#!/usr/bin/env python3
"""nomarchy-state-sync — state writer for Nomarchy's declarative theming.

Single source of truth: $NOMARCHY_PATH/state.json (inside the flake,
read purely by Home Manager via the nomarchy.stateFile option).
Legacy name `theme-state.json` is still read (and migrated on write).
The old binary name `nomarchy-theme-sync` is a symlink to this tool.

Theme changes are applied by Home Manager: this tool writes the new state
and runs `home-manager switch` (override with $NOMARCHY_REBUILD, or skip
with --no-switch). All app theming — Hyprland, Waybar, Kitty, btop,
Stylix — is baked into the generation; nothing is patched at runtime.

The one runtime exception is the wallpaper: swww is imperative by nature,
so `bg next` cycles instantly and `wallpaper` (re-)applies the current one
at session start and after a switch.

Commands:
  list                       list theme presets
  apply <name|file.json>     merge a preset into the state + rebuild
  set <dotted.path> <value>  tweak one key (e.g. `set ui.gapsOut 16`) + rebuild
  get [dotted.path]          print the current state (or one key)
  auto [--which]             apply the day/night theme for the current time
  validate                   check the state file against the schema (read-only)
  wallpaper                  apply the current wallpaper via swww
  bg [next|auto]             cycle the theme's wallpapers (instant, no rebuild)
"""

import argparse
import json
import os
import re
import shlex
import shutil
import subprocess
import sys
import tempfile
import time
from pathlib import Path

# ─── Paths ────────────────────────────────────────────────────────────────

FLAKE_DIR = Path(os.environ.get("NOMARCHY_PATH", Path.home() / ".nomarchy")).expanduser()
# Canonical name after #107. Legacy theme-state.json (and a brief theme.json
# misnomer some notes used) are still accepted for existing checkouts.
STATE_NAME = "state.json"
LEGACY_STATE_NAMES = ("theme-state.json", "theme.json")


def resolve_state_file(flake_dir: Path = FLAKE_DIR) -> Path:
    preferred = flake_dir / STATE_NAME
    if preferred.exists():
        return preferred
    for name in LEGACY_STATE_NAMES:
        legacy = flake_dir / name
        if legacy.exists():
            return legacy
    return preferred


STATE_FILE = resolve_state_file()

# Preset search path: the user's flake first (their custom themes win),
# then the presets baked into this package by the Nix build.
THEMES_DIRS = [FLAKE_DIR / "themes"]
if os.environ.get("NOMARCHY_DEFAULT_THEMES"):
    THEMES_DIRS.append(Path(os.environ["NOMARCHY_DEFAULT_THEMES"]))

WALLPAPER_EXTS = {".png", ".jpg", ".jpeg", ".webp"}

QUIET = False

# argv[0] may still be the compatibility name nomarchy-theme-sync.
_TOOL = Path(sys.argv[0]).name or "nomarchy-state-sync"


def log(msg: str) -> None:
    if not QUIET:
        print(f"{_TOOL}: {msg}")


def die(msg: str) -> "None":
    print(f"{_TOOL}: error: {msg}", file=sys.stderr)
    sys.exit(1)


# All Nomarchy theme notifications share this synchronous tag, so the
# notification daemon (swaync) REPLACES the previous one in place instead
# of stacking — the "rebuilding…" toast becomes the "applied ✓" toast.
NOTIFY_SYNC_TAG = "nomarchy-state-sync"


def notify(body: str, summary: str = "Nomarchy", *,
           persistent: bool = False, urgency: str = "normal") -> None:
    """Desktop notification. persistent (timeout 0) keeps it up for the
    whole rebuild so a slow switch never reads as a failed selection;
    the success/failure call replaces it via the synchronous tag."""
    if shutil.which("notify-send") is None:
        return
    subprocess.run(
        ["notify-send", "-a", "Nomarchy",
         "-u", urgency,
         "-t", "0" if persistent else "5000",
         "-h", f"string:x-canonical-private-synchronous:{NOTIFY_SYNC_TAG}",
         summary, body],
        capture_output=True,
    )


