#!/usr/bin/env python3
"""Shelly recon: sweep an IPv4 range for Shelly devices and identify them.

Read-only. Hits each host's unauthenticated `/shelly` endpoint (works on Gen1
and Gen2+), collects gen/model/fw/mac, and cross-references the project
inventory (inventory/bf.csv) by MAC so DHCP-drifted devices are still matched
to their logical name.

Usage:
  python3 discover.py                 # default sweep 10.40.41.200-240
  python3 discover.py 10.40.41.180-250
  python3 discover.py --json          # machine-readable to stdout
"""
import csv, json, os, sys, urllib.request, socket
from concurrent.futures import ThreadPoolExecutor

REPO = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
INVENTORY = os.path.join(REPO, "inventory", "bf.csv")


def load_inventory():
    """MAC(lower, colon) -> {name, ip, section} for shelly rows."""
    by_mac = {}
    if not os.path.exists(INVENTORY):
        return by_mac
    with open(INVENTORY) as f:
        for row in csv.DictReader(f):
            host = (row.get("hostname") or "")
            if "shelly" not in host.lower():
                continue
            mac = (row.get("mac") or "").strip().lower()
            entry = {"name": (row.get("note") or host).strip(),
                     "shelly_id": host.replace("shelly:", "").strip(),
                     "inv_ip": (row.get("ip") or "").strip(),
                     "mac": mac}
            if mac:
                by_mac[mac] = entry
    return by_mac


def probe(ip, timeout=3.0):
    """Return identity dict for a Shelly at ip, or None."""
    try:
        req = urllib.request.Request(f"http://{ip}/shelly")
        with urllib.request.urlopen(req, timeout=timeout) as r:
            d = json.load(r)
    except Exception:
        return None
    gen = d.get("gen", 1)
    mac = (d.get("mac") or "").lower()
    # normalise MAC to colon form for inventory matching
    if mac and ":" not in mac and len(mac) == 12:
        mac = ":".join(mac[i:i+2] for i in range(0, 12, 2))
    return {
        "ip": ip,
        "gen": gen,
        "model": d.get("model") or d.get("type") or "?",
        "fw": d.get("fw") or d.get("ver") or "?",
        "mac": mac,
        "auth": d.get("auth", d.get("auth_en", None)),
        "name_dev": d.get("name"),
    }


def expand(spec):
    """'10.40.41.200-240' or '10.40.41.208' -> list of IPs."""
    if "-" in spec.split(".")[-1]:
        base, rng = spec.rsplit(".", 1)
        lo, hi = rng.split("-")
        return [f"{base}.{i}" for i in range(int(lo), int(hi) + 1)]
    return [spec]


def main():
    args = [a for a in sys.argv[1:] if not a.startswith("--")]
    as_json = "--json" in sys.argv
    spec = args[0] if args else "10.40.41.200-240"
    ips = expand(spec)
    inv = load_inventory()

    found = []
    with ThreadPoolExecutor(max_workers=32) as ex:
        for res in ex.map(probe, ips):
            if res:
                found.append(res)

    # match to inventory
    seen_macs = set()
    for f in found:
        m = inv.get(f["mac"])
        f["inv_name"] = m["name"] if m else None
        f["inv_id"] = m["shelly_id"] if m else None
        f["inv_ip"] = m["inv_ip"] if m else None
        f["ip_drifted"] = bool(m and m["inv_ip"] and m["inv_ip"] != f["ip"])
        if m:
            seen_macs.add(f["mac"])

    missing = [{"mac": mac, **e} for mac, e in inv.items() if mac not in seen_macs]

    if as_json:
        print(json.dumps({"found": found, "missing_from_inventory": missing,
                          "swept": spec, "reachable": len(found),
                          "inventory_total": len(inv)}, indent=2))
        return

    found.sort(key=lambda x: x["inv_id"] or "zzz")
    print(f"Sweep {spec}: {len(found)} Shellys reachable "
          f"(inventory has {len(inv)} with MAC)\n")
    print(f"{'shelly':7} {'ip':15} {'gen':4} {'model':18} {'fw':10} {'name':26} drift")
    print("-" * 100)
    for f in found:
        drift = f"was {f['inv_ip']}" if f["ip_drifted"] else ""
        print(f"{(f['inv_id'] or '?'):7} {f['ip']:15} g{f['gen']:<3} "
              f"{str(f['model']):18} {str(f['fw']):10} "
              f"{str(f['inv_name'] or f.get('name_dev') or '?'):26} {drift}")
    if missing:
        print(f"\n{len(missing)} in inventory but NOT reachable in sweep "
              f"(offline / seasonal / outside range):")
        for m in sorted(missing, key=lambda x: x["shelly_id"]):
            print(f"  {m['shelly_id']:5} {m['inv_ip']:15} {m['mac']:18} {m['name']}")


if __name__ == "__main__":
    main()