"""
Billing Models for Credit System
"""
from decimal import Decimal
from django.db import models
from django.core.validators import MinValueValidator
from django.conf import settings
from igny8_core.auth.models import AccountBaseModel
from simple_history.models import HistoricalRecords


# Centralized payment method choices - single source of truth
PAYMENT_METHOD_CHOICES = [
    ('stripe', 'Stripe (Credit/Debit Card)'),
    ('paypal', 'PayPal'),
    ('bank_transfer', 'Bank Transfer (Manual)'),
    ('local_wallet', 'Local Wallet (Manual)'),
    ('manual', 'Manual Payment'),
]


class CreditTransaction(AccountBaseModel):
    """Track all credit transactions (additions, deductions)"""
    TRANSACTION_TYPE_CHOICES = [
        ('purchase', 'Purchase'),
        ('subscription', 'Subscription Renewal'),
        ('refund', 'Refund'),
        ('deduction', 'Usage Deduction'),
        ('adjustment', 'Manual Adjustment'),
    ]
    
    transaction_type = models.CharField(max_length=20, choices=TRANSACTION_TYPE_CHOICES, db_index=True)
    amount = models.IntegerField(help_text="Positive for additions, negative for deductions")
    balance_after = models.IntegerField(help_text="Credit balance after this transaction")
    description = models.CharField(max_length=255)
    metadata = models.JSONField(default=dict, help_text="Additional context (AI call details, etc.)")
    
    # Payment FK - preferred over reference_id string
    payment = models.ForeignKey(
        'billing.Payment',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='credit_transactions',
        help_text='Payment that triggered this credit transaction'
    )
    
    # Deprecated: Use payment FK instead
    reference_id = models.CharField(
        max_length=255,
        blank=True,
        help_text="DEPRECATED: Use payment FK. Legacy reference (e.g., payment id, invoice id)"
    )
    
    created_at = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_credit_transactions'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['account', 'transaction_type']),
            models.Index(fields=['account', 'created_at']),
        ]
    
    def __str__(self):
        account = getattr(self, 'account', None)
        return f"{self.get_transaction_type_display()} - {self.amount} credits - {account.name if account else 'No Account'}"


class CreditUsageLog(AccountBaseModel):
    """Detailed log of credit usage per AI operation"""
    OPERATION_TYPE_CHOICES = [
        ('clustering', 'Keyword Clustering'),
        ('idea_generation', 'Content Ideas Generation'),
        ('content_generation', 'Content Generation'),
        ('image_generation', 'Image Generation'),
        ('image_prompt_extraction', 'Image Prompt Extraction'),
        ('linking', 'Internal Linking'),
        ('optimization', 'Content Optimization'),
        ('reparse', 'Content Reparse'),
        ('site_page_generation', 'Site Page Generation'),
        ('site_structure_generation', 'Site Structure Generation'),
        ('ideas', 'Content Ideas Generation'),  # Legacy
        ('content', 'Content Generation'),  # Legacy
        ('images', 'Image Generation'),  # Legacy
    ]
    
    operation_type = models.CharField(max_length=50, choices=OPERATION_TYPE_CHOICES, db_index=True)
    credits_used = models.IntegerField(validators=[MinValueValidator(0)])
    cost_usd = models.DecimalField(max_digits=10, decimal_places=4, null=True, blank=True)
    model_used = models.CharField(max_length=100, blank=True)
    tokens_input = models.IntegerField(null=True, blank=True, validators=[MinValueValidator(0)])
    tokens_output = models.IntegerField(null=True, blank=True, validators=[MinValueValidator(0)])
    related_object_type = models.CharField(max_length=50, blank=True)  # 'keyword', 'cluster', 'task'
    related_object_id = models.IntegerField(null=True, blank=True)
    metadata = models.JSONField(default=dict)
    created_at = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_credit_usage_logs'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['account', 'operation_type']),
            models.Index(fields=['account', 'created_at']),
            models.Index(fields=['account', 'operation_type', 'created_at']),
        ]
    
    def __str__(self):
        account = getattr(self, 'account', None)
        return f"{self.get_operation_type_display()} - {self.credits_used} credits - {account.name if account else 'No Account'}"


class CreditCostConfig(models.Model):
    """
    Fixed credit costs per operation type.
    