# ─── State management ─────────────────────────────────────────────────────

def load_state(path: Path | None = None) -> dict:
    path = path or resolve_state_file()
    try:
        return json.loads(path.read_text())
    except FileNotFoundError:
        die(f"state file not found: {path} (set $NOMARCHY_PATH to your flake checkout)")
    except json.JSONDecodeError as e:
        die(f"{path.name} has a JSON syntax error at line {e.lineno}, "
            f"column {e.colno}: {e.msg}\n"
            f"  file: {path}\n"
            f"  fix:  correct the syntax by hand (a trailing comma is the "
            f"usual culprit) — nothing was changed")


def write_state(state: dict) -> None:
    """Atomic write: render to a temp file in the same dir, then rename.
    Validates first — an invalid state never reaches disk (the old file
    stays untouched), so a bad `set` can't brick the next rebuild.
    Always writes the canonical state.json; removes a legacy-named sibling
    so a checkout never has two competing sources of truth."""
    errors, warnings = validate_state(state)
    for w in warnings:
        log(f"warning: {w}")
    if errors:
        die("refusing to write an invalid state (nothing changed):\n  ✖ "
            + "\n  ✖ ".join(errors))
    out = FLAKE_DIR / STATE_NAME
    out.parent.mkdir(parents=True, exist_ok=True)
    fd, tmp = tempfile.mkstemp(dir=out.parent, prefix=".state.", suffix=".json")
    try:
        with os.fdopen(fd, "w") as f:
            json.dump(state, f, indent=2)
            f.write("\n")
        os.replace(tmp, out)
    except BaseException:
        os.unlink(tmp)
        raise
    for name in LEGACY_STATE_NAMES:
        legacy = FLAKE_DIR / name
        if legacy.exists() and legacy.resolve() != out.resolve():
            try:
                legacy.unlink()
                log(f"migrated: removed legacy {name} (now {STATE_NAME})")
            except OSError as e:
                log(f"warning: could not remove legacy {name}: {e}")
    log(f"state written to {out}")

    # Flakes only see git-tracked files. state.json ships tracked,
    # but make sure a fresh checkout / reset can't silently hide it.
    if (FLAKE_DIR / ".git").exists() and shutil.which("git"):
        subprocess.run(
            ["git", "-C", str(FLAKE_DIR), "add", "--intent-to-add", STATE_NAME],
            capture_output=True,
        )
        for name in LEGACY_STATE_NAMES:
            subprocess.run(
                ["git", "-C", str(FLAKE_DIR), "rm", "-f", "--ignore-unmatch", name],
                capture_output=True,
            )


def auto_commit_enabled(state: dict) -> bool:
    return bool((state.get("settings") or {}).get("autoCommit"))


def auto_commit(message: str) -> None:
    """Opt-in (settings.autoCommit): commit state.json — and nothing
    else — after a mutation, so settings history is `git log`. The pathspec
    keeps unrelated dirty files out of the commit; a missing git identity
    falls back to a Nomarchy one so a fresh machine never errors. Callers
    fire this when the flag is on before OR after the write, so the
    disable-toggle itself lands in history instead of staying dirty.
    `bg` is deliberately excluded (runtime wallpaper churn); the wallpaper
    path rides along with the next apply/set commit. The rest of a dirty
    tree (hand edits, lock bumps) is swept by nomarchy-lifecycle's
    nomarchy-autocommit right before a pull/rebuild/home switch — same
    flag, honest message — so it never rides a settings-named commit."""
    if not (FLAKE_DIR / ".git").exists() or shutil.which("git") is None:
        return
    git = ["git", "-C", str(FLAKE_DIR)]
    # Pathspec: preferred name plus any leftover legacy file still staged.
    paths = [STATE_NAME, *LEGACY_STATE_NAMES]
    # No-op when the file already matches HEAD (a `set` to the same value).
    # On a repo with no commits yet this diff errors — then just commit.
    if subprocess.run(git + ["diff", "--quiet", "HEAD", "--"] + paths,
                      capture_output=True).returncode == 0:
        return
    if not subprocess.run(git + ["config", "user.email"],
                          capture_output=True, text=True).stdout.strip():
        git += ["-c", "user.name=Nomarchy", "-c", "user.email=nomarchy@localhost"]
    result = subprocess.run(
        git + ["commit", "--quiet", "-m", message, "--"] + paths,
        capture_output=True, text=True)
    if result.returncode == 0:
        log(f"auto-committed: {message}")
    else:
        log(f"auto-commit skipped: {(result.stderr or result.stdout).strip()}")


def deep_merge(base: dict, override: dict) -> dict:
    out = dict(base)
    for k, v in override.items():
        if isinstance(v, dict) and isinstance(out.get(k), dict):
            out[k] = deep_merge(out[k], v)
        else:
            out[k] = v
    return out


