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

This module handles nursing encounters, vital signs, anthropometric measurements,
and growth chart tracking based on MD-N-F-1 form.
"""

from django.db import models
from django.utils.translation import gettext_lazy as _
from simple_history.models import HistoricalRecords

from core.models import (
    UUIDPrimaryKeyMixin,
    TimeStampedMixin,
    TenantOwnedMixin,
    ClinicallySignableMixin,
)


class NursingEncounter(UUIDPrimaryKeyMixin, TimeStampedMixin, TenantOwnedMixin, ClinicallySignableMixin):
    """
    Nursing encounter with vital signs and anthropometric measurements.
    Based on MD-N-F-1 form.
    """
    
    class CRT(models.TextChoices):
        LESS_THAN_2S = 'LESS_THAN_2S', _('< 2 seconds')
        MORE_THAN_2S = 'MORE_THAN_2S', _('> 2 seconds')
    
    # Core Relationships
    patient = models.ForeignKey(
        'core.Patient',
        on_delete=models.CASCADE,
        related_name='nursing_encounters',
        verbose_name=_("Patient")
    )
    appointment = models.ForeignKey(
        'appointments.Appointment',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='nursing_encounters',
        verbose_name=_("Appointment")
    )
    encounter_date = models.DateField(
        verbose_name=_("Encounter Date")
    )
    filled_by = models.ForeignKey(
        'core.User',
        on_delete=models.SET_NULL,
        null=True,
        related_name='nursing_encounters_filled',
        verbose_name=_("Filled By")
    )
    
    # Anthropometric Measurements
    height_cm = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Height in centimeters"),
        verbose_name=_("Height (cm)")
    )
    weight_kg = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Weight in kilograms"),
        verbose_name=_("Weight (kg)")
    )
    head_circumference_cm = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Head circumference in centimeters"),
        verbose_name=_("Head Circumference (cm)")
    )
    
    # Vital Signs
    hr_bpm = models.PositiveIntegerField(
        null=True,
        blank=True,
        help_text=_("Heart rate in beats per minute"),
        verbose_name=_("Heart Rate (bpm)")
    )
    bp_systolic = models.PositiveIntegerField(
        null=True,
        blank=True,
        help_text=_("Systolic blood pressure in mmHg"),
        verbose_name=_("BP Systolic (mmHg)")
    )
    bp_diastolic = models.PositiveIntegerField(
        null=True,
        blank=True,
        help_text=_("Diastolic blood pressure in mmHg"),
        verbose_name=_("BP Diastolic (mmHg)")
    )
    respiratory_rate = models.PositiveIntegerField(
        null=True,
        blank=True,
        help_text=_("Respiratory rate per minute"),
        verbose_name=_("Respiratory Rate (/min)")
    )
    spo2 = models.PositiveIntegerField(
        null=True,
        blank=True,
        help_text=_("Oxygen saturation percentage"),
        verbose_name=_("SpO2 (%)")
    )
    temperature = models.DecimalField(
        max_digits=4,
        decimal_places=1,
        null=True,
        blank=True,
        help_text=_("Temperature in Celsius"),
        verbose_name=_("Temperature (°C)")
    )
    crt = models.CharField(
        max_length=20,
        choices=CRT.choices,
        blank=True,
        help_text=_("Capillary Refill Time"),
        verbose_name=_("CRT")
    )
    
    # Pain Assessment
    pain_score = models.PositiveSmallIntegerField(
        null=True,
        blank=True,
        help_text=_("Pain score from 0 (no pain) to 10 (worst pain)"),
        verbose_name=_("Pain Score (0-10)")
    )
    
    # Allergies
    allergy_present = models.BooleanField(
        default=False,
        verbose_name=_("Allergy Present")
    )
    allergy_details = models.TextField(
        blank=True,
        verbose_name=_("Allergy Details")
    )
    
    # Observations
    observations = models.TextField(
        blank=True,
        verbose_name=_("Observations")
    )
    
    history = HistoricalRecords()
    
    class Meta:
        verbose_name = _("Nursing Encounter")
        verbose_name_plural = _("Nursing Encounters")
        ordering = ['-encounter_date', '-created_at']
        indexes = [
            models.Index(fields=['patient', 'encounter_date']),
            models.Index(fields=['appointment']),
            models.Index(fields=['tenant', 'encounter_date']),
        ]
    
    def __str__(self):
        return f"Nursing Encounter - {self.patient} - {self.encounter_date}"
    
    @property
    def bmi(self):
        """Calculate BMI from height and weight."""
        if self.height_cm and self.weight_kg:
            height_m = float(self.height_cm) / 100
            return round(float(self.weight_kg) / (height_m ** 2), 2)
        return None
    
    @property
    def bmi_category(self):
        """Categorize BMI (simplified for adults)."""
        bmi = self.bmi
        if not bmi:
            return None
        
        if bmi < 18.5:
            return _("Underweight")
        elif bmi < 25:
            return _("Normal weight")
        elif bmi < 30:
            return _("Overweight")
        else:
            return _("Obese")
    
    @property
    def blood_pressure(self):
        """Return formatted blood pressure."""
        if self.bp_systolic and self.bp_diastolic:
            return f"{self.bp_systolic}/{self.bp_diastolic}"
        return None
    
    @property
    def has_abnormal_vitals(self):
        """Check if any vital signs are outside normal ranges (simplified)."""
        abnormal = []
        
        # Heart rate (normal adult: 60-100 bpm)
        if self.hr_bpm and (self.hr_bpm < 60 or self.hr_bpm > 100):
            abnormal.append('HR')
        
