# -*- coding: utf-8 -*-
#
# Copyright (C) 2003-2009 Edgewall Software
# Copyright (C) 2003-2005 Jonas Borgström <jonas@edgewall.com>
# Copyright (C) 2004-2005 Christopher Lenz <cmlenz@gmx.de>
# Copyright (C) 2005-2006 Christian Boos <cboos@edgewall.org>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.org/wiki/TracLicense.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://trac.edgewall.org/log/.
#
# Author: Jonas Borgström <jonas@edgewall.com>
#         Christopher Lenz <cmlenz@gmx.de>

from datetime import datetime, timedelta
import pkg_resources
import re

from genshi.builder import tag

from trac.config import IntOption, BoolOption
from trac.core import *
from trac.mimeview import Context
from trac.perm import IPermissionRequestor
from trac.timeline.api import ITimelineEventProvider
from trac.util import as_int
from trac.util.datefmt import format_date, format_datetime, parse_date, \
                              to_utimestamp, to_datetime, utc, pretty_timedelta
from trac.util.text import exception_to_unicode, to_unicode
from trac.util.translation import _, tag_
from trac.web import IRequestHandler, IRequestFilter
from trac.web.chrome import add_link, add_stylesheet, prevnext_nav, Chrome, \
                            INavigationContributor, ITemplateProvider
                            
from trac.wiki.api import IWikiSyntaxProvider


class TimelineModule(Component):

    implements(INavigationContributor, IPermissionRequestor, IRequestHandler,
               IRequestFilter, ITemplateProvider, IWikiSyntaxProvider)

    event_providers = ExtensionPoint(ITimelineEventProvider)

    default_daysback = IntOption('timeline', 'default_daysback', 30,
        """Default number of days displayed in the Timeline, in days.
        (''since 0.9.'')""")

    max_daysback = IntOption('timeline', 'max_daysback', 90,
        """Maximum number of days (-1 for unlimited) displayable in the 
        Timeline. (''since 0.11'')""")

    abbreviated_messages = BoolOption('timeline', 'abbreviated_messages',
                                      True,
        """Whether wiki-formatted event messages should be truncated or not.

        This only affects the default rendering, and can be overriden by
        specific event providers, see their own documentation.
        (''Since 0.11'')""")

    _authors_pattern = re.compile(r'(-)?(?:"([^"]*)"|\'([^\']*)\'|([^\s]+))')

    # INavigationContributor methods

    def get_active_navigation_item(self, req):
        return 'timeline'

    def get_navigation_items(self, req):
        if 'TIMELINE_VIEW' in req.perm:
            yield ('mainnav', 'timeline',
                   tag.a(_('Timeline'), href=req.href.timeline(), accesskey=2))

    # IPermissionRequestor methods

    def get_permission_actions(self):
        return ['TIMELINE_VIEW']

    # IRequestHandler methods

    def match_request(self, req):
        return req.path_info == '/timeline'

    def process_request(self, req):
        req.perm.assert_permission('TIMELINE_VIEW')

        format = req.args.get('format')
        maxrows = int(req.args.get('max', format == 'rss' and 50 or 0))

        # Parse the from date and adjust the timestamp to the last second of
        # the day
        fromdate = today = datetime.now(req.tz)
        yesterday = to_datetime(today.replace(tzinfo=None) - timedelta(days=1),
                                req.tz)
        precisedate = precision = None
        if 'from' in req.args:
            # Acquire from date only from non-blank input
            reqfromdate = req.args['from'].strip()
            if reqfromdate:
                precisedate = parse_date(reqfromdate, req.tz)
                fromdate = precisedate.astimezone(req.tz)
            precision = req.args.get('precision', '')
            if precision.startswith('second'):
                precision = timedelta(seconds=1)
            elif precision.startswith('minute'):
                precision = timedelta(minutes=1)
            elif precision.startswith('hour'):
                precision = timedelta(hours=1)
            else:
                precision = None
        fromdate = to_datetime(datetime(fromdate.year, fromdate.month,
                                        fromdate.day, 23, 59, 59, 999999),
                               req.tz)

        daysback = as_int(req.args.get('daysback'),
                          format == 'rss' and 90 or None)
        if daysback is None:
            daysback = as_int(req.session.get('timeline.daysback'), None)
        if daysback is None:
            daysback = self.default_daysback
        daysback = max(0, daysback)
        if self.max_daysback >= 0:
            daysback = min(self.max_daysback, daysback)

