"""
django-helpdesk - A Django powered ticket tracker for small enterprise.

(c) Copyright 2008 Jutda. All Rights Reserved. See LICENSE for details.

forms.py - Definitions of newforms-based forms for creating and maintaining
           tickets.
"""


from datetime import datetime
from django import forms
from django.conf import settings
from django.contrib.auth import get_user_model
from django.core.exceptions import ObjectDoesNotExist, ValidationError
from django.utils import timezone
from django.utils.translation import gettext_lazy as _
from helpdesk import settings as helpdesk_settings
from helpdesk.lib import convert_value, process_attachments, safe_template_context
from helpdesk.models import (
    CustomField,
    FollowUp,
    IgnoreEmail,
    Queue,
    Ticket,
    TicketCC,
    TicketCustomFieldValue,
    TicketDependency,
    UserSettings
)
from helpdesk.settings import (
    CUSTOMFIELD_DATE_FORMAT,
    CUSTOMFIELD_DATETIME_FORMAT,
    CUSTOMFIELD_TIME_FORMAT,
    CUSTOMFIELD_TO_FIELD_DICT
)
from helpdesk.validators import validate_file_extension
import logging


if helpdesk_settings.HELPDESK_KB_ENABLED:
    from helpdesk.models import KBItem

logger = logging.getLogger(__name__)
User = get_user_model()


class CustomFieldMixin(object):
    """
    Mixin that provides a method to turn CustomFields into an actual field
    """

    def customfield_to_field(self, field, instanceargs):
        # Use TextInput widget by default
        instanceargs['widget'] = forms.TextInput(
            attrs={'class': 'form-control'})
        # if-elif branches start with special cases
        if field.data_type == 'varchar':
            fieldclass = forms.CharField
            instanceargs['max_length'] = field.max_length
        elif field.data_type == 'text':
            fieldclass = forms.CharField
            instanceargs['widget'] = forms.Textarea(
                attrs={'class': 'form-control'})
            instanceargs['max_length'] = field.max_length
        elif field.data_type == 'integer':
            fieldclass = forms.IntegerField
            instanceargs['widget'] = forms.NumberInput(
                attrs={'class': 'form-control'})
        elif field.data_type == 'decimal':
            fieldclass = forms.DecimalField
            instanceargs['decimal_places'] = field.decimal_places
            instanceargs['max_digits'] = field.max_length
            instanceargs['widget'] = forms.NumberInput(
                attrs={'class': 'form-control'})
        elif field.data_type == 'list':
            fieldclass = forms.ChoiceField
            instanceargs['choices'] = field.get_choices()
            instanceargs['widget'] = forms.Select(
                attrs={'class': 'form-control'})
        else:
            # Try to use the immediate equivalences dictionary
            try:
                fieldclass = CUSTOMFIELD_TO_FIELD_DICT[field.data_type]
                # Change widgets for the following classes
                if fieldclass == forms.DateField:
                    instanceargs['widget'] = forms.DateInput(
                        attrs={'class': 'form-control date-field'})
                elif fieldclass == forms.DateTimeField:
                    instanceargs['widget'] = forms.DateTimeInput(
                        attrs={'class': 'form-control datetime-field'})
                elif fieldclass == forms.TimeField:
                    instanceargs['widget'] = forms.TimeInput(
                        attrs={'class': 'form-control time-field'})
                elif fieldclass == forms.BooleanField:
                    instanceargs['widget'] = forms.CheckboxInput(
                        attrs={'class': 'form-control'})

            except KeyError:
                # The data_type was not found anywhere
                raise NameError("Unrecognized data_type %s" % field.data_type)

        self.fields['custom_%s' % field.name] = fieldclass(**instanceargs)


class EditTicketForm(CustomFieldMixin, forms.ModelForm):

    class Meta:
        model = Ticket
        exclude = ('created', 'modified', 'status', 'on_hold',
                   'resolution', 'last_escalation', 'assigned_to')

    class Media:
        js = ('helpdesk/js/init_due_date.js',
              'helpdesk/js/init_datetime_classes.js')

    def __init__(self, *args, **kwargs):
        """
        Add any custom fields that are defined to the form
        """
        super(EditTicketForm, self).__init__(*args, **kwargs)

