models.py

from datetime import date

from django.core.exceptions import ValidationError
from django.db import models
from django.db.models.expressions import RawSQL, OrderBy
from django.contrib.postgres.fields import JSONField
from django.db import models
from django.db.models import Q
from django.http import Http404
from django.urls import reverse
from django.utils.text import mark_safe

from modelcluster.fields import ParentalKey
from wagtail.wagtailadmin.edit_handlers import (
    FieldPanel,
    InlinePanel,
    FieldRowPanel,
    MultiFieldPanel,
    StreamFieldPanel,
)
from wagtail.wagtailcore.fields import StreamField
from wagtail.wagtailcore.models import Orderable
from wagtail.wagtailforms.models import AbstractFormSubmission

from opentech.apply.stream_forms.models import AbstractStreamForm

from .blocks import CustomFormFieldsBlock, REQUIRED_BLOCK_NAMES
from .forms import WorkflowFormAdminForm
from .workflow import SingleStage, DoubleStage


WORKFLOW_CLASS = {
    SingleStage.name: SingleStage,
    DoubleStage.name: DoubleStage,
}


def admin_url(page):
    return reverse('wagtailadmin_pages:edit', args=(page.id,))


class FundType(AbstractStreamForm):
    parent_page_types = ['apply_home.ApplyHomePage']
    subpage_types = ['funds.Round']

    base_form_class = WorkflowFormAdminForm

    WORKFLOWS = {
        'single': SingleStage.name,
        'double': DoubleStage.name,
    }

    workflow = models.CharField(choices=WORKFLOWS.items(), max_length=100, default='single')

    def get_defined_fields(self):
        # Only return the first form, will need updating for when working with 2 stage WF
        return self.forms.all()[0].fields

    def get_submission_class(self):
        return ApplicationSubmission

    def process_form_submission(self, form):
        # Handle passing to JSONField
        return self.get_submission_class().objects.create(
            form_data=form.cleaned_data,
            page=self,
        )

    @property
    def workflow_class(self):
        return WORKFLOW_CLASS[self.get_workflow_display()]

    @property
    def open_round(self):
        rounds = Round.objects.child_of(self).live().public().specific()
        return rounds.filter(
            Q(start_date__lte=date.today()) &
            Q(Q(end_date__isnull=True) | Q(end_date__gte=date.today()))
        ).first()

    def next_deadline(self):
        return self.open_round.end_date

    content_panels = AbstractStreamForm.content_panels + [
        FieldPanel('workflow'),
        InlinePanel('forms', label="Forms"),
    ]

    def serve(self, request):
        if hasattr(request, 'is_preview'):
            return super().serve(request)

        # delegate to the open_round to use the latest form instances
        request.show_page = True
        return self.open_round.serve(request)


class FundForm(Orderable):
    form = models.ForeignKey('ApplicationForm')
    fund = ParentalKey('FundType', related_name='forms')

    @property
    def fields(self):
        return self.form.form_fields


class ApplicationForm(models.Model):
    name = models.CharField(max_length=255)
    form_fields = StreamField(CustomFormFieldsBlock())

    panels = [
        FieldPanel('name'),
        StreamFieldPanel('form_fields'),
    ]

    def __str__(self):
        return self.name


class Round(AbstractStreamForm):
    parent_page_types = ['funds.FundType']
    subpage_types = []  # type: ignore

    start_date = models.DateField(default=date.today)
    end_date = models.DateField(
        blank=True,
        null=True,
        default=date.today,
        help_text='When no end date is provided the round will remain open indefinitely.'
    )

    content_panels = AbstractStreamForm.content_panels + [
        MultiFieldPanel([
            FieldRowPanel([
                FieldPanel('start_date'),
                FieldPanel('end_date'),
            ]),
        ], heading="Dates")
    ]

    def get_defined_fields(self):
        # Only return the first form, will need updating for when working with 2 stage WF
        return self.get_parent().specific.forms.all()[0].fields

    def clean(self):
        super().clean()

        if self.end_date and self.start_date > self.end_date:
            raise ValidationError({
                'end_date': 'End date must come after the start date',
            })

        if self.end_date:
            conflict_query = (
                Q(start_date__range=[self.start_date, self.end_date]) |
                Q(end_date__range=[self.start_date, self.end_date]) |
                Q(start_date__lte=self.start_date, end_date__gte=self.end_date)
            )
        else:
            conflict_query = (
                Q(start_date__lte=self.start_date, end_date__isnull=True) |
                Q(end_date__gte=self.start_date)
            )

        if hasattr(self, 'parent_page'):
            # Check if the create hook has added the parent page, we aren't an object yet.
            # Ensures we can access related objects during the clean phase instead of save.
            base_query = Round.objects.child_of(self.parent_page)
        else:
            # don't need parent page, we are an actual object now.
            base_query = Round.objects.sibling_of(self)

        conflicting_rounds = base_query.filter(
            conflict_query
        ).exclude(id=self.id)

        if conflicting_rounds.exists():
            error_message = mark_safe('Overlaps with the following rounds:<br> {}'.format(
                '<br>'.join([
                    f'<a href="{admin_url(round)}">{round.title}</a>: {round.start_date} - {round.end_date}'
                    for round in conflicting_rounds]
                )
            ))
            error = {
                'start_date': error_message,
            }
            if self.end_date:
                error['end_date'] = error_message

            raise ValidationError(error)

    def serve(self, request):
        if hasattr(request, 'is_preview') or hasattr(request, 'show_page'):
            return super().serve(request)

        # We hide the round as only the open round is used which is displayed through the
        # fund page
        raise Http404()


class JSONOrderable(models.QuerySet):
    def order_by(self, *field_names):
        def build_json_order_by(field):
            if field.replace('-', '') not in REQUIRED_BLOCK_NAMES:
                return field

            if field[0] == '-':
                descending = True
                field = field[1:]
            else:
                descending = False
            return OrderBy(RawSQL("LOWER(form_data->>%s)", (field,)), descending=descending)

        field_ordering = [build_json_order_by(field) for field in field_names]
        return super().order_by(*field_ordering)


class ApplicationSubmission(AbstractFormSubmission):
    form_data = JSONField()

    objects = JSONOrderable.as_manager()

    def get_data(self):
        # Updated for JSONField
        form_data = self.form_data
        form_data.update({
            'submit_time': self.submit_time,
        })

        return form_data

    def __getattr__(self, item):
        # fall back to values defined on the data
        if item in REQUIRED_BLOCK_NAMES:
            return self.get_data()[item]
        return super().__getattr__(item)

    def __str__(self):
        return str(super().__str__())