import logging

from infrasynth.shared.enums import SubscriptionStatus

from .base import BasePaymentGateway, CheckoutSessionResult, WebhookResult

logger = logging.getLogger(__name__)


class MercadoPagoGateway(BasePaymentGateway):
    """MercadoPago payment gateway.

    Configuration keys (read from ``PaymentGateway.config``):
    - ``access_token`` (required for most operations)
    """

    gateway_slug = "mercadopago"

    STATUS_MAP = {
        "authorized": SubscriptionStatus.ACTIVE,
        "pending": SubscriptionStatus.PAST_DUE,
        "paused": SubscriptionStatus.PAST_DUE,
        "cancelled": SubscriptionStatus.CANCELLED,
    }

    def __init__(self, config: dict | None = None):
        config = {str(key).lower(): value for key, value in (config or {}).items()}
        self.access_token = config.get("access_token")
        self.webhook_secret = config.get("webhook_secret")
        self._sdk = None

    @property
    def sdk(self):
        if self._sdk is None:
            import mercadopago

            self._sdk = mercadopago.SDK(self.access_token)
        return self._sdk

    def create_checkout_session(self, plan, user=None, *, tenant=None, **kwargs) -> CheckoutSessionResult:
        self._require_credentials()
        preference = {
            "items": [
                {
                    "title": plan.name,
                    "quantity": 1,
                    "currency_id": plan.price_currency,
                    "unit_price": int(plan.price_amount),
                }
            ],
            "back_urls": {
                "success": kwargs.get("success_url") or "https://example.com/success",
                "failure": kwargs.get("cancel_url") or "https://example.com/cancel",
                "pending": kwargs.get("cancel_url") or "https://example.com/cancel",
            },
            "auto_return": "approved",
            "notification_url": kwargs.get("notification_url") or "",
            "metadata": {
                "plan_slug": plan.slug,
                "app_slug": getattr(getattr(plan, "app", None), "slug", ""),
                "user_id": str(getattr(user, "pk", "")),
                "tenant_id": str(getattr(tenant, "pk", "")),
            },
        }
        result = self.sdk.preference().create(preference)
        if result.get("status") != 201:
            raise ValueError(f"MercadoPago error: {result.get('response')}")
        response = result["response"]
        return CheckoutSessionResult(
            session_id=response["id"],
            checkout_url=response.get("init_point") or "",
            client_secret="",
        )

    def handle_webhook(self, payload, headers) -> WebhookResult:
        event_type = payload.get("type") or payload.get("action") or "payment"
        data = payload.get("data") or payload
        # MercadoPago signs a manifest of id/request-id/ts with HMAC-SHA256.
        if self.webhook_secret:
            if not self._verify_signature(payload, headers):
                return WebhookResult(event_type=event_type, is_handled=False, data=data)
        return WebhookResult(
            event_type=event_type,
            is_handled=True,
            data=data,
        )

    def _verify_signature(self, payload, headers) -> bool:
        import hashlib
        import hmac

        secret = self.webhook_secret or ""
        signature = headers.get("x-signature") or headers.get("X-Signature") or ""
        request_id = headers.get("x-request-id") or headers.get("X-Request-Id") or ""
        parts = dict(part.split("=", 1) for part in signature.split(",") if "=" in part)
        ts = parts.get("ts", "")
        v1 = parts.get("v1", "")
        if not ts or not v1:
            return False
        data_id = str((payload.get("data") or {}).get("id") or "")
        manifest = f"id:{data_id};request-id:{request_id};ts:{ts};"
        expected = hmac.new(secret.encode(), manifest.encode(), hashlib.sha256).hexdigest()
        return hmac.compare_digest(expected, v1)

    def cancel_subscription(self, subscription) -> bool:
        self._require_credentials()
        if not subscription.external_id:
            return False
        result = self.sdk.preapproval().update(subscription.external_id, {"status": "cancelled"})
        return result.get("status") in (200, 201)

    def sync_subscription(self, subscription) -> dict:
        self._require_credentials()
        if not subscription.external_id:
            return {}
        result = self.sdk.preapproval().get(subscription.external_id)
        if result.get("status") != 200:
            return {}
        data = result.get("response") or {}
        raw_status: str | None = data.get("status") if isinstance(data, dict) else None
        return {
            "status": self.STATUS_MAP.get(raw_status or "", raw_status),
            "current_period_start": self._parse_datetime(data.get("date_created")),
            "current_period_end": self._parse_datetime(data.get("next_payment_date")),
            "trial_end": self._parse_datetime(data.get("trial_end_date")),
            "cancel_at_period_end": data.get("auto_recurring", {}).get("end_date") is None
            and data.get("status") == "cancelled",
            "metadata": data.get("metadata") or {},
        }

    def get_invoice(self, invoice) -> dict:
        self._require_credentials()
        if not invoice.external_id:
            return {}
        result = self.sdk.payment().get(invoice.external_id)
        if result.get("status") != 200:
            return {}
        data = result.get("response") or {}
        return {
            "external_id": data.get("id"),
            "status": data.get("status"),
            "amount": data.get("transaction_amount"),
            "currency": (data.get("currency_id") or "USD").upper(),
            "paid_at": self._parse_datetime(data.get("date_approved")),
            "payment_method": data.get("payment_method_id") or "",
        }

    def health_check(self) -> bool:
        return bool(self.access_token)

    def _require_credentials(self) -> None:
        if not self.access_token:
            raise ValueError("MercadoPago access token not configured")

    @staticmethod
    def _parse_datetime(value):
        if not value:
            return None
        from django.utils.dateparse import parse_datetime

        return parse_datetime(value)