        # Disable and add help_text to the merged_to field on this form
        self.fields['merged_to'].disabled = True
        self.fields['merged_to'].help_text = _(
            'This ticket is merged into the selected ticket.')

        for field in CustomField.objects.all():
            initial_value = None
            try:
                current_value = TicketCustomFieldValue.objects.get(
                    ticket=self.instance, field=field)
                initial_value = current_value.value
                # Attempt to convert from fixed format string to date/time data
                # type
                if 'datetime' == current_value.field.data_type:
                    initial_value = datetime.strptime(
                        initial_value, CUSTOMFIELD_DATETIME_FORMAT)
                elif 'date' == current_value.field.data_type:
                    initial_value = datetime.strptime(
                        initial_value, CUSTOMFIELD_DATE_FORMAT)
                elif 'time' == current_value.field.data_type:
                    initial_value = datetime.strptime(
                        initial_value, CUSTOMFIELD_TIME_FORMAT)
                # If it is boolean field, transform the value to a real boolean
                # instead of a string
                elif 'boolean' == current_value.field.data_type:
                    initial_value = 'True' == initial_value
            except (TicketCustomFieldValue.DoesNotExist, ValueError, TypeError):
                # ValueError error if parsing fails, using initial_value = current_value.value
                # TypeError if parsing None type
                pass
            instanceargs = {
                'label': field.label,
                'help_text': field.help_text,
                'required': field.required,
                'initial': initial_value,
            }

            self.customfield_to_field(field, instanceargs)

    def save(self, *args, **kwargs):

        for field, value in self.cleaned_data.items():
            if field.startswith('custom_'):
                field_name = field.replace('custom_', '', 1)
                customfield = CustomField.objects.get(name=field_name)
                try:
                    cfv = TicketCustomFieldValue.objects.get(
                        ticket=self.instance, field=customfield)
                except ObjectDoesNotExist:
                    cfv = TicketCustomFieldValue(
                        ticket=self.instance, field=customfield)

                cfv.value = convert_value(value)
                cfv.save()

        return super(EditTicketForm, self).save(*args, **kwargs)


class EditFollowUpForm(forms.ModelForm):

    class Meta:
        model = FollowUp
        exclude = ('date', 'user',)

    def __init__(self, *args, **kwargs):
        """Filter not openned tickets here."""
        super(EditFollowUpForm, self).__init__(*args, **kwargs)
        self.fields["ticket"].queryset = Ticket.objects.filter(
            status__in=(Ticket.OPEN_STATUS, Ticket.REOPENED_STATUS))


class AbstractTicketForm(CustomFieldMixin, forms.Form):
    """
    Contain all the common code and fields between "TicketForm" and
    "PublicTicketForm". This Form is not intended to be used directly.
    """
    queue = forms.ChoiceField(
        widget=forms.Select(attrs={'class': 'form-control'}),
        label=_('Queue'),
        required=True,
        choices=()
    )

    title = forms.CharField(
        max_length=100,
        required=True,
        widget=forms.TextInput(attrs={'class': 'form-control'}),
        label=_('Summary of the problem'),
    )

    body = forms.CharField(
        widget=forms.Textarea(attrs={'class': 'form-control'}),
        label=_('Description of your issue'),
        required=True,
        help_text=_(
            'Please be as descriptive as possible and include all details'),
    )

    priority = forms.ChoiceField(
        widget=forms.Select(attrs={'class': 'form-control'}),
        choices=Ticket.PRIORITY_CHOICES,
        required=True,
        initial=getattr(settings, 'HELPDESK_PUBLIC_TICKET_PRIORITY', '3'),
        label=_('Priority'),
        help_text=_(
            "Please select a priority carefully. If unsure, leave it as '3'."),
    )