# ─── Schema validation ─────────────────────────────────────────────────────
# The friendly-errors contract (with theme.nix, which enforces the same
# rules at eval time): a hand-edited state file fails HERE, before it is
# written, with the field, the problem, and the fix — never as a Nix
# stack trace at rebuild. Hard errors cover the appearance schema the
# modules consume; settings.* (menu-writer territory) and unknown keys
# only warn, so custom keys and newer/older schemas keep working.

HEX_RE = re.compile(r"^#[0-9a-fA-F]{6}$")
COLOR_ROLES = ("base", "mantle", "surface", "overlay", "text", "subtext",
               "muted", "accent", "accentAlt", "good", "warn", "bad")
TOP_KEYS = {"version", "name", "slug", "mode", "wallpaper", "colors", "ansi",
            "fonts", "ui", "icons", "border", "settings"}
UI_UINTS = ("gapsIn", "gapsOut", "borderSize", "rounding", "iconSize")
UI_OPACITIES = ("activeOpacity", "inactiveOpacity", "terminalOpacity")
UI_BOOLS = ("blur", "shadow")


def _is_hex(v) -> bool:
    return isinstance(v, str) and bool(HEX_RE.match(v))


def _is_num(v) -> bool:
    return isinstance(v, (int, float)) and not isinstance(v, bool)


def validate_state(state) -> tuple:
    """Return (errors, warnings) — friendly strings, one problem each."""
    errors, warnings = [], []

    def err(field, problem, fix):
        errors.append(f"{field}: {problem}\n    fix: {fix}")

    if not isinstance(state, dict):
        err("top level", "must be a JSON object",
            "re-apply a preset: nomarchy-state-sync apply boreal")
        return errors, warnings

    for k in state:
        if k not in TOP_KEYS:
            warnings.append(f"unknown top-level key '{k}' — a typo? (it is ignored)")

    for field, want in (("name", "the theme's display name"),
                        ("slug", "the theme's directory name"),
                        ("wallpaper", "a filename in the theme's backgrounds/ (or \"\")"),
                        ("icons", "an icon theme name (or \"\" for pick-by-mode)")):
        v = state.get(field)
        if v is not None and not isinstance(v, str):
            err(field, f"must be a string ({want}), got {v!r}", 'quote it, e.g. "boreal"')

    mode = state.get("mode")
    if mode is not None and mode not in ("dark", "light"):
        err("mode", f'must be "dark" or "light", got {mode!r}', 'set it to "dark" or "light"')

    colors = state.get("colors", {})
    if not isinstance(colors, dict):
        err("colors", "must be an object of palette roles",
            "re-apply a preset to restore the palette")
    else:
        for k, v in colors.items():
            if k not in COLOR_ROLES:
                warnings.append(f"colors.{k}: not a Nomarchy palette role (it is ignored)")
            elif not _is_hex(v):
                err(f"colors.{k}", f'must be "#RRGGBB", got {v!r}',
                    'use a 6-digit hex color like "#7aa2f7"')

    ansi = state.get("ansi")
    if ansi is not None and not (isinstance(ansi, list) and len(ansi) == 16
                                 and all(_is_hex(c) for c in ansi)):
        err("ansi", 'must be a list of exactly 16 "#RRGGBB" strings',
            "re-apply a preset to restore the terminal palette")

    fonts = state.get("fonts", {})
    if isinstance(fonts, dict):
        for k in ("mono", "ui"):
            v = fonts.get(k)
            if v is not None and not isinstance(v, str):
                err(f"fonts.{k}", f"must be a font family name (string), got {v!r}",
                    'quote it, e.g. "JetBrainsMono Nerd Font"')
        size = fonts.get("size")
        if size is not None and not (_is_num(size) and size > 0):
            err("fonts.size", f"must be a positive number (points), got {size!r}",
                "use a plain number like 11 (no quotes)")
    else:
        err("fonts", "must be an object", 're-add: {"mono": "...", "ui": "...", "size": 11}')

