paymentservice/payments/models.py

from django.db import models


class PaymentGatewayConfig(models.Model):
    """Configuration and health tracking for each integrated payment gateway."""
    HEALTH_CHOICES = [
        ('HEALTHY', 'Healthy'),
        ('DEGRADED', 'Degraded'),
        ('DOWN', 'Down'),
    ]
    ENV_CHOICES = [
        ('sandbox', 'Sandbox'),
        ('production', 'Production'),
    ]

    name = models.CharField(max_length=50, unique=True, help_text="Gateway identifier e.g. CASHFREE, RAZORPAY")
    display_name = models.CharField(max_length=100)
    is_active = models.BooleanField(default=True)
    priority = models.PositiveIntegerField(default=1, help_text="Routing priority: 1 is primary, 2 is secondary")
    health_status = models.CharField(max_length=20, choices=HEALTH_CHOICES, default='HEALTHY')
    consecutive_failures = models.PositiveIntegerField(default=0)
    failure_threshold = models.PositiveIntegerField(default=3, help_text="Number of failures before circuit trips to DOWN")
    app_id = models.CharField(max_length=255, blank=True, default='')
    secret_key = models.CharField(max_length=255, blank=True, default='')
    environment = models.CharField(max_length=20, choices=ENV_CHOICES, default='sandbox')
    api_version = models.CharField(max_length=20, default='2023-08-01')
    last_health_check = models.DateTimeField(blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['priority', 'name']

    def __str__(self):
        return f"{self.display_name} ({self.name}) - Priority: {self.priority} [{self.health_status}]"

    def record_success(self):
        """Reset failures and set health to HEALTHY."""
        self.consecutive_failures = 0
        self.health_status = 'HEALTHY'
        self.save(update_fields=['consecutive_failures', 'health_status', 'updated_at'])

    def record_failure(self):
        """Increment failure counter and degrade/trip circuit if threshold exceeded."""
        self.consecutive_failures += 1
        if self.consecutive_failures >= self.failure_threshold:
            self.health_status = 'DOWN'
        else:
            self.health_status = 'DEGRADED'
        self.save(update_fields=['consecutive_failures', 'health_status', 'updated_at'])


class PaymentOrder(models.Model):
    """Unified Order model across all gateways."""
    STATUS_CHOICES = [
        ('INITIATED', 'Initiated'),
        ('ACTIVE', 'Active'),
        ('PAID', 'Paid'),
        ('FAILED', 'Failed'),
        ('EXPIRED', 'Expired'),
        ('TERMINATED', 'Terminated'),
        ('REFUNDED', 'Refunded'),
    ]

    order_id = models.CharField(max_length=100, unique=True, primary_key=True)
    amount = models.DecimalField(max_digits=12, decimal_places=2)
    currency = models.CharField(max_length=3, default='INR')
    customer_id = models.CharField(max_length=100)
    customer_name = models.CharField(max_length=200, blank=True, default='')
    customer_email = models.EmailField(blank=True, null=True)
    customer_phone = models.CharField(max_length=20, blank=True, default='')
    status = models.CharField(max_length=30, choices=STATUS_CHOICES, default='INITIATED')
    active_gateway = models.CharField(max_length=50, default='CASHFREE')
    return_url = models.TextField(blank=True, null=True)
    notify_url = models.TextField(blank=True, null=True)
    order_note = models.TextField(blank=True, null=True)
    metadata = models.JSONField(blank=True, default=dict)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return f"{self.order_id} - {self.amount} {self.currency} [{self.status}]"


class PaymentAttempt(models.Model):
    """Tracks each payment attempt with a specific gateway."""
    STATUS_CHOICES = [
        ('INITIATED', 'Initiated'),
        ('SUCCESS', 'Success'),
        ('FAILED', 'Failed'),
        ('PENDING', 'Pending'),
        ('USER_DROPPED', 'User Dropped'),
        ('CANCELLED', 'Cancelled'),
    ]

    order = models.ForeignKey(PaymentOrder, on_delete=models.CASCADE, related_name='attempts')
    gateway_name = models.CharField(max_length=50)
    gateway_order_id = models.CharField(max_length=100, blank=True, null=True)
    payment_session_id = models.TextField(blank=True, null=True)
    gateway_payment_id = models.CharField(max_length=100, blank=True, null=True)
    status = models.CharField(max_length=30, choices=STATUS_CHOICES, default='INITIATED')
    payment_method = models.CharField(max_length=50, blank=True, null=True)
    bank_reference = models.CharField(max_length=100, blank=True, null=True)
    error_code = models.CharField(max_length=100, blank=True, null=True)
    error_message = models.TextField(blank=True, null=True)
    raw_response = models.JSONField(blank=True, default=dict)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return f"Attempt {self.id} for {self.order_id} via {self.gateway_name}: {self.status}"


class PaymentRefund(models.Model):
    """Refunds issued against orders."""
    STATUS_CHOICES = [
        ('PENDING', 'Pending'),
        ('SUCCESS', 'Success'),
        ('FAILED', 'Failed'),
        ('CANCELLED', 'Cancelled'),
    ]

    refund_id = models.CharField(max_length=100, unique=True, primary_key=True)
    order = models.ForeignKey(PaymentOrder, on_delete=models.CASCADE, related_name='refunds')
    gateway_name = models.CharField(max_length=50, default='CASHFREE')
    gateway_refund_id = models.CharField(max_length=100, blank=True, null=True)
    amount = models.DecimalField(max_digits=12, decimal_places=2)
    status = models.CharField(max_length=30, choices=STATUS_CHOICES, default='PENDING')
    speed = models.CharField(max_length=20, default='STANDARD')
    refund_arn = models.CharField(max_length=100, blank=True, null=True)
    reason = models.TextField(blank=True, null=True)
    raw_response = models.JSONField(blank=True, default=dict)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return f"Refund {self.refund_id} for {self.order_id}: {self.amount} [{self.status}]"


class WebhookLog(models.Model):
    """Audit log of incoming webhooks from all gateways."""
    gateway_name = models.CharField(max_length=50)
    event_type = models.CharField(max_length=100, blank=True, default='')
    signature_valid = models.BooleanField(default=False)
    payload = models.JSONField(default=dict)
    processed = models.BooleanField(default=False)
    error_message = models.TextField(blank=True, null=True)
    received_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-received_at']

    def __str__(self):
        return f"{self.gateway_name} Webhook {self.event_type} at {self.received_at} [Valid: {self.signature_valid}]"