"""
Nursing views for the Tenhal Multidisciplinary Healthcare Platform.

This module contains views for nursing documentation including:
- Nursing encounters (vitals, anthropometrics)
- Growth charts
- Allergy tracking
- Observation notes
"""

from django.contrib.auth.mixins import LoginRequiredMixin
from django.db.models import Q
from django.http import JsonResponse, HttpResponseRedirect
from django.shortcuts import get_object_or_404, redirect
from django.utils import timezone
from django.views.generic import ListView, DetailView, CreateView, UpdateView, View
from django.urls import reverse_lazy
from django.contrib import messages

from core.mixins import (
    SignedDocumentEditPreventionMixin,
    TenantFilterMixin,
    RolePermissionMixin,
    AuditLogMixin,
    HTMXResponseMixin,
    SuccessMessageMixin,
    PaginationMixin,
)
from core.models import User, Patient
from appointments.models import Appointment
from .models import NursingEncounter
from .forms import NursingEncounterForm


# Sign View
class NursingEncounterSignView(LoginRequiredMixin, RolePermissionMixin, TenantFilterMixin, View):
    """Sign a nursing encounter."""
    allowed_roles = [User.Role.ADMIN, User.Role.NURSE]
    
    def post(self, request, pk):
        encounter = get_object_or_404(NursingEncounter, pk=pk, tenant=request.user.tenant)
        if encounter.signed_by:
            messages.warning(request, "This encounter has already been signed.")
            return HttpResponseRedirect(reverse_lazy('nursing:encounter_detail', kwargs={'pk': pk}))
        if encounter.filled_by != request.user and request.user.role != User.Role.ADMIN:
            messages.error(request, "Only the nurse who filled this encounter or an administrator can sign it.")
            return HttpResponseRedirect(reverse_lazy('nursing:encounter_detail', kwargs={'pk': pk}))
        encounter.signed_by = request.user
        encounter.signed_at = timezone.now()
        encounter.save()
        messages.success(
            request,
            "Encounter signed successfully! This document can no longer be edited.")
        return HttpResponseRedirect(reverse_lazy('nursing:encounter_detail', kwargs={'pk': pk}))


class NursingEncounterListView(LoginRequiredMixin, TenantFilterMixin, PaginationMixin,
                               HTMXResponseMixin, ListView):
    """
    Nursing encounter list view.
    
    Features:
    - Filter by patient, date range
    - Search by patient name/MRN
    - Role-based filtering (nurses see their encounters)
    - Quick vitals summary
    """
    model = NursingEncounter
    template_name = 'nursing/encounter_list.html'
    htmx_template_name = 'nursing/partials/encounter_list_partial.html'
    context_object_name = 'encounters'
    paginate_by = 25
    
    def get_queryset(self):
        """Get filtered queryset."""
        queryset = super().get_queryset()
        user = self.request.user
        
        # Role-based filtering
        if user.role == User.Role.NURSE:
            queryset = queryset.filter(filled_by=user)
        
        # Apply search
        search_query = self.request.GET.get('search', '').strip()
        if search_query:
            queryset = queryset.filter(
                Q(patient__first_name_en__icontains=search_query) |
                Q(patient__last_name_en__icontains=search_query) |
                Q(patient__mrn__icontains=search_query)
            )
        
        # Apply filters
        patient_id = self.request.GET.get('patient')
        if patient_id:
            queryset = queryset.filter(patient_id=patient_id)
        
        date_from = self.request.GET.get('date_from')
        if date_from:
            queryset = queryset.filter(encounter_date__gte=date_from)
        
        date_to = self.request.GET.get('date_to')
        if date_to:
            queryset = queryset.filter(encounter_date__lte=date_to)
        
        return queryset.select_related('patient', 'filled_by', 'appointment', 'signed_by').order_by('-encounter_date')
    
    def get_context_data(self, **kwargs):
        """Add filter options and unsigned counts."""
        context = super().get_context_data(**kwargs)
        user = self.request.user
        
        # Get unsigned encounters
        unsigned_query = NursingEncounter.objects.filter(tenant=user.tenant, signed_by__isnull=True)
        if user.role == User.Role.NURSE:
            unsigned_query = unsigned_query.filter(filled_by=user)
        
        context['unsigned_count'] = unsigned_query.count()
        context['unsigned_items'] = unsigned_query.select_related('patient', 'filled_by').order_by('-encounter_date')[:10]
        
        # Add current filters
        context['current_filters'] = {
            'search': self.request.GET.get('search', ''),
            'patient': self.request.GET.get('patient', ''),
            'date_from': self.request.GET.get('date_from', ''),
            'date_to': self.request.GET.get('date_to', ''),
        }
        
        return context


class NursingEncounterDetailView(LoginRequiredMixin, TenantFilterMixin, DetailView):
    """
    Nursing encounter detail view.
    
