import datetime
from collections import OrderedDict

from django import forms
from django.forms import ModelForm, Form
from django.utils.dates import MONTHS

from web.models import Subject, StudySubject, Worker, Appointment, Visit, AppointmentType, ContactAttempt, AppointmentTypeLink, \
    Availability, Holiday
from web.models.constants import SUBJECT_TYPE_CHOICES, SCREENING_NUMBER_PREFIXES_FOR_TYPE, COUNTRY_OTHER_ID
from web.views.notifications import get_filter_locations

"""
Possible redundancy, but if need arises, contents of forms can be easily customized
"""

DATE_FORMAT_TIME = "%H:%M"
CURRENT_YEAR = datetime.datetime.now().year
YEAR_CHOICES = tuple(range(CURRENT_YEAR, CURRENT_YEAR - 120, -1))
FUTURE_YEAR_CHOICES = tuple(range(CURRENT_YEAR, CURRENT_YEAR + 5, 1))
DATEPICKER_DATE_ATTRS = {
    'class': 'datepicker',
    'data-date-format': 'yyyy-mm-dd',
    'data-date-orientation': 'bottom'
}
DATETIMEPICKER_DATE_ATTRS = {
    'class': 'datetimepicker',
    'data-date-format': 'Y-MM-DD HH:mm',
}
TIMEPICKER_DATE_ATTRS = {
    'class': 'datetimepicker',
    'data-date-format': 'HH:mm',
    'data-date-stepping': 15,
}
START_YEAR_STATISTICS = 2015
APPOINTMENT_TYPES_FIELD_POSITION = 1


def validate_subject_nd_number(self, cleaned_data):
    if cleaned_data['nd_number'] != "":
        subjects_from_db = StudySubject.objects.filter(nd_number=cleaned_data['nd_number'])
        if subjects_from_db:
            if subjects_from_db[0].screening_number != cleaned_data.get('screening_number', ''):
                self.add_error('nd_number', "ND number already in use")


def validate_subject_country(self, cleaned_data):
    if cleaned_data['country'].id == COUNTRY_OTHER_ID:
        self.add_error('country', "Select valid country")


def validate_subject_resign_reason(self, cleaned_data):
    if cleaned_data['resigned'] and cleaned_data['resign_reason'] == '':
        self.add_error('resign_reason', "Resign reason cannot be empty")


def validate_subject_mpower_number(self, cleaned_data):
    if cleaned_data['mpower_id'] != "":
        subjects_from_db = StudySubject.objects.filter(mpower_id=cleaned_data['mpower_id'])
        if subjects_from_db:
            if subjects_from_db[0].screening_number != cleaned_data.get('screening_number', ''):
                self.add_error('mpower_id', "mPower number already in use")


class StudySubjectAddForm(ModelForm):
    date_born = forms.DateField(label="Date of birth",
                                widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d"),
                                required=False
                                )

    datetime_contact_reminder = forms.DateTimeField(label="Contact on",
                                                    widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS),
                                                    required=False
                                                    )

    class Meta:
        model = StudySubject
        fields = '__all__'
        exclude = ['dead', 'resigned', 'resign_reason']

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        if user is None:
            raise TypeError("User not defined")
        self.user = Worker.get_by_user(user)
        if self.user is None:
            raise TypeError("Worker not defined for: " + user.username)

        super(ModelForm, self).__init__(*args, **kwargs)
        self.fields['screening_number'].required = False

    def build_screening_number(self, cleaned_data):
        screening_number = cleaned_data.get('screening_number', None)
        if not screening_number:
            prefix_screening_number = self.get_prefix_screening_number()
            if prefix_screening_number is not None:
                screening_number = get_new_screening_number(prefix_screening_number)
        return screening_number

    def clean(self):
        cleaned_data = super(StudySubjectAddForm, self).clean()
        screening_number = self.build_screening_number(cleaned_data)
        if screening_number is not None:
            cleaned_data['screening_number'] = screening_number
            subjects_from_db = StudySubject.objects.filter(screening_number=screening_number)

