"""
PawCare Data Models

All sensitive fields (phone, address, payment info) are AES-256 encrypted
at rest using django-encrypted-model-fields (Fernet / cryptography library).
"""

import uuid
from django.db import models
from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin, BaseUserManager
from django.utils import timezone
from encrypted_model_fields.fields import EncryptedCharField, EncryptedTextField


# ─────────────────────────────────────────────────────────────────────────────
# Role Constants
# ─────────────────────────────────────────────────────────────────────────────
class Role(models.TextChoices):
    ADMIN = 'admin', 'Admin'
    USER = 'user', 'User'
    CAREGIVER = 'caregiver', 'Caregiver'


# ─────────────────────────────────────────────────────────────────────────────
# Custom User Manager
# ─────────────────────────────────────────────────────────────────────────────
class UserManager(BaseUserManager):
    def create_user(self, email, password=None, **extra_fields):
        if not email:
            raise ValueError('Email is required.')
        email = self.normalize_email(email)
        extra_fields.setdefault('role', Role.USER)
        user = self.model(email=email, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email, password=None, **extra_fields):
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)
        extra_fields.setdefault('role', Role.ADMIN)
        return self.create_user(email, password, **extra_fields)


# ─────────────────────────────────────────────────────────────────────────────
# User
# ─────────────────────────────────────────────────────────────────────────────
class User(AbstractBaseUser, PermissionsMixin):
    """Custom user model — email-based auth with RBAC."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    email = models.EmailField(unique=True, db_index=True)
    first_name = models.CharField(max_length=100)
    last_name = models.CharField(max_length=100)
    role = models.CharField(max_length=20, choices=Role.choices, default=Role.USER)
    avatar_url = models.URLField(blank=True)

    # Encrypted PII
    phone = EncryptedCharField(max_length=255, blank=True)
    address = EncryptedTextField(blank=True)

    is_active = models.BooleanField(default=True)
    is_staff = models.BooleanField(default=False)
    date_joined = models.DateTimeField(default=timezone.now)
    last_login = models.DateTimeField(null=True, blank=True)

    objects = UserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['first_name', 'last_name']

    class Meta:
        db_table = 'users'
        verbose_name = 'User'
        verbose_name_plural = 'Users'
        ordering = ['-date_joined']

    def __str__(self):
        return f'{self.first_name} {self.last_name} <{self.email}>'

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

    @property
    def is_admin(self):
        return self.role == Role.ADMIN

    @property
    def is_caregiver(self):
        return self.role == Role.CAREGIVER


# ─────────────────────────────────────────────────────────────────────────────
# Service
# ─────────────────────────────────────────────────────────────────────────────
class Service(models.Model):
    """Pet care service types offered on the platform."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=100)
    description = models.TextField(blank=True)
    icon = models.CharField(max_length=50, blank=True)  # emoji / icon name
    base_price = models.DecimalField(max_digits=8, decimal_places=2)
    duration_minutes = models.PositiveIntegerField(default=60)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'services'
        ordering = ['name']

    def __str__(self):
        return self.name


# ─────────────────────────────────────────────────────────────────────────────
# Caregiver
# ─────────────────────────────────────────────────────────────────────────────
class Caregiver(models.Model):
    """
    Caregiver profile — created by admin only via Django Admin.
    The linked User account has role = 'caregiver'.
    """

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    user = models.OneToOneField(
        User, on_delete=models.CASCADE, related_name='caregiver_profile'
    )

    # Bio & Professional Info
    bio = models.TextField(blank=True)
    years_of_experience = models.PositiveSmallIntegerField(default=0)
    specializations = models.JSONField(default=list)   # ['dogs', 'cats', …]
    certifications = models.JSONField(default=list)    # ['First Aid', …]
    languages = models.JSONField(default=list, blank=True)

    # Services & Pricing
    services = models.ManyToManyField(Service, blank=True, through='CaregiverService')

    # Location
    latitude = models.DecimalField(max_digits=9, decimal_places=6, null=True, blank=True)
    longitude = models.DecimalField(max_digits=9, decimal_places=6, null=True, blank=True)
    city = models.CharField(max_length=100, blank=True)
    country = models.CharField(max_length=100, default='Nepal')

    # Media — stored on Hugging Face Hub; these are public CDN URLs
    profile_image_url = models.URLField(blank=True)
    gallery_images = models.JSONField(default=list)   # list of HF Hub URLs

    # Stats (computed periodically)
    rating = models.DecimalField(max_digits=3, decimal_places=2, default=0.00)
    total_reviews = models.PositiveIntegerField(default=0)
    total_bookings = models.PositiveIntegerField(default=0)

    # Availability & Status
    is_available = models.BooleanField(default=True)
    is_verified = models.BooleanField(default=False)
    is_featured = models.BooleanField(default=False)
    background_check_passed = models.BooleanField(default=False)

    # Encrypted sensitive contact info
    emergency_contact = EncryptedCharField(max_length=255, blank=True)

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = 'caregivers'
        ordering = ['-rating', '-total_bookings']

    def __str__(self):
        return f'{self.user.full_name} ({self.rating}★)'


class CaregiverService(models.Model):
    """Through table — caregiver-specific pricing per service."""

