"""Module containing the views for all the textbook project related activities.

"""

__authors__ = [

    '"Nishanth Amuluru" <nishanth@fossee.in>',

    '"Madhusudan.C.S" <madhusudancs@fossee.in>',

    ]

from datetime import datetime

from django import shortcuts

from django import http

from django.contrib.auth.decorators import login_required

from django.contrib.auth.models import User

from django.core.context_processors import csrf

from django.core.urlresolvers import reverse

from django.template import RequestContext

from django.utils.translation import ugettext

from tagging.managers import TaggedItem

from pytask.helpers import exceptions

from pytask.profile import models as profile_models

from pytask.taskapp import forms as taskapp_forms

from pytask.taskapp import models as taskapp_models

from pytask.taskapp.views import task as task_view

from pytask.taskapp.views.utils import get_intial_tags_for_chapter

DONT_CLAIM_TASK_MSG = ugettext(

  "Please don't submit any claims for the tasks until you get an email "

  "to start claiming tasks. Please be warned that the task claim work-"

  "flow may change. So all the claims submitted before the workshop may "

  "not be valid.")

NO_EDIT_RIGHT = ugettext(

  "You are not authorized to edit this page.")

NOT_A_PARENT_FOR_CHAPTER = ugettext(

  "There is an error in your request. The chapter you are requesting is "

  "does not belong to the textbook you have requested.")

@login_required

def create_textbook(request):

    user = request.user

    profile = user.get_profile()

    if profile.role != profile_models.ROLES_CHOICES[3][0]:

        can_create = True

    else:

        can_create= False

    if not can_create:

        raise http.HttpResponseForbidden

    context = {

      'user': user,

      'profile': profile,

      }

    context.update(csrf(request))

    if request.method == 'POST':

        form = taskapp_forms.CreateTextbookForm(request.POST)

        if form.is_valid():

            data = form.cleaned_data.copy()

            data.update({"created_by": user,

                         "creation_datetime": datetime.now()})

            del data['chapters']

            new_textbook = taskapp_models.TextBook(**data)

            new_textbook.save()

            new_textbook.chapters = form.cleaned_data['chapters']

            textbook_url = reverse(

              'view_textbook', kwargs={'task_id': new_textbook.id})

            return shortcuts.redirect(textbook_url)

        else:

            context.update({"form": form})

            return shortcuts.render_to_response(

              "task/edit.html", RequestContext(request, context))

    else:

        form = taskapp_forms.CreateTextbookForm()

        context.update({"form": form})

        return shortcuts.render_to_response(

          "task/edit.html", RequestContext(request, context))

def view_textbook(request, task_id, template='task/view_textbook.html'):

    # Shortcut to get_object_or_404 is not used since django-tagging

    # api expects a queryset object for tag filtering.

    task = taskapp_models.Task.objects.filter(pk=task_id)

    textbooks = TaggedItem.objects.get_by_model(task, ['Textbook'])

    if textbooks:

        textbook = textbooks[0]

    else:

        raise http.Http404

    chapters = textbook.children_tasks.all()

    user = request.user

    context = {

      'user': user,

      'textbook': textbook,

      'chapters': chapters,

      }

    if not user.is_authenticated():

        return shortcuts.render_to_response(template,

                                            RequestContext(request, context))

    profile = user.get_profile()

    context.update({

      'profile': profile,

      'textbook': textbook,

      })

    context.update(csrf(request))

    user_role = user.get_profile().role

    if ((user == textbook.created_by or

      user_role != profile_models.ROLES_CHOICES[3][0]) and

      textbook.status in [taskapp_models.TB_STATUS_CHOICES[0][0],

      taskapp_models.TB_STATUS_CHOICES[1][0]]):

        can_edit = True

        can_create_chapters = True

    else:

        can_edit = False

        can_create_chapters = False

    if (profile.role in [profile_models.ROLES_CHOICES[0][0],

      profile_models.ROLES_CHOICES[1][0]] and

      textbook.status == taskapp_models.TB_STATUS_CHOICES[0][0]):

        can_approve = True

    else:

        can_approve = False

    context.update({

      'can_edit': can_edit,

      'can_approve': can_approve,

      'can_create_chapters': can_create_chapters,

      })

    return shortcuts.render_to_response(template,

                                        RequestContext(request, context))

def browse_textbooks(request):

    """View to list all the open textbooks. This view fetches tasks

    tagged with Textbook.

    """

    user = request.user

    # Get all the textbooks that are Open.

    open_textbooks = taskapp_models.Task.objects.filter(

      status=taskapp_models.TASK_STATUS_CHOICES[1][0]).order_by(

      'creation_datetime')

    context = {

      'aero_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'Aerospace']),

      'chemical_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'Chemical']),

      'computerscience_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'ComputerScience']),

      'electrical_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'Electrical']),

      'engineeringphysics_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'EngineeringPhysics']),

      'mechanical_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Mechanical', 'Textbook']),

      'metallurgical_textbooks': TaggedItem.objects.get_by_model(

        open_textbooks, ['Textbook', 'Metallurgical']),

      }

    # Nothing

    if user.is_authenticated() and (user.get_profile().role in

      [profile_models.ROLES_CHOICES[0][0], profile_models.ROLES_CHOICES[1][0]]):

        unpub_textbooks = taskapp_models.TextBook.objects.filter(

          status=taskapp_models.TB_STATUS_CHOICES[0][0])

        context.update({"unpub_textbooks": unpub_textbooks})

    return shortcuts.render_to_response("task/browse_textbooks.html",

                                        RequestContext(request, context))

