#!/usr/bin/env python3
"""ncp - the NexusOS management CLI, one implementation for Linux and Windows.

This replaces the logic that lived in management/nexus-cli.sh. That script was
bash + pkill + fuser + /proc, so the Windows box had no `ncp` at all - the same
split that made bin/install.sh rot until it was rsyncing from a path retired
months earlier. Same fix as bin/sync.py: the portable half is Python, and the
per-platform pieces are small and explicit.

nexus-cli.sh is now a two-line wrapper, so `ncp`, launch_nexus.sh,
bin/restore-linux.sh, controlpanel.py, nexus-popup.py and nexus-app.sh all keep
calling what they always called.

psutil does the process work (cmdlines, pattern sweeps, port owners). It is
declared in requirements-base.txt AND requirements-windows.txt, so both boxes have
it - but it is imported lazily so `ncp backup`/`restore` still run before the
venv exists, exactly as they did when they shelled out to sync.py.
"""
from __future__ import annotations

import json
import os
import shutil
import subprocess
import sys
import time
import urllib.request
from dataclasses import dataclass, field
from pathlib import Path

from synapse.nexus_config import SOURCE_CHECKOUT, settings

ROOT = settings.project_root
PID_DIR = settings.runtime_dir / "pids"
LOG_DIR = settings.runtime_dir
FRONTEND_DIR = settings.frontend_source_dir
OLLAMA_BIN = ROOT / "ollama" / "bin" / ("ollama.exe" if os.name == "nt" else "ollama")
OLLAMA_MODELS_DIR = settings.models_dir

WINDOWS = os.name == "nt"
_VENV_PYTHON = ROOT / "Promethean" / ("Scripts/python.exe" if WINDOWS else "bin/python3")
PYTHON = Path(os.getenv("NEXUS_PYTHON", "")) if os.getenv("NEXUS_PYTHON") else (
    _VENV_PYTHON if _VENV_PYTHON.exists() else Path(sys.executable)
)

PID_DIR.mkdir(parents=True, exist_ok=True)
LOG_DIR.mkdir(parents=True, exist_ok=True)

# The output carries em-dashes and check marks (matching what nexus-cli.sh
# printed). On Windows a redirected stdout defaults to cp1252, which raises
# UnicodeEncodeError on both - so pin UTF-8 rather than degrade the output.
for _stream in (sys.stdout, sys.stderr):
    try:
        _stream.reconfigure(encoding="utf-8", errors="replace")
    except (AttributeError, ValueError):
        pass


# -- small helpers -------------------------------------------------------------

def http_ok(url: str, timeout: float = 1.0) -> bool:
    """True if the URL answers at all. Any HTTP status counts - a 404 still
    proves something is listening, which is all the port checks care about."""
    try:
        urllib.request.urlopen(url, timeout=timeout).read(1)
        return True
    except urllib.error.HTTPError:
        return True
    except Exception:
        return False


def ollama_bin() -> str | None:
    """The bundled binary if we have one, else whatever is on PATH.

    Only Linux ships a copy in the repo (bin/fetch-ollama.sh); on Windows the
    installer gets Ollama from winget, which puts it in %LOCALAPPDATA%\\Programs
    and on PATH. Checking only the bundled path made `ncp doctor` report a red
    "Ollama binary missing" on every Windows box, and made `ncp models install`
    refuse to run there at all. Mirrors _ollama_bin() in ollama_manager.py."""
    if OLLAMA_BIN.exists():
        return str(OLLAMA_BIN)
    return shutil.which("ollama")


def npm() -> str | None:
    """npm, resolving through nvm. The bash version sourced ~/.nvm/nvm.sh; a
    non-login shell has neither, so fall back to globbing the nvm install."""
    found = shutil.which("npm")        # resolves npm.cmd on Windows
    if found:
        return found
    versions = sorted((Path.home() / ".nvm" / "versions" / "node").glob("*/bin/npm"))
    return str(versions[-1]) if versions else None


def _psutil():
    try:
        import psutil
        return psutil
    except ImportError:
        return None


# -- services ------------------------------------------------------------------

@dataclass
class Service:
    key: str
    label: str
    port: int
    cwd: Path
    patterns: list
    _argv: object = None
    pid_file: Path = field(init=False)
    log_file: Path = field(init=False)

    def __post_init__(self):
        self.pid_file = PID_DIR / f"{self.key}.pid"
        self.log_file = LOG_DIR / f"{self.key}.log"

    @property
    def url(self) -> str:
        return f"http://localhost:{self.port}/"

    def argv(self):
        return self._argv() if callable(self._argv) else self._argv


