comments=enable_comments)

        stats = diff_processor.stat()

    else:

        html_diff = wrap_to_table(_('Changeset was too big and was cut off, use '

                               'diff menu to display this diff'))

        stats = (0, 0)

    if not html_diff:

        submodules = filter(lambda o: isinstance(o, SubModuleNode),

                            [filenode_new, filenode_old])

        if submodules:

        else:

            html_diff = wrap_to_table(_('No changes detected'))

    cs1 = filenode_old.changeset.raw_id

    cs2 = filenode_new.changeset.raw_id

    return cs1, cs2, a_path, html_diff, stats, op

def get_gitdiff(filenode_old, filenode_new, ignore_whitespace=True, context=3):

    """

    Returns git style diff between given ``filenode_old`` and ``filenode_new``.

    """

    # make sure we pass in default context

    context = context or 3

    submodules = filter(lambda o: isinstance(o, SubModuleNode),

                        [filenode_new, filenode_old])

    if submodules:

        return ''

    for filenode in (filenode_old, filenode_new):

        if not isinstance(filenode, FileNode):

            raise VCSError("Given object should be FileNode object, not %s"

                % filenode.__class__)

    repo = filenode_new.changeset.repository

    old_raw_id = getattr(filenode_old.changeset, 'raw_id', repo.EMPTY_CHANGESET)

    new_raw_id = getattr(filenode_new.changeset, 'raw_id', repo.EMPTY_CHANGESET)

    vcs_gitdiff = get_diff(repo, old_raw_id, new_raw_id, filenode_new.path,

                           ignore_whitespace, context)

    return vcs_gitdiff

def get_diff(scm_instance, rev1, rev2, path=None, ignore_whitespace=False, context=3):

    """

    A thin wrapper around vcs lib get_diff.

    """

    return scm_instance.get_diff(rev1, rev2, path=path,

                                 ignore_whitespace=ignore_whitespace, context=context)

NEW_FILENODE = 1

DEL_FILENODE = 2

MOD_FILENODE = 3

RENAMED_FILENODE = 4

COPIED_FILENODE = 5

CHMOD_FILENODE = 6

BIN_FILENODE = 7

class DiffProcessor(object):

    """

    Give it a unified or git diff and it returns a list of the files that were

    mentioned in the diff together with a dict of meta information that

    can be used to render it in a HTML template.

    """

    _diff_git_re = re.compile('^diff --git', re.MULTILINE)

    def __init__(self, diff, vcs='hg', diff_limit=None, inline_diff=True):

        """

        :param diff:   a text in diff format

        :param vcs: type of version control hg or git

        :param diff_limit: define the size of diff that is considered "big"