from django.db import models
# from django.contrib.auth.models import User
from django.core.validators import MinValueValidator, MaxValueValidator
from django.utils import timezone
from datetime import timedelta
from hr.models import Department
from patients.models import PatientProfile
from accounts.models import User

class BloodGroup(models.Model):
    """Blood group types (A, B, AB, O) with Rh factor"""
    ABO_CHOICES = [
        ('A', 'A'),
        ('B', 'B'),
        ('AB', 'AB'),
        ('O', 'O'),
    ]

    RH_CHOICES = [
        ('POS', 'Positive'),
        ('NEG', 'Negative'),
    ]

    abo_type = models.CharField(max_length=2, choices=ABO_CHOICES)
    rh_factor = models.CharField(max_length=8, choices=RH_CHOICES)

    class Meta:
        unique_together = ['abo_type', 'rh_factor']
        ordering = ['abo_type', 'rh_factor']

    def __str__(self):
        return f"{self.abo_type} {self.rh_factor.capitalize()}"

    @property
    def display_name(self):
        rh_symbol = '+' if self.rh_factor == 'POS' else '-'
        return f"{self.abo_type}{rh_symbol}"


class Donor(models.Model):
    """Blood donor information and eligibility"""
    DONOR_TYPE_CHOICES = [
        ('voluntary', 'Voluntary'),
        ('replacement', 'Replacement'),
        ('autologous', 'Autologous'),
        ('directed', 'Directed'),
    ]

    STATUS_CHOICES = [
        ('active', 'Active'),
        ('deferred', 'Deferred'),
        ('permanently_deferred', 'Permanently Deferred'),
        ('inactive', 'Inactive'),
    ]

    donor_id = models.CharField(max_length=20, unique=True)
    first_name = models.CharField(max_length=100)
    last_name = models.CharField(max_length=100)
    date_of_birth = models.DateField()
    gender = models.CharField(max_length=10, choices=[('M', 'Male'), ('F', 'Female'), ('O', 'Other')])
    national_id = models.CharField(max_length=10, unique=True)
    blood_group = models.ForeignKey(BloodGroup, on_delete=models.PROTECT)
    phone = models.CharField(max_length=20)
    email = models.EmailField(blank=True)
    address = models.TextField()
    emergency_contact_name = models.CharField(max_length=100)
    emergency_contact_phone = models.CharField(max_length=20)
    donor_type = models.CharField(max_length=20, choices=DONOR_TYPE_CHOICES, default='voluntary')
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='active')
    registration_date = models.DateTimeField(auto_now_add=True)
    last_donation_date = models.DateTimeField(null=True, blank=True)
    total_donations = models.PositiveIntegerField(default=0)
    weight = models.FloatField(validators=[MinValueValidator(45.0)])  # Minimum weight for donation
    height = models.FloatField(validators=[MinValueValidator(140.0)])  # In cm
    notes = models.TextField(blank=True)
    created_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='created_donors')
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-registration_date']

    def __str__(self):
        return f"{self.donor_id} - {self.first_name} {self.last_name}"

    @property
    def full_name(self):
        return f"{self.first_name} {self.last_name}"

    @property
    def age(self):
        today = timezone.now().date()
        return today.year - self.date_of_birth.year - (
                    (today.month, today.day) < (self.date_of_birth.month, self.date_of_birth.day))

    @property
    def is_eligible_for_donation(self):
        """Check if donor is eligible for donation based on last donation date"""
        if self.status != 'active':
            return False

        if not self.last_donation_date:
            return True

        # Minimum 56 days between whole blood donations
        days_since_last = (timezone.now() - self.last_donation_date).days
        return days_since_last >= 56