    Per final-model-schemas.md:
    | Field | Type | Required | Notes |
    |-------|------|----------|-------|
    | operation_type | CharField(50) PK | Yes | Unique operation ID |
    | display_name | CharField(100) | Yes | Human-readable |
    | base_credits | IntegerField | Yes | Fixed credits per operation |
    | is_active | BooleanField | Yes | Enable/disable |
    | description | TextField | No | Admin notes |
    """
    # Operation identification (Primary Key)
    operation_type = models.CharField(
        max_length=50,
        unique=True,
        primary_key=True,
        help_text="Unique operation ID (e.g., 'article_generation', 'image_generation')"
    )
    
    # Human-readable name
    display_name = models.CharField(
        max_length=100,
        help_text="Human-readable name"
    )
    
    # Fixed credits per operation
    base_credits = models.IntegerField(
        default=1,
        validators=[MinValueValidator(0)],
        help_text="Fixed credits per operation"
    )
    
    # Status
    is_active = models.BooleanField(
        default=True,
        help_text="Enable/disable this operation"
    )
    
    # Admin notes
    description = models.TextField(
        blank=True,
        help_text="Admin notes about this operation"
    )
    
    # History tracking
    history = HistoricalRecords()
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_credit_cost_config'
        verbose_name = 'Credit Cost Configuration'
        verbose_name_plural = 'Credit Cost Configurations'
        ordering = ['operation_type']
    
    def __str__(self):
        return f"{self.display_name} - {self.base_credits} credits"


class BillingConfiguration(models.Model):
    """
    System-wide billing configuration (Singleton).
    Global settings for token-credit pricing.
    """
    # Default token-to-credit ratio
    default_tokens_per_credit = models.IntegerField(
        default=100,
        validators=[MinValueValidator(1)],
        help_text="Default: How many tokens equal 1 credit (e.g., 100)"
    )
    
    # Credit pricing
    default_credit_price_usd = models.DecimalField(
        max_digits=10,
        decimal_places=4,
        default=Decimal('0.01'),
        validators=[MinValueValidator(Decimal('0.0001'))],
        help_text="Default price per credit in USD"
    )
    
    # Reporting settings
    enable_token_based_reporting = models.BooleanField(
        default=True,
        help_text="Show token metrics in all reports"
    )
    
    # Rounding settings
    ROUNDING_CHOICES = [
        ('up', 'Round Up'),
        ('down', 'Round Down'),
        ('nearest', 'Round to Nearest'),
    ]
    
    credit_rounding_mode = models.CharField(
        max_length=10,
        default='up',
        choices=ROUNDING_CHOICES,
        help_text="How to round fractional credits"
    )
    
    # Audit fields
    updated_at = models.DateTimeField(auto_now=True)
    updated_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        help_text="Admin who last updated"
    )
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_billing_configuration'
        verbose_name = 'Billing Configuration'
        verbose_name_plural = 'Billing Configuration'
    
    def save(self, *args, **kwargs):
        """Enforce singleton pattern"""
        self.pk = 1
        super().save(*args, **kwargs)
    
