"""Starting, stopping and reloading the node: systemd here, the Startup
launcher or the service task on Windows."""

import sys

from meshbay_node.cli.api import _daemon_api, _systemctl_user
from meshbay_node.config import DEFAULT_CONFIG_PATH, load_config


def reload(args) -> None:
    if sys.platform == "win32":
        # No systemd, no SIGHUP: the daemon exposes a hot reload on its
        # own loopback API (the same one ops.reload_config drives).
        cfg = load_config(args.config or DEFAULT_CONFIG_PATH)
        _daemon_api(cfg, "/api/reload", method="POST")
        print("sent reload to the running node")
        return
    _systemctl_user(
        "reload", "meshbay-node",
        not_running_hint="Node is not running as a systemd unit — start it "
                          "with: systemctl --user start meshbay-node",
        success="sent reload to meshbay-node",
        watch="watch the result:  journalctl --user -u meshbay-node -f")
    return


def _await_daemon(cfg, since: float, timeout: float = 30.0) -> dict | None:
    """The status of a daemon started at or after `since`, or None.

    The token file is rewritten at every start, so one older than `since`
    belongs to the instance that was just stopped — answering from it would
    report the old daemon as the new one.
    """
    import json
    import time
    import urllib.request

    token_file = cfg.data_dir / "ui-token"
    deadline = time.monotonic() + timeout
    while time.monotonic() < deadline:
        try:
            if token_file.stat().st_mtime >= since:
                token = token_file.read_text(encoding="utf-8").strip()
                url = f"http://127.0.0.1:{cfg.node.ui_port}/api/status?t={token}"
                with urllib.request.urlopen(url, timeout=2) as r:
                    return json.loads(r.read())
        except (OSError, ValueError):
            pass
        time.sleep(0.5)
    return None


def _running_status(cfg) -> dict | None:
    """The status of whatever node answers right now, or None."""
    return _await_daemon(cfg, since=0, timeout=0.1)


def _stop_node(cfg) -> str:
    """Stop the node, whichever session it runs in: through its own control API
    first, so it shuts down properly, then by force. Returns how it went."""
    import time

    from meshbay_node.platform import (
        autostart_end,
        request_graceful_stop,
        service_end,
        service_state,
        service_status,
    )
    if request_graceful_stop(cfg.data_dir, cfg.node.ui_port):
        how = "stopped"
    elif _running_status(cfg) is None:
        how = "not running"
    else:
        how = "stopped (forced)"
    if service_status()["installed"]:
        # Also leaves the task "Ready": a /run while it still reads "Running"
        # is dropped (MultipleInstances IgnoreNew), leaving no node at all.
        service_end()
        deadline = time.monotonic() + 15
        while service_state().lower() == "running" and time.monotonic() < deadline:
            time.sleep(0.25)
    autostart_end()   # a node in this session that would not stop
    return how


def _start_and_confirm(args, action: str) -> None:
    """Start the node the way this machine is set up to, and report what
    actually answered -- never "started" about a node nobody checked."""
    import time

    from meshbay_node import __version__
    from meshbay_node.platform import autostart_run, log_file, service_run, service_status

    cfg = load_config(args.config or DEFAULT_CONFIG_PATH)
    if action == "restart":
        _stop_node(cfg)
    else:
        already = _running_status(cfg)
        if already is not None:
            print(f"already running — node {already.get('version', '?')}, "
                  f"{already.get('status', '?')}")
            return
    since = time.time() - 1
    service = service_status()["installed"]
    try:
        service_run() if service else autostart_run()
    except RuntimeError as e:
        print(f"Could not start the node: {e}")
        sys.exit(1)
    status = _await_daemon(cfg, since)
    if status is None:
        print("no node answered within 30s of being started"
              + (" by the service task." if service else "."))
        print(f"See the node's log: {log_file()}")
        sys.exit(1)
    running = status.get("version", "?")
    print(f"{'restarted' if action == 'restart' else 'started'} — node {running}, "
          f"{status.get('status', '?')}")
    if running != __version__:
        print(f"warning: that is node {running} but this is {__version__} — "
              "its files were not replaced, or another copy was started.")