    ui = state.get("ui", {})
    if isinstance(ui, dict):
        for k in UI_UINTS:
            v = ui.get(k)
            if v is not None and not (isinstance(v, int) and not isinstance(v, bool) and v >= 0):
                err(f"ui.{k}", f"must be a non-negative whole number (pixels), got {v!r}",
                    "use a plain number like 12 (no quotes)")
        for k in UI_OPACITIES:
            v = ui.get(k)
            if v is not None and not (_is_num(v) and 0 <= v <= 1):
                err(f"ui.{k}", f"must be a number between 0 and 1, got {v!r}",
                    "use e.g. 0.95 (no quotes)")
        for k in UI_BOOLS:
            v = ui.get(k)
            if v is not None and not isinstance(v, bool):
                err(f"ui.{k}", f"must be true or false, got {v!r}",
                    "use true or false (no quotes)")
    else:
        err("ui", "must be an object", "re-apply a preset to restore the UI block")

    border = state.get("border")
    if border is not None:
        if not isinstance(border, dict):
            err("border", "must be an object", 're-add: {"active": "accent", "inactive": "overlay"}')
        else:
            for k in ("active", "inactive"):
                v = border.get(k)
                if v is not None and not (isinstance(v, str)
                                          and (v in COLOR_ROLES or _is_hex(v))):
                    err(f"border.{k}",
                        f'must be a palette role ({", ".join(COLOR_ROLES)}) or "#RRGGBB", got {v!r}',
                        'use e.g. "accent" or "#7aa2f7"')

    settings = state.get("settings")
    if settings is not None and not isinstance(settings, dict):
        err("settings", "must be an object (the menu writes feature flags here)",
            're-add: "settings": {}')

    slug = state.get("slug")
    if isinstance(slug, str) and slug and find_preset(slug) is None:
        warnings.append(f"slug '{slug}' matches no shipped/custom preset — "
                        f"fine for a hand-rolled theme, but per-theme assets won't resolve")

    return errors, warnings


def cmd_validate(_args) -> None:
    state = load_state()  # dies with the friendly syntax error on bad JSON
    errors, warnings = validate_state(state)
    for w in warnings:
        print(f"  ● {w}")
    if errors:
        print(f"nomarchy-state-sync: {STATE_FILE} has "
              f"{len(errors)} problem(s):", file=sys.stderr)
        for e in errors:
            print(f"  ✖ {e}", file=sys.stderr)
        sys.exit(1)
    log(f"{STATE_FILE} is valid ({len(warnings)} warning(s))")


# ─── Font verification ────────────────────────────────────────────────────

def check_fonts(state: dict) -> None:
    """Warn when a configured font family isn't installed. fontconfig
    substitutes silently, so a typo'd or missing fonts.mono would just
    render the whole desktop in some fallback with no error anywhere."""
    if shutil.which("fc-match") is None:
        return
    for key in ("mono", "ui"):
        name = (state.get("fonts") or {}).get(key)
        if not name:
            continue
        result = subprocess.run(["fc-match", "-f", "%{family}", name],
                                capture_output=True, text=True)
        families = [f.strip().lower() for f in result.stdout.split(",")]
        if result.returncode != 0 or name.strip().lower() not in families:
            fallback = result.stdout.strip() or "unknown"
            print(f"nomarchy-state-sync: warning: fonts.{key} '{name}' is not "
                  f"installed — fontconfig will substitute '{fallback}'",
                  file=sys.stderr)
            notify(f"Font '{name}' is not installed — using '{fallback}'")