        authors = req.args.get('authors')
        if authors is None and format != 'rss':
            authors = req.session.get('timeline.authors')
        authors = (authors or '').strip()

        data = {'fromdate': fromdate, 'daysback': daysback,
                'authors': authors,
                'today': format_date(today, tzinfo=req.tz),
                'yesterday': format_date(yesterday, tzinfo=req.tz),
                'precisedate': precisedate, 'precision': precision,
                'events': [], 'filters': [],
                'abbreviated_messages': self.abbreviated_messages}

        available_filters = []
        for event_provider in self.event_providers:
            available_filters += event_provider.get_timeline_filters(req) or []

        # check the request or session for enabled filters, or use default
        filters = [f[0] for f in available_filters if f[0] in req.args]
        if not filters and format != 'rss':
            filters = [f[0] for f in available_filters
                       if req.session.get('timeline.filter.' + f[0]) == '1']
        if not filters:
            filters = [f[0] for f in available_filters if len(f) == 2 or f[2]]

        # save the results of submitting the timeline form to the session
        if 'update' in req.args:
            for filter in available_filters:
                key = 'timeline.filter.%s' % filter[0]
                if filter[0] in req.args:
                    req.session[key] = '1'
                elif key in req.session:
                    del req.session[key]

        stop = fromdate
        start = to_datetime(stop.replace(tzinfo=None) - \
                                timedelta(days=daysback + 1),
                            req.tz)

        # create author include and exclude sets
        include = set()
        exclude = set()
        for match in self._authors_pattern.finditer(authors):
            name = (match.group(2) or match.group(3) or match.group(4)).lower()
            if match.group(1):
                exclude.add(name)
            else:
                include.add(name)
        
        # gather all events for the given period of time
        events = []
        for provider in self.event_providers:
            try:
                for event in provider.get_timeline_events(req, start, stop,
                                                          filters) or []:
                    # Check for 0.10 events
                    author = (event[len(event) < 6 and 2 or 4] or '').lower()
                    if (not include or author in include) \
                       and not author in exclude:
                        events.append(self._event_data(provider, event))
            except Exception, e: # cope with a failure of that provider
                self._provider_failure(e, req, provider, filters,
                                       [f[0] for f in available_filters])

        # prepare sorted global list
        events = sorted(events, key=lambda e: e['date'], reverse=True)
        if maxrows:
            events = events[:maxrows]

        data['events'] = events
        
        if format == 'rss':
            data['email_map'] = Chrome(self.env).get_email_map()
            rss_context = Context.from_request(req, absurls=True)
            rss_context.set_hints(wiki_flavor='html', shorten_lines=False)
            data['context'] = rss_context
            return 'timeline.rss', data, 'application/rss+xml'
        else:
            req.session.set('timeline.daysback', daysback,
                            self.default_daysback)
            req.session.set('timeline.authors', authors, '')
            html_context = Context.from_request(req)
            html_context.set_hints(wiki_flavor='oneliner', 
                                   shorten_lines=self.abbreviated_messages)
            data['context'] = html_context

        add_stylesheet(req, 'common/css/timeline.css')
        rss_href = req.href.timeline([(f, 'on') for f in filters],
                                     daysback=90, max=50, authors=authors,
                                     format='rss')
        add_link(req, 'alternate', rss_href, _('RSS Feed'),
                 'application/rss+xml', 'rss')

        for filter_ in available_filters:
            data['filters'].append({'name': filter_[0], 'label': filter_[1],
                                    'enabled': filter_[0] in filters})

        # Navigation to the previous/next period of 'daysback' days
        previous_start = fromdate.replace(tzinfo=None) - \
                            timedelta(days=daysback + 1)
        previous_start = format_date(to_datetime(previous_start, req.tz),
                                     format='%Y-%m-%d', tzinfo=req.tz)
        add_link(req, 'prev', req.href.timeline(from_=previous_start,
                                                authors=authors,
                                                daysback=daysback),
                 _('Previous Period'))
        if today - fromdate > timedelta(days=0):
            next_start = fromdate.replace(tzinfo=None) + \
                            timedelta(days=daysback + 1)
            next_start = format_date(to_datetime(next_start, req.tz),
                                     format='%Y-%m-%d', tzinfo=req.tz)
            add_link(req, 'next', req.href.timeline(from_=next_start,
                                                    authors=authors,
                                                    daysback=daysback),
                     _('Next Period'))
        prevnext_nav(req, _('Previous Period'), _('Next Period'))
        
        return 'timeline.html', data, None

    # ITemplateProvider methods

    def get_htdocs_dirs(self):
        return []

    def get_templates_dirs(self):
        return [pkg_resources.resource_filename('trac.timeline', 'templates')]