    @classmethod
    def get_config(cls):
        """Get or create the singleton config"""
        config, created = cls.objects.get_or_create(pk=1)
        return config
    
    def __str__(self):
        return f"Billing Configuration (1 credit = {self.default_tokens_per_credit} tokens)"


class PlanLimitUsage(AccountBaseModel):
    """
    Track monthly usage of plan limits (ideas, words, images, prompts)
    Resets at start of each billing period
    """
    LIMIT_TYPE_CHOICES = [
        ('content_ideas', 'Content Ideas'),
        ('content_words', 'Content Words'),
        ('images_basic', 'Basic Images'),
        ('images_premium', 'Premium Images'),
        ('image_prompts', 'Image Prompts'),
    ]
    
    limit_type = models.CharField(
        max_length=50,
        choices=LIMIT_TYPE_CHOICES,
        db_index=True,
        help_text="Type of limit being tracked"
    )
    amount_used = models.IntegerField(
        default=0,
        validators=[MinValueValidator(0)],
        help_text="Amount used in current period"
    )
    
    # Billing period tracking
    period_start = models.DateField(
        help_text="Start date of billing period"
    )
    period_end = models.DateField(
        help_text="End date of billing period"
    )
    
    # Metadata
    metadata = models.JSONField(
        default=dict,
        blank=True,
        help_text="Additional tracking data (e.g., breakdown by site)"
    )
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_plan_limit_usage'
        verbose_name = 'Plan Limit Usage'
        verbose_name_plural = 'Plan Limit Usage Records'
        unique_together = [['account', 'limit_type', 'period_start']]
        ordering = ['-period_start', 'limit_type']
        indexes = [
            models.Index(fields=['account', 'limit_type']),
            models.Index(fields=['account', 'period_start', 'period_end']),
            models.Index(fields=['limit_type', 'period_start']),
        ]
    
    def __str__(self):
        account = getattr(self, 'account', None)
        return f"{account.name if account else 'No Account'} - {self.get_limit_type_display()} - {self.amount_used} used"
    
    def is_current_period(self):
        """Check if this record is for the current billing period"""
        from django.utils import timezone
        today = timezone.now().date()
        return self.period_start <= today <= self.period_end
    
    def remaining_allowance(self, plan_limit):
        """Calculate remaining allowance"""
        return max(0, plan_limit - self.amount_used)
    
    def percentage_used(self, plan_limit):
        """Calculate percentage of limit used"""
        if plan_limit == 0:
            return 0
        return min(100, int((self.amount_used / plan_limit) * 100))


class Invoice(AccountBaseModel):
    """
    Invoice for subscription or credit purchases
    Tracks billing invoices with line items and payment status
    """
    STATUS_CHOICES = [
        ('draft', 'Draft'),
        ('pending', 'Pending'),
        ('paid', 'Paid'),
        ('void', 'Void'),
        ('uncollectible', 'Uncollectible'),
    ]
    
    invoice_number = models.CharField(max_length=50, unique=True, db_index=True)
    
    # Subscription relationship
    subscription = models.ForeignKey(
        'igny8_core_auth.Subscription',
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='invoices',
        help_text='Subscription this invoice is for (if subscription-based)'
    )
    
    # Amounts
    subtotal = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    tax = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    total = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    currency = models.CharField(max_length=3, default='USD')
    
    # Status
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='pending', db_index=True)
    
    # Dates
    invoice_date = models.DateField(db_index=True)
    due_date = models.DateField()
    paid_at = models.DateTimeField(null=True, blank=True)
    
    # Line items
    line_items = models.JSONField(default=list, help_text="Invoice line items: [{description, amount, quantity}]")
    
    # Payment integration
    stripe_invoice_id = models.CharField(max_length=255, null=True, blank=True)
    payment_method = models.CharField(max_length=50, null=True, blank=True)
    
    # Metadata
    notes = models.TextField(blank=True)
    metadata = models.JSONField(default=dict)
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_invoices'
        ordering = ['-invoice_date', '-created_at']
        indexes = [
            models.Index(fields=['account', 'status']),
            models.Index(fields=['account', 'invoice_date']),
            models.Index(fields=['invoice_number']),
        ]
    
    def __str__(self):
        return f"Invoice {self.invoice_number} - {self.account.name if self.account else 'No Account'}"

    # ------------------------------------------------------------------
    # Helpers to keep service code working with legacy field names
    # ------------------------------------------------------------------
    @property
    def subtotal_amount(self):
        return self.subtotal

