Instructor training workflow

Later on, I'll split this commit into 7 smaller commits:

1. Instructor Training: Schema changes

- introduce new models: TrainingProgress and TrainingRequirement

- add `TrainingRequest.state` and `TrainingRequest.person` fields

- add `TrainingRequirement` to django-admin site

- put everything in one migration

2. Instructor Training: Modify trainee dashboard

- display progress of becoming SWC/DC Instructor

- let the trainee send SWC or DC homework using SendHomeworkForm

3. Instructor Training: Modify training requests list view

- add bulk operations:

    - discard selected requests (BulkChangeTrainingRequestForm)

    - unmatch selected people from trainings
      (BulkChangeTrainingRequestForm again)

    - match selected people to chosen training
      (BulkMatchTrainingRequestForm)

- added filtering sidebar (TrainingRequestFilter)

- "mail selected people" feature (piece of JS in `bulk_email.js`)

4. Instructor Training: Modify Training request detailed view

- display new fields (state and matched person)

- add form to match request with selected person or with a new one
  (AcceptTrainingRequestForm); this form suggest matching Person

5. Instructor Training: Add training request edit view

- introduce TrainingRequestUpdateForm

6. Instructor Training: Add trainees list view

- add filtering sidebar (TraineeFilter, TTTEventLookup)

- add bulk operations:

    - add training progress (BulkAddTrainingProgressForm)

    - discard training progress (BulkDiscardProgressesForm)

7. Instructor Training: add CRUD views for TrainingProgress

- introduce TrainingProgressForm

workshops/admin.py

@@ -9,7 +9,7 @@
     Lesson,
     KnowledgeDomain,
     Badge,
-)
+    TrainingRequirement)
 
 
 class RoleAdmin(admin.ModelAdmin):
@@ -24,3 +24,4 @@ class RoleAdmin(admin.ModelAdmin):
 admin.site.register(Lesson)
 admin.site.register(KnowledgeDomain)
 admin.site.register(Badge)
+admin.site.register(TrainingRequirement)

workshops/filters.py

@@ -1,3 +1,7 @@
+from django.db.models import Q
+
+from django.forms import widgets
+
 import django.forms.widgets
 
 import django_filters
@@ -15,7 +19,7 @@
     InvoiceRequest,
     EventSubmission,
     DCSelfOrganizedEventRequest,
-)
+    TrainingRequest)
 
 EMPTY_SELECTION = (None, '---------')
 
@@ -207,6 +211,139 @@ def get_order_by(self, order_value):
         return super().get_order_by(order_value)
 
 
+def filter_all_persons(queryset, all_persons):
+    if all_persons:
+        return queryset
+    else:
+        return queryset.filter(
+            task__role__name='learner',
+            task__event__tags__name='TTT').distinct()
+
+
+def filter_trainee_name(queryset, name):
+    return queryset.filter(Q(personal__icontains=name) |
+                           Q(family__icontains=name) |
+                           Q(email__icontains=name) |
+                           Q(github__icontains=name))
+
+
+def filter_unevaluated_homework(queryset, flag):
+    if flag is None:
+        return queryset
+    elif flag:  # return only trainees with an unevaluated homework
+        return queryset.filter(trainingprogress__state='n') \
+                       .distinct()
+    else:  # return only trainees without unevaluated homework
+        return queryset.exclude(trainingprogress__state='n') \
+                       .distinct()
+
+
+def filter_training(queryset, training):
+    if training is None:
+        return queryset
+    else:
+        print(training)
+        return queryset.filter(task__role__name='learner',
+                               task__event=training).distinct()
+
+
+class TraineeFilter(FilterSetWithoutHelpText):
+    search = django_filters.CharFilter(
+        action=filter_trainee_name,
+        label='Name or GitHub or email')
+
+    all_persons = django_filters.BooleanFilter(
+        label='Include all people, not only trainees',
+        action=filter_all_persons,
+        widget=widgets.CheckboxInput)
+
+    is_swc_instructor = django_filters.BooleanFilter(
+        label='Is SWC Instructor?',
+        name='is_swc_instructor',
+    )
+
+    is_dc_instructor = django_filters.BooleanFilter(
+        label='Is DC Instructor?',
+        name='is_dc_instructor',
+    )
+
+    non_evaluated_homework = django_filters.BooleanFilter(
+        label='Unevaluated homework?',
+        action=filter_unevaluated_homework,
+    )
+
+    training = django_filters.ModelChoiceFilter(
+        queryset=Event.objects.ttt(),
+        action=filter_training,
+    )
+
+    class Meta:
+        model = Person
+        fields = [
+            'search',
+            'all_persons',
+            'is_swc_instructor',
+            'is_dc_instructor',
+            'training',
+        ]
+        order_by = ["-last_login", "lastname", "-lastname", "firstname", "-firstname",
+                    "email", "-email"]
+
+    def get_order_by(self, order_value):
+        if order_value == 'firstname':
+            return ['personal', 'middle', 'family']
+        elif order_value == '-firstname':
+            return ['-personal', '-middle', '-family']
+        elif order_value == 'lastname':
+            return ['family', 'middle', 'personal']
+        elif order_value == '-lastname':
+            return ['-family', '-middle', '-personal']
+        else:
+            return super().get_order_by(order_value)
+
+
+def filter_matched(queryset, choice):
+    if choice == '':
+        return queryset
+    elif choice == 'u':  # unmatched
+        return queryset.filter(person=None)
+    elif choice == 'p':  # matched person, unmatched training
+        return queryset.filter(person__isnull=False)\
+                       .exclude(person__task__role__name='learner',
+                                person__task__event__tags__name='TTT')\
+                       .distinct()
+    else:
+        assert choice == 't'  # matched person and training
+        return queryset.filter(person__task__role__name='learner',
+                               person__task__event__tags__name='TTT')\
+                       .distinct()
+
+
+class TrainingRequestFilter(FilterSetWithoutHelpText):
+    state = django_filters.ChoiceFilter(
+        choices=(('', 'All'),) + TrainingRequest.STATES,
+    )
+
+    matched = django_filters.ChoiceFilter(
+        label='Matched?',
+        choices=(
+            ('', 'Unknown'),
+            ('u', 'Unmatched'),
+            ('p', 'Matched person, unmatched training'),
+            ('t', 'Matched person and training'),
+        ),
+        action=filter_matched,
+    )
+
+    class Meta:
+        model = TrainingRequest
+        fields = [
+            'state',
+            'matched',
+        ]
+        order_by = ['created_at', '-created_at']
+
+
 class TaskFilter(FilterSetWithoutHelpText):
     class Meta:
         model = Task