# Bind loopback by default: the backend REST API is unauthenticated, so
# binding 0.0.0.0 handed the full admin+data plane to any host on the LAN. Set
# NEXUS_BIND_HOST=0.0.0.0 to opt into LAN exposure once real auth is in place.
BIND_HOST = settings.bind_host


def _uvicorn(app: str, port: int):
    # No --reload. It is a dev-loop flag: uvicorn's reloader runs a supervisor
    # that spawns the real server as a CHILD, so every service became two
    # processes - and on Windows that child, spawned from a parent with no
    # console, got handed a brand new console WINDOW. `ncp web` popped two black
    # terminals for what should have been a silent start. launch_nexus.sh still
    # passes --reload for the Linux dev loop, where a visible console is the
    # point; this launcher is the one users run.
    return [str(PYTHON), "-m", "uvicorn", app, "--host", BIND_HOST,
            "--port", str(port)]


SERVICES = {
    "memory": Service("memory", "NEXUS MEMORY SERVICE", settings.memory_port, settings.state_dir,
                      ["uvicorn synapse.memory"],
                      lambda: _uvicorn("synapse.memory.service:app", settings.memory_port)),
    "backend": Service("backend", "NEXUS BACKEND SERVICE", settings.backend_port, settings.state_dir,
                       ["uvicorn synapse.main"],
                       lambda: _uvicorn("synapse.main:sio_app", settings.backend_port)),
    "frontend": Service("frontend", "NEXUS FRONTEND SERVICE", 5173, FRONTEND_DIR,
                        ["vite --host", "npm run dev"],
                        lambda: [npm(), "run", "dev", "--", "--host", "0.0.0.0"]),
}


def read_pid(svc: Service):
    try:
        return int(svc.pid_file.read_text().strip())
    except (OSError, ValueError):
        return None


def alive(pid) -> bool:
    ps = _psutil()
    if pid is None:
        return False
    if ps is not None:
        return ps.pid_exists(pid)
    try:
        os.kill(pid, 0)
        return True
    except (OSError, ValueError):
        return False


def pid_is_ours(pid, patterns) -> bool:
    """True only if the live PID's command line matches one of the service
    patterns. PID files outlive reboots and the OS recycles the number onto an
    unrelated process - often a desktop-session one - so a bare liveness check
    is not enough. TERMing a recycled PID can log the user out."""
    ps = _psutil()
    try:
        if ps is not None:
            cmd = " ".join(ps.Process(pid).cmdline())
        elif os.name != "nt":
            cmd = (Path(f"/proc/{pid}/cmdline").read_bytes()
                   .replace(b"\0", b" ").decode(errors="replace"))
        else:
            return False
    except Exception:
        return False
    return any(p in cmd for p in patterns)


def launch(svc: Service) -> None:
    pid = read_pid(svc)
    if alive(pid) and pid_is_ours(pid, svc.patterns):
        return
    argv = svc.argv()
    if argv[0] is None:
        print(f"  {svc.label}: npm not found - install Node, or run ./install.sh")
        return
    svc.log_file.write_text("")
    with open(svc.log_file, "ab") as log:
        # Detach so the service outlives this process, on both platforms.
        # CREATE_NO_WINDOW, not DETACHED_PROCESS: detached means the process has
        # NO console, and Windows then gives a console window to any console
        # program it starts in turn. CREATE_NO_WINDOW gives it a console that is
        # never shown, which its children inherit - so nothing flashes up.
        kwargs = ({"creationflags": subprocess.CREATE_NEW_PROCESS_GROUP
                   | getattr(subprocess, "CREATE_NO_WINDOW", 0)}
                  if WINDOWS else {"start_new_session": True})
        proc = subprocess.Popen(argv, cwd=str(svc.cwd), stdout=log,
                                stderr=subprocess.STDOUT, stdin=subprocess.DEVNULL,
                                **kwargs)
    svc.pid_file.write_text(str(proc.pid))


def check(svc: Service) -> bool:
    pid = read_pid(svc)
    if alive(pid):
        print(f"{svc.label} STARTED")
        return True
    print(f"{svc.label} FAILED TO START")
    try:
        tail = svc.log_file.read_text(errors="replace").splitlines()[-8:]
        for line in tail:
            print(f"  {line}")
    except OSError:
        pass
    svc.pid_file.unlink(missing_ok=True)
    return False