    Features:
    - Full vitals and anthropometrics
    - BMI calculation and interpretation
    - Growth chart visualization
    - Allergy information
    - Observation notes
    """
    model = NursingEncounter
    template_name = 'nursing/encounter_detail.html'
    context_object_name = 'encounter'
    
    def get_context_data(self, **kwargs):
        """Add calculated values and interpretations."""
        context = super().get_context_data(**kwargs)
        encounter = self.object
        
        # BMI interpretation
        if encounter.bmi:
            context['bmi_interpretation'] = self._interpret_bmi(encounter.bmi)
        
        # Vital signs interpretation
        context['vitals_interpretation'] = self._interpret_vitals(encounter)
        
        # Get previous encounters for comparison
        context['previous_encounters'] = NursingEncounter.objects.filter(
            patient=encounter.patient,
            encounter_date__lt=encounter.encounter_date
        ).order_by('-encounter_date')[:5]
        
        # Growth chart data (for visualization)
        context['growth_data'] = self._get_growth_chart_data(encounter.patient)
        
        return context
    
    def _interpret_bmi(self, bmi):
        """Interpret BMI value."""
        if bmi < 18.5:
            return {'category': 'Underweight', 'color': 'warning'}
        elif 18.5 <= bmi < 25:
            return {'category': 'Normal weight', 'color': 'success'}
        elif 25 <= bmi < 30:
            return {'category': 'Overweight', 'color': 'warning'}
        else:
            return {'category': 'Obese', 'color': 'danger'}
    
    def _interpret_vitals(self, encounter):
        """Interpret vital signs."""
        interpretations = {}
        
        # Heart rate
        if encounter.hr_bpm:
            if encounter.hr_bpm < 60:
                interpretations['hr'] = {'status': 'Low', 'color': 'warning'}
            elif 60 <= encounter.hr_bpm <= 100:
                interpretations['hr'] = {'status': 'Normal', 'color': 'success'}
            else:
                interpretations['hr'] = {'status': 'High', 'color': 'danger'}
        
        # Blood pressure
        if encounter.bp_systolic and encounter.bp_diastolic:
            if encounter.bp_systolic < 120 and encounter.bp_diastolic < 80:
                interpretations['bp'] = {'status': 'Normal', 'color': 'success'}
            elif encounter.bp_systolic < 140 and encounter.bp_diastolic < 90:
                interpretations['bp'] = {'status': 'Elevated', 'color': 'warning'}
            else:
                interpretations['bp'] = {'status': 'High', 'color': 'danger'}
        
        # SpO2
        if encounter.spo2:
            if encounter.spo2 >= 95:
                interpretations['spo2'] = {'status': 'Normal', 'color': 'success'}
            elif encounter.spo2 >= 90:
                interpretations['spo2'] = {'status': 'Low', 'color': 'warning'}
            else:
                interpretations['spo2'] = {'status': 'Critical', 'color': 'danger'}
        
        return interpretations
    
    def _get_growth_chart_data(self, patient):
        """Get growth chart data for patient."""
        encounters = NursingEncounter.objects.filter(
            patient=patient
        ).order_by('encounter_date')
        
        data = {
            'dates': [],
            'weight': [],
            'height': [],
            'head_circ': [],
            'bmi': [],
        }
        
        for encounter in encounters:
            data['dates'].append(encounter.encounter_date.strftime('%Y-%m-%d'))
            data['weight'].append(float(encounter.weight_kg) if encounter.weight_kg else None)
            data['height'].append(float(encounter.height_cm) if encounter.height_cm else None)
            data['head_circ'].append(float(encounter.head_circumference_cm) if encounter.head_circumference_cm else None)
            data['bmi'].append(float(encounter.bmi) if encounter.bmi else None)
        
        return data


class NursingEncounterCreateView(LoginRequiredMixin, RolePermissionMixin, AuditLogMixin,
                                SuccessMessageMixin, CreateView):
    """
    Nursing encounter creation view.
    