    @property
    def tax_amount(self):
        return self.tax

    @property
    def tax_rate(self):
        """Get tax rate from metadata if stored"""
        if self.metadata and 'tax_rate' in self.metadata:
            return self.metadata['tax_rate']
        return 0
    
    @property
    def discount_amount(self):
        """Get discount amount from metadata if stored"""
        if self.metadata and 'discount_amount' in self.metadata:
            return self.metadata['discount_amount']
        return 0

    @property
    def total_amount(self):
        return self.total

    @property
    def billing_period_start(self):
        """Get from subscription - single source of truth"""
        if self.account and hasattr(self.account, 'subscription'):
            return self.account.subscription.current_period_start
        return None
    
    @property
    def billing_period_end(self):
        """Get from subscription - single source of truth"""
        if self.account and hasattr(self.account, 'subscription'):
            return self.account.subscription.current_period_end
        return None
    
    @property
    def billing_email(self):
        """Get from metadata snapshot or account"""
        if self.metadata and 'billing_snapshot' in self.metadata:
            return self.metadata['billing_snapshot'].get('email')
        return self.account.billing_email if self.account else None

    def add_line_item(self, description: str, quantity: int, unit_price: Decimal, amount: Decimal = None):
        """Append a line item and keep JSON shape consistent."""
        items = list(self.line_items or [])
        qty = quantity or 1
        amt = Decimal(amount) if amount is not None else Decimal(unit_price) * qty
        items.append({
            'description': description,
            'quantity': qty,
            'unit_price': str(unit_price),
            'amount': str(amt),
        })
        self.line_items = items

    def calculate_totals(self):
        """Recompute subtotal, tax, and total from line_items."""
        subtotal = Decimal('0')
        for item in self.line_items or []:
            try:
                subtotal += Decimal(str(item.get('amount') or 0))
            except Exception:
                pass
        self.subtotal = subtotal
        self.total = subtotal + (self.tax or Decimal('0'))


class Payment(AccountBaseModel):
    """
    Payment record for invoices
    Supports: Stripe, PayPal, Manual (Bank Transfer, Local Wallet)
    """
    STATUS_CHOICES = [
        ('pending_approval', 'Pending Approval'),  # Manual payment submitted by user
        ('succeeded', 'Succeeded'),                # Payment approved and processed
        ('failed', 'Failed'),                      # Payment rejected or failed
        ('refunded', 'Refunded'),                  # Payment refunded (rare)
    ]
    
    # Use centralized payment method choices
    PAYMENT_METHOD_CHOICES = PAYMENT_METHOD_CHOICES
    
    invoice = models.ForeignKey(Invoice, on_delete=models.CASCADE, related_name='payments')
    
    # Amount
    amount = models.DecimalField(max_digits=10, decimal_places=2)
    currency = models.CharField(max_length=3, default='USD')
    
    # Status
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='pending_approval', db_index=True)
    
    # Payment method
    payment_method = models.CharField(max_length=50, choices=PAYMENT_METHOD_CHOICES, db_index=True)
    
    # Stripe integration
    stripe_payment_intent_id = models.CharField(max_length=255, null=True, blank=True)
    stripe_charge_id = models.CharField(max_length=255, null=True, blank=True)
    
    # PayPal integration
    paypal_order_id = models.CharField(max_length=255, null=True, blank=True)
    paypal_capture_id = models.CharField(max_length=255, null=True, blank=True)
    
    # Manual payment details
    manual_reference = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        help_text="Bank transfer reference, wallet transaction ID, etc."
    )
    manual_notes = models.TextField(blank=True, help_text="Admin notes for manual payments")
    admin_notes = models.TextField(blank=True, help_text="Internal notes on approval/rejection")
    approved_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name='approved_payments'
    )
    approved_at = models.DateTimeField(null=True, blank=True)
    