# Poll granularity for both waiters below. 1s steps used to mean every
# start/stop paid up to a full second of dead latency per service on top of
# however long the process actually took - three services in sequence could
# lose several seconds to nothing but sleep(). 0.25s still amounts to one
# cheap local HTTP HEAD every quarter second, not a busy-loop.
_POLL_STEP = 0.25


def wait_for_port(svc: Service, timeout: int = 30) -> bool:
    if http_ok(svc.url):
        # "READY", not "already running": `ncp start` launches its services and
        # only then waits on each, so by the time a service's turn comes it is
        # normally up - and reporting "already running" for a service this same
        # command started two seconds ago reads like a stale process.
        print(f"  {svc.label} READY (:{svc.port})")
        return True
    for _ in range(int(timeout / _POLL_STEP)):
        time.sleep(_POLL_STEP)
        if http_ok(svc.url):
            print(f"{svc.label} STARTED")
            return True
    print(f"  {svc.label} timed out after {timeout}s")
    return check(svc)


def wait_for_port_close(port: int, timeout: int = 15) -> bool:
    for _ in range(int(timeout / _POLL_STEP)):
        if not http_ok(f"http://localhost:{port}/"):
            return True
        time.sleep(_POLL_STEP)
    return False


def kill_matching(patterns, force=False) -> int:
    """The pkill -f sweep: catches reparented grandchildren (npm -> sh -> node
    vite), uvicorn --reload workers, and instances started outside this CLI.
    Returns how many processes it signalled, so callers can stay quiet when
    there was nothing to kill."""
    ps = _psutil()
    me = os.getpid()
    hit = 0
    if ps is None:
        if os.name == "nt":
            return 0
        for entry in Path("/proc").iterdir():
            if not entry.name.isdigit() or int(entry.name) == me:
                continue
            try:
                cmd = (entry / "cmdline").read_bytes().replace(b"\0", b" ").decode(errors="replace")
                if any(pattern in cmd for pattern in patterns):
                    os.kill(int(entry.name), 9 if force else 15)
                    hit += 1
            except (OSError, ValueError):
                pass
        return hit
    for proc in ps.process_iter(["pid", "cmdline"]):
        if proc.info["pid"] == me:
            continue
        cmd = " ".join(proc.info["cmdline"] or [])
        if any(p in cmd for p in patterns):
            try:
                proc.kill() if force else proc.terminate()
                hit += 1
            except Exception:
                pass
    return hit


def kill_port(port: int) -> bool:
    """Whatever holds the port IS the service - this is the backstop that makes
    stop reliable regardless of process-tree shape or PID-file accuracy."""
    ps = _psutil()
    if ps is None:
        return False
    killed = False
    try:
        conns = ps.net_connections(kind="inet")
    except Exception:
        return False
    for conn in conns:
        if conn.laddr and conn.laddr.port == port and conn.status == "LISTEN" and conn.pid:
            try:
                ps.Process(conn.pid).kill()
                killed = True
            except Exception:
                pass
    return killed


def stop_service(svc: Service) -> bool:
    """Three escalating passes, with the PORT as the source of truth for
    whether the service is actually down."""
    pid = read_pid(svc)
    if pid is not None:
        if alive(pid) and pid_is_ours(pid, svc.patterns):
            ps = _psutil()
            try:
                if ps is not None:
                    proc = ps.Process(pid)
                    for child in proc.children(recursive=True):
                        try:
                            child.terminate()
                        except Exception:
                            pass
                    proc.terminate()
                elif os.name != "nt":
                    os.kill(pid, 15)
            except Exception:
                pass
        svc.pid_file.unlink(missing_ok=True)

    kill_matching(svc.patterns)

    if not wait_for_port_close(svc.port):
        kill_port(svc.port)
        kill_matching(svc.patterns, force=True)
        wait_for_port_close(svc.port)
    if http_ok(svc.url):
        print(f"{svc.label} STILL RUNNING (:{svc.port}) — try 'ncp kill'")
        return False
    print(f"{svc.label} STOPPED")
    return True


# -- ollama --------------------------------------------------------------------

def start_ollama(background: bool = False) -> None:
    """Driven through the backend endpoint (the path the control panel uses)
    rather than launching the binary, because OllamaManager owns model and GPU
    selection. Requires the backend to be up.

    background=True (`ncp start`): the endpoint returns as soon as `ollama serve`
    is up and warms the model in a background task, so boot finishes in seconds
    and the model loads concurrently into the first chat.
    background=False (`ncp start --ai`): blocks until the model is warmed - weights
    read off disk into RAM/VRAM, routinely about a minute - so "started" means the
    AI can actually answer."""
    if not settings.manage_ollama:
        running = http_ok(settings.ollama_host.rstrip("/") + "/api/tags", timeout=3)
        print(
            f"REMOTE OLLAMA {'REACHABLE' if running else 'UNREACHABLE'} "
            f"({settings.ollama_host})"
        )
        return
    print("Starting OLLAMA...")
    url = settings.api_url + "/ollama/start" + ("?background=true" if background else "")
    req = urllib.request.Request(url, method="POST")
    try:
        urllib.request.urlopen(req, timeout=180).read(1)
        print("NEXUS OLLAMA WARMING (background)" if background else "NEXUS OLLAMA STARTED")
    except Exception as e:
        print(f"  OLLAMA start failed: {e}")


