## $Id$
##
## Copyright (C) 2012 Uli Fouquet & Henrik Bettermann
## 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
"""Components for report generation.
"""
import grok
import zc.async.interfaces
from persistent.list import PersistentList
from zope import schema
from zope.component import (
    getUtility, getUtilitiesFor, queryUtility)
from zope.component.hooks import setSite
from zope.interface import implementer
from zope.interface import Interface, Attribute
from waeup.kofa.async import AsyncJob
from waeup.kofa.interfaces import (
    IJobManager, JOB_STATUS_MAP, IKofaPluggable, IKofaObject, IKofaUtils)
from waeup.kofa.interfaces import MessageFactory as _
from waeup.kofa.utils.helpers import now

#: A status map that reflects the really interesting types of status
#: for reports.
#:
#: For reports we want to know whether a job was finished
#: and/or whether it failed. All the other possible states ('new',
#: etc.) are not really interesting in that regard.
STATUS_MAP = {
    'unknown': _('unknown'),
    'running': _('running'),
    'finished': _('finished'),
    'failed': _('FAILED'),
    }

class IReport(Interface):
    """A report.
    """
    args = Attribute("""The args passed to constructor""")

    kwargs = Attribute("""The keywords passed to constructor""")

    creation_dt = Attribute(
        """Datetime when a report was created. The datetime should """
        """reflect the point of time when the data was fetched, """
        """not when any output was created.""")

    title = schema.TextLine(
        title = u"A human readable short description for a report.",
        default = u'Untitled',
        )

    description = schema.Text(
        title = u"A human readable text describing a report.",
        default = u'No description'
        )

    def create_pdf():
        """Generate a PDF copy.
        """

class IReportGenerator(IKofaObject):
    """A report generator.
    """
    title = Attribute("""Human readable description of report type.""")
    def generate(site, args=[], kw={}):
        """Generate a report.

        `args` and `kw` are the parameters needed to create a specific
        report (if any).
        """

class IReportJob(zc.async.interfaces.IJob):

    finished = schema.Bool(
        title = u'`True` if the job finished.`',
        default = False,
        )

    failed = schema.Bool(
        title = u"`True` iff the job finished and didn't provide a report.",
        default = None,
        )

    description = schema.TextLine(
        title = u"""Textual representation of arguments and keywords.""",
        default = u"",
        )

    report_status = schema.TextLine(
        title = u"""Translated status string.""",
        default = STATUS_MAP['unknown'],
        )

    def __init__(site, generator_name):
        """Create a report job via generator."""

class IReportJobContainer(Interface):
    """A component that contains (maybe virtually) report jobs.
    """
    def start_report_job(report_generator_name, user_id, args=[], kw={}):
        """Start asynchronous report job.

        `report_generator_name`
            is the name of a report generator utility to be used.

        `user_id`
            is the ID of the user that triggers the report generation.

        `args` and `kw`
            args and keywords passed to the generators `generate()`
            method.

        The job_id is stored along with exporter name and user id in a
        persistent list.

        Returns the job ID of the job started.
        """

    def get_running_report_jobs(user_id=None):
        """Get report jobs for user with `user_id` as list of tuples.

        Each tuples holds ``<job_id>, <generator_name>, <user_id>`` in
        that order. The ``<generator_name>`` is the utility name of the
        used report generator.

        If `user_id` is ``None``, all running report jobs are returned.
        """

    def get_report_jobs_status(user_id=None):
        """Get running/completed report jobs for `user_id` as list of tuples.

        Each tuple holds ``<raw status>, <status translated>,
        <generator title>`` in that order, where ``<status
        translated>`` and ``<generator title>`` are translated strings
        representing the status of the job and the human readable
        title of the report generator used.
        """

    def get_report_jobs_description(user_id=None):
        """Get running/completed report jobs for `user_id` as list of tuples.

        The results contain enough information to render a status page
        or similar. Each tuple holds::

          (``<job_id>, <description>, <status_translated>,
          <discardable>, <downloadable>``)

        in that order, with

        ``<job_id>``
            The job id of the represented job. A string.

        ``<description>``
            A human readable description of the report run.

        ``<status_translated>``
            The status of report jobs' status (translated)

        ``<discardable>``
            Boolean indicating whether the job can be discarded.
            Only completed jobs can be discarded.

        ``<downloadable>``
            Boolean indicating whether the job result can be
            downloaded. This is only true if the job finished and
            didn't raised exceptions.

        If ``user_id`` is ``None``, all jobs are returned.
        """

    def delete_report_entry(entry):
        """Delete the report job denoted by `entry`.

        Removes `entry` from the local `running_report_jobs` list and
        also removes the regarding job via the local job manager.

        `entry` is a tuple ``(<job id>, <generator name>, <user id>)``
        as created by :meth:`start_report_job` or returned by
        :meth:`get_running_report_jobs`.
        """

    def report_entry_from_job_id(job_id):
        """Get entry tuple for `job_id`.