        # Blood pressure (normal: <120/<80)
        if self.bp_systolic and self.bp_systolic >= 140:
            abnormal.append('BP Systolic')
        if self.bp_diastolic and self.bp_diastolic >= 90:
            abnormal.append('BP Diastolic')
        
        # SpO2 (normal: >95%)
        if self.spo2 and self.spo2 < 95:
            abnormal.append('SpO2')
        
        # Temperature (normal: 36.5-37.5°C)
        if self.temperature and (self.temperature < 36.5 or self.temperature > 37.5):
            abnormal.append('Temperature')
        
        return abnormal


class GrowthChart(UUIDPrimaryKeyMixin, TimeStampedMixin):
    """
    Growth chart data points for tracking patient growth over time.
    Used to plot growth curves and percentiles.
    """
    
    patient = models.ForeignKey(
        'core.Patient',
        on_delete=models.CASCADE,
        related_name='growth_chart_data',
        verbose_name=_("Patient")
    )
    nursing_encounter = models.ForeignKey(
        NursingEncounter,
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='growth_chart_entries',
        verbose_name=_("Nursing Encounter")
    )
    measurement_date = models.DateField(
        verbose_name=_("Measurement Date")
    )
    age_months = models.PositiveIntegerField(
        help_text=_("Age in months at time of measurement"),
        verbose_name=_("Age (months)")
    )
    
    # Measurements
    height_cm = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        verbose_name=_("Height (cm)")
    )
    weight_kg = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        verbose_name=_("Weight (kg)")
    )
    head_circumference_cm = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        verbose_name=_("Head Circumference (cm)")
    )
    
    # Percentiles (calculated based on WHO/CDC growth charts)
    percentile_height = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Height percentile (0-100)"),
        verbose_name=_("Height Percentile")
    )
    percentile_weight = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Weight percentile (0-100)"),
        verbose_name=_("Weight Percentile")
    )
    percentile_head_circumference = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("Head circumference percentile (0-100)"),
        verbose_name=_("Head Circumference Percentile")
    )
    percentile_bmi = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        null=True,
        blank=True,
        help_text=_("BMI percentile (0-100)"),
        verbose_name=_("BMI Percentile")
    )
    
    class Meta:
        verbose_name = _("Growth Chart Entry")
        verbose_name_plural = _("Growth Chart Entries")
        ordering = ['patient', 'measurement_date']
        indexes = [
            models.Index(fields=['patient', 'measurement_date']),
            models.Index(fields=['patient', 'age_months']),
        ]
    
    def __str__(self):
        return f"Growth Chart - {self.patient} - {self.measurement_date} ({self.age_months} months)"
    
    @property
    def bmi(self):
        """Calculate BMI."""
        if self.height_cm and self.weight_kg:
            height_m = float(self.height_cm) / 100
            return round(float(self.weight_kg) / (height_m ** 2), 2)
        return None
    
    def save(self, *args, **kwargs):
        # Auto-populate from nursing encounter if linked
        if self.nursing_encounter and not self.height_cm:
            self.height_cm = self.nursing_encounter.height_cm
            self.weight_kg = self.nursing_encounter.weight_kg
            self.head_circumference_cm = self.nursing_encounter.head_circumference_cm
            self.measurement_date = self.nursing_encounter.encounter_date
        
        # Calculate age in months if not provided
        if not self.age_months and self.measurement_date:
            from dateutil.relativedelta import relativedelta
            age_delta = relativedelta(self.measurement_date, self.patient.date_of_birth)
            self.age_months = age_delta.years * 12 + age_delta.months
        
        super().save(*args, **kwargs)


class VitalSignsAlert(UUIDPrimaryKeyMixin, TimeStampedMixin, TenantOwnedMixin):
    """
    Alerts for abnormal vital signs that require attention.
    Auto-generated when vitals are outside normal ranges.
    """
    
    class Severity(models.TextChoices):
        LOW = 'LOW', _('Low')
        MEDIUM = 'MEDIUM', _('Medium')
        HIGH = 'HIGH', _('High')
        CRITICAL = 'CRITICAL', _('Critical')
    
    class Status(models.TextChoices):
        ACTIVE = 'ACTIVE', _('Active')
        ACKNOWLEDGED = 'ACKNOWLEDGED', _('Acknowledged')
        RESOLVED = 'RESOLVED', _('Resolved')
    
    nursing_encounter = models.ForeignKey(
        NursingEncounter,
        on_delete=models.CASCADE,
        related_name='alerts',
        verbose_name=_("Nursing Encounter")
    )
    vital_sign = models.CharField(
        max_length=50,
        help_text=_("Which vital sign triggered the alert"),
        verbose_name=_("Vital Sign")
    )
    value = models.CharField(
        max_length=50,
        verbose_name=_("Value")
    )
    severity = models.CharField(
        max_length=20,
        choices=Severity.choices,
        verbose_name=_("Severity")
    )
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.ACTIVE,
        verbose_name=_("Status")
    )
    acknowledged_by = models.ForeignKey(
        'core.User',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='acknowledged_alerts',
        verbose_name=_("Acknowledged By")
    )
    acknowledged_at = models.DateTimeField(
        null=True,
        blank=True,
        verbose_name=_("Acknowledged At")
    )
    notes = models.TextField(
        blank=True,
        verbose_name=_("Notes")
    )
    
    class Meta:
        verbose_name = _("Vital Signs Alert")
        verbose_name_plural = _("Vital Signs Alerts")
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['status', 'severity']),
            models.Index(fields=['nursing_encounter']),
            models.Index(fields=['tenant', 'status']),
        ]
    
    def __str__(self):
        return f"Alert: {self.vital_sign} - {self.nursing_encounter.patient} - {self.get_severity_display()}"