    @property
    def next_eligible_date(self):
        """Calculate next eligible donation date"""
        if not self.last_donation_date:
            return timezone.now().date()

        return (self.last_donation_date + timedelta(days=56)).date()


class BloodComponent(models.Model):
    """Types of blood components (Whole Blood, RBC, Plasma, Platelets, etc.)"""
    COMPONENT_CHOICES = [
        ('whole_blood', 'Whole Blood'),
        ('packed_rbc', 'Packed Red Blood Cells'),
        ('fresh_frozen_plasma', 'Fresh Frozen Plasma'),
        ('platelets', 'Platelets'),
        ('cryoprecipitate', 'Cryoprecipitate'),
        ('granulocytes', 'Granulocytes'),
    ]

    name = models.CharField(max_length=50, choices=COMPONENT_CHOICES, unique=True)
    description = models.TextField()
    shelf_life_days = models.PositiveIntegerField()  # Storage duration in days
    storage_temperature = models.CharField(max_length=50)  # Storage requirements
    volume_ml = models.PositiveIntegerField()  # Standard volume in ml
    is_active = models.BooleanField(default=True)

    class Meta:
        ordering = ['name']

    def __str__(self):
        return self.get_name_display()


class BloodUnit(models.Model):
    """Individual blood unit from donation to disposal"""
    STATUS_CHOICES = [
        ('collected', 'Collected'),
        ('testing', 'Testing'),
        ('quarantine', 'Quarantine'),
        ('available', 'Available'),
        ('reserved', 'Reserved'),
        ('issued', 'Issued'),
        ('transfused', 'Transfused'),
        ('expired', 'Expired'),
        ('discarded', 'Discarded'),
    ]

    unit_number = models.CharField(max_length=20, unique=True)
    donor = models.ForeignKey(Donor, on_delete=models.PROTECT, related_name='blood_units')
    component = models.ForeignKey(BloodComponent, on_delete=models.PROTECT)
    blood_group = models.ForeignKey(BloodGroup, on_delete=models.PROTECT)
    collection_date = models.DateTimeField()
    expiry_date = models.DateTimeField()
    volume_ml = models.PositiveIntegerField()
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='collected')
    location = models.CharField(max_length=100)  # Storage location/refrigerator
    bag_type = models.CharField(max_length=50)
    anticoagulant = models.CharField(max_length=50, default='CPDA-1')
    collection_site = models.CharField(max_length=100)
    collected_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='collected_units')
    notes = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-collection_date']

    def __str__(self):
        return f"{self.unit_number} - {self.component} ({self.blood_group})"

    @property
    def is_expired(self):
        return timezone.now() > self.expiry_date

    @property
    def days_to_expiry(self):
        delta = self.expiry_date - timezone.now()
        return delta.days if delta.days > 0 else 0

    @property
    def is_available(self):
        return self.status == 'available' and not self.is_expired


class BloodTest(models.Model):
    """Blood testing results for infectious diseases and compatibility"""
    TEST_TYPE_CHOICES = [
        ('abo_rh', 'ABO/Rh Typing'),
        ('antibody_screen', 'Antibody Screening'),
        ('hiv', 'HIV'),
        ('hbv', 'Hepatitis B'),
        ('hcv', 'Hepatitis C'),
        ('syphilis', 'Syphilis'),
        ('htlv', 'HTLV'),
        ('cmv', 'CMV'),
        ('malaria', 'Malaria'),
    ]

    RESULT_CHOICES = [
        ('positive', 'Positive'),
        ('negative', 'Negative'),
        ('indeterminate', 'Indeterminate'),
        ('pending', 'Pending'),
    ]

    blood_unit = models.ForeignKey(BloodUnit, on_delete=models.CASCADE, related_name='tests')
    test_type = models.CharField(max_length=20, choices=TEST_TYPE_CHOICES)
    result = models.CharField(max_length=15, choices=RESULT_CHOICES, default='pending')
    test_date = models.DateTimeField()
    tested_by = models.ForeignKey(User, on_delete=models.PROTECT)
    equipment_used = models.CharField(max_length=100, blank=True)
    lot_number = models.CharField(max_length=50, blank=True)
    notes = models.TextField(blank=True)
    verified_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='verified_tests', null=True,
                                    blank=True)
    verified_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        unique_together = ['blood_unit', 'test_type']
        ordering = ['-test_date']

    def __str__(self):
        return f"{self.blood_unit.unit_number} - {self.get_test_type_display()}: {self.result}"


class CrossMatch(models.Model):
    """Cross-matching tests between donor blood and recipient"""
    COMPATIBILITY_CHOICES = [
        ('compatible', 'Compatible'),
        ('incompatible', 'Incompatible'),
        ('pending', 'Pending'),
    ]