# ─── Rebuild dispatch ─────────────────────────────────────────────────────

def run_switch() -> None:
    """Bake the new state into a Home Manager generation."""
    override = os.environ.get("NOMARCHY_REBUILD")
    argv = shlex.split(override) if override else \
        ["home-manager", "switch", "--flake", str(FLAKE_DIR)]

    if shutil.which(argv[0]) is None:
        log(f"'{argv[0]}' not found — state written; rebuild manually to apply")
        return

    log(f"rebuilding: {' '.join(argv)}")
    # Persistent (timeout 0): stays up for the whole rebuild — replaced
    # in place by the success/failure notification below — so a multi-
    # minute switch never looks like it silently failed.
    notify("Applying changes — rebuilding the desktop…", persistent=True)
    result = subprocess.run(argv)  # stream output to the caller's terminal
    if result.returncode != 0:
        # BACKLOG #56: point at doctor, not a silent wall of Nix noise.
        notify(
            "Rebuild FAILED — scroll up for last lines; run nomarchy-doctor",
            urgency="critical",
        )
        # Live ISO pins only the *default* theme's HM generation. Applying
        # another preset offline tries to build the world from source (#113).
        offline_hint = ""
        try:
            import socket
            socket.create_connection(("1.1.1.1", 53), timeout=1.5).close()
        except OSError:
            offline_hint = (
                " Offline? Only the live ISO's already-pinned theme is "
                "guaranteed without a network — other themes need builds "
                "or a binary cache. Connect and retry, or apply the default "
                "theme (boreal)."
            )
        die(
            "rebuild failed (state already written; fix and re-run). "
            "Diagnose: nomarchy-doctor. Recovery: docs/RECOVERY.md."
            + offline_hint
        )
    notify("Changes applied ✓")
    # Waybar runs from Hyprland's exec-once (not a systemd unit HM would
    # restart on switch), so nudge the running bar onto the freshly rebuilt
    # config/style. Under the nomarchy-waybar supervisor a plain kill IS a
    # clean restart with the new files — waybar's in-place SIGUSR2 reload
    # is what crashed the bar on hardware (double-reload race with
    # reload_style_on_change while the symlinks flip), so prefer the
    # restart whenever the supervisor is there to catch it; fall back to
    # SIGUSR2 for unsupervised/custom bars. No-ops if nothing is running.
    if shutil.which("pkill"):
        supervised = subprocess.run(
            ["pgrep", "-f", "nomarchy-waybar"], capture_output=True
        ).returncode == 0
        if supervised:
            subprocess.run(["pkill", "-x", "waybar"], check=False)
        else:
            subprocess.run(["pkill", "--signal", "SIGUSR2", "-x", "waybar"], check=False)


# ─── Theme assets (wallpapers) ────────────────────────────────────────────
# Convention: a preset themes/<slug>.json may have a sibling directory
# themes/<slug>/ with assets: backgrounds/ (wallpapers), btop.theme,
# waybar.css / waybar.jsonc. All except backgrounds/ are consumed by the
# Nix modules at eval time; wallpapers are applied here via swww.

def find_asset(slug: str, name: str):
    for themes_dir in THEMES_DIRS:
        candidate = themes_dir / slug / name
        if candidate.exists():
            return candidate
    return None


def backgrounds_for(slug: str) -> list:
    bg_dir = find_asset(slug, "backgrounds")
    if bg_dir is None or not bg_dir.is_dir():
        return []
    return sorted(p for p in bg_dir.iterdir() if p.suffix.lower() in WALLPAPER_EXTS)


def resolve_wallpaper(state: dict):
    """Explicit path in the state wins; empty means 'first theme background'."""
    explicit = state.get("wallpaper", "")
    if explicit:
        path = Path(explicit).expanduser()
        if path.is_file():
            return path
        log(f"wallpaper not found, using theme default: {explicit}")
    backgrounds = backgrounds_for(state.get("slug", ""))
    return backgrounds[0] if backgrounds else None


def apply_wallpaper(state: dict, wait: bool = False) -> None:
    wallpaper = resolve_wallpaper(state)
    if wallpaper is None:
        log(f"no wallpaper for theme '{state.get('slug', '?')}', skipping")
        return
    # nixpkgs renamed swww to awww (CLI-compatible fork); accept either.
    swww = shutil.which("awww") or shutil.which("swww")
    if swww is None:
        log("awww/swww not found, skipping wallpaper")
        return
    # At session start the daemon may still be coming up.
    for _ in range(10 if wait else 1):
        if subprocess.run([swww, "query"], capture_output=True).returncode == 0:
            break
        time.sleep(0.5)
    result = subprocess.run(
        [swww, "img", str(wallpaper),
         "--transition-type", "grow",
         "--transition-pos", "center",
         "--transition-duration", "1",
         "--transition-fps", "60"],
        capture_output=True,
    )
    log(f"wallpaper: {wallpaper.name}" if result.returncode == 0
        else "wallpaper: awww failed (daemon not running?)")


