#!/usr/bin/env python3
"""
netvm-registry.py — single source of truth for node -> CDP port mapping.

Parses NODES.md (the fleet registry). Every script that needs a node's
CDP port reads it from here instead of hardcoding — new nodes propagate
automatically.

Usage:
    from netvm_registry import port_for, load
    port_for("muse")          # -> 9410 (int), None if unknown

CLI:
    netvm-registry.py               # prints "node:port" lines for active nodes
    netvm-registry.py <node>        # prints just the port (for bash)
"""
import os
import re
import sys

REGISTRY = os.path.join(os.path.dirname(os.path.dirname(
    os.path.abspath(__file__))), "NODES.md")


def load(registry_path=None):
    """Return {node: {netns, egress_ip, cdp_port, status, agent}}."""
    path = registry_path or REGISTRY
    nodes = {}
    try:
        with open(path) as f:
            for line in f:
                line = line.rstrip("\n")
                if not line.startswith("|"):
                    continue
                cells = [c.strip() for c in line.strip("|").split("|")]
                if len(cells) < 6:
                    continue
                node, netns, egress, port, status, agent = cells[:6]
                if node in ("node", "") or not re.fullmatch(r"[a-z0-9-]+",
                                                            node):
                    continue
                if node.startswith("-"):
                    continue
                try:
                    port_n = int(port)
                except ValueError:
                    continue
                nodes[node] = {"netns": netns, "egress_ip": egress,
                               "cdp_port": port_n, "status": status,
                               "agent": agent}
    except FileNotFoundError:
        pass
    return nodes


def port_for(node, registry_path=None):
    """CDP port for a node, or None if the node isn't registered."""
    rec = load(registry_path).get(node)
    return rec["cdp_port"] if rec else None


def active_nodes(registry_path=None):
    """{node: port} for nodes with status == active."""
    return {n: r["cdp_port"] for n, r in load(registry_path).items()
            if r["status"] == "active"}


if __name__ == "__main__":
    if len(sys.argv) == 2:
        port = port_for(sys.argv[1])
        if port is None:
            print("unknown node: %s" % sys.argv[1], file=sys.stderr)
            sys.exit(1)
        print(port)
    else:
        for node, port in sorted(active_nodes().items()):
            print("%s:%d" % (node, port))