"""Mesin status order (FR-ORD-04, FR-ORD-09, FR-ORD-10, UC-07, UC-08)."""

from datetime import timedelta
from enum import Enum

AUTO_COMPLETE_AFTER = timedelta(days=3)


class OrderStatus(Enum):
    PENDING_PAYMENT = "PENDING_PAYMENT"
    PAID = "PAID"
    SHIPPED = "SHIPPED"
    COMPLETED = "COMPLETED"
    CANCELLED = "CANCELLED"
    EXPIRED = "EXPIRED"


class InvalidTransitionError(Exception):
    """Event tidak diizinkan pada status order saat ini."""


class PermissionDeniedError(Exception):
    """Pelaku tidak berhak memicu event ini."""


S = OrderStatus

# Tabel transisi: (status asal, event) -> status tujuan. Pasangan lain ditolak.
TRANSITIONS = {
    (S.PENDING_PAYMENT, "pay"): S.PAID,
    (S.PENDING_PAYMENT, "cancel"): S.CANCELLED,
    (S.PENDING_PAYMENT, "expire"): S.EXPIRED,
    (S.PAID, "ship"): S.SHIPPED,
    (S.SHIPPED, "complete"): S.COMPLETED,
}


class Order:
    def __init__(self, order_id, buyer_id, seller_id):
        self.order_id = order_id
        self.buyer_id = buyer_id
        self.seller_id = seller_id
        self.status = S.PENDING_PAYMENT
        self.shipped_at = None

    def _fire(self, event):
        target = TRANSITIONS.get((self.status, event))
        if target is None:
            raise InvalidTransitionError(f"{event} tidak valid pada status {self.status.value}")
        self.status = target

    def pay(self):
        """Event payment.succeeded dari Payment Service."""
        self._fire("pay")

    def cancel(self, actor_id):
        """Pembeli membatalkan order yang belum dibayar."""
        if actor_id != self.buyer_id:
            raise PermissionDeniedError("hanya pembeli yang dapat membatalkan")
        self._fire("cancel")

    def expire(self):
        """Batas waktu pembayaran habis (dipicu sistem)."""
        self._fire("expire")

    def ship(self, actor_id, now):
        """Seller pemilik toko menandai order terkirim."""
        if actor_id != self.seller_id:
            raise PermissionDeniedError("hanya seller pemilik toko yang dapat mengirim")
        self._fire("ship")
        self.shipped_at = now

    def confirm_received(self, actor_id):
        """Pembeli mengonfirmasi pesanan diterima. Seller tidak boleh."""
        if actor_id != self.buyer_id:
            raise PermissionDeniedError("hanya pembeli yang dapat mengonfirmasi")
        self._fire("complete")

    def auto_complete(self, now):
        """Sistem menyelesaikan order 3 hari setelah SHIPPED tanpa konfirmasi."""
        if self.status is S.SHIPPED and now - self.shipped_at < AUTO_COMPLETE_AFTER:
            raise InvalidTransitionError("belum 3 hari sejak SHIPPED")
        self._fire("complete")