    TEST_TYPE_CHOICES = [
        ('major', 'Major Crossmatch'),
        ('minor', 'Minor Crossmatch'),
        ('immediate_spin', 'Immediate Spin'),
        ('antiglobulin', 'Antiglobulin Test'),
    ]

    blood_unit = models.ForeignKey(BloodUnit, on_delete=models.CASCADE, related_name='crossmatches')
    recipient = models.ForeignKey(PatientProfile, on_delete=models.PROTECT)
    test_type = models.CharField(max_length=20, choices=TEST_TYPE_CHOICES)
    compatibility = models.CharField(max_length=15, choices=COMPATIBILITY_CHOICES, default='pending')
    test_date = models.DateTimeField()
    tested_by = models.ForeignKey(User, on_delete=models.PROTECT)
    temperature = models.CharField(max_length=20, default='37°C')
    incubation_time = models.PositiveIntegerField(default=15)  # minutes
    notes = models.TextField(blank=True)
    verified_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='verified_crossmatches', null=True,
                                    blank=True)
    verified_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ['-test_date']

    def __str__(self):
        return f"{self.blood_unit.unit_number} x {self.recipient} - {self.compatibility}"


class BloodRequest(models.Model):
    """Blood transfusion requests from clinical departments"""
    URGENCY_CHOICES = [
        ('routine', 'Routine'),
        ('urgent', 'Urgent'),
        ('emergency', 'Emergency'),
    ]

    STATUS_CHOICES = [
        ('pending', 'Pending'),
        ('processing', 'Processing'),
        ('ready', 'Ready'),
        ('issued', 'Issued'),
        ('completed', 'Completed'),
        ('cancelled', 'Cancelled'),
    ]

    request_number = models.CharField(max_length=20, unique=True)
    patient = models.ForeignKey(PatientProfile, on_delete=models.PROTECT, related_name='blood_requests')
    requesting_department = models.ForeignKey(Department, on_delete=models.PROTECT)
    requesting_physician = models.ForeignKey(User, on_delete=models.PROTECT, related_name='blood_requests')
    component_requested = models.ForeignKey(BloodComponent, on_delete=models.PROTECT)
    units_requested = models.PositiveIntegerField(validators=[MinValueValidator(1)])
    urgency = models.CharField(max_length=10, choices=URGENCY_CHOICES, default='routine')
    indication = models.TextField()  # Clinical indication for transfusion
    special_requirements = models.TextField(blank=True)  # CMV negative, irradiated, etc.
    patient_blood_group = models.ForeignKey(BloodGroup, on_delete=models.PROTECT)
    hemoglobin_level = models.FloatField(null=True, blank=True)
    platelet_count = models.IntegerField(null=True, blank=True)
    status = models.CharField(max_length=15, choices=STATUS_CHOICES, default='pending')
    request_date = models.DateTimeField(auto_now_add=True)
    required_by = models.DateTimeField()
    processed_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='processed_requests', null=True,
                                     blank=True)
    processed_at = models.DateTimeField(null=True, blank=True)
    notes = models.TextField(blank=True)

    # Cancellation fields
    cancellation_reason = models.TextField(blank=True)
    cancelled_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='cancelled_requests', null=True,
                                     blank=True)
    cancellation_date = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ['-request_date']

    def __str__(self):
        return f"{self.request_number} - {self.patient} ({self.component_requested})"

