from django.db import models
from django.contrib.auth.models import AbstractUser


class User(AbstractUser):
    full_name = models.CharField(max_length=100)

    email = models.EmailField(unique=True)

    user_age = models.PositiveIntegerField(null=True, blank=True)

    GENDER_CHOICES = [
        ('Male', 'Male'),
        ('Female', 'Female'),
        ('Other', 'Other'),
        ('Prefer not to say', 'Prefer not to say'),
    ]

    user_gender = models.CharField(
        max_length=20,
        choices=GENDER_CHOICES,
        default='Prefer not to say'
    )

    created_at = models.DateTimeField(auto_now_add=True)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['username']

class Address(models.Model):
    user = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name='addresses'
    )

    line1 = models.CharField(max_length=255)
    line2 = models.CharField(max_length=255, blank=True)

    city = models.CharField(max_length=100)
    state = models.CharField(max_length=100)
    country = models.CharField(max_length=100)

    pincode = models.CharField(max_length=20)

    is_default = models.BooleanField(default=False)

    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"{self.line1}, {self.city}"


class Product(models.Model):
    product_name = models.CharField(max_length=255, db_index=True)

    base_price = models.DecimalField(
        max_digits=10,
        decimal_places=2,
        db_index=True
    )

    stock_quantity = models.PositiveIntegerField(default=0)

    class Meta:
        ordering = ['id']

    def __str__(self):
        return self.product_name

class Order(models.Model):

    PAYMENT_CHOICES = [
        ('Credit Card', 'Credit Card'),
        ('Debit Card', 'Debit Card'),
        ('PayPal', 'PayPal'),
        ('Gift Card', 'Gift Card'),
    ]

    SHIPPING_CHOICES = [
        ('Standard', 'Standard'),
        ('Express', 'Express'),
        ('Next-Day', 'Next-Day'),
    ]

    user = models.ForeignKey(
        User,
        on_delete=models.CASCADE,
        related_name='orders'
    )

    shipping_address = models.ForeignKey(
        Address,
        on_delete=models.PROTECT,
        related_name='orders'
    )

    order_date = models.DateTimeField(auto_now_add=True, db_index=True)

    payment_method = models.CharField(
        max_length=20,
        choices=PAYMENT_CHOICES
    )

    shipping_method = models.CharField(
        max_length=20,
        choices=SHIPPING_CHOICES
    )

    def __str__(self):
        return f"Order {self.id}"


class OrderDetail(models.Model):

    RETURN_STATUS = [
        ('Not Returned', 'Not Returned'),
        ('Return Initiated', 'Return Initiated'),
        ('Returned', 'Returned'),
    ]

    order = models.ForeignKey(
        Order,
        on_delete=models.CASCADE,
        related_name='items'
    )

    product = models.ForeignKey(
        Product,
        on_delete=models.PROTECT
    )

    order_quantity = models.PositiveIntegerField()

    product_price = models.DecimalField(
        max_digits=10,
        decimal_places=2
    )

    discount_applied = models.DecimalField(
        max_digits=5,
        decimal_places=2,
        default=0
    )

    return_status = models.CharField(
        max_length=20,
        choices=RETURN_STATUS,
        default='Not Returned',
        db_index=True
    )

    return_date = models.DateTimeField(null=True, blank=True)
    return_reason = models.CharField(max_length=255, blank=True)

    days_to_return = models.PositiveIntegerField(default=0)

    # NEW FIELDS
    is_exchanged = models.BooleanField(default=False)

    exchange_order = models.ForeignKey(
        Order,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='exchange_items'
    )

    def __str__(self):
        return f"{self.product} in Order {self.order.id}"

class ExchangeLog(models.Model):
    exchange_id = models.AutoField(primary_key=True)
    order = models.ForeignKey(
        'Order',
        on_delete=models.CASCADE,
        related_name='exchange_logs'
    )
    pickup_date = models.DateField(null=True, blank=True)
    pickup_time = models.TimeField(null=True, blank=True)
    inference_status = models.CharField(
        max_length=20,
        choices=[('scrap', 'Scrap'), ('refurb', 'Refurbish'), ('resale', 'Resale')],
        default='refurb'
    )
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"Exchange {self.exchange_id} for Order {self.order.id}"

class ReturnLog(models.Model):
    return_id = models.AutoField(primary_key=True)

    order = models.ForeignKey(
        'Order',
        on_delete=models.CASCADE,
        related_name='return_logs'
    )

    refund_id = models.CharField(max_length=100)

    pickup_date = models.DateField(null=True, blank=True)
    pickup_time = models.TimeField(null=True, blank=True)

    created_at = models.DateTimeField(auto_now_add=True)

    refund_amount = models.DecimalField(max_digits=10, decimal_places=2, null = True)
    def __str__(self):
        return f"Return {self.return_id} for Order {self.order.id}"


class VoiceSession(models.Model):
    """One record per voice-bot conversation session."""
    session_id = models.CharField(max_length=100, unique=True, db_index=True)
    user = models.ForeignKey(
        User, on_delete=models.SET_NULL,
        null=True, blank=True, related_name='voice_sessions',
    )
    started_at = models.DateTimeField(auto_now_add=True)
    ended_at = models.DateTimeField(null=True, blank=True)

    # Final outcome
    STATUS_CHOICES = [
        ('in_progress', 'In Progress'),
        ('completed', 'Completed'),
        ('abandoned', 'Abandoned'),
    ]
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='in_progress')
    request_type = models.CharField(max_length=20, blank=True)       # exchange / return
    order_id = models.CharField(max_length=50, blank=True)
    reason = models.TextField(blank=True)
    exchange_preference = models.TextField(blank=True)
    tracking_number = models.CharField(max_length=100, blank=True)

    # Snapshot of all collected session data as JSON
    session_data_json = models.JSONField(default=dict, blank=True)

    def __str__(self):
        return f"VoiceSession {self.session_id[:8]} ({self.status})"


class VoiceMessage(models.Model):
    """One record per turn (user utterance + bot reply) inside a session."""
    session = models.ForeignKey(
        VoiceSession, on_delete=models.CASCADE,
        related_name='messages',
    )
    turn_number = models.PositiveIntegerField()
    step = models.CharField(max_length=50)           # greeting, ask_order_id …
    next_step = models.CharField(max_length=50, blank=True)

    user_text = models.TextField(blank=True)          # what the user said
    bot_text = models.TextField(blank=True)           # what the bot replied

    llm_input = models.TextField(blank=True)          # prompt sent to LLM
    llm_output = models.TextField(blank=True)         # raw LLM response
    extracted_value = models.CharField(max_length=255, blank=True)  # parsed value

    session_data_snapshot = models.JSONField(default=dict, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['session', 'turn_number']

    def __str__(self):
        return f"Turn {self.turn_number} ({self.step}) in {self.session.session_id[:8]}"