def stop_ollama() -> None:
    """Prefer the backend endpoint for a clean OllamaManager shutdown; if the
    backend is already down, kill `ollama serve` directly so it never lingers
    holding VRAM/RAM. Must run BEFORE the backend is torn down."""
    if not settings.manage_ollama:
        print(f"REMOTE OLLAMA IS EXTERNALLY MANAGED ({settings.ollama_host})")
        return
    req = urllib.request.Request(settings.api_url + "/ollama/stop", method="POST")
    try:
        urllib.request.urlopen(req, timeout=5).read(1)
        print("NEXUS OLLAMA STOPPED")
        return
    except Exception:
        pass
    # Silent when there was nothing to stop - the bash version only announced a
    # direct kill if `pgrep ollama serve` actually matched, and claiming to have
    # stopped a service that was never running is worse than saying nothing.
    if kill_matching(["ollama serve"]):
        print("NEXUS OLLAMA STOPPED (direct)")


# -- commands ------------------------------------------------------------------

def cmd_start(target) -> None:
    if target in ("--backend", "-b"):
        launch(SERVICES["backend"]); wait_for_port(SERVICES["backend"])
        start_ollama()
    elif target in ("--frontend", "-f"):
        if not SOURCE_CHECKOUT:
            print("Vite source is unavailable in wheel installs; the backend serves the bundled UI.")
            return
        launch(SERVICES["frontend"]); wait_for_port(SERVICES["frontend"])
    elif target in ("--ai", "-a"):
        start_ollama()
    elif target in (None, "", "all"):
        # Bring the UI up first, then kick off Ollama and (on Linux) Vite in the
        # background without waiting on either — neither gates the app being
        # usable. The backend already serves the built interface/web/dist at
        # :8000 on both platforms (single-process design), and that's the URL
        # nexus-app.sh/ncp web actually opens; nothing points a user at :5173.
        # Vite only exists for whoever is hot-reload-editing the frontend, and
        # they'll open :5173 themselves once it's ready - polling for it here
        # just delayed "boot done" for a benefit nobody in the critical path
        # gets. Skipped outright on Windows, where it's not part of the normal
        # workflow at all and is the slow part of `ncp stop` to boot (npm's
        # cmd.exe -> node -> esbuild tree doesn't die from a plain terminate()
        # and falls through to the ~30s force-kill path). Still available on
        # demand via `ncp start --frontend`.
        t0 = time.perf_counter()
        launch(SERVICES["backend"])
        wait_for_port(SERVICES["backend"])
        t_services = time.perf_counter()
        start_ollama(background=True)
        if SOURCE_CHECKOUT and not WINDOWS:
            launch(SERVICES["frontend"])
        t_bg = time.perf_counter()
        print("\nBoot timing:")
        print(f"  backend                        : {t_services - t0:5.1f}s")
        print(f"  ollama + frontend (bg kickoff) : {t_bg - t_services:5.1f}s")
        print(f"  total to interactive           : {t_bg - t0:5.1f}s")
    else:
        show_help()


def cmd_stop(target) -> None:
    if target in ("--backend", "-b"):
        stop_ollama(); stop_service(SERVICES["backend"])
    elif target in ("--frontend", "-f"):
        stop_service(SERVICES["frontend"])
    elif target in ("--ai", "-a"):
        stop_ollama()
    elif target in (None, "", "all"):
        stop_ollama()
        stop_service(SERVICES["backend"])
        stop_service(SERVICES["frontend"])
    else:
        show_help()


def cmd_kill() -> None:
    print("Force-killing all Nexus processes...")
    targets = [
        (settings.backend_port, "SYNAPSE"),
        (settings.memory_port, "MEMORY"),
        (5173, "INTERFACE"),
    ]
    patterns = ["uvicorn synapse", "npm run dev", "vite --host"]
    if settings.manage_ollama:
        targets.append((11434, "OLLAMA"))
        patterns.append("ollama serve")
    for port, name in targets:
        if kill_port(port):
            print(f"  KILLED:      {name} (:{port})")
        else:
            print(f"  NOT RUNNING: {name} (:{port})")
    kill_matching(patterns, force=True)
    for pid_file in PID_DIR.glob("*.pid"):
        pid_file.unlink(missing_ok=True)
    print("Done.")