        Returns ``None`` if no such entry can be found.
        """

class IReportsContainer(grok.interfaces.IContainer, IReportJobContainer,
                        IKofaObject):
    """A grok container that holds report jobs.
    """

class manageReportsPermission(grok.Permission):
    """A permission to manage reports.
    """
    grok.name('waeup.manageReports')

def get_generators():
    """Get available report generators.

    Returns an iterator of tuples ``<NAME, GENERATOR>`` with ``NAME``
    being the name under which the respective generator was
    registered.
    """
    for name, util in getUtilitiesFor(IReportGenerator):
        yield name, util
    pass

@implementer(IReport)
class Report(object):
    creation_dt = None

    @property
    def title(self):
        return _(u'A report')

    @property
    def description(self):
        return _(u'A dummy report')

    def __init__(self, args=[], kwargs={}):
        self.args = args
        self.kwargs = kwargs
        self.creation_dt = now()

    def create_pdf(self):
        raise NotImplementedError()

    def __repr__(self):
        return 'Report(args=%r, kwargs=%r)' % (self.args, self.kwargs)


@implementer(IReportGenerator)
class ReportGenerator(object):

    title = _("Unnamed Report")
    def generate(self, site, args=[], kw={}):
        result = Report()
        return result

def report_job(site, generator_name, args=[], kw={}):
    """Get a generator and perform report creation.

    `site`
        is the site for which the report should be created.
    `generator_name`
        the global utility name under which the desired generator is
        registered.
    `args` and `kw`
        Arguments and keywords to be passed to the `generate()` method of
        the desired generator. While `args` should be a list, `kw` should
        be a dictionary.
    """
    setSite(site)
    generator = getUtility(IReportGenerator, name=generator_name)
    report = generator.generate(site, *args, **kw)
    return report

@implementer(IReportJob)
class AsyncReportJob(AsyncJob):
    """An IJob that creates reports.

    `AsyncReportJob` instances are regular `AsyncJob` instances with a
    different constructor API. Instead of a callable to execute, you
    must pass a `site`, some `generator_name`, and additional args and
    keywords to create a report.

    The real work is done when an instance of this class is put into a
    queue. See :mod:`waeup.kofa.async` to learn more about
    asynchronous jobs.

    The `generator_name` must be the name under which an IReportGenerator
    utility was registered with the ZCA.

    The `site` must be a valid site  or ``None``.

    The result of an `AsyncReportJob` is an IReport object.
    """
    def __init__(self, site, generator_name, args=[], kw={}):
        self._generator_name = generator_name
        super(AsyncReportJob, self).__init__(
            report_job, site, generator_name, args=args, kw=kw)

    @property
    def finished(self):
        """A job is marked `finished` if it is completed.

        Please note: a finished report job does not neccessarily
        provide an IReport result. See meth:`failed`.
        """
        return self.status == zc.async.interfaces.COMPLETED

    @property
    def failed(self):
        """A report job is marked failed iff it is finished and the
        result does not provide IReport.

        While a job is unfinished, the `failed` status is ``None``.

        Failed jobs normally provide a `traceback` to examine reasons.
        """
        if not self.finished:
            return None
        if not IReport.providedBy(getattr(self, 'result', None)):
            return True
        return False

    @property
    def report_status(self):
        """The status of a report as translated string.
        """
        if not self.finished:
            return STATUS_MAP['running']
        if self.failed:
            return STATUS_MAP['failed']
        return STATUS_MAP['finished']

    @property
    def description(self):
        """A description gives a representation of the report to generate.

        The description contains the name of the report generator
        (trying to fetch the `name` attribute of the requested report
        generator) and the arguments and keywords passed in.

        Please note that this method is expensive!
        """
        args = self.kwargs.get('args', [])
        kw = self.kwargs.get('kw', dict())
        args = ', '.join(["%r" % x for x in args])
        #kw = ', '.join(['%s = %r' % (key, val) for key, val in kw.items()])
        kw = ', '.join(['%s' % val for val in kw.values()])
        if len(args) and len(kw):
            str_repr = args + ', ' + kw
        else:
            str_repr = args + kw
        str_repr = '(' + str_repr + ')'
        try:
            generator = getUtility(
                IReportGenerator, name=self._generator_name)
            name = generator.title
        except:
            name = _('Unregistered Report Generator')
        return name + ' ' + str_repr

@implementer(IReportJobContainer)
class ReportJobContainer(object):
    """A mix-in that provides functionality for asynchronous report jobs.
    """
    running_report_jobs = PersistentList()

    def start_report_job(self, generator_name, user_id, args=[], kw={}):
        """Start asynchronous export job.

        `generator_name`
            is the name of a report generator utility to be used.

        `user_id`
            is the ID of the user that triggers the report generation.

        `args` and `kw`
            args and keywords passed to the generators `generate()`
            method.

        The job_id is stored along with exporter name and user id in a
        persistent list.