# ─── Commands ─────────────────────────────────────────────────────────────

def find_preset(name: str):
    for themes_dir in THEMES_DIRS:
        candidate = themes_dir / f"{name}.json"
        if candidate.is_file():
            return candidate
    return None


def cmd_list(_args) -> None:
    names = sorted({f.stem for d in THEMES_DIRS if d.is_dir() for f in d.glob("*.json")})
    if not names:
        die(f"no theme presets found (searched: {', '.join(map(str, THEMES_DIRS))})")
    print("\n".join(names))


def apply_named(theme: str, no_switch: bool = False) -> None:
    """Merge a preset (name or JSON file) into the state and rebuild. Shared
    by `apply` and `auto` so the day/night switch is the *same* one engine."""
    candidate = Path(theme).expanduser()
    preset_path = candidate if candidate.is_file() else find_preset(theme)
    if preset_path is None:
        die(f"unknown theme '{theme}' (try `nomarchy-state-sync list`)")

    preset = json.loads(preset_path.read_text())
    # Merge over current state. Presets carry a full appearance block —
    # palette, border, fonts and ui — so a switch always replaces the last
    # theme's look (a theme can ship a bespoke font/opacity/geometry, e.g.
    # Boreal, without it leaking into the next). settings.* (feature state,
    # keyboard/monitor memory) live outside any preset and survive. A
    # per-key `set ui.<k>`/`fonts.<k>` tweak holds until the next apply.
    old = load_state()
    state = deep_merge(old, preset)
    write_state(state)
    if auto_commit_enabled(old) or auto_commit_enabled(state):
        auto_commit(f"nomarchy: apply theme {state.get('name', theme)}")
    log(f"theme: {state.get('name', theme)}")
    check_fonts(state)
    if not no_switch:
        run_switch()
        apply_wallpaper(state)


def cmd_apply(args) -> None:
    apply_named(args.theme, no_switch=args.no_switch)


def _hhmm_to_min(s: str, default: str) -> int:
    """'HH:MM' → minutes since midnight; falls back to `default` on garbage."""
    for candidate in (s, default):
        try:
            h, m = str(candidate).split(":")
            return int(h) * 60 + int(m)
        except (ValueError, AttributeError):
            continue
    return 0


def cmd_auto(args) -> None:
    """Apply the day or night theme for the current local time, per
    settings.autoTheme = {enable, day, night, sunrise, sunset}. Slice 1 of
    the auto time-of-day pair (BACKLOG #79): the timer (slice 2) and menu
    (slice 3) drive this; it can also be run by hand or from a user cron."""
    state = load_state()
    at = (state.get("settings") or {}).get("autoTheme") or {}
    if not at.get("enable"):
        if not args.which:
            log("auto-theme: off (enable via settings.autoTheme.enable)")
        return
    day, night = at.get("day"), at.get("night")
    if not day or not night:
        die("auto-theme needs settings.autoTheme.day and .night (theme slugs)")

    sunrise = _hhmm_to_min(at.get("sunrise", "07:00"), "07:00")
    sunset = _hhmm_to_min(at.get("sunset", "20:00"), "20:00")
    now = time.localtime()
    mins = now.tm_hour * 60 + now.tm_min
    # Daytime is the span between sunrise and sunset. Also handle a
    # wrap-around pair (sunrise after sunset → the day window crosses
    # midnight), so an inverted schedule still switches both ways.
    if sunrise <= sunset:
        daytime = sunrise <= mins < sunset
    else:
        daytime = mins >= sunrise or mins < sunset
    target = day if daytime else night

    if args.which:
        print(target)
        return
    if state.get("slug") == target and not args.force:
        log(f"auto-theme: already on {target} ({'day' if daytime else 'night'})")
        return
    apply_named(target, no_switch=args.no_switch)