def cmd_status() -> None:
    print("Nexus Service Status:\n")

    def one(name, svc):
        pid = read_pid(svc)
        if alive(pid):
            print(f"  {name}: RUNNING (PID {pid})")
        elif http_ok(svc.url):
            print(f"  {name}: RUNNING (port :{svc.port}, PID stale — consider ncp kill)")
        else:
            print(f"  {name}: STOPPED")

    print("Backend:")
    one("Synapse       ", SERVICES["backend"])
    print("\nFrontend:")
    one("Vite          ", SERVICES["frontend"])
    print("\nModel server:")
    running = http_ok(settings.ollama_host.rstrip("/") + "/api/tags")
    mode = "remote" if not settings.manage_ollama else "local"
    print(f"  Ollama ({mode}) : {'RUNNING' if running else 'STOPPED'} ({settings.ollama_host})")


def _tail(path: Path, n: int) -> None:
    try:
        for line in path.read_text(errors="replace").splitlines()[-n:]:
            print(line)
    except OSError:
        print(f"  (no log at {path})")


LOG_HEADINGS = {"backend": "BACKEND", "frontend": "FRONTEND"}


def cmd_logs(target) -> None:
    named = {"--frontend": "frontend", "-f": "frontend",
             "--backend": "backend", "-b": "backend"}
    if target in named:
        key = named[target]
        print(f"=== {LOG_HEADINGS[key]} LOGS ===")
        _tail(SERVICES[key].log_file, 50)
    elif target in (None, "", "all"):
        for i, key in enumerate(("backend", "frontend")):
            if i:
                print()
            print(f"=== {LOG_HEADINGS[key]} LOGS ===")
            _tail(SERVICES[key].log_file, 30)
    else:
        print(f"Unknown logs target: '{target}'")
        print("Usage: ncp logs [frontend|backend|all]")


def _apply_fixes() -> None:
    """Opt-in safe repairs (ncp doctor --fix). Only idempotent, non-destructive
    actions: build the UI, install deps, fetch the Ollama binary. Anything that
    could lose data or needs a decision is left to the user with a hint."""
    print("\nApplying safe fixes...\n")
    did = False
    web, npm_path = FRONTEND_DIR, npm()

    if not PYTHON.exists():
        print("  ✘ Promethean venv missing — run ./install.sh to build it (skipped: heavy).")
    else:
        importable = subprocess.run(
            [str(PYTHON), "-c", "from synapse.main import sio_app"],
            cwd=str(ROOT), capture_output=True).returncode == 0
        if not importable:
            print("  Backend import failed — reinstalling Python dependencies...")
            sys.path.insert(0, str(ROOT / "bin"))
            import importlib.util
            spec = importlib.util.spec_from_file_location("sync", ROOT / "bin" / "sync.py")
            sync = importlib.util.module_from_spec(spec)
            spec.loader.exec_module(sync)
            subprocess.run([str(PYTHON), "-m", "pip", "install", "-r", sync.requirements()], cwd=str(ROOT))
            did = True

    if npm_path and web.is_dir() and not (web / "node_modules").is_dir():
        print("  node_modules missing — running npm install...")
        subprocess.run([npm_path, "install"], cwd=str(web))
        did = True

    if npm_path and web.is_dir() and not (web / "dist" / "index.html").exists():
        print("  Built UI missing — running npm run build...")
        subprocess.run([npm_path, "run", "build"], cwd=str(web))
        did = True

    if not ollama_bin() and os.name != "nt" and (ROOT / "bin" / "fetch-ollama.sh").exists():
        print("  Ollama binary missing — fetching...")
        subprocess.run(["bash", str(ROOT / "bin" / "fetch-ollama.sh")])
        did = True

    print("\n" + ("Fixes applied — re-run 'ncp doctor' to confirm." if did
                  else "Nothing to fix (all safe-repairable checks already pass)."))


def cmd_doctor(fix: bool = False) -> None:
    def mark(ok, good, bad):
        print(f"  {'✔' if ok else '✘'} {good if ok else bad}")

    print("Running Nexus Diagnostics...\n")
    print("Checking directories...")
    mark(ROOT.is_dir(), "Nexus root found", "Missing Nexus root")
    mark(FRONTEND_DIR.is_dir(), "Frontend directory found", "Missing frontend directory")

    print("\nChecking Python venv...")
    if PYTHON.exists():
        ver = subprocess.run([str(PYTHON), "--version"], capture_output=True,
                             text=True).stdout.strip()
        mark(True, f"Promethean venv found ({ver})", "")
    else:
        mark(False, "", f"Promethean venv missing at {PYTHON}")

    print("\nChecking Node & npm...")

