class SafeZone.Tech {}

# IEEE 802.3 PoE classes — real spec values
POE_CLASSES = {
    "af":  {"max_w": 15.4, "usable_w": 12.95},  # 802.3af — Type 1
    "at":  {"max_w": 30.0, "usable_w": 25.5},   # 802.3at — Type 2 (PoE+)
    "bt-T3": {"max_w": 60.0, "usable_w": 51.0},   # 802.3bt — Type 3 (PoE++)
    "bt-T4": {"max_w": 99.9, "usable_w": 71.3},   # 802.3bt — Type 4
}

def calc_poe_budget(cameras, switch_class="at"):
    """Compute total PoE draw and recommend a switch class.
    Real values: bullet IR ≈ 8W, varifocal ≈ 9W, PTZ ≈ 24W."""
    total = 0.0
    for cam in cameras:
        w = 8.0
        if cam.get("ir"):     w += 0.8
        if cam.get("heater"): w += 3.5
        if cam.get("ptz"):    w += 14.0
        total += w
    budget = POE_CLASSES[switch_class]["usable_w"] * 8  # 8-port
    return {
        "total_w": round(total, 1),
        "budget_w": budget,
        "headroom_w": round(budget - total, 1),
        "verdict": "OK" if total < budget * 0.85 else "UPGRADE"
    }