            if len(subjects_from_db) > 0:
                self.add_error('screening_number', "Screening number already in use")
        validate_subject_country(self, cleaned_data)
        validate_subject_nd_number(self, cleaned_data)
        validate_subject_mpower_number(self, cleaned_data)
        return cleaned_data

    def get_prefix_screening_number(self):
        default_location = self.cleaned_data.get('default_location', None)
        screening_number_prefix = None
        if default_location is not None and default_location.prefix:
            screening_number_prefix = default_location.prefix
        else:
            subject_type = self.cleaned_data.get('type', None)
            if subject_type is not None:
                screening_number_prefix = SCREENING_NUMBER_PREFIXES_FOR_TYPE[subject_type]
        if screening_number_prefix is None:
            return None
        prefix_screening_number = screening_number_prefix + "-"
        return prefix_screening_number


def get_new_screening_number(screening_number_prefix):
    result_number = 0
    subjects = StudySubject.objects.filter(screening_number__contains=screening_number_prefix)
    for subject in subjects:
        screening_numbers = subject.screening_number.split(";")
        for screening_number in screening_numbers:
            screening_number = screening_number.strip()
            if screening_number.startswith(screening_number_prefix):
                number = screening_number[len(screening_number_prefix):]
                try:
                    result_number = max(result_number, int(number))
                except ValueError:
                    pass

    return screening_number_prefix + str(result_number + 1).zfill(3)


class SubjectDetailForm(ModelForm):
    class Meta:
        model = StudySubject
        fields = '__all__'


class StudySubjectEditForm(ModelForm):
    datetime_contact_reminder = forms.DateTimeField(label="Contact on",
                                                    widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS),
                                                    required=False
                                                    )
    date_born = forms.DateField(label="Date of birth",
                                widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d"),
                                required=False
                                )

    def __init__(self, *args, **kwargs):
        was_dead = kwargs.get('was_dead', False)
        was_resigned = kwargs.get('was_resigned', False)
        if 'was_resigned' in kwargs:
            kwargs.pop('was_resigned')
        if 'was_dead' in kwargs:
            kwargs.pop('was_dead')
        super(StudySubjectEditForm, self).__init__(*args, **kwargs)
        instance = getattr(self, 'instance', None)
        if instance and instance.id:
            self.fields['screening_number'].widget.attrs['readonly'] = True
        if was_dead:
            self.fields['dead'].disabled = True
        if was_resigned:
            self.fields['resigned'].disabled = True

    def clean(self):
        validate_subject_nd_number(self, self.cleaned_data)
        validate_subject_mpower_number(self, self.cleaned_data)
        validate_subject_country(self, self.cleaned_data)
        validate_subject_resign_reason(self, self.cleaned_data)

    class Meta:
        model = StudySubject
        fields = '__all__'
        exclude = ['subject']



class WorkerAddForm(ModelForm):
    class Meta:
        model = Worker
        exclude = ['appointments']


class WorkerEditForm(ModelForm):
    class Meta:
        model = Worker
        fields = '__all__'


class AppointmentDetailForm(ModelForm):
    class Meta:
        model = Appointment
        fields = '__all__'

    datetime_when = forms.DateTimeField(label='Appointment on (YYYY-MM-DD HH:MM)',
                                        widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS)
                                        )


class AppointmentEditForm(ModelForm):
    class Meta:
        model = Appointment
        fields = '__all__'
        exclude = ['appointment_types']

    datetime_when = forms.DateTimeField(label='Appointment on (YYYY-MM-DD HH:MM)',
                                        widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS)
                                        )