    Features:
    - Record vitals and anthropometrics
    - Auto-calculate BMI
    - Link to appointment
    - Allergy documentation
    """
    model = NursingEncounter
    form_class = NursingEncounterForm
    template_name = 'nursing/encounter_form.html'
    success_message = "Nursing encounter recorded successfully!"
    allowed_roles = [User.Role.ADMIN, User.Role.NURSE]
    
    def get_success_url(self):
        """Redirect to encounter detail."""
        return reverse_lazy('nursing:encounter_detail', kwargs={'pk': self.object.pk})
    
    def form_valid(self, form):
        """Set tenant and filled_by."""
        # Set tenant
        form.instance.tenant = self.request.user.tenant
        
        # Set filled_by
        form.instance.filled_by = self.request.user
        
        # Set encounter date if not provided
        if not form.instance.encounter_date:
            form.instance.encounter_date = timezone.now().date()
        
        # Calculate BMI if height and weight provided
        if form.instance.height_cm and form.instance.weight_kg:
            height_m = form.instance.height_cm / 100
            form.instance.bmi = form.instance.weight_kg / (height_m ** 2)
        
        # Save encounter
        response = super().form_valid(form)
        
        # Update appointment status if linked
        if self.object.appointment:
            appointment = self.object.appointment
            if appointment.status == Appointment.Status.IN_PROGRESS:
                # Keep in progress, nursing is part of the visit
                pass
        
        return response
    
    def get_context_data(self, **kwargs):
        """Add form title and patient/appointment info."""
        context = super().get_context_data(**kwargs)
        context['form_title'] = 'Record Nursing Encounter'
        context['submit_text'] = 'Save Encounter'
        
        # Get patient if provided
        patient_id = self.request.GET.get('patient')
        if patient_id:
            try:
                context['patient'] = Patient.objects.get(
                    pk=patient_id,
                    tenant=self.request.user.tenant
                )
            except Patient.DoesNotExist:
                pass
        
        # Get appointment if provided
        appointment_id = self.request.GET.get('appointment_id')
        if appointment_id:
            try:
                context['appointment'] = Appointment.objects.get(
                    pk=appointment_id,
                    tenant=self.request.user.tenant
                )
                context['patient'] = context['appointment'].patient
            except Appointment.DoesNotExist:
                pass
        
        return context


class NursingEncounterUpdateView(LoginRequiredMixin, RolePermissionMixin, TenantFilterMixin,
                                AuditLogMixin, SuccessMessageMixin, UpdateView):
    """
    Nursing encounter update view.
    
    Features:
    - Update vitals and anthropometrics
    - Recalculate BMI
    - Version history
    """
    model = NursingEncounter
    form_class = NursingEncounterForm
    template_name = 'nursing/encounter_form.html'
    success_message = "Nursing encounter updated successfully!"
    allowed_roles = [User.Role.ADMIN, User.Role.NURSE]
    
    def get_success_url(self):
        """Redirect to encounter detail."""
        return reverse_lazy('nursing:encounter_detail', kwargs={'pk': self.object.pk})
    
    def form_valid(self, form):
        """Recalculate BMI if needed."""
        # Recalculate BMI if height or weight changed
        if form.instance.height_cm and form.instance.weight_kg:
            height_m = form.instance.height_cm / 100
            form.instance.bmi = form.instance.weight_kg / (height_m ** 2)
        
        return super().form_valid(form)
    
    def get_context_data(self, **kwargs):
        """Add form title and history."""
        context = super().get_context_data(**kwargs)
        context['form_title'] = f'Update Nursing Encounter - {self.object.patient.mrn}'
        context['submit_text'] = 'Update Encounter'
        
        # Add version history if available
        if hasattr(self.object, 'history'):
            context['history'] = self.object.history.all()[:10]
        
        return context


class PatientVitalsHistoryView(LoginRequiredMixin, TenantFilterMixin, ListView):
    """
    Patient vitals history view.
    
    Features:
    - All vitals for a specific patient
    - Trend visualization
    - Growth charts
    - Export to PDF
    """
    model = NursingEncounter
    template_name = 'nursing/patient_vitals_history.html'
    context_object_name = 'encounters'
    paginate_by = 50
    
    def get_queryset(self):
        """Get all encounters for patient."""
        patient_id = self.kwargs.get('patient_id')
        return NursingEncounter.objects.filter(
            patient_id=patient_id,
            tenant=self.request.user.tenant
        ).order_by('-encounter_date')
    
    def get_context_data(self, **kwargs):
        """Add patient and chart data."""
        context = super().get_context_data(**kwargs)
        
        patient_id = self.kwargs.get('patient_id')
        context['patient'] = get_object_or_404(
            Patient,
            pk=patient_id,
            tenant=self.request.user.tenant
        )
        