def restart_daemon(args) -> None:
    if sys.platform == "win32":
        _start_and_confirm(args, "restart")
        return
    _systemctl_user(
        "restart", "meshbay-node",
        not_running_hint="meshbay-node is not installed as a systemd unit — "
                          "see packaging/systemd/",
        success="meshbay-node restarted via systemd",
        watch="check status:  systemctl --user status meshbay-node\n"
              "watch logs:    journalctl --user -u meshbay-node -f")
    return


def autostart(args) -> None:
    from meshbay_node import platform as _plat
    if sys.platform != "win32":
        print("autostart is Windows-only — elsewhere use "
              "'systemctl --user enable --now meshbay-node'.")
        sys.exit(1)
    sub = args.subcommand or "status"
    service_mode = _plat.service_status()["installed"]
    if sub == "install":
        if service_mode:
            # Both would start the node: at boot, then again at sign-in.
            print("The node already runs as a background service. Remove it "
                  "first (meshbay-node service remove, elevated) to start it at "
                  "sign-in instead.")
            sys.exit(1)
        _plat.autostart_install()
        print("Installed the Startup launcher — meshbay-node starts at "
              "each sign-in (no window, no admin).")
        print("Start it now with: meshbay-node autostart start")
    elif sub == "remove":
        _plat.autostart_remove()
        print("Removed the Startup launcher.")
    elif sub == "start":
        _start_and_confirm(args, "start")
    elif sub == "stop":
        print(_stop_node(load_config(args.config or DEFAULT_CONFIG_PATH)))
    elif sub == "status":
        st = _plat.autostart_status()
        if st["installed"]:
            print("autostart    installed — runs meshbay-node at sign-in")
        elif service_mode:
            print("autostart    not used — the node runs as a background service")
        else:
            print("autostart    not installed — meshbay-node autostart install")
    else:
        print("autostart: install | remove | start | stop | status")
        sys.exit(1)
    return


def service(args) -> None:
    from meshbay_node import platform as _plat
    if sys.platform != "win32":
        print("service mode is Windows-only — elsewhere use "
              "'systemctl --user enable --now meshbay-node'.")
        sys.exit(1)
    sub = args.subcommand or "status"
    if sub == "install":
        # A node already running in this session holds the control API's port:
        # the service's own would exit at once, leaving the old one in charge.
        _stop_node(load_config(args.config or DEFAULT_CONFIG_PATH))
        try:
            _plat.service_install()
        except RuntimeError as e:
            print(f"Could not install: {e}")
            if "denied" in str(e).lower():
                print("Run this from an elevated (Administrator) prompt.")
            sys.exit(1)
        print(f"Registered the {_plat.TASK_NAME!r} scheduled task — it starts "
              "meshbay-node at boot, as this user, whether or not you have "
              "signed in yet (no password stored).")
        print("Start it now with: meshbay-node service start")
    elif sub == "remove":
        # Deleting a task does not end its running instance: stop the node
        # first, or it runs on in session 0 with nothing left to stop it.
        _stop_node(load_config(args.config or DEFAULT_CONFIG_PATH))
        _plat.service_remove()
        print(f"Removed the {_plat.TASK_NAME!r} scheduled task.")
    elif sub == "start":
        if not _plat.service_status()["installed"]:
            print("service       not installed — meshbay-node service install "
                  "(needs an elevated prompt)")
            sys.exit(1)
        _start_and_confirm(args, "start")
    elif sub == "stop":
        print(_stop_node(load_config(args.config or DEFAULT_CONFIG_PATH)))
    elif sub == "status":
        st = _plat.service_status()
        if st["installed"]:
            print(f"service       installed — {st['state'] or 'unknown state'}")
        else:
            print("service       not installed — meshbay-node service install "
                  "(needs an elevated prompt)")
    else:
        print("service: install | remove | start | stop | status")
        sys.exit(1)
    return