"""
Run INSIDE the NetBox Django shell to export the field-switch topology
(switches + every patch panel / splice module they physically pass through)
as JSON, for generate_drawio.py to render.

Usage (from the NetBox host, e.g. /opt/netbox):

    docker exec netbox-netbox-1 python3 /opt/netbox/netbox/manage.py shell \
        -c "$(cat topology/export_topology.py)" 2>/dev/null > topology/topo_full.json

The script only reads data -- it never modifies NetBox. If a switch's
connected_endpoints comes back empty when it clearly shouldn't, that is a
NetBox cable-path bug, not a bug in this script -- see the "gotchas" section
of the repo README before assuming the physical link doesn't exist.

Two passes:
  1. Walk every switch's cable path (Interface.trace()) to find every
     device -- patch panel, splice module, other switch -- it physically
     touches. This is just to build the device set; NetBox's cached path
     is what can go stale (see README), which is why pass 2 doesn't rely
     on it for the edges themselves.
  2. Pull every real Cable among those devices directly, so each edge
     carries the exact port name on both ends (what generate_drawio.py
     labels connectors with) instead of just "these two are connected."
"""
from dcim.models import Device, Interface, Cable
import json

switch_ids = set(
    Device.objects.filter(
        role__slug__in=["core-switch", "dist-switch", "field-switch"]
    ).values_list("id", flat=True)
)

ifaces = Interface.objects.filter(
    device_id__in=switch_ids, cable__isnull=False
).select_related("device")

touched_devices = set(switch_ids)
for i in ifaces:
    path = i._path
    if not path or not path.is_active:
        continue
    for hop in i.trace():
        for item in hop:
            for t in item:
                dev = getattr(t, "device", None)
                if dev:
                    touched_devices.add(dev.id)

cables = Cable.objects.filter(
    terminations__termination_type__model__in=["interface", "frontport", "rearport"],
).distinct()

edges = {}
for c in cables:
    terms = list(c.terminations.all())
    a_side = [t for t in terms if t.cable_end == "A"]
    b_side = [t for t in terms if t.cable_end == "B"]
    for ta in a_side:
        for tb in b_side:
            da = getattr(ta.termination, "device", None)
            db = getattr(tb.termination, "device", None)
            if not da or not db:
                continue
            if da.id in touched_devices and db.id in touched_devices and da.id != db.id:
                key = tuple(sorted((da.id, db.id)))
                edges[key] = {
                    "a": da.id, "a_port": ta.termination.name,
                    "b": db.id, "b_port": tb.termination.name,
                }

devs = Device.objects.filter(id__in=touched_devices).select_related(
    "site", "role", "device_type"
)

out = {
    "devices": [
        {
            "id": d.id,
            "name": d.name,
            "role": d.role.slug,
            "role_name": d.role.name,
            "site": d.site.name if d.site else "",
            "status": str(d.status),
            "device_type": d.device_type.model,
        }
        for d in devs
    ],
    "edges": list(edges.values()),
}
print(json.dumps(out))