    due_date = forms.DateTimeField(
        widget=forms.TextInput(
            attrs={'class': 'form-control', 'autocomplete': 'off'}),
        required=False,
        input_formats=[CUSTOMFIELD_DATE_FORMAT,
                       CUSTOMFIELD_DATETIME_FORMAT, '%d/%m/%Y', '%m/%d/%Y', "%d.%m.%Y"],
        label=_('Due on'),
    )

    attachment = forms.FileField(
        widget=forms.FileInput(attrs={'class': 'form-control-file'}),
        required=False,
        label=_('Attach File'),
        help_text=_('You can attach a file to this ticket. '
                    'Only file types such as plain text (.txt), '
                    'a document (.pdf, .docx, or .odt), '
                    'or screenshot (.png or .jpg) may be uploaded.'),
        validators=[validate_file_extension]
    )

    class Media:
        js = ('helpdesk/js/init_due_date.js',
              'helpdesk/js/init_datetime_classes.js')

    def __init__(self, kbcategory=None, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if helpdesk_settings.HELPDESK_KB_ENABLED:
            if kbcategory:
                self.fields['kbitem'] = forms.ChoiceField(
                    widget=forms.Select(attrs={'class': 'form-control'}),
                    required=False,
                    label=_('Knowledge Base Item'),
                    choices=[(kbi.pk, kbi.title) for kbi in KBItem.objects.filter(
                        category=kbcategory.pk, enabled=True)],
                )

    def _add_form_custom_fields(self, staff_only_filter=None):
        if staff_only_filter is None:
            queryset = CustomField.objects.all()
        else:
            queryset = CustomField.objects.filter(staff_only=staff_only_filter)

        for field in queryset:
            instanceargs = {
                'label': field.label,
                'help_text': field.help_text,
                'required': field.required,
            }

            self.customfield_to_field(field, instanceargs)

    def _get_queue(self):
        # this procedure is re-defined for public submission form
        return Queue.objects.get(id=int(self.cleaned_data['queue']))

    def _create_ticket(self):
        queue = self._get_queue()
        kbitem = None
        if 'kbitem' in self.cleaned_data:
            kbitem = KBItem.objects.get(id=int(self.cleaned_data['kbitem']))

        ticket = Ticket(
            title=self.cleaned_data['title'],
            submitter_email=self.cleaned_data['submitter_email'],
            created=timezone.now(),
            status=Ticket.OPEN_STATUS,
            queue=queue,
            description=self.cleaned_data['body'],
            priority=self.cleaned_data.get(
                'priority',
                getattr(settings, "HELPDESK_PUBLIC_TICKET_PRIORITY", "3")
            ),
            due_date=self.cleaned_data.get(
                'due_date',
                getattr(settings, "HELPDESK_PUBLIC_TICKET_DUE_DATE", None)
            ) or None,
            kbitem=kbitem,
        )

        return ticket, queue

    def _create_custom_fields(self, ticket):
        ticket.save_custom_field_values(self.cleaned_data)

    def _create_follow_up(self, ticket, title, user=None):
        followup = FollowUp(ticket=ticket,
                            title=title,
                            date=timezone.now(),
                            public=True,
                            comment=self.cleaned_data['body'],
                            )
        if user:
            followup.user = user
        return followup

    def _attach_files_to_follow_up(self, followup):
        files = self.cleaned_data['attachment']
        if files:
            files = process_attachments(followup, [files])
        return files

    @staticmethod
    def _send_messages(ticket, queue, followup, files, user=None):
        context = safe_template_context(ticket)
        context['comment'] = followup.comment

        roles = {'submitter': ('newticket_submitter', context),
                 'new_ticket_cc': ('newticket_cc', context),
                 'ticket_cc': ('newticket_cc', context)}
        if ticket.assigned_to and ticket.assigned_to.usersettings_helpdesk.email_on_ticket_assign:
            roles['assigned_to'] = ('assigned_owner', context)
        ticket.send(
            roles,
            fail_silently=True,
            files=files,
        )