    caregiver = models.ForeignKey(Caregiver, on_delete=models.CASCADE)
    service = models.ForeignKey(Service, on_delete=models.CASCADE)
    price_per_hour = models.DecimalField(max_digits=8, decimal_places=2)
    is_active = models.BooleanField(default=True)

    class Meta:
        db_table = 'caregiver_services'
        unique_together = ('caregiver', 'service')

    def __str__(self):
        return f'{self.caregiver} — {self.service} @ {self.price_per_hour}/hr'


# ─────────────────────────────────────────────────────────────────────────────
# Pet
# ─────────────────────────────────────────────────────────────────────────────
class PetType(models.TextChoices):
    DOG = 'dog', 'Dog'
    CAT = 'cat', 'Cat'
    BIRD = 'bird', 'Bird'
    FISH = 'fish', 'Fish'
    RABBIT = 'rabbit', 'Rabbit'
    OTHER = 'other', 'Other'


class Pet(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    owner = models.ForeignKey(User, on_delete=models.CASCADE, related_name='pets')
    name = models.CharField(max_length=100)
    pet_type = models.CharField(max_length=20, choices=PetType.choices)
    breed = models.CharField(max_length=100, blank=True)
    age_years = models.PositiveSmallIntegerField(null=True, blank=True)
    weight_kg = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
    color = models.CharField(max_length=100, blank=True)
    image_url = models.URLField(blank=True)

    # Medical info
    is_vaccinated = models.BooleanField(default=False)
    is_neutered = models.BooleanField(default=False)
    medical_notes = EncryptedTextField(blank=True)   # encrypted
    special_needs = models.TextField(blank=True)

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = 'pets'
        ordering = ['name']

    def __str__(self):
        return f'{self.name} ({self.pet_type}) — {self.owner.full_name}'


# ─────────────────────────────────────────────────────────────────────────────
# Booking
# ─────────────────────────────────────────────────────────────────────────────
class BookingStatus(models.TextChoices):
    PENDING = 'pending', 'Pending'
    CONFIRMED = 'confirmed', 'Confirmed'
    IN_PROGRESS = 'in_progress', 'In Progress'
    COMPLETED = 'completed', 'Completed'
    CANCELLED = 'cancelled', 'Cancelled'
    DISPUTED = 'disputed', 'Disputed'


class Booking(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    user = models.ForeignKey(User, on_delete=models.PROTECT, related_name='bookings')
    caregiver = models.ForeignKey(Caregiver, on_delete=models.PROTECT, related_name='bookings')
    pet = models.ForeignKey(Pet, on_delete=models.PROTECT, related_name='bookings')
    service = models.ForeignKey(Service, on_delete=models.PROTECT)

    status = models.CharField(
        max_length=20, choices=BookingStatus.choices, default=BookingStatus.PENDING
    )

    scheduled_start = models.DateTimeField()
    scheduled_end = models.DateTimeField()
    actual_start = models.DateTimeField(null=True, blank=True)
    actual_end = models.DateTimeField(null=True, blank=True)

    # Pricing
    price_subtotal = models.DecimalField(max_digits=10, decimal_places=2)
    price_fees = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    price_total = models.DecimalField(max_digits=10, decimal_places=2)

    # Encrypted payment reference
    payment_reference = EncryptedCharField(max_length=255, blank=True)
    payment_status = models.CharField(max_length=20, default='pending')

    # Location snapshot at booking time
    service_address = EncryptedTextField(blank=True)

    notes = models.TextField(blank=True)
    cancellation_reason = models.TextField(blank=True)

    # Review
    rating = models.PositiveSmallIntegerField(null=True, blank=True)
    review = models.TextField(blank=True)
    reviewed_at = models.DateTimeField(null=True, blank=True)

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = 'bookings'
        ordering = ['-created_at']

    def __str__(self):
        return f'Booking #{str(self.id)[:8]} — {self.user.full_name} + {self.caregiver}'


# ─────────────────────────────────────────────────────────────────────────────
# Messaging
# ─────────────────────────────────────────────────────────────────────────────
class Conversation(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    participants = models.ManyToManyField(User, related_name='conversations')
    booking = models.OneToOneField(
        Booking, on_delete=models.SET_NULL, null=True, blank=True,
        related_name='conversation'
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = 'conversations'
        ordering = ['-updated_at']

    def __str__(self):
        names = ', '.join(p.full_name for p in self.participants.all()[:2])
        return f'Conv [{names}]'


class Message(models.Model):
    class MessageType(models.TextChoices):
        TEXT = 'text', 'Text'
        IMAGE = 'image', 'Image'
        SYSTEM = 'system', 'System'

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    conversation = models.ForeignKey(
        Conversation, on_delete=models.CASCADE, related_name='messages'
    )
    sender = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
    message_type = models.CharField(max_length=10, choices=MessageType.choices, default=MessageType.TEXT)

    # Content is encrypted at rest
    content = EncryptedTextField()
    image_url = models.URLField(blank=True)

    is_read = models.BooleanField(default=False)
    read_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'messages'
        ordering = ['created_at']

    def __str__(self):
        return f'Msg from {self.sender} in {self.conversation}'