@login_required

def edit_textbook(request, task_id):

    user = request.user

    profile = user.get_profile()

    textbook = shortcuts.get_object_or_404(taskapp_models.Task, pk=task_id)

    textbook_url = reverse(

      'view_textbook', kwargs={'task_id': textbook.id})

    if ((user == textbook.created_by or 

      user.get_profile().role != profile_models.ROLES_CHOICES[3][0])

      and textbook.status in [taskapp_models.TASK_STATUS_CHOICES[0][0],

      taskapp_models.TASK_STATUS_CHOICES[1][0]]):

        can_edit = True

    else:

        can_edit = False

    if not can_edit:

        raise exceptions.UnauthorizedAccess(NO_EDIT_RIGHT)

    context = {

      'user': user,

      'profile': profile,

      'textbook': textbook,

      }

    context.update(csrf(request))

    if request.method == "POST":

        form = taskapp_forms.EditTextbookForm(request.POST, instance=textbook)

        if form.is_valid():

            form.save()

            return shortcuts.redirect(textbook_url)

        else:

            context.update({"form": form})

            return shortcuts.render_to_response(

              "task/edit.html", RequestContext(request, context))

    else:

        form = taskapp_forms.EditTextbookForm(instance=textbook)

        context.update({"form": form})

        return shortcuts.render_to_response("task/edit.html",

                                            RequestContext(request, context))

@login_required

def create_chapter(request, book_id, template='task/chapter_edit.html'):

    """View function to let Coordinators and TAs (Mentor in

    PyTask terminology) create chapters out of textbooks.

    Args:

      book_id: ID of the text book to which this chapter belongs to

    """

    user = request.user

    profile = user.get_profile()

    if profile.role != profile_models.ROLES_CHOICES[3][0]:

        can_create = True

    else:

        can_create= False

    if not can_create:

        raise http.HttpResponseForbidden

    context = {

      'user': user,

      'profile': profile,

      }

    context.update(csrf(request))

    textbook = shortcuts.get_object_or_404(taskapp_models.Task, pk=book_id)

    if request.method == 'POST':

        form = taskapp_forms.CreateChapterForm(request.POST)

        if form.is_valid():

            data = form.cleaned_data.copy()

            data.update({

              'created_by': user,

              'creation_datetime': datetime.now(),

              'parent': textbook,

              })

            # TODO: remove hard coded default publish for chapters

            data['status'] = 'Open'

            new_chapter = taskapp_models.Task(**data)

            new_chapter.save()

            textbook_url = reverse(

              'view_textbook', kwargs={'task_id': textbook.id})

            return shortcuts.redirect(textbook_url)

        else:

            context.update({"form": form})

            return shortcuts.render_to_response(

              template, RequestContext(request, context))

    else:

        form = taskapp_forms.CreateChapterForm(

          initial={'tags_field': get_intial_tags_for_chapter(textbook)})

        context.update({'form': form})

        return shortcuts.render_to_response(

          template, RequestContext(request, context))

@login_required

def edit_chapter(request, book_id, chapter_id,

                 template='task/chapter_edit.html'):

    """View function that lets edit chapters from textbooks.

    """

    chapter = shortcuts.get_object_or_404(taskapp_models.Task, pk=chapter_id)

    if chapter.parent.id != int(book_id):

        raise exceptions.PyTaskException(NOT_A_PARENT_FOR_CHAPTER)

def view_chapter(request, book_id, chapter_id,

                 template='task/chapter_edit.html'):

    """View that displays the chapter of the textbook.

    Args:

        book_id: the id of the book to which this chapter belongs.

        chapter_id: id of the chapter that must be displayed.

    """

    chapter = shortcuts.get_object_or_404(taskapp_models.Task, pk=chapter_id)

    if chapter.parent.id != int(book_id):

        raise exceptions.PyTaskException(NOT_A_PARENT_FOR_CHAPTER)

    context = {

      'edit_url': reverse('edit_chapter', kwargs={

        'book_id': book_id, 'chapter_id': chapter_id})

      }

    return task_view.view_task(request, chapter_id, **kwargs)

@login_required

def approve_textbook(request, task_id):

    user = request.user

    profile = user.get_profile()

    textbook = shortcuts.get_object_or_404(taskapp_models.TextBook, pk=task_id)

    if profile.role not in [profile_models.ROLES_CHOICES[0][0], profile_models.ROLES_CHOICES[1][0]] or textbook.status != taskapp_models.TB_STATUS_CHOICES[0][0]:

        raise http.Http404

    context = {"user": user,

               "profile": profile,

               "textbook": textbook,

              }

    return shortcuts.render_to_response(

      "task/confirm_textbook_approval.html",

      RequestContext(request, context))

@login_required

def approved_textbook(request, task_id):

    user = request.user

    profile = user.get_profile()

    textbook = shortcuts.get_object_or_404(taskapp_models.TextBook, pk=task_id)

    if profile.role not in [profile_models.ROLES_CHOICES[0][0], profile_models.ROLES_CHOICES[1][0]] or textbook.status != taskapp_models.TB_STATUS_CHOICES[0][0]:

        raise http.Http404

    textbook.approved_by = user

    textbook.approval_datetime = datetime.now()

    textbook.status = taskapp_models.TB_STATUS_CHOICES[1][0]

    textbook.save()

    context = {"user": user,

               "profile": profile,

               "textbook": textbook,

              }

    return shortcuts.render_to_response(

      "task/approved_textbook.html", RequestContext(request, context))