    def version(exe):
        if not exe:
            return ""
        try:
            return subprocess.run([exe, "-v"], capture_output=True, text=True).stdout.strip()
        except OSError:
            return ""

    def node_ok(ver: str) -> bool:
        # Vite needs Node 20.19+ (or 22.12+); Debian's apt 'nodejs' is EOL 18.
        try:
            parts = ver.lstrip("v").split(".")
            major, minor = int(parts[0]), int(parts[1])
        except (ValueError, IndexError):
            return False
        return major >= 21 or (major == 20 and minor >= 19)

    node, npm_path = shutil.which("node"), npm()
    node_ver = version(node)
    mark(bool(node), f"Node installed ({node_ver})", "Node missing")
    if node:
        mark(node_ok(node_ver),
             f"Node version OK ({node_ver} >= 20.19, Vite requirement)",
             f"Node {node_ver} too old for Vite (needs 20.19+). Install Node 20 "
             f"(re-run ./install.sh, or NodeSource), then rebuild with: ncp update")
    mark(bool(npm_path), f"npm installed ({version(npm_path)})", "npm missing")
    mark((FRONTEND_DIR / "node_modules").is_dir(),
         "Frontend node_modules installed",
         "Frontend node_modules missing (run: ncp update)")

    print("\nChecking Uvicorn...")
    uvicorn_ok = subprocess.run([str(PYTHON), "-m", "uvicorn", "--version"],
                                capture_output=True).returncode == 0
    mark(uvicorn_ok, "Uvicorn installed", "Uvicorn missing")

    def importable(stmt):
        return subprocess.run([str(PYTHON), "-c", stmt], cwd=str(ROOT),
                              capture_output=True).returncode == 0

    print("\nChecking backend service...")
    mark(importable("from synapse.main import sio_app"),
         "Backend module importable", "Backend module failed to import")

    print("\nChecking memory...")
    mark((ROOT / "synapse" / "memory").is_dir(),
         "Memory module directory found", "Missing memory module directory")
    mark(importable("from synapse.memory.curator import extract_for_conversation"),
         "Memory curator importable", "Memory curator failed to import")
    mark(os.access(ROOT / "synapse" / "memory", os.W_OK),
         "Memory database directory writable", "Memory database directory not writable")

    print("\nChecking Ollama...")
    _obin = ollama_bin()
    mark(bool(_obin), f"Ollama binary found ({_obin})",
         f"Ollama binary missing (not at {OLLAMA_BIN}, not on PATH)")
    mark(OLLAMA_MODELS_DIR.is_dir(), f"Ollama models directory found ({OLLAMA_MODELS_DIR})",
         f"Ollama models directory missing at {OLLAMA_MODELS_DIR}")
    print()
    cmd_status()
    if fix:
        _apply_fixes()


def cmd_update() -> None:
    print("Updating Project Nexus...\n")
    print("Skipping git pull — update only refreshes dependencies.\n")
    # Same overlay choice sync.py makes, so update and restore cannot install
    # different PyTorch builds on the same host.
    sys.path.insert(0, str(ROOT / "bin"))
    import importlib.util
    spec = importlib.util.spec_from_file_location("sync", ROOT / "bin" / "sync.py")
    sync = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(sync)
    req = sync.requirements()
    print(f"Updating backend Python dependencies ({req})...")
    subprocess.run([str(PYTHON), "-m", "pip", "install", "-r", req], cwd=str(ROOT))

    print("\nUpdating frontend dependencies...")
    npm_path = npm()
    if npm_path and FRONTEND_DIR.is_dir():
        subprocess.run([npm_path, "install"], cwd=str(FRONTEND_DIR))
    else:
        print("npm or frontend directory missing — skipping npm install.")

    print("\nRunning post-update diagnostics...")
    cmd_doctor()


def cmd_upgrade() -> int:
    """Pull + rebuild + restart the backend. This is what the web UI's "install
    update" button runs, so it must be spawned DETACHED from the backend - it
    stops the very server that asked for it.

    Ollama is deliberately left alone (stop_service, not cmd_stop): it is a
    separate process on :11434, the restore does not touch a present binary, and
    reloading a multi-GB model is the slowest part of a restart.
    """
    print("Stopping backend...")
    stop_service(SERVICES["backend"])
    # --no-desktop: an in-app update should not rewrite XFCE panels/theme.
    rc = sync_py("restore", "--no-desktop")
    print("\nRestarting backend...")
    launch(SERVICES["backend"])
    ok = wait_for_port(SERVICES["backend"])
    print("Backend is back up." if ok else "Backend did not come back - see runtime/backend.log")
    return rc if ok else 1


def cmd_clean() -> None:
    print("Cleaning Nexus runtime files...\n")
    print("Removing PID files...")
    for f in PID_DIR.glob("*.pid"):
        f.unlink(missing_ok=True)
    print("Removing logs...")
    for f in LOG_DIR.glob("*.log"):
        f.unlink(missing_ok=True)
    print("Removing Python cache...")
    for d in ROOT.rglob("__pycache__"):
        shutil.rmtree(d, ignore_errors=True)
    print("Removing Node/Vite cache...")
    for d in FRONTEND_DIR.rglob(".vite"):
        shutil.rmtree(d, ignore_errors=True)
    print("\nCleanup complete.")