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        if user is None:
            raise TypeError("User not defined")
        self.user = Worker.get_by_user(user)
        if self.user is None:
            raise TypeError("Worker not defined for: " + user.username)
        super(ModelForm, self).__init__(*args, **kwargs)
        if 'instance' in kwargs:
            initial_appointment_types = AppointmentTypeLink.objects.filter(appointment=kwargs['instance']).values_list(
                'appointment_type', flat=True)
        else:
            initial_appointment_types = []
        fields = OrderedDict()
        for i, tuple in enumerate(self.fields.items()):
            key, value = tuple
            fields[key] = value
            if i == APPOINTMENT_TYPES_FIELD_POSITION:
                fields['appointment_types'] = forms.ModelMultipleChoiceField(required=False,
                                                                             widget=forms.CheckboxSelectMultiple,
                                                                             queryset=AppointmentType.objects.all(),
                                                                             initial=initial_appointment_types)
        self.fields = fields
        self.fields['worker_assigned'].queryset = Worker.objects.filter(
            locations__in=get_filter_locations(self.user)).distinct().order_by('first_name', 'last_name')
        self.fields['location'].queryset = get_filter_locations(self.user)

    def clean_location(self):
        location = self.cleaned_data['location']
        if self.user.locations.filter(id=location.id).count() == 0:
            self.add_error('location', "You cannot create appointment for this location")
        else:
            return location

    def save(self, commit=True):
        appointment = super(AppointmentEditForm, self).save(commit)
        # if appointment date change, remove appointment_type links
        if 'datetime_when' in self.changed_data:
            AppointmentTypeLink.objects.filter(appointment=appointment).delete()
            appointment_type_links = []
        else:
            appointment_type_links = AppointmentTypeLink.objects.filter(appointment=appointment).all()
        appointment_types_from_links = []
        appointment_types = self.cleaned_data['appointment_types']
        for appointment_type_link in appointment_type_links:
            if appointment_type_link.appointment_type not in appointment_types:
                # we delete appointment links for appointments types that have been removed
                appointment_type_link.delete()
            else:
                appointment_types_from_links.append(appointment_type_link.appointment_type)
        for appointment_type in appointment_types:
            if appointment_type not in appointment_types_from_links:
                # we create new appointment links for appointments types that have been added
                appointment_type_link = AppointmentTypeLink(appointment=appointment,
                                                            appointment_type=appointment_type)
                appointment_type_link.save()
        return appointment


class AppointmentAddForm(ModelForm):
    class Meta:
        model = Appointment
        exclude = ['status', 'appointment_types']

    datetime_when = forms.DateTimeField(label='Appointment on (YYYY-MM-DD HH:MM)',
                                        widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS)
                                        )

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        if user is None:
            raise TypeError("User not defined")
        self.user = Worker.get_by_user(user)
        if self.user is None:
            raise TypeError("Worker not defined for: " + user.username)

        super(ModelForm, self).__init__(*args, **kwargs)
        fields = OrderedDict()
        for i, tuple in enumerate(self.fields.items()):
            key, value = tuple
            fields[key] = value
            if i == APPOINTMENT_TYPES_FIELD_POSITION:
                fields['appointment_types'] = forms.ModelMultipleChoiceField(required=False,
                                                                             widget=forms.CheckboxSelectMultiple,
                                                                             queryset=AppointmentType.objects.all(),
                                                                             )
        self.fields = fields
        self.fields['worker_assigned'].queryset = Worker.objects.filter(
            locations__in=get_filter_locations(self.user)).distinct().order_by('first_name', 'last_name')
        self.fields['location'].queryset = get_filter_locations(self.user)

    def clean_location(self):
        location = self.cleaned_data['location']
        if self.user.locations.filter(id=location.id).count() == 0:
            self.add_error('location', "You cannot create appointment for this location")
        else:
            return location

    def save(self, commit=True):
        appointment = super(AppointmentAddForm, self).save(commit)
        appointment_types = self.cleaned_data['appointment_types']
        for appointment_type in appointment_types:
            appointment_type_link = AppointmentTypeLink(appointment=appointment, appointment_type=appointment_type)
            appointment_type_link.save()
        return appointment