    @property
    def is_overdue(self):
        return timezone.now() > self.required_by and self.status not in ['completed', 'cancelled']


class BloodIssue(models.Model):
    """Blood unit issuance to patients"""
    blood_request = models.ForeignKey(BloodRequest, on_delete=models.PROTECT, related_name='issues')
    blood_unit = models.OneToOneField(BloodUnit, on_delete=models.PROTECT, related_name='issue')
    crossmatch = models.ForeignKey(CrossMatch, on_delete=models.PROTECT, null=True, blank=True)
    issued_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='issued_units')
    issued_to = models.ForeignKey(User, on_delete=models.PROTECT, related_name='received_units')  # Nurse/physician
    issue_date = models.DateTimeField(auto_now_add=True)
    expiry_time = models.DateTimeField()  # 4 hours from issue for RBC
    returned = models.BooleanField(default=False)
    return_date = models.DateTimeField(null=True, blank=True)
    return_reason = models.TextField(blank=True)
    notes = models.TextField(blank=True)

    class Meta:
        ordering = ['-issue_date']

    def __str__(self):
        return f"{self.blood_unit.unit_number} issued to {self.blood_request.patient}"

    @property
    def is_expired(self):
        return timezone.now() > self.expiry_time and not self.returned


class Transfusion(models.Model):
    """Blood transfusion administration records"""
    STATUS_CHOICES = [
        ('started', 'Started'),
        ('in_progress', 'In Progress'),
        ('completed', 'Completed'),
        ('stopped', 'Stopped'),
        ('adverse_reaction', 'Adverse Reaction'),
    ]

    blood_issue = models.OneToOneField(BloodIssue, on_delete=models.PROTECT, related_name='transfusion')
    start_time = models.DateTimeField()
    end_time = models.DateTimeField(null=True, blank=True)
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='started')
    volume_transfused = models.PositiveIntegerField(null=True, blank=True)  # ml
    transfusion_rate = models.CharField(max_length=50, blank=True)  # ml/hour
    administered_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='administered_transfusions')
    witnessed_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='witnessed_transfusions', null=True,
                                     blank=True)
    pre_transfusion_vitals = models.JSONField(default=dict)  # BP, HR, Temp, etc.
    post_transfusion_vitals = models.JSONField(default=dict)
    vital_signs_history = models.JSONField(default=list)  # Array of vital signs during transfusion
    current_blood_pressure = models.CharField(max_length=20, blank=True)
    current_heart_rate = models.IntegerField(null=True, blank=True)
    current_temperature = models.FloatField(null=True, blank=True)
    current_respiratory_rate = models.IntegerField(null=True, blank=True)
    current_oxygen_saturation = models.IntegerField(null=True, blank=True)
    last_vitals_check = models.DateTimeField(null=True, blank=True)
    patient_consent = models.BooleanField(default=False)
    consent_date = models.DateTimeField(null=True, blank=True)
    notes = models.TextField(blank=True)

    # Completion/Stop fields
    stop_reason = models.TextField(blank=True)
    stopped_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='stopped_transfusions', null=True,
                                   blank=True)
    completed_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='completed_transfusions', null=True,
                                     blank=True)
    completion_notes = models.TextField(blank=True)

    class Meta:
        ordering = ['-start_time']

    def __str__(self):
        return f"Transfusion: {self.blood_issue.blood_unit.unit_number} to {self.blood_issue.blood_request.patient}"

    @property
    def duration_minutes(self):
        if self.end_time:
            return int((self.end_time - self.start_time).total_seconds() / 60)
        return None


class AdverseReaction(models.Model):
    """Adverse transfusion reactions"""
    SEVERITY_CHOICES = [
        ('mild', 'Mild'),
        ('moderate', 'Moderate'),
        ('severe', 'Severe'),
        ('life_threatening', 'Life Threatening'),
    ]

    REACTION_TYPE_CHOICES = [
        ('febrile', 'Febrile Non-Hemolytic'),
        ('allergic', 'Allergic'),
        ('hemolytic_acute', 'Acute Hemolytic'),
        ('hemolytic_delayed', 'Delayed Hemolytic'),
        ('anaphylactic', 'Anaphylactic'),
        ('septic', 'Septic'),
        ('circulatory_overload', 'Circulatory Overload'),
        ('lung_injury', 'Transfusion-Related Acute Lung Injury'),
        ('other', 'Other'),
    ]

