# -*- coding: utf-8 -*-

# 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 3 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, 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()

    return idstring

def as_html(table_class='code-difftable', line_class='line',

            old_lineno_class='lineno old', new_lineno_class='lineno new',

            no_lineno_class='lineno',

            code_class='code', enable_comments=False, parsed_lines=None):

    """

    Return given diff as html table with customized css classes

    """

    def _link_to_if(condition, label, url):

        """

        Generates a link if condition is meet or just the label if not.

        """

        if condition:

            return '''<a href="%(url)s">%(label)s</a>''' % {

                'url': url,

                'label': label

            }

        else:

            return label

    _html_empty = True

    _html = []

    _html.append('''<table class="%(table_class)s">\n''' % {

        'table_class': table_class

    })

    for diff in parsed_lines:

        for line in diff['chunks']:

            _html_empty = False

            for change in line:

                _html.append('''<tr class="%(lc)s %(action)s">\n''' % {

                    'lc': line_class,

                    'action': change['action']

                })

                anchor_old_id = ''

                anchor_new_id = ''

                anchor_old = "%(filename)s_o%(oldline_no)s" % {

                    'filename': _safe_id(diff['filename']),

                    'oldline_no': change['old_lineno']

                }

                anchor_new = "%(filename)s_n%(oldline_no)s" % {

                    'filename': _safe_id(diff['filename']),

                    'oldline_no': change['new_lineno']

                }

                cond_old = (change['old_lineno'] != '...' and

                            change['old_lineno'])

                cond_new = (change['new_lineno'] != '...' and

                            change['new_lineno'])

                no_lineno = (change['old_lineno'] == '...' and

                             change['new_lineno'] == '...')

                if cond_old:

                    anchor_old_id = 'id="%s"' % anchor_old

                if cond_new:

                    anchor_new_id = 'id="%s"' % anchor_new

                ###########################################################

                # OLD LINE NUMBER

                ###########################################################

                _html.append('''\t<td %(a_id)s class="%(olc)s" %(colspan)s>''' % {

                    'a_id': anchor_old_id,

                    'olc': no_lineno_class if no_lineno else old_lineno_class,

                    'colspan': 'colspan="2"' if no_lineno else ''

                })

                _html.append('''%(link)s''' % {

                    'link': _link_to_if(not no_lineno, change['old_lineno'],

                                        '#%s' % anchor_old)

                })

                _html.append('''</td>\n''')

                ###########################################################

                # NEW LINE NUMBER

                ###########################################################

                if not no_lineno:

                    _html.append('''\t<td %(a_id)s class="%(nlc)s">''' % {

                        'a_id': anchor_new_id,

                        'nlc': new_lineno_class

                    })

                    _html.append('''%(link)s''' % {

                        'link': _link_to_if(True, change['new_lineno'],

                                            '#%s' % anchor_new)

                    })

                    _html.append('''</td>\n''')

                ###########################################################

                # CODE

                ###########################################################

                comments = '' if enable_comments else 'no-comment'

                _html.append('''\t<td class="%(cc)s %(inc)s">''' % {

                    'cc': code_class,

                    'inc': comments

                })

                _html.append('''\n\t\t<div class="add-bubble"><div>&nbsp;</div></div><pre>%(code)s</pre>\n''' % {

                    'code': change['line']

                })

                _html.append('''\t</td>''')

                _html.append('''\n</tr>\n''')

    _html.append('''</table>''')

    if _html_empty:

        return None

    return ''.join(_html)

def wrap_to_table(html):

    """Given a string with html, return it wrapped in a table, similar to what

    DiffProcessor returns."""

    return '''\

              <table class="code-difftable">

                <tr class="line no-comment">

                <td class="lineno new"></td>

                <td class="code no-comment"><pre>%s</pre></td>

                </tr>

              </table>''' % html

def wrapped_diff(filenode_old, filenode_new, diff_limit=None,

                ignore_whitespace=True, line_context=3,

                enable_comments=False):

    """

    Returns a file diff wrapped into a table.

    Checks for diff_limit and presents a message if the diff is too big.

    """

    if filenode_old is None:

        filenode_old = FileNode(filenode_new.path, '', EmptyChangeset())

    op = None

    a_path = filenode_old.path # default, might be overriden by actual rename in diff

    if filenode_old.is_binary or filenode_new.is_binary:

        html_diff = wrap_to_table(_('Binary file'))

        stats = (0, 0)

    elif diff_limit != -1 and (

            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"

            based on that parameter cut off will be triggered, set to None

            to show full diff

        """

        if not isinstance(diff, basestring):

            raise Exception('Diff must be a basestring got %s instead' % type(diff))

        self._diff = diff

        self.adds = 0

        self.removes = 0

        self.diff_limit = diff_limit

        self.limited_diff = False

        self.vcs = vcs

        self.parsed = self._parse_gitdiff(inline_diff=inline_diff)

    def _parse_gitdiff(self, inline_diff):

        """Parse self._diff and return a list of dicts with meta info and chunks for each file.

        Might set limited_diff.

        Optionally, do an extra pass and to extra markup of one-liner changes.

        """

        _files = [] # list of dicts with meta info and chunks

        starts = [m.start() for m in self._diff_git_re.finditer(self._diff)]

        starts.append(len(self._diff))

        for start, end in zip(starts, starts[1:]):

            if self.diff_limit and end > self.diff_limit:

                self.limited_diff = True

                continue

            head, diff_lines = _get_header(self.vcs, buffer(self._diff, start, end - start))

            op = None

            stats = {

                'added': 0,

                'deleted': 0,

                'binary': False,

                'ops': {},

            }

            if head['deleted_file_mode']:

                op = 'D'

                stats['binary'] = True

                stats['ops'][DEL_FILENODE] = 'deleted file'

            elif head['new_file_mode']:

                op = 'A'

                stats['binary'] = True

                stats['ops'][NEW_FILENODE] = 'new file %s' % head['new_file_mode']

            else:  # modify operation, can be cp, rename, chmod

                # CHMOD

                if head['new_mode'] and head['old_mode']:

                    op = 'M'

                    stats['binary'] = True

                    stats['ops'][CHMOD_FILENODE] = ('modified file chmod %s => %s'

                                        % (head['old_mode'], head['new_mode']))

                # RENAME

                if (head['rename_from'] and head['rename_to']

                      and head['rename_from'] != head['rename_to']):

                    op = 'R'

                    stats['binary'] = True

                    stats['ops'][RENAMED_FILENODE] = ('file renamed from %s to %s'

                                    % (head['rename_from'], head['rename_to']))

                # COPY

                if head.get('copy_from') and head.get('copy_to'):

                    op = 'M'

                    stats['binary'] = True

                    stats['ops'][COPIED_FILENODE] = ('file copied from %s to %s'

                                        % (head['copy_from'], head['copy_to']))

                # FALL BACK: detect missed old style add or remove

                if op is None:

                    if not head['a_file'] and head['b_file']:

                        op = 'A'