add some basics

structures.py

@@ -0,0 +1,61 @@
+from dataclasses import dataclass, field
+from typing import Dict, Any
+
+
+@dataclass
+class Device:
+    name: str
+    model: str
+    properties: Dict[str, Any] = field(default_factory=dict)
+
+    def __post_init__(self):
+        if not self.name:
+            raise ValueError("Device name cannot be empty")
+        if not self.model:
+            raise ValueError("Device model cannot be empty")
+        if not isinstance(self.properties, dict):
+            raise TypeError("properties must be a dict")
+
+
+@dataclass
+class Switch(Device):
+    def __post_init__(self):
+        super().__post_init__()
+
+        if "ports" not in self.properties:
+            raise ValueError(f"Switch '{self.name}' must define 'ports'")
+        if (
+            not isinstance(self.properties["ports"], int)
+            or self.properties["ports"] <= 0
+        ):
+            raise ValueError("'ports' must be a positive integer")
+
+
+@dataclass
+class Router(Device):
+    def __post_init__(self):
+        super().__post_init__()
+
+        if "interfaces" not in self.properties:
+            raise ValueError(f"Router '{self.name}' must define 'interfaces'")
+        if (
+            not isinstance(self.properties["interfaces"], int)
+            or self.properties["interfaces"] <= 0
+        ):
+            raise ValueError("'interfaces' must be a positive integer")
+
+
+@dataclass
+class Host(Device):
+    def __post_init__(self):
+        super().__post_init__()
+
+        ip = self.properties.get("ip")
+        if not ip or not isinstance(ip, str):
+            raise ValueError(f"Host '{self.name}' must contain a valid 'ip' string")
+
+
+@dataclass
+class Wire:
+    from_device: Device
+    to_device: Device