MODEL_CATALOG = [
    ("gemma3:1b", "~815 MB", "Google Gemma 3 — fast, lightweight"),
    ("gemma3:4b", "~3.3 GB", "Google Gemma 3 — balanced"),
    ("gemma3:12b", "~8.1 GB", "Google Gemma 3 — capable"),
    ("llama3.2:1b", "~1.3 GB", "Meta Llama 3.2 — fast, lightweight"),
    ("llama3.2:3b", "~2.0 GB", "Meta Llama 3.2 — compact, capable"),
    ("llama3.1:8b", "~4.7 GB", "Meta Llama 3.1 — strong general use"),
    ("mistral:latest", "~4.1 GB", "Mistral 7B — solid all-rounder"),
    ("mistral-nemo", "~7.1 GB", "Mistral Nemo 12B — strong reasoning"),
    ("qwen2.5:3b", "~2.0 GB", "Alibaba Qwen 2.5 — great at code"),
    ("qwen2.5:7b", "~4.7 GB", "Alibaba Qwen 2.5 — strong coder"),
    ("phi4-mini", "~2.5 GB", "Microsoft Phi-4 Mini — efficient"),
    ("phi4:14b", "~8.9 GB", "Microsoft Phi-4 — strong reasoning"),
    ("deepseek-r1:7b", "~4.7 GB", "DeepSeek R1 — reasoning model"),
    ("deepseek-r1:14b", "~9.0 GB", "DeepSeek R1 — strong reasoning"),
    ("codellama:7b", "~3.8 GB", "Meta Code Llama — code focused"),
    ("nomic-embed-text", "~274 MB", "Text embeddings model"),
]


def cmd_models(action, name) -> None:
    if action == "list":
        if not http_ok(settings.ollama_host.rstrip("/") + "/api/tags"):
            print("Ollama is not running. Start the backend first with: ncp start -b")
            return
        raw = urllib.request.urlopen(settings.ollama_host.rstrip("/") + "/api/tags", timeout=5).read()
        models = json.loads(raw).get("models", [])
        print("Installed models:\n")
        if not models:
            print("  No models installed.")
            return
        for m in models:
            mb = m["size"] // 1024 // 1024
            size = f"{mb / 1024:.1f} GB" if mb >= 1024 else f"{mb} MB"
            print(f"  {m['name']:<35} {size}")
    elif action in ("available", "search"):
        print("Available models (via Ollama library):\n")
        print(f"  {'MODEL':<30} {'SIZE':<10} DESCRIPTION")
        print(f"  {'-----':<30} {'----':<10} -----------")
        for model, size, desc in MODEL_CATALOG:
            print(f"  {model:<30} {size:<10} {desc}")
        print("\nInstall any model with: ncp models install <model>")
        print("Browse more at: https://ollama.com/library")
    elif action == "install":
        if not name:
            print("Usage: ncp models install <model>")
            print("Run 'ncp models available' to see options.")
            return
        obin = ollama_bin()
        if not obin:
            print(f"Ollama binary not found at {OLLAMA_BIN}, and no 'ollama' on PATH")
            return
        print(f"Pulling '{name}' into {OLLAMA_MODELS_DIR} ...\n")
        subprocess.run([obin, "pull", name],
                       env={**os.environ, "OLLAMA_MODELS": str(OLLAMA_MODELS_DIR)})
        print("\nDone. Run 'ncp models list' to verify.")
    else:
        print("Usage: ncp models <list|available|install <model>>")


def sync_py(*args) -> int:
    """sync.py is stdlib-only, so system python works before the venv exists."""
    py = str(PYTHON) if PYTHON.exists() else sys.executable
    return subprocess.run([py, str(ROOT / "bin" / "sync.py"), *args]).returncode


def cmd_restore(flag) -> int:
    if flag in ("-c", "--claude", "check"):
        return sync_py("restore", "--check")     # dry run: no prompt, changes nothing
    print("This pulls the latest backup from Gitea and rebuilds the environment")
    print("(venv, npm, theme, panel). Local commits must be pushed or stashed first.")
    if input("Continue? [y/N] ").strip().lower() != "y":
        print("Restore cancelled.")
        return 0
    return sync_py("restore")


def cmd_web() -> int:
    """Per-platform UI launcher. On Linux nexus-app.sh already raises an existing
    window, acts as a viewer when the stack is up, and only stops services it
    started. Windows uses the pywebview window launch_nexus.ps1 opens."""
    if WINDOWS:
        if not http_ok(SERVICES["backend"].url):
            launch(SERVICES["backend"])
            wait_for_port(SERVICES["backend"])
        return subprocess.run([str(PYTHON), str(ROOT / "bin" / "nexus_window.py")]).returncode
    return subprocess.run([str(ROOT / "management" / "nexus-app.sh")]).returncode


def show_help() -> None:
    print("""Nexus Command Tree

Usage: ncp <command> [options]