class VisitDetailForm(ModelForm):
    datetime_begin = forms.DateField(label="Visit begins on",
                                     widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d")
                                     )
    datetime_end = forms.DateField(label="Visit ends on",
                                   widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d")
                                   )

    post_mail_sent = forms.RadioSelect()
    appointment_types = forms.ModelMultipleChoiceField(required=False, widget=forms.CheckboxSelectMultiple,
                                                       queryset=AppointmentType.objects.all())

    class Meta:
        model = Visit
        exclude = ['is_finished', 'visit_number']


class VisitAddForm(ModelForm):
    subject = forms.ModelChoiceField(queryset=StudySubject.objects.order_by('last_name', 'first_name'))
    datetime_begin = forms.DateField(label="Visit begins on",
                                     widget=forms.TextInput(attrs=DATEPICKER_DATE_ATTRS)
                                     )
    datetime_end = forms.DateField(label="Visit ends on",
                                   widget=forms.TextInput(attrs=DATEPICKER_DATE_ATTRS)
                                   )
    appointment_types = forms.ModelMultipleChoiceField(required=False, widget=forms.CheckboxSelectMultiple,
                                                       queryset=AppointmentType.objects.all())

    class Meta:
        model = Visit
        exclude = ['is_finished', 'visit_number']

    def clean(self):
        super(VisitAddForm, self).clean()
        if 'datetime_begin' not in self.cleaned_data or 'datetime_end' not in self.cleaned_data:
            return
        if self.cleaned_data['datetime_begin'] >= self.cleaned_data['datetime_end']:
            self.add_error('datetime_begin', "Start date must be before end date")
            self.add_error('datetime_end', "End date must be after start date")


class ContactAttemptForm(ModelForm):
    datetime_when = forms.DateTimeField(label='When? (YYYY-MM-DD HH:MM)',
                                        widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS)
                                        )

    class Meta:
        model = ContactAttempt
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        if user is None:
            raise TypeError("User not defined")
        self.user = Worker.get_by_user(user)
        if self.user is None:
            raise TypeError("Worker not defined for: " + user.username)
        subject = kwargs.pop('subject', None)
        super(ContactAttemptForm, self).__init__(*args, **kwargs)
        self.fields['subject'].initial = subject.id
        self.fields['subject'].disabled = True
        self.fields['worker'].initial = self.user


class ContactAttemptEditForm(ModelForm):
    datetime_when = forms.DateTimeField(label='When? (YYYY-MM-DD HH:MM)',
                                        widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS)
                                        )

    class Meta:
        model = ContactAttempt
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        if user is None:
            raise TypeError("User not defined")
        self.user = Worker.get_by_user(user)
        if self.user is None:
            raise TypeError("Worker not defined for: " + user.username)
        super(ContactAttemptEditForm, self).__init__(*args, **kwargs)
        self.fields['subject'].disabled = True


class KitRequestForm(Form):
    start_date = forms.DateField(label="From date",
                                 widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d"),
                                 required=False
                                 )

    end_date = forms.DateField(label="End date",
                               widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d"),
                               required=False
                               )


class StatisticsForm(Form):
    def __init__(self, *args, **kwargs):
        super(StatisticsForm, self).__init__(*args)
        visit_choices = kwargs['visit_choices']
        month = kwargs['month']
        year = kwargs['year']
        now = datetime.datetime.now()
        year_now = now.year
        number_of_years_for_statistics = year_now - START_YEAR_STATISTICS + 2

        year_choices = [(START_YEAR_STATISTICS + i, START_YEAR_STATISTICS + i) for i in
                        range(0, number_of_years_for_statistics + 1)]
        self.fields['month'] = forms.ChoiceField(choices=MONTHS.items(), initial=month)
        self.fields['year'] = forms.ChoiceField(choices=year_choices, initial=year)
        choices = [(-1, "all")]
        choices.extend(SUBJECT_TYPE_CHOICES.items())
        self.fields['subject_type'] = forms.ChoiceField(choices=choices, initial="-1")
        self.fields['visit'] = forms.ChoiceField(choices=visit_choices, initial="-1")


