# -*- 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/>.
"""
rhodecode.controllers.compare
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compare controller for pylons showing differences between two
repos, branches, bookmarks or tips

:created_on: May 6, 2012
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH.
:license: GPLv3, see LICENSE for more details.
"""


import logging
import traceback
import re

from webob.exc import HTTPNotFound, HTTPBadRequest
from pylons import request, response, session, tmpl_context as c, url
from pylons.controllers.util import abort, redirect
from pylons.i18n.translation import _

from rhodecode.lib.vcs.exceptions import EmptyRepositoryError, RepositoryError
from rhodecode.lib.vcs.utils import safe_str
from rhodecode.lib.vcs.utils.hgcompat import unionrepo
from rhodecode.lib import helpers as h
from rhodecode.lib.base import BaseRepoController, render
from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator
from rhodecode.lib import diffs
from rhodecode.model.db import Repository
from rhodecode.lib.diffs import LimitedDiffContainer


log = logging.getLogger(__name__)


class CompareController(BaseRepoController):

    def __before__(self):
        super(CompareController, self).__before__()

    def __get_rev_or_redirect(self, ref, repo, redirect_after=True,
                              partial=False):
        """
        Safe way to get changeset if error occur it redirects to changeset with
        proper message. If partial is set then don't do redirect raise Exception
        instead

        :param ref:
        :param repo:
        :param redirect_after:
        :param partial:
        """
        rev = ref[1] # default and used for git
        if repo.scm_instance.alias == 'hg':
            # lookup up the exact node id
            _revset_predicates = {
                    'branch': 'branch',
                    'book': 'bookmark',
                    'tag': 'tag',
                    'rev': 'id',
                }
            rev_spec = "max(%s(%%s))" % _revset_predicates[ref[0]]
            revs = repo.scm_instance._repo.revs(rev_spec, safe_str(ref[1]))
            if revs:
                rev = revs[-1]
            # else: TODO: just report 'not found'

        try:
            return repo.scm_instance.get_changeset(rev).raw_id
        except EmptyRepositoryError, e:
            if not redirect_after:
                return None
            h.flash(h.literal(_('There are no changesets yet')),
                    category='warning')
            redirect(url('summary_home', repo_name=repo.repo_name))

        except RepositoryError, e:
            log.error(traceback.format_exc())
            h.flash(safe_str(e), category='warning')
            if not partial:
                redirect(h.url('summary_home', repo_name=repo.repo_name))
            raise HTTPBadRequest()

    def _get_changesets(self, alias, org_repo, org_rev, other_repo, other_rev, merge):
        """
        Returns a list of changesets that can be merged from org_repo at org_rev
        to other_repo at other_rev ... and the ancestor that would be used for merge.

        :param org_repo: repo object, that is most likely the orginal repo we forked from
        :param org_rev: the revision we want our compare to be made
        :param other_repo: repo object, mostl likely the fork of org_repo. It hass
            all changesets that we need to obtain
        :param other_rev: revision we want out compare to be made on other_repo

        """
        ancestor = None
        if org_rev == other_rev:
            changesets = []
            if merge:
                ancestor = org_rev

        elif alias == 'hg':
            #case two independent repos
            if org_repo != other_repo:
                hgrepo = unionrepo.unionrepository(other_repo.baseui,
                                                   other_repo.path,
                                                   org_repo.path)
                # all the changesets we are looking for will be in other_repo,
                # so rev numbers from hgrepo can be used in other_repo

            #no remote compare do it on the same repository
            else:
                hgrepo = other_repo._repo

            if merge:
                revs = hgrepo.revs(
                    "ancestors(id(%s)) and not ancestors(id(%s)) and not id(%s)",
                    other_rev, org_rev, org_rev)

                ancestors = hgrepo.revs("ancestor(id(%s), id(%s))", org_rev,
                                        other_rev)
                if ancestors:
                    # pick arbitrary ancestor - but there is usually only one
                    ancestor = hgrepo[ancestors[0]].hex()
            else:
                # TODO: have both + and - changesets
                revs = hgrepo.revs("id(%s) :: id(%s) - id(%s)",
                                   org_rev, other_rev, org_rev)

            changesets = [other_repo.get_changeset(rev) for rev in revs]

        elif alias == 'git':
            if org_repo != other_repo:
                from dulwich.repo import Repo
                from dulwich.client import SubprocessGitClient

                gitrepo = Repo(org_repo.path)
                SubprocessGitClient(thin_packs=False).fetch(other_repo.path, gitrepo)

                gitrepo_remote = Repo(other_repo.path)
                SubprocessGitClient(thin_packs=False).fetch(org_repo.path, gitrepo_remote)

                revs = []
                for x in gitrepo_remote.get_walker(include=[other_rev],
                                                   exclude=[org_rev]):
                    revs.append(x.commit.id)

                changesets = [other_repo.get_changeset(rev) for rev in reversed(revs)]
                if changesets:
                    ancestor = changesets[0].parents[0].raw_id
                else:
                    # no changesets from other repo, ancestor is the other_rev
                    ancestor = other_rev

            else:
                so, se = org_repo.run_git_command(
                    'log --reverse --pretty="format: %%H" -s %s..%s'
                        % (org_rev, other_rev)
                )
                changesets = [org_repo.get_changeset(cs)
                              for cs in re.findall(r'[0-9a-fA-F]{40}', so)]

        else:
            raise Exception('Bad alias only git and hg is allowed')

        return changesets, ancestor

    @LoginRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    def index(self, repo_name):
        c.compare_home = True
        org_repo = c.rhodecode_db_repo.repo_name
        other_repo = request.GET.get('other_repo', org_repo)
        c.org_repo = Repository.get_by_repo_name(org_repo)
        c.other_repo = Repository.get_by_repo_name(other_repo)
        c.org_ref = c.other_ref = _('Select changeset')
        return render('compare/compare_diff.html')