    # Timestamps
    processed_at = models.DateTimeField(null=True, blank=True)
    failed_at = models.DateTimeField(null=True, blank=True)
    refunded_at = models.DateTimeField(null=True, blank=True)
    
    # Error tracking
    failure_reason = models.TextField(blank=True)
    
    # Metadata
    metadata = models.JSONField(default=dict)
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    # History tracking
    history = HistoricalRecords()
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_payments'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['account', 'status']),
            models.Index(fields=['account', 'payment_method']),
            models.Index(fields=['invoice', 'status']),
        ]
        constraints = [
            # Ensure manual_reference is unique when not null/empty
            # This prevents duplicate bank transfer references
            models.UniqueConstraint(
                fields=['manual_reference'],
                name='unique_manual_reference_when_not_null',
                condition=models.Q(manual_reference__isnull=False) & ~models.Q(manual_reference='')
            ),
        ]
    
    def __str__(self):
        return f"Payment {self.id} - {self.get_payment_method_display()} - {self.amount} {self.currency}"
    
    def save(self, *args, **kwargs):
        """Normalize empty manual_reference to NULL for proper uniqueness handling"""
        if self.manual_reference == '':
            self.manual_reference = None
        super().save(*args, **kwargs)


class CreditPackage(models.Model):
    """
    One-time credit purchase packages
    Defines available credit bundles for purchase
    """
    name = models.CharField(max_length=100)
    slug = models.SlugField(unique=True, db_index=True)
    
    # Credits
    credits = models.IntegerField(validators=[MinValueValidator(1)])
    
    # Pricing
    price = models.DecimalField(max_digits=10, decimal_places=2)
    discount_percentage = models.IntegerField(default=0, help_text="Discount percentage (0-100)")
    
    # Stripe
    stripe_product_id = models.CharField(max_length=255, null=True, blank=True)
    stripe_price_id = models.CharField(max_length=255, null=True, blank=True)
    
    # PayPal
    paypal_plan_id = models.CharField(max_length=255, null=True, blank=True)
    
    # Status
    is_active = models.BooleanField(default=True, db_index=True)
    is_featured = models.BooleanField(default=False, help_text="Show as featured package")
    
    # Display
    description = models.TextField(blank=True)
    features = models.JSONField(default=list, help_text="Bonus features or highlights")
    
    # Sort order
    sort_order = models.IntegerField(default=0, help_text="Display order (lower = first)")
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_credit_packages'
        ordering = ['sort_order', 'price']
    
    def __str__(self):
        return f"{self.name} - {self.credits} credits - ${self.price}"


class PaymentMethodConfig(models.Model):
    """
    Configure payment methods availability per country.
    
    For online payments (stripe, paypal): Credentials stored in IntegrationProvider.
    For manual payments (bank_transfer, local_wallet): Bank/wallet details stored here.
    """
    # Use centralized choices
    PAYMENT_METHOD_CHOICES = PAYMENT_METHOD_CHOICES
    
    country_code = models.CharField(
        max_length=2,
        db_index=True,
        help_text="ISO 2-letter country code (e.g., US, GB, PK) or '*' for global"
    )
    payment_method = models.CharField(max_length=50, choices=PAYMENT_METHOD_CHOICES)
    is_enabled = models.BooleanField(default=True)
    
    # Display info
    display_name = models.CharField(max_length=100, blank=True)
    instructions = models.TextField(blank=True, help_text="Payment instructions for users")
    
    # Manual payment details (for bank_transfer only)
    bank_name = models.CharField(max_length=255, blank=True)
    account_number = models.CharField(max_length=255, blank=True)
    account_title = models.CharField(max_length=255, blank=True, help_text="Account holder name")
    routing_number = models.CharField(max_length=255, blank=True, help_text="Routing/Sort code")
    swift_code = models.CharField(max_length=255, blank=True, help_text="SWIFT/BIC code for international")
    iban = models.CharField(max_length=255, blank=True, help_text="IBAN for international transfers")
    