class TicketForm(AbstractTicketForm):
    """
    Ticket Form creation for registered users.
    """
    submitter_email = forms.EmailField(
        required=False,
        label=_('Submitter E-Mail Address'),
        widget=forms.TextInput(
            attrs={'class': 'form-control', 'type': 'email'}),
        help_text=_('This e-mail address will receive copies of all public '
                    'updates to this ticket.'),
    )
    assigned_to = forms.ChoiceField(
        widget=(
            forms.Select(attrs={'class': 'form-control'})
            if not helpdesk_settings.HELPDESK_CREATE_TICKET_HIDE_ASSIGNED_TO
            else forms.HiddenInput()
        ),
        required=False,
        label=_('Case owner'),
        help_text=_('If you select an owner other than yourself, they\'ll be '
                    'e-mailed details of this ticket immediately.'),

        choices=()
    )

    def __init__(self, *args, **kwargs):
        """
        Add any custom fields that are defined to the form.
        """
        queue_choices = kwargs.pop("queue_choices")

        super().__init__(*args, **kwargs)

        self.fields['queue'].choices = queue_choices
        if helpdesk_settings.HELPDESK_STAFF_ONLY_TICKET_OWNERS:
            assignable_users = User.objects.filter(
                is_active=True, is_staff=True).order_by(User.USERNAME_FIELD)
        else:
            assignable_users = User.objects.filter(
                is_active=True).order_by(User.USERNAME_FIELD)
        self.fields['assigned_to'].choices = [
            ('', '--------')] + [(u.id, u.get_username()) for u in assignable_users]
        self._add_form_custom_fields()

    def save(self, user):
        """
        Writes and returns a Ticket() object
        """

        ticket, queue = self._create_ticket()
        if self.cleaned_data['assigned_to']:
            try:
                u = User.objects.get(id=self.cleaned_data['assigned_to'])
                ticket.assigned_to = u
            except User.DoesNotExist:
                ticket.assigned_to = None
        ticket.save()

        self._create_custom_fields(ticket)

        if self.cleaned_data['assigned_to']:
            title = _('Ticket Opened & Assigned to %(name)s') % {
                'name': ticket.get_assigned_to or _("<invalid user>")
            }
        else:
            title = _('Ticket Opened')
        followup = self._create_follow_up(ticket, title=title, user=user)
        followup.save()

        files = self._attach_files_to_follow_up(followup)
        self._send_messages(ticket=ticket,
                            queue=queue,
                            followup=followup,
                            files=files,
                            user=user)
        return ticket


class PublicTicketForm(AbstractTicketForm):
    """
    Ticket Form creation for all users (public-facing).
    """
    submitter_email = forms.EmailField(
        widget=forms.TextInput(
            attrs={'class': 'form-control', 'type': 'email'}),
        required=True,
        label=_('Your E-Mail Address'),
        help_text=_('We will e-mail you when your ticket is updated.'),
    )

    def __init__(self, hidden_fields=(), readonly_fields=(), *args, **kwargs):
        """
        Add any (non-staff) custom fields that are defined to the form
        """
        super(PublicTicketForm, self).__init__(*args, **kwargs)
        self._add_form_custom_fields(False)

        for field in self.fields.keys():
            if field in hidden_fields:
                self.fields[field].widget = forms.HiddenInput()
            if field in readonly_fields:
                self.fields[field].disabled = True

        field_deletion_table = {
            'queue': 'HELPDESK_PUBLIC_TICKET_QUEUE',
            'priority': 'HELPDESK_PUBLIC_TICKET_PRIORITY',
            'due_date': 'HELPDESK_PUBLIC_TICKET_DUE_DATE',
        }

        for field_name, field_setting_key in field_deletion_table.items():
            has_settings_default_value = getattr(
                settings, field_setting_key, None)
            if has_settings_default_value is not None:
                del self.fields[field_name]

        public_queues = Queue.objects.filter(allow_public_submission=True)

        if len(public_queues) == 0:
            logger.warning(
                "There are no public queues defined - public ticket creation is impossible"
            )

        if 'queue' in self.fields:
            self.fields['queue'].choices = [('', '--------')] + [
                (q.id, q.title) for q in public_queues]