    # IRequestFilter methods

    def pre_process_request(self, req, handler):
        return handler
    
    def post_process_request(self, req, template, data, content_type):
        if data:
            def dateinfo(date):
                return self.get_timeline_link(req, date,
                                              pretty_timedelta(date),
                                              precision='second')
            data['dateinfo'] = dateinfo
        return template, data, content_type

    # IWikiSyntaxProvider methods

    def get_wiki_syntax(self):
        return []

    def get_link_resolvers(self):
        def link_resolver(formatter, ns, target, label):
            precision = None
            time = target.split("T", 1)
            if len(time) > 1:
                time = time[1].split("Z")[0]
                if len(time) >= 6:
                    precision = 'seconds'
                elif len(time) >= 4:
                    precision = 'minutes'
                elif len(time) >= 2:
                    precision = 'hours'
            try:
                return self.get_timeline_link(formatter.req,
                                              parse_date(target, utc),
                                              label, precision)
            except TracError, e:
                return tag.a(label, title=to_unicode(e),
                             class_='timeline missing')
        yield ('timeline', link_resolver)

    # Public methods

    def get_timeline_link(self, req, date, label=None, precision='hours'):
        iso_date = display_date = format_datetime(date, 'iso8601', req.tz)
        fmt = req.session.get('datefmt')
        if fmt and fmt != 'iso8601':
            display_date = format_datetime(date, fmt, req.tz)
        return tag.a(label or iso_date, class_='timeline',
                     title=_("%(date)s in Timeline", date=display_date),
                     href=req.href.timeline(from_=iso_date,
                                            precision=precision))

    # Internal methods

    def _event_data(self, provider, event):
        """Compose the timeline event date from the event tuple and prepared
        provider methods"""
        if len(event) == 6: # 0.10 events
            kind, url, title, date, author, markup = event
            data = {'url': url, 'title': title, 'description': markup}
            render = lambda field, context: data.get(field)
        else: # 0.11 events
            if len(event) == 5: # with special provider
                kind, date, author, data, provider = event
            else:
                kind, date, author, data = event
            render = lambda field, context: \
                    provider.render_timeline_event(context, field, event)
        if not isinstance(date, datetime):
            date = datetime.fromtimestamp(date, utc)
        dateuid = to_utimestamp(date)
        return {'kind': kind, 'author': author, 'date': date,
                'dateuid': dateuid, 'render': render, 'event': event,
                'data': data, 'provider': provider}

    def _provider_failure(self, exc, req, ep, current_filters, all_filters):
        """Raise a TracError exception explaining the failure of a provider.

        At the same time, the message will contain a link to the timeline
        without the filters corresponding to the guilty event provider `ep`.
        """
        self.log.error('Timeline event provider failed: %s', 
                       exception_to_unicode(exc, traceback=True))

        ep_kinds = dict((f[0], f[1])
                        for f in ep.get_timeline_filters(req) or [])
        ep_filters = set(ep_kinds.keys())
        current_filters = set(current_filters)
        other_filters = set(current_filters) - ep_filters
        if not other_filters:
            other_filters = set(all_filters) -  ep_filters
        args = [(a, req.args.get(a)) for a in ('from', 'format', 'max',
                                               'daysback')]
        href = req.href.timeline(args + [(f, 'on') for f in other_filters])
        # TRANSLATOR: ...want to see the 'other kinds of events' from... (link)
        other_events = tag.a(_('other kinds of events'), href=href)
        raise TracError(tag(
            tag.p(tag_("Event provider %(name)s failed for filters "
                       "%(kinds)s: ",
                       name=tag.tt(ep.__class__.__name__),
                       kinds=', '.join('"%s"' % ep_kinds[f] for f in 
                                       current_filters & ep_filters)),
                  tag.b(exception_to_unicode(exc)), class_='message'),
            tag.p(tag_("You may want to see the %(other_events)s from the "
                       "Timeline or notify your Trac administrator about the "
                       "error (detailed information was written to the log).",
                       other_events=other_events))))