    @LoginRequired()
    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',
                                   'repository.admin')
    def compare(self, repo_name, org_ref_type, org_ref, other_ref_type, other_ref):
        # org_ref will be evaluated in org_repo
        org_repo = c.rhodecode_db_repo.repo_name
        org_ref = (org_ref_type, org_ref)
        # other_ref will be evaluated in other_repo
        other_ref = (other_ref_type, other_ref)
        other_repo = request.GET.get('other_repo', org_repo)
        # If merge is True:
        #   Show what org would get if merged with other:
        #   List changesets that are ancestors of other but not of org.
        #   New changesets in org is thus ignored.
        #   Diff will be from common ancestor, and merges of org to other will thus be ignored.
        # If merge is False:
        #   Make a raw diff from org to other, no matter if related or not.
        #   Changesets in one and not in the other will be ignored
        merge = bool(request.GET.get('merge'))
        # fulldiff disables cut_off_limit
        c.fulldiff = request.GET.get('fulldiff')
        # partial uses compare_cs.html template directly
        partial = request.environ.get('HTTP_X_PARTIAL_XHR')
        # as_form puts hidden input field with changeset revisions
        c.as_form = partial and request.GET.get('as_form')
        # swap url for compare_diff page - never partial and never as_form
        c.swap_url = h.url('compare_url',
            repo_name=other_repo,
            org_ref_type=other_ref[0], org_ref=other_ref[1],
            other_repo=org_repo,
            other_ref_type=org_ref[0], other_ref=org_ref[1],
            merge=merge or '')

        org_repo = Repository.get_by_repo_name(org_repo)
        other_repo = Repository.get_by_repo_name(other_repo)

        if org_repo is None:
            msg = 'Could not find org repo %s' % org_repo
            log.error(msg)
            h.flash(msg, category='error')
            return redirect(url('compare_home', repo_name=c.repo_name))

        if other_repo is None:
            msg = 'Could not find other repo %s' % other_repo
            log.error(msg)
            h.flash(msg, category='error')
            return redirect(url('compare_home', repo_name=c.repo_name))

        if org_repo.scm_instance.alias != other_repo.scm_instance.alias:
            msg = 'compare of two different kind of remote repos not available'
            log.error(msg)
            h.flash(msg, category='error')
            return redirect(url('compare_home', repo_name=c.repo_name))

        org_rev = self.__get_rev_or_redirect(ref=org_ref, repo=org_repo, partial=partial)
        other_rev = self.__get_rev_or_redirect(ref=other_ref, repo=other_repo, partial=partial)

        c.compare_home = False
        c.org_repo = org_repo
        c.other_repo = other_repo
        c.org_ref = org_ref[1]
        c.other_ref = other_ref[1]
        c.org_ref_type = org_ref[0]
        c.other_ref_type = other_ref[0]

        c.cs_ranges, c.ancestor = self._get_changesets(
            org_repo.scm_instance.alias, org_repo.scm_instance, org_rev,
            other_repo.scm_instance, other_rev, merge)
        c.statuses = c.rhodecode_db_repo.statuses(
            [x.raw_id for x in c.cs_ranges])

        if merge and not c.ancestor:
            log.error('Unable to find ancestor revision')

        if partial:
            return render('compare/compare_cs.html')
        if c.ancestor:
            assert merge
            # case we want a simple diff without incoming changesets,
            # previewing what will be merged.
            # Make the diff on the other repo (which is known to have other_ref)
            log.debug('Using ancestor %s as org_ref instead of %s'
                      % (c.ancestor, org_ref))
            org_rev = c.ancestor
            org_repo = other_repo

        diff_limit = self.cut_off_limit if not c.fulldiff else None

        log.debug('running diff between %s and %s in %s'
                  % (org_rev, other_rev, org_repo.scm_instance.path))

        txtdiff = org_repo.scm_instance.get_diff(rev1=org_rev, rev2=other_rev)
        diff_processor = diffs.DiffProcessor(txtdiff or '', format='gitdiff',
                                             diff_limit=diff_limit)
        _parsed = diff_processor.prepare()

        c.limited_diff = False
        if isinstance(_parsed, LimitedDiffContainer):
            c.limited_diff = True

        c.files = []
        c.changes = {}
        c.lines_added = 0
        c.lines_deleted = 0
        for f in _parsed:
            st = f['stats']
            if not st['binary']:
                c.lines_added += st['added']
                c.lines_deleted += st['deleted']
            fid = h.FID('', f['filename'])
            c.files.append([fid, f['operation'], f['filename'], f['stats']])
            htmldiff = diff_processor.as_html(enable_comments=False, parsed_lines=[f])
            c.changes[fid] = [f['operation'], f['filename'], htmldiff]

        return render('compare/compare_diff.html')