Commands:
  panel                 Launch the Nexus Control Panel (tkinter)
  web                   Open the web interface (starts the stack if needed)

  chat <message>        Send a message, stream the reply
  memory list           List memory facts
    add <text>          Add a fact (--section <name>)
    rm <id>             Delete a fact by id
  playbook list         List playbooks (* = active)
    show <id>           Print a playbook's goal + instructions
  history [query]       Recent conversations (optional keyword)

  start                 Start ALL Nexus services (backend + frontend)
   --frontend,-f        Start only the frontend
   --backend, -b        Start only the backend
   --ai,      -a        Start only the AI (Ollama); `start`/`start -b` already include it

  stop                  Stop ALL Nexus services
   --frontend,-f        Stop only the frontend
   --backend, -b        Stop only the backend

  kill                  Force-kill all Nexus processes by port (nuclear option)
  refresh               Restart all services

  status                Show service status
  logs                  Show logs for all services
   --frontend,-f        Frontend logs
   --backend, -b        Backend logs

  doctor [--fix]        Run Nexus diagnostics (--fix applies safe repairs)
  update                Update Nexus dependencies
  upgrade               Pull, rebuild and restart the backend (what the UI's update button runs)
  clean                 Remove runtime files and caches

  models
    list                List installed models
    available           Show models available to install
    install <name>      Pull a model into Nexus

  backup                Backup Nexus to Gitea (git commit + push)
  backup -f, full       Backup + snapshot live desktop wiring/notes
  backup -c             Dry run: what a backup would commit/push
  restore               Restore Nexus from Gitea (git pull + rebuild)
  restore -c            Dry run: what a restore would apply

  help, -h              Show this help message""")


def main(argv) -> int:
    cmd = argv[0] if argv else ""
    rest = argv[1:]
    arg = rest[0] if rest else None

    if cmd in ("help", "-h", ""):
        show_help()
    elif cmd == "panel":
        return subprocess.run([str(PYTHON), str(ROOT / "management" / "controlpanel.py")]).returncode
    elif cmd == "web":
        return cmd_web()
    elif cmd in ("chat", "memory", "playbook", "history"):
        return subprocess.run([str(PYTHON), str(ROOT / "management" / "nexus_api.py"),
                               cmd, *rest]).returncode
    elif cmd == "start":
        cmd_start(arg)
    elif cmd == "stop":
        cmd_stop(arg)
    elif cmd == "refresh":
        cmd_stop(None)
        cmd_start(None)
    elif cmd == "kill":
        cmd_kill()
    elif cmd == "status":
        cmd_status()
    elif cmd == "logs":
        cmd_logs(arg)
    elif cmd == "doctor":
        cmd_doctor(fix="--fix" in rest)
    elif cmd == "update":
        cmd_update()
    elif cmd == "upgrade":
        return cmd_upgrade()
    elif cmd == "clean":
        cmd_clean()
    elif cmd == "nvidia-reqs":
        return subprocess.run([str(PYTHON), str(ROOT / "bin" / "gen-nvidia-reqs.py")]).returncode
    elif cmd == "backup":
        if arg in ("-f", "full"):
            return sync_py("backup", "--full")
        if arg in ("-c", "--claude", "check"):
            return sync_py("backup", "--check")
        if arg in (None, ""):
            return sync_py("backup")
        print("Usage: ncp backup [-f|full|-c]")
    elif cmd == "restore":
        if arg in (None, "", "-f", "full", "-c", "--claude", "check"):
            return cmd_restore(arg)
        print("Usage: ncp restore [-c]")
    elif cmd == "models":
        cmd_models(arg, rest[1] if len(rest) > 1 else None)
    else:
        print(f"Unknown Nexus command: '{cmd}'")
        print("Use 'ncp help' for available commands.")
    return 0


if __name__ == "__main__":
    try:
        sys.exit(main(sys.argv[1:]))
    except KeyboardInterrupt:
        # Ctrl+C is how you quit `ncp web` - it waits on the UI window. Without
        # this it printed a six-frame traceback ending in WaitForSingleObject,
        # which reads as a crash rather than "you pressed Ctrl+C". 130 is the
        # conventional exit status for SIGINT.
        print()
        sys.exit(130)