完成py_plan.md

sim/core/packet.py

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+"""
+Packet model for LoRa route simulation.
+
+Defines packet types and structure for HELLO, DATA, and ACK packets.
+"""
+
+from dataclasses import dataclass
+from enum import IntEnum
+from typing import Optional
+
+
+class PacketType(IntEnum):
+    """Packet type enumeration."""
+
+    HELLO = 1
+    DATA = 2
+    ACK = 3
+
+
+@dataclass
+class Packet:
+    """
+    LoRa packet structure.
+
+    Attributes:
+        type: Packet type (HELLO, DATA, or ACK)
+        src: Source node ID
+        dst: Destination node ID (-1 for broadcast)
+        seq: Sequence number
+        hop: Current hop count
+        payload: Optional payload data
+        rssi: Received signal strength indicator (set on receive)
+    """
+
+    type: PacketType
+    src: int
+    dst: int
+    seq: int
+    hop: int = 0
+    payload: Optional[str] = None
+    rssi: Optional[float] = None  # Set by receiver
+
+    def __repr__(self) -> str:
+        return (
+            f"Packet({self.type.name}, src={self.src}, dst={self.dst}, "
+            f"seq={self.seq}, hop={self.hop})"
+        )
+
+    @property
+    def is_broadcast(self) -> bool:
+        """Check if packet is broadcast (dst = -1)."""
+        return self.dst == -1
+
+    @property
+    def is_hello(self) -> bool:
+        """Check if packet is a HELLO packet."""
+        return self.type == PacketType.HELLO
+
+    @property
+    def is_data(self) -> bool:
+        """Check if packet is a DATA packet."""
+        return self.type == PacketType.DATA
+
+    @property
+    def is_ack(self) -> bool:
+        """Check if packet is an ACK packet."""
+        return self.type == PacketType.ACK
+
+    def to_dict(self) -> dict:
+        """Convert packet to dictionary for serialization."""
+        return {
+            "type": self.type.name,
+            "src": self.src,
+            "dst": self.dst,
+            "seq": self.seq,
+            "hop": self.hop,
+            "payload": self.payload,
+            "rssi": self.rssi,
+        }