    # Additional fields for local wallets
    wallet_type = models.CharField(max_length=100, blank=True, help_text="E.g., JazzCash, EasyPaisa, etc.")
    wallet_id = models.CharField(max_length=255, blank=True, help_text="Mobile number or wallet ID")
    
    # Order/priority
    sort_order = models.IntegerField(default=0)
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_payment_method_config'
        unique_together = [['country_code', 'payment_method']]
        ordering = ['country_code', 'sort_order']
        verbose_name = 'Payment Method Configuration'
        verbose_name_plural = 'Payment Method Configurations'
    
    def __str__(self):
        return f"{self.country_code} - {self.get_payment_method_display()}"


class AccountPaymentMethod(AccountBaseModel):
    """
    Account-scoped payment methods (Stripe/PayPal/manual bank/wallet).
    Only metadata/refs are stored here; no secrets.
    """
    # Use centralized choices
    PAYMENT_METHOD_CHOICES = PAYMENT_METHOD_CHOICES

    type = models.CharField(max_length=50, choices=PAYMENT_METHOD_CHOICES, db_index=True)
    display_name = models.CharField(max_length=100, help_text="User-visible label", default='')
    is_default = models.BooleanField(default=False, db_index=True)
    is_enabled = models.BooleanField(default=True, db_index=True)
    is_verified = models.BooleanField(default=False, db_index=True)
    country_code = models.CharField(max_length=2, blank=True, default='', help_text="ISO-2 country code (optional)")

    # Manual/bank/local wallet details (non-sensitive metadata)
    instructions = models.TextField(blank=True, default='')
    metadata = models.JSONField(default=dict, blank=True, help_text="Provider references or display metadata")

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

    class Meta:
        app_label = 'billing'
        db_table = 'igny8_account_payment_methods'
        ordering = ['-is_default', 'display_name', 'id']
        indexes = [
            models.Index(fields=['account', 'is_default']),
            models.Index(fields=['account', 'type']),
        ]
        unique_together = [['account', 'display_name']]

    def __str__(self):
        return f"{self.account_id} - {self.display_name} ({self.type})"


class AIModelConfig(models.Model):
    """
    All AI models (text + image) with pricing and credit configuration.
    Single Source of Truth for Models.
    
    Per final-model-schemas.md:
    | Field | Type | Required | Notes |
    |-------|------|----------|-------|
    | id | AutoField PK | Auto | |
    | model_name | CharField(100) | Yes | gpt-5.1, dall-e-3, runware:97@1 |
    | model_type | CharField(20) | Yes | text / image |
    | provider | CharField(50) | Yes | Links to IntegrationProvider |
    | display_name | CharField(200) | Yes | Human-readable |
    | is_default | BooleanField | Yes | One default per type |
    | is_active | BooleanField | Yes | Enable/disable |
    | cost_per_1k_input | DecimalField | No | Provider cost (USD) - text models |
    | cost_per_1k_output | DecimalField | No | Provider cost (USD) - text models |
    | tokens_per_credit | IntegerField | No | Text: tokens per 1 credit (e.g., 1000) |
    | credits_per_image | IntegerField | No | Image: credits per image (e.g., 1, 5, 15) |
    | quality_tier | CharField(20) | No | basic / quality / premium |
    | max_tokens | IntegerField | No | Model token limit |
    | context_window | IntegerField | No | Model context size |
    | capabilities | JSONField | No | vision, function_calling, etc. |
    | created_at | DateTime | Auto | |
    | updated_at | DateTime | Auto | |
    """
    
    MODEL_TYPE_CHOICES = [
        ('text', 'Text Generation'),
        ('image', 'Image Generation'),
    ]
    
    PROVIDER_CHOICES = [
        ('openai', 'OpenAI'),
        ('anthropic', 'Anthropic'),
        ('runware', 'Runware'),
        ('google', 'Google'),
    ]
    
