from rest_framework import serializers

from .models import (
    App,
    Entitlement,
    Invoice,
    PaymentGateway,
    PaymentTransaction,
    Plan,
    Subscription,
)


class AppSerializer(serializers.ModelSerializer):
    class Meta:
        model = App
        fields = ["id", "slug", "name", "monetization", "is_active", "metadata"]
        read_only_fields = ["id"]


class PlanSerializer(serializers.ModelSerializer):
    app_info = serializers.SerializerMethodField()
    gateway_info = serializers.SerializerMethodField()

    class Meta:
        model = Plan
        fields = [
            "id",
            "app",
            "app_info",
            "slug",
            "name",
            "price_amount",
            "price_currency",
            "interval",
            "trial_days",
            "features",
            "limits",
            "is_active",
            "gateway",
            "gateway_info",
            "external_id",
        ]
        read_only_fields = ["id"]

    def get_app_info(self, obj):
        return {"id": obj.app_id, "slug": obj.app.slug, "name": obj.app.name}

    def get_gateway_info(self, obj):
        if obj.gateway_id:
            return {"slug": obj.gateway_id, "display_name": obj.gateway.display_name}
        return None


class EntitlementSerializer(serializers.ModelSerializer):
    app_info = serializers.SerializerMethodField()
    plan_info = serializers.SerializerMethodField()

    class Meta:
        model = Entitlement
        fields = [
            "id",
            "app",
            "app_info",
            "plan",
            "plan_info",
            "status",
            "started_at",
            "current_period_end",
            "expires_at",
            "cancel_at_period_end",
            "source",
            "metadata",
        ]
        read_only_fields = ["id", "started_at"]

    def get_app_info(self, obj):
        return {"slug": obj.app.slug, "name": obj.app.name}

    def get_plan_info(self, obj):
        if obj.plan_id:
            return {"id": obj.plan_id, "slug": obj.plan.slug, "name": obj.plan.name}
        return None


class PaymentGatewaySerializer(serializers.ModelSerializer):
    class Meta:
        model = PaymentGateway
        fields = [
            "slug",
            "display_name",
            "gateway_class",
            "config",
            "is_active",
            "supported_currencies",
            "webhook_secret",
        ]
        read_only_fields = ["slug"]


class SubscriptionSerializer(serializers.ModelSerializer):
    plan_info = serializers.SerializerMethodField()
    gateway_info = serializers.SerializerMethodField()
    entitlement_info = serializers.SerializerMethodField()

    class Meta:
        model = Subscription
        fields = [
            "id",
            "entitlement",
            "entitlement_info",
            "plan",
            "plan_info",
            "gateway",
            "gateway_info",
            "external_id",
            "status",
            "current_period_start",
            "current_period_end",
            "cancel_at_period_end",
            "cancelled_at",
            "trial_end",
            "metadata",
        ]
        read_only_fields = ["id"]

    def get_plan_info(self, obj):
        if obj.plan_id:
            return {"id": obj.plan_id, "name": obj.plan.name, "slug": obj.plan.slug}
        return None

    def get_gateway_info(self, obj):
        if obj.gateway_id:
            return {"slug": obj.gateway_id, "display_name": obj.gateway.display_name}
        return None

    def get_entitlement_info(self, obj):
        if obj.entitlement_id:
            return {"id": obj.entitlement_id, "status": obj.entitlement.status}
        return None


class InvoiceSerializer(serializers.ModelSerializer):
    subscription_info = serializers.SerializerMethodField()
    gateway_info = serializers.SerializerMethodField()
    pdf_file_info = serializers.SerializerMethodField()

    class Meta:
        model = Invoice
        fields = [
            "id",
            "subscription",
            "subscription_info",
            "gateway",
            "gateway_info",
            "external_id",
            "invoice_number",
            "amount",
            "currency",
            "tax_amount",
            "tax_name",
            "status",
            "due_date",
            "paid_at",
            "line_items",
            "pdf_file",
            "pdf_file_info",
            "metadata",
        ]
        read_only_fields = ["id"]

    def get_subscription_info(self, obj):
        if obj.subscription_id:
            return {"id": obj.subscription_id}
        return None

    def get_gateway_info(self, obj):
        if obj.gateway_id:
            return {"slug": obj.gateway_id, "display_name": obj.gateway.display_name}
        return None

    def get_pdf_file_info(self, obj):
        if obj.pdf_file_id:
            return {"id": obj.pdf_file_id, "filename": obj.pdf_file.original_filename}
        return None


class PaymentTransactionSerializer(serializers.ModelSerializer):
    invoice_info = serializers.SerializerMethodField()
    gateway_info = serializers.SerializerMethodField()

    class Meta:
        model = PaymentTransaction
        fields = [
            "id",
            "invoice",
            "invoice_info",
            "gateway",
            "gateway_info",
            "external_id",
            "amount",
            "currency",
            "status",
            "payment_method",
            "metadata",
            "created_at",
        ]
        read_only_fields = ["id", "created_at"]

    def get_invoice_info(self, obj):
        if obj.invoice_id:
            return {
                "id": obj.invoice_id,
                "invoice_number": obj.invoice.invoice_number,
            }
        return None

    def get_gateway_info(self, obj):
        if obj.gateway_id:
            return {"slug": obj.gateway_id, "display_name": obj.gateway.display_name}
        return None


class CheckoutSerializer(serializers.Serializer):
    """``POST /billing/checkout/`` — tenant comes from the token, never the body."""

    app = serializers.SlugField()
    plan = serializers.SlugField()
    success_url = serializers.URLField(required=False)
    cancel_url = serializers.URLField(required=False)


class SubscribeSerializer(serializers.Serializer):
    plan_slug = serializers.SlugField()
    success_url = serializers.URLField(required=False)
    cancel_url = serializers.URLField(required=False)