"""
Serializers for Billing Models
"""
from typing import Any, Dict, Optional
from decimal import Decimal
from rest_framework import serializers
from .models import CreditTransaction, CreditUsageLog
from igny8_core.auth.models import Account
from igny8_core.business.billing.models import PaymentMethodConfig, Payment


class CreditTransactionSerializer(serializers.ModelSerializer):
    """Serializer for credit transactions"""
    transaction_type_display: serializers.CharField = serializers.CharField(
        source='get_transaction_type_display', 
        read_only=True
    )
    
    class Meta:
        model = CreditTransaction
        fields = [
            'id', 'transaction_type', 'transaction_type_display', 'amount',
            'balance_after', 'description', 'metadata', 'created_at'
        ]
        read_only_fields = ['created_at', 'account']


class CreditUsageLogSerializer(serializers.ModelSerializer):
    """Serializer for credit usage logs"""
    operation_type_display: serializers.CharField = serializers.CharField(
        source='get_operation_type_display', 
        read_only=True
    )
    
    class Meta:
        model = CreditUsageLog
        fields = [
            'id', 'operation_type', 'operation_type_display', 'credits_used',
            'cost_usd', 'model_used', 'tokens_input', 'tokens_output',
            'related_object_type', 'related_object_id', 'metadata', 'created_at'
        ]
        read_only_fields = ['created_at', 'account']


class CreditBalanceSerializer(serializers.Serializer):
    """Serializer for credit balance response"""
    credits: serializers.IntegerField = serializers.IntegerField()
    plan_credits_per_month: serializers.IntegerField = serializers.IntegerField()
    credits_used_this_month: serializers.IntegerField = serializers.IntegerField()
    credits_remaining: serializers.IntegerField = serializers.IntegerField()


class UsageSummarySerializer(serializers.Serializer):
    """Serializer for usage summary response"""
    period: serializers.DictField = serializers.DictField()
    total_credits_used: serializers.IntegerField = serializers.IntegerField()
    total_cost_usd: serializers.DecimalField = serializers.DecimalField(max_digits=10, decimal_places=2)
    by_operation: serializers.DictField = serializers.DictField()
    by_model: serializers.DictField = serializers.DictField()


class PaymentMethodConfigSerializer(serializers.ModelSerializer):
    """Serializer for payment method configuration"""
    payment_method_display: serializers.CharField = serializers.CharField(
        source='get_payment_method_display', 
        read_only=True
    )
    
    class Meta:
        model = PaymentMethodConfig
        fields = [
            'id', 'country_code', 'payment_method', 'payment_method_display',
            'is_enabled', 'display_name', 'instructions', 
            'bank_name', 'account_number', 'swift_code',
            'wallet_type', 'wallet_id', 'sort_order'
        ]
        read_only_fields = ['id']


class PaymentConfirmationSerializer(serializers.Serializer):
    """Serializer for manual payment confirmation"""
    invoice_id: serializers.IntegerField = serializers.IntegerField(required=True)
    payment_method: serializers.ChoiceField = serializers.ChoiceField(
        choices=['bank_transfer', 'local_wallet'],
        required=True
    )
    manual_reference: serializers.CharField = serializers.CharField(
        required=True,
        max_length=255,
        help_text="Transaction reference number"
    )
    manual_notes: serializers.CharField = serializers.CharField(
        required=False,
        allow_blank=True,
        help_text="Additional notes about the payment"
    )
    amount: serializers.DecimalField = serializers.DecimalField(
        max_digits=10,
        decimal_places=2,
        required=True
    )
    proof_url: serializers.URLField = serializers.URLField(
        required=False,
        allow_blank=True,
        help_text="URL to receipt/proof of payment"
    )
    
    def validate_proof_url(self, value: Optional[str]) -> Optional[str]:
        """Validate proof_url is a valid URL format"""
        if value and not value.strip():
            raise serializers.ValidationError("Proof URL cannot be empty if provided")
        if value:
            # Additional validation: must be http or https
            if not value.startswith(('http://', 'https://')):
                raise serializers.ValidationError("Proof URL must start with http:// or https://")
        return value
    
    def validate_amount(self, value: Optional[Decimal]) -> Decimal:
        """Validate amount has max 2 decimal places"""
        if value is None:
            raise serializers.ValidationError("Amount is required")
        if value <= 0:
            raise serializers.ValidationError("Amount must be greater than 0")
        # Check decimal precision (max 2 decimal places)
        if value.as_tuple().exponent < -2:
            raise serializers.ValidationError("Amount can have maximum 2 decimal places")
        return value


class LimitCardSerializer(serializers.Serializer):
    """Serializer for individual limit card"""
    title: serializers.CharField = serializers.CharField()
    limit: serializers.IntegerField = serializers.IntegerField()
    used: serializers.IntegerField = serializers.IntegerField()
    available: serializers.IntegerField = serializers.IntegerField()
    unit: serializers.CharField = serializers.CharField()
    category: serializers.CharField = serializers.CharField()
    percentage: serializers.FloatField = serializers.FloatField()


class UsageLimitsSerializer(serializers.Serializer):
    """Serializer for usage limits response"""
    limits: LimitCardSerializer = LimitCardSerializer(many=True)


class AIModelConfigSerializer(serializers.Serializer):
    """
    Serializer for AI Model Configuration (Read-Only API)
    Provides model information for frontend dropdowns and displays
    """
    model_name = serializers.CharField(read_only=True)
    display_name = serializers.CharField(read_only=True)
    model_type = serializers.CharField(read_only=True)
    provider = serializers.CharField(read_only=True)
    
    # Text model fields
    input_cost_per_1m = serializers.DecimalField(
        max_digits=10, 
        decimal_places=4, 
        read_only=True,
        allow_null=True
    )
    output_cost_per_1m = serializers.DecimalField(
        max_digits=10, 
        decimal_places=4, 
        read_only=True,
        allow_null=True
    )
    context_window = serializers.IntegerField(read_only=True, allow_null=True)
    max_output_tokens = serializers.IntegerField(read_only=True, allow_null=True)
    
    # Image model fields
    cost_per_image = serializers.DecimalField(
        max_digits=10, 
        decimal_places=4, 
        read_only=True,
        allow_null=True
    )
    valid_sizes = serializers.ListField(read_only=True, allow_null=True)
    
    # Capabilities
    supports_json_mode = serializers.BooleanField(read_only=True)
    supports_vision = serializers.BooleanField(read_only=True)
    supports_function_calling = serializers.BooleanField(read_only=True)
    
    # Status
    is_default = serializers.BooleanField(read_only=True)
    sort_order = serializers.IntegerField(read_only=True)
    
    # Computed field
    pricing_display = serializers.SerializerMethodField()
    
    def get_pricing_display(self, obj):
        """Generate pricing display string based on model type"""
        if obj.model_type == 'text':
            return f"${obj.input_cost_per_1m}/{obj.output_cost_per_1m} per 1M"
        elif obj.model_type == 'image':
            return f"${obj.cost_per_image} per image"
        return ""