        # Get chart data
        encounters = self.get_queryset()
        context['chart_data'] = self._prepare_chart_data(encounters)
        
        # Get statistics
        context['stats'] = self._calculate_statistics(encounters)
        
        return context
    
    def _prepare_chart_data(self, encounters):
        """Prepare data for charts."""
        data = {
            'dates': [],
            'weight': [],
            'height': [],
            'bmi': [],
            'hr': [],
            'bp_sys': [],
            'bp_dia': [],
            'spo2': [],
            'temperature': [],
        }
        
        for encounter in encounters.order_by('encounter_date'):
            data['dates'].append(encounter.encounter_date.strftime('%Y-%m-%d'))
            data['weight'].append(float(encounter.weight_kg) if encounter.weight_kg else None)
            data['height'].append(float(encounter.height_cm) if encounter.height_cm else None)
            data['bmi'].append(float(encounter.bmi) if encounter.bmi else None)
            data['hr'].append(encounter.hr_bpm if encounter.hr_bpm else None)
            data['bp_sys'].append(encounter.bp_systolic if encounter.bp_systolic else None)
            data['bp_dia'].append(encounter.bp_diastolic if encounter.bp_diastolic else None)
            data['spo2'].append(encounter.spo2 if encounter.spo2 else None)
            data['temperature'].append(float(encounter.temperature) if encounter.temperature else None)
        
        return data
    
    def _calculate_statistics(self, encounters):
        """Calculate statistics from encounters."""
        if not encounters:
            return {}
        
        latest = encounters.first()
        oldest = encounters.last()
        
        stats = {
            'total_encounters': encounters.count(),
            'latest_weight': latest.weight_kg if latest.weight_kg else None,
            'latest_height': latest.height_cm if latest.height_cm else None,
            'latest_bmi': latest.bmi if latest.bmi else None,
        }
        
        # Calculate weight change if we have both
        if latest.weight_kg and oldest.weight_kg and encounters.count() > 1:
            stats['weight_change'] = latest.weight_kg - oldest.weight_kg
        
        # Calculate height change if we have both
        if latest.height_cm and oldest.height_cm and encounters.count() > 1:
            stats['height_change'] = latest.height_cm - oldest.height_cm
        
        return stats


class GrowthChartView(LoginRequiredMixin, TenantFilterMixin, DetailView):
    """
    Growth chart visualization view.
    
    Features:
    - WHO growth standards overlay
    - Patient measurements plotted
    - Percentile calculations
    - Export to PDF
    """
    model = Patient
    template_name = 'nursing/growth_chart.html'
    context_object_name = 'patient'
    pk_url_kwarg = 'patient_id'
    
    def get_context_data(self, **kwargs):
        """Add growth chart data."""
        context = super().get_context_data(**kwargs)
        patient = self.object
        
        # Get all encounters
        encounters = NursingEncounter.objects.filter(
            patient=patient
        ).order_by('encounter_date')
        
        # Prepare chart data
        context['chart_data'] = self._prepare_growth_chart_data(encounters, patient)
        
        # Get WHO standards (placeholder - would need actual WHO data)
        context['who_standards'] = self._get_who_standards(patient)
        
        return context
    
    def _prepare_growth_chart_data(self, encounters, patient):
        """Prepare growth chart data."""
        data = {
            'age_months': [],
            'weight': [],
            'height': [],
            'head_circ': [],
            'bmi': [],
        }
        
        for encounter in encounters:
            # Calculate age in months at encounter
            age_months = self._calculate_age_months(patient.date_of_birth, encounter.encounter_date)
            
            data['age_months'].append(age_months)
            data['weight'].append(float(encounter.weight_kg) if encounter.weight_kg else None)
            data['height'].append(float(encounter.height_cm) if encounter.height_cm else None)
            data['head_circ'].append(float(encounter.head_circumference_cm) if encounter.head_circumference_cm else None)
            data['bmi'].append(float(encounter.bmi) if encounter.bmi else None)
        
        return data
    
    def _calculate_age_months(self, birth_date, encounter_date):
        """Calculate age in months."""
        years = encounter_date.year - birth_date.year
        months = encounter_date.month - birth_date.month
        return years * 12 + months
    
    def _get_who_standards(self, patient):
        """Get WHO growth standards for patient's gender."""
        # TODO: Implement WHO growth standards
        # This would load actual WHO percentile data based on patient gender
        return {
            'percentiles': [3, 15, 50, 85, 97],
            'weight': {},
            'height': {},
            'bmi': {},
        }