    QUALITY_TIER_CHOICES = [
        ('basic', 'Basic'),
        ('quality', 'Quality'),
        ('premium', 'Premium'),
    ]
    
    # Basic Information
    model_name = models.CharField(
        max_length=100,
        unique=True,
        db_index=True,
        help_text="Model identifier (e.g., 'gpt-5.1', 'dall-e-3', 'runware:97@1')"
    )
    
    model_type = models.CharField(
        max_length=20,
        choices=MODEL_TYPE_CHOICES,
        db_index=True,
        help_text="text / image"
    )
    
    provider = models.CharField(
        max_length=50,
        choices=PROVIDER_CHOICES,
        db_index=True,
        help_text="Links to IntegrationProvider"
    )
    
    display_name = models.CharField(
        max_length=200,
        help_text="Human-readable name"
    )
    
    is_default = models.BooleanField(
        default=False,
        db_index=True,
        help_text="One default per type"
    )
    
    is_active = models.BooleanField(
        default=True,
        db_index=True,
        help_text="Enable/disable"
    )
    
    # Text Model Pricing (cost per 1K tokens)
    cost_per_1k_input = models.DecimalField(
        max_digits=10,
        decimal_places=6,
        null=True,
        blank=True,
        help_text="Provider cost per 1K input tokens (USD) - text models"
    )
    
    cost_per_1k_output = models.DecimalField(
        max_digits=10,
        decimal_places=6,
        null=True,
        blank=True,
        help_text="Provider cost per 1K output tokens (USD) - text models"
    )
    
    # Credit Configuration
    tokens_per_credit = models.IntegerField(
        null=True,
        blank=True,
        help_text="Text: tokens per 1 credit (e.g., 1000, 10000)"
    )
    
    credits_per_image = models.IntegerField(
        null=True,
        blank=True,
        help_text="Image: credits per image (e.g., 1, 5, 15)"
    )
    
    quality_tier = models.CharField(
        max_length=20,
        choices=QUALITY_TIER_CHOICES,
        null=True,
        blank=True,
        help_text="basic / quality / premium - for image models"
    )
    
    # Image Size Configuration (for image models)
    landscape_size = models.CharField(
        max_length=20,
        null=True,
        blank=True,
        help_text="Landscape image size for this model (e.g., '1792x1024', '1280x768')"
    )
    
    square_size = models.CharField(
        max_length=20,
        default='1024x1024',
        blank=True,
        help_text="Square image size for this model (e.g., '1024x1024')"
    )
    
    valid_sizes = models.JSONField(
        default=list,
        blank=True,
        help_text="List of valid sizes for this model (e.g., ['1024x1024', '1792x1024'])"
    )
    
    # Model Limits
    max_tokens = models.IntegerField(
        null=True,
        blank=True,
        help_text="Model token limit"
    )
    
    context_window = models.IntegerField(
        null=True,
        blank=True,
        help_text="Model context size"
    )
    
    # Capabilities
    capabilities = models.JSONField(
        default=dict,
        blank=True,
        help_text="Capabilities: vision, function_calling, json_mode, etc."
    )
    
    # Timestamps
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    
    # History tracking
    history = HistoricalRecords()
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_ai_model_config'
        verbose_name = 'AI Model Configuration'
        verbose_name_plural = 'AI Model Configurations'
        ordering = ['model_type', 'model_name']
        indexes = [
            models.Index(fields=['model_type', 'is_active']),
            models.Index(fields=['provider', 'is_active']),
            models.Index(fields=['is_default', 'model_type']),
        ]
    
    def __str__(self):
        return self.display_name
    
    def save(self, *args, **kwargs):
        """Ensure only one is_default per model_type"""
        if self.is_default:
            AIModelConfig.objects.filter(
                model_type=self.model_type,
                is_default=True
            ).exclude(pk=self.pk).update(is_default=False)
        super().save(*args, **kwargs)
    