    def _get_queue(self):
        if getattr(settings, 'HELPDESK_PUBLIC_TICKET_QUEUE', None) is not None:
            # force queue to be the pre-defined one
            # (only for public submissions)
            public_queue = Queue.objects.filter(
                slug=settings.HELPDESK_PUBLIC_TICKET_QUEUE
            ).first()
            if not public_queue:
                logger.fatal(
                    "Public queue '%s' is configured as default but can't be found",
                    settings.HELPDESK_PUBLIC_TICKET_QUEUE
                )
            return public_queue
        else:
            # get the queue user entered
            return Queue.objects.get(id=int(self.cleaned_data['queue']))

    def save(self, user):
        """
        Writes and returns a Ticket() object
        """
        ticket, queue = self._create_ticket()
        if queue.default_owner and not ticket.assigned_to:
            ticket.assigned_to = queue.default_owner
        ticket.save()

        self._create_custom_fields(ticket)

        followup = self._create_follow_up(
            ticket, title=_('Ticket Opened Via Web'), user=user)
        followup.save()

        files = self._attach_files_to_follow_up(followup)
        self._send_messages(ticket=ticket,
                            queue=queue,
                            followup=followup,
                            files=files)
        return ticket


class UserSettingsForm(forms.ModelForm):

    class Meta:
        model = UserSettings
        exclude = ['user', 'settings_pickled']


class EmailIgnoreForm(forms.ModelForm):

    class Meta:
        model = IgnoreEmail
        exclude = []


class TicketCCForm(forms.ModelForm):
    ''' Adds either an email address or helpdesk user as a CC on a Ticket. Used for processing POST requests. '''

    class Meta:
        model = TicketCC
        exclude = ('ticket',)

    def __init__(self, *args, **kwargs):
        super(TicketCCForm, self).__init__(*args, **kwargs)
        if helpdesk_settings.HELPDESK_STAFF_ONLY_TICKET_CC:
            users = User.objects.filter(
                is_active=True, is_staff=True).order_by(User.USERNAME_FIELD)
        else:
            users = User.objects.filter(
                is_active=True).order_by(User.USERNAME_FIELD)
        self.fields['user'].queryset = users


class TicketCCUserForm(forms.ModelForm):
    ''' Adds a helpdesk user as a CC on a Ticket '''

    def __init__(self, *args, **kwargs):
        super(TicketCCUserForm, self).__init__(*args, **kwargs)
        if helpdesk_settings.HELPDESK_STAFF_ONLY_TICKET_CC:
            users = User.objects.filter(
                is_active=True, is_staff=True).order_by(User.USERNAME_FIELD)
        else:
            users = User.objects.filter(
                is_active=True).order_by(User.USERNAME_FIELD)
        self.fields['user'].queryset = users

    class Meta:
        model = TicketCC
        exclude = ('ticket', 'email',)


class TicketCCEmailForm(forms.ModelForm):
    ''' Adds an email address as a CC on a Ticket '''

    def __init__(self, *args, **kwargs):
        super(TicketCCEmailForm, self).__init__(*args, **kwargs)

    class Meta:
        model = TicketCC
        exclude = ('ticket', 'user',)


class TicketDependencyForm(forms.ModelForm):
    ''' Adds a different ticket as a dependency for this Ticket '''

    class Meta:
        model = TicketDependency
        exclude = ('ticket',)


class MultipleTicketSelectForm(forms.Form):
    tickets = forms.ModelMultipleChoiceField(
        label=_('Tickets to merge'),
        queryset=Ticket.objects.filter(merged_to=None),
        widget=forms.SelectMultiple(attrs={'class': 'form-control'})
    )

    def clean_tickets(self):
        tickets = self.cleaned_data.get('tickets')
        if len(tickets) < 2:
            raise ValidationError(_('Please choose at least 2 tickets.'))
        if len(tickets) > 4:
            raise ValidationError(
                _('Impossible to merge more than 4 tickets...'))
        queues = tickets.order_by('queue').distinct(
        ).values_list('queue', flat=True)
        if len(queues) != 1:
            raise ValidationError(
                _('All selected tickets must share the same queue in order to be merged.'))
        return tickets