        Returns the job ID of the job started.
        """
        site = grok.getSite()
        manager = getUtility(IJobManager)
        job = AsyncReportJob(site, generator_name, args=args, kw=kw)
        job_id = manager.put(job)
        # Make sure that the persisted list is stored in ZODB
        self.running_report_jobs = PersistentList(self.running_report_jobs)
        self.running_report_jobs.append((job_id, generator_name, user_id),)
        return job_id

    def get_running_report_jobs(self, user_id=None):
        """Get report jobs for user with `user_id` as list of tuples.

        Each tuples holds ``<job_id>, <generator_name>, <user_id>`` in
        that order. The ``<generator_name>`` is the utility name of the
        used report generator.

        If `user_id` is ``None``, all running report jobs are returned.
        """
        entries = []
        to_delete = []
        manager = getUtility(IJobManager)
        for entry in self.running_report_jobs:
            if user_id is not None and entry[2] != user_id:
                continue
            if manager.get(entry[0]) is None:
                to_delete.append(entry)
                continue
            entries.append(entry)
        if to_delete:
            self.running_report_jobs = PersistentList(
                [x for x in self.running_report_jobs if x not in to_delete])
        return entries

    def get_report_jobs_status(self, user_id=None):
        """Get running/completed report jobs for `user_id` as list of tuples.

        Each tuple holds ``<raw status>, <status translated>,
        <generator title>`` in that order, where ``<status
        translated>`` and ``<generator title>`` are translated strings
        representing the status of the job and the human readable
        title of the report generator used.
        """
        entries = self.get_running_report_jobs(user_id)
        result = []
        manager = getUtility(IJobManager)
        for entry in entries:
            job = manager.get(entry[0])
            status, status_translated = JOB_STATUS_MAP[job.status]
            generator = getUtility(IReportGenerator, name=entry[1])
            generator_name = getattr(generator, 'title', 'unnamed')
            result.append((status, status_translated, generator_name))
        return result

    def get_report_jobs_description(self, user_id=None):
        """Get running/completed report jobs fur `user_id` as list of tuples.

        The results contain enough information to render a status page
        or similar. Each tuple holds::

          (``<job_id>, <description>, <status_translated>,
          <discardable>, <downloadable>``)

        in that order, with

        ``<job_id>``
            The job id of the represented job. A string.

        ``<description>``
            A human readable description of the report run.

        ``<status_translated>``
            The status of report jobs' status (translated)

        ``<discardable>``
            Boolean indicating whether the job can be discarded.
            Only completed jobs can be discarded.

        ``<downloadable>``
            Boolean indicating whether the job result can be
            downloaded. This is only true if the job finished and
            didn't raised exceptions.

        ``<starttime>``
            Datetime object indicating when the job was started.

        If ``user_id`` is ``None``, all jobs are returned.
        """
        entries = self.get_running_report_jobs(user_id)
        result = []
        for (job_id, gen_name, user_name) in entries:
            manager = getUtility(IJobManager)
            job = manager.get(job_id)
            status = job.report_status
            discardable = job.finished
            downloadable = job.finished and not job.failed
            starttime = getattr(job, 'begin_after', None)
            if starttime:
                starttime = starttime.astimezone(getUtility(IKofaUtils).tzinfo)
                starttime = starttime.strftime("%Y-%m-%d %H:%M:%S %Z")
            if not hasattr(job, 'description'):
                continue
            result.append((job_id, job.description, status,
                           discardable, downloadable, starttime, user_name),)
        return result

    def delete_report_entry(self, entry):
        """Delete the report job denoted by `entry`.

        Removes `entry` from the local `running_report_jobs` list and
        also removes the regarding job via the local job manager.

        `entry` is a tuple ``(<job id>, <generator name>, <user id>)``
        as created by :meth:`start_report_job` or returned by
        :meth:`get_running_report_jobs`.
        """
        manager = getUtility(IJobManager)
        manager.remove(entry[0], self)
        new_entries = [x for x in self.running_report_jobs
                       if x != entry]
        self.running_report_jobs = PersistentList(new_entries)
        return

    def report_entry_from_job_id(self, job_id):
        """Get entry tuple for `job_id`.

        Returns ``None`` if no such entry can be found.
        """
        for entry in self.running_report_jobs:
            if entry[0] == job_id:
                return entry
        return None

@implementer(IReportsContainer)
class ReportsContainer(grok.Container, ReportJobContainer):
    """A container for reports.
    """

@implementer(IKofaPluggable)
class ReportsContainerPlugin(grok.GlobalUtility):
    """A plugin that updates sites to contain a reports container.
    """

    grok.name('reports')

    deprecated_attributes = []

    def setup(self, site, name, logger):
        """Add a reports container for `site`.

        If there is such an object already, we install a fresh one.
        """
        if site.get('reports', None) is not None:
            del site['reports']
            logger.info('Removed reports container for site "%s"' % name)
        return self.update(site, name, logger)

    def update(self, site, name, logger):
        """Install a reports container in `site`.

        If one exists already, do nothing.
        """
        if site.get('reports', None) is not None:
            return
        site['reports'] = ReportsContainer()
        logger.info('Added reports container for site "%s"' % name)
        return