    @classmethod
    def get_default_text_model(cls):
        """Get the default text generation model"""
        return cls.objects.filter(model_type='text', is_default=True, is_active=True).first()
    
    @classmethod
    def get_default_image_model(cls):
        """Get the default image generation model"""
        return cls.objects.filter(model_type='image', is_default=True, is_active=True).first()
    
    @classmethod
    def get_image_models_by_tier(cls):
        """Get all active image models grouped by quality tier"""
        return cls.objects.filter(
            model_type='image', 
            is_active=True
        ).order_by('quality_tier', 'model_name')
    
    def validate_size(self, size: str) -> bool:
        """Validate that the given size is valid for this image model"""
        if not self.valid_sizes:
            # If no valid_sizes defined, accept common sizes
            return True
        return size in self.valid_sizes
    
    def get_landscape_size(self) -> str:
        """Get the landscape size for this model"""
        return self.landscape_size or '1792x1024'
    
    def get_square_size(self) -> str:
        """Get the square size for this model"""
        return self.square_size or '1024x1024'


class WebhookEvent(models.Model):
    """
    Store all incoming webhook events for audit and replay capability.
    
    This model provides:
    - Audit trail of all webhook events
    - Idempotency verification (via event_id)
    - Ability to replay failed events
    - Debugging and monitoring
    """
    PROVIDER_CHOICES = [
        ('stripe', 'Stripe'),
        ('paypal', 'PayPal'),
    ]
    
    # Unique identifier from the payment provider
    event_id = models.CharField(
        max_length=255,
        unique=True,
        db_index=True,
        help_text="Unique event ID from the payment provider"
    )
    
    # Payment provider
    provider = models.CharField(
        max_length=20,
        choices=PROVIDER_CHOICES,
        db_index=True,
        help_text="Payment provider (stripe or paypal)"
    )
    
    # Event type (e.g., 'checkout.session.completed', 'PAYMENT.CAPTURE.COMPLETED')
    event_type = models.CharField(
        max_length=100,
        db_index=True,
        help_text="Event type from the provider"
    )
    
    # Full payload for debugging and replay
    payload = models.JSONField(
        help_text="Full webhook payload"
    )
    
    # Processing status
    processed = models.BooleanField(
        default=False,
        db_index=True,
        help_text="Whether this event has been successfully processed"
    )
    processed_at = models.DateTimeField(
        null=True,
        blank=True,
        help_text="When the event was processed"
    )
    
    # Error tracking
    error_message = models.TextField(
        blank=True,
        help_text="Error message if processing failed"
    )
    retry_count = models.IntegerField(
        default=0,
        help_text="Number of processing attempts"
    )
    
    # Timestamps
    created_at = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        app_label = 'billing'
        db_table = 'igny8_webhook_events'
        verbose_name = 'Webhook Event'
        verbose_name_plural = 'Webhook Events'
        ordering = ['-created_at']
        indexes = [
            models.Index(fields=['provider', 'event_type']),
            models.Index(fields=['processed', 'created_at']),
            models.Index(fields=['provider', 'processed']),
        ]
    
    def __str__(self):
        return f"{self.provider}:{self.event_type} - {self.event_id[:20]}..."
    
    @classmethod
    def record_event(cls, event_id: str, provider: str, event_type: str, payload: dict):
        """
        Record a webhook event. Returns (event, created) tuple.
        If the event already exists, returns the existing event.
        """
        return cls.objects.get_or_create(
            event_id=event_id,
            defaults={
                'provider': provider,
                'event_type': event_type,
                'payload': payload,
            }
        )
    
    def mark_processed(self):
        """Mark the event as successfully processed"""
        from django.utils import timezone
        self.processed = True
        self.processed_at = timezone.now()
        self.save(update_fields=['processed', 'processed_at'])
    
    def mark_failed(self, error_message: str):
        """Mark the event as failed with error message"""
        self.error_message = error_message
        self.retry_count += 1
        self.save(update_fields=['error_message', 'retry_count'])