    transfusion = models.ForeignKey(Transfusion, on_delete=models.CASCADE, related_name='adverse_reactions')
    reaction_type = models.CharField(max_length=30, choices=REACTION_TYPE_CHOICES)
    severity = models.CharField(max_length=20, choices=SEVERITY_CHOICES)
    onset_time = models.DateTimeField()
    symptoms = models.TextField()
    treatment_given = models.TextField()
    outcome = models.TextField()
    reported_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='reported_reactions')
    investigated_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='investigated_reactions',
                                        null=True, blank=True)
    investigation_notes = models.TextField(blank=True)
    regulatory_reported = models.BooleanField(default=False)
    report_date = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ['-onset_time']

    def __str__(self):
        return f"{self.get_reaction_type_display()} - {self.severity} ({self.transfusion.blood_issue.blood_request.patient})"


class InventoryLocation(models.Model):
    """Blood bank storage locations"""
    LOCATION_TYPE_CHOICES = [
        ('refrigerator', 'Refrigerator'),
        ('freezer', 'Freezer'),
        ('platelet_agitator', 'Platelet Agitator'),
        ('quarantine', 'Quarantine'),
        ('testing', 'Testing Area'),
    ]

    name = models.CharField(max_length=100, unique=True)
    location_type = models.CharField(max_length=20, choices=LOCATION_TYPE_CHOICES)
    temperature_range = models.CharField(max_length=50)
    temperature = models.FloatField(null=True, blank=True)  # Current temperature
    capacity = models.PositiveIntegerField()  # Number of units
    current_stock = models.PositiveIntegerField(default=0)
    is_active = models.BooleanField(default=True)
    notes = models.TextField(blank=True)

    class Meta:
        ordering = ['name']

    def __str__(self):
        return f"{self.name} ({self.get_location_type_display()})"

    @property
    def utilization_percentage(self):
        if self.capacity == 0:
            return 0
        return (self.current_stock / self.capacity) * 100


class QualityControl(models.Model):
    """Quality control tests and monitoring"""
    TEST_TYPE_CHOICES = [
        ('temperature_monitoring', 'Temperature Monitoring'),
        ('equipment_calibration', 'Equipment Calibration'),
        ('reagent_testing', 'Reagent Testing'),
        ('proficiency_testing', 'Proficiency Testing'),
        ('process_validation', 'Process Validation'),
    ]

    STATUS_CHOICES = [
        ('pass', 'Pass'),
        ('fail', 'Fail'),
        ('pending', 'Pending'),
    ]

    test_type = models.CharField(max_length=30, choices=TEST_TYPE_CHOICES)
    test_date = models.DateTimeField()
    equipment_tested = models.CharField(max_length=100, blank=True)
    parameters_tested = models.TextField()
    expected_results = models.TextField()
    actual_results = models.TextField()
    status = models.CharField(max_length=10, choices=STATUS_CHOICES)
    performed_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='qc_tests')
    reviewed_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='reviewed_qc_tests', null=True,
                                    blank=True)
    review_date = models.DateTimeField(null=True, blank=True)
    review_notes = models.TextField(blank=True)
    corrective_action = models.TextField(blank=True)
    next_test_date = models.DateTimeField(null=True, blank=True)

    # CAPA (Corrective and Preventive Action) fields
    capa_initiated = models.BooleanField(default=False)
    capa_number = models.CharField(max_length=50, blank=True)
    capa_priority = models.CharField(max_length=10, choices=[('low', 'Low'), ('medium', 'Medium'), ('high', 'High')],
                                     blank=True)
    capa_initiated_by = models.ForeignKey(User, on_delete=models.PROTECT, related_name='initiated_capas', null=True,
                                          blank=True)
    capa_date = models.DateTimeField(null=True, blank=True)
    capa_assessment = models.TextField(blank=True)
    capa_status = models.CharField(max_length=20,
                                   choices=[('open', 'Open'), ('in_progress', 'In Progress'), ('closed', 'Closed')],
                                   blank=True)

    class Meta:
        ordering = ['-test_date']

    def __str__(self):
        return f"{self.get_test_type_display()} - {self.test_date.strftime('%Y-%m-%d')} ({self.status})"