class AvailabilityAddForm(ModelForm):
    available_from = forms.TimeField(label="Available from",
                                     widget=forms.TimeInput(TIMEPICKER_DATE_ATTRS),
                                     initial="8:00",
                                     )
    available_till = forms.TimeField(label="Available until",
                                     widget=forms.TimeInput(TIMEPICKER_DATE_ATTRS),
                                     initial="17:00",
                                     )

    class Meta:
        model = Availability
        fields = '__all__'

    def clean(self):
        worker = Worker.objects.get(id=self.cleaned_data["person"].id)
        availabilities = worker.availability_set.all()
        for availability in availabilities:
            validate_availability_conflict(self, self.cleaned_data, availability)


class AvailabilityEditForm(ModelForm):
    available_from = forms.TimeField(label="Available from",
                                     widget=forms.TimeInput(TIMEPICKER_DATE_ATTRS),
                                     )
    available_till = forms.TimeField(label="Available until",
                                     widget=forms.TimeInput(TIMEPICKER_DATE_ATTRS),
                                     )

    class Meta:
        model = Availability
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super(ModelForm, self).__init__(*args, **kwargs)
        instance = getattr(self, 'instance', None)
        if instance is not None:
            self.availability_id = instance.id
        self.fields['person'].disabled = True

    def clean(self):
        worker = Worker.objects.get(id=self.cleaned_data["person"].id)
        availabilities = worker.availability_set.all()
        for availability in availabilities:
            if availability.id <> self.availability_id:
                validate_availability_conflict(self, self.cleaned_data, availability)


def validate_availability_conflict(self, cleaned_data, availability):
    start_hour = self.cleaned_data.get("available_from", None)
    end_hour = self.cleaned_data.get("available_till", None)
    if availability.day_number == self.cleaned_data.get("day_number", None) and \
            ((start_hour <= availability.available_from < end_hour) or
                 (start_hour < availability.available_till <= end_hour) or
                 (availability.available_from <= start_hour < availability.available_till) or
                 (availability.available_from < end_hour <= availability.available_till)):
        error = "User has defined availability for this day that overlaps: " + availability.available_from.strftime(
            DATE_FORMAT_TIME) + ", " + availability.available_till.strftime(DATE_FORMAT_TIME)
        self.add_error('day_number', error)
        self.add_error('available_from', error)
        self.add_error('available_till', error)


class HolidayAddForm(ModelForm):
    datetime_start = forms.DateTimeField(widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS),
                                         initial=datetime.datetime.now().replace(hour=8, minute=0),
                                         )
    datetime_end = forms.DateTimeField(widget=forms.DateTimeInput(DATETIMEPICKER_DATE_ATTRS),
                                       initial=datetime.datetime.now().replace(hour=17, minute=0),
                                       )

    class Meta:
        model = Holiday
        fields = '__all__'

    def clean(self):
        worker = Worker.objects.get(id=self.cleaned_data["person"].id)
        availabilities = worker.availability_set.all()
        for availability in availabilities:
            validate_availability_conflict(self, self.cleaned_data, availability)


class SubjectAddForm(ModelForm):
    date_born = forms.DateField(label="Date of birth",
                                widget=forms.DateInput(DATEPICKER_DATE_ATTRS, "%Y-%m-%d"),
                                required=False
                                )

    class Meta:
        model = Subject
        fields = '__all__'
        exclude = ['dead']

    def build_screening_number(self, cleaned_data):
        screening_number = cleaned_data.get('screening_number', None)
        if not screening_number:
            prefix_screening_number = self.get_prefix_screening_number()
            if prefix_screening_number is not None:
                screening_number = get_new_screening_number(prefix_screening_number)
        return screening_number

    def clean(self):
        cleaned_data = super(SubjectAddForm, self).clean()
        validate_subject_country(self, cleaned_data)
        return cleaned_data