def cmd_set(args) -> None:
    state = load_state()
    try:
        value = json.loads(args.value)  # numbers, bools, null, quoted strings
    except json.JSONDecodeError:
        value = args.value  # bare string ("#7aa2f7", font names, paths)

    was_on = auto_commit_enabled(state)
    node = state
    keys = args.path.split(".")
    for key in keys[:-1]:
        node = node.setdefault(key, {})
        if not isinstance(node, dict):
            die(f"cannot descend into non-object at '{key}' in '{args.path}'")
    node[keys[-1]] = value

    write_state(state)
    if was_on or auto_commit_enabled(state):
        auto_commit(f"nomarchy: set {args.path} = {json.dumps(value)}")
    log(f"set {args.path} = {value!r}")
    if args.path.startswith("fonts."):
        check_fonts(state)
    if not args.no_switch:
        run_switch()
        # Only wallpaper/theme keys change what swww shows; skip the re-apply
        # (and its transition) for unrelated keys like ui.* or settings.* so a
        # gaps tweak or a feature toggle doesn't flash the background.
        if args.path.split(".")[0] in ("wallpaper", "slug"):
            apply_wallpaper(state)


def cmd_get(args) -> None:
    state = load_state()
    if args.path:
        node = state
        for key in args.path.split("."):
            try:
                node = node[key]
            except (KeyError, TypeError):
                die(f"no such key: {args.path}")
        # Booleans and null print JSON-style (true/false/null, not Python's
        # True/False/None) so shell consumers can compare against the same
        # literal they `set`. null matters for genuinely-nullable keys like
        # settings.greeter.autoLogin, where "None" would silently miss every
        # `case ... null)` a caller writes.
        print(json.dumps(node, indent=2)
              if node is None or isinstance(node, (dict, list, bool)) else node)
    else:
        print(json.dumps(state, indent=2))


def cmd_wallpaper(_args) -> None:
    """Apply the current wallpaper (session start, switch, output hotplug)."""
    apply_wallpaper(load_state(), wait=True)


def cmd_bg(args) -> None:
    """Cycle the theme's wallpapers — instant, no rebuild needed (the
    wallpaper is runtime state for swww; nothing in Nix consumes it)."""
    state = load_state()
    if args.action == "auto":
        state["wallpaper"] = ""
    else:  # next
        backgrounds = backgrounds_for(state.get("slug", ""))
        if not backgrounds:
            die(f"theme '{state.get('slug', '?')}' has no backgrounds/ directory")
        current = resolve_wallpaper(state)
        idx = (backgrounds.index(current) + 1) % len(backgrounds) if current in backgrounds else 0
        state["wallpaper"] = str(backgrounds[idx])
    write_state(state)
    apply_wallpaper(state)


# ─── Entry point ──────────────────────────────────────────────────────────

def main() -> None:
    global QUIET

    parser = argparse.ArgumentParser(
        prog="nomarchy-state-sync",
        description="Nomarchy theming — state writer + Home Manager rebuild dispatcher.",
    )
    parser.add_argument("--quiet", action="store_true", help="suppress progress output")
    sub = parser.add_subparsers(dest="command", required=True)

    sub.add_parser("list", help="list theme presets").set_defaults(func=cmd_list)

    p = sub.add_parser("apply", help="apply a theme preset (name or JSON file) + rebuild")
    p.add_argument("theme")
    p.add_argument("--no-switch", action="store_true", help="write state only, skip the rebuild")
    p.set_defaults(func=cmd_apply)

    p = sub.add_parser("set", help="set one key, e.g. `set ui.gapsOut 16` + rebuild")
    p.add_argument("path")
    p.add_argument("value")
    p.add_argument("--no-switch", action="store_true", help="write state only, skip the rebuild")
    p.set_defaults(func=cmd_set)

    p = sub.add_parser("get", help="print state (or one dotted key)")
    p.add_argument("path", nargs="?")
    p.set_defaults(func=cmd_get)

    p = sub.add_parser("auto", help="apply the day/night theme for the current time (settings.autoTheme)")
    p.add_argument("--which", action="store_true", help="print the theme that WOULD apply, don't switch")
    p.add_argument("--force", action="store_true", help="apply even if already on the target theme")
    p.add_argument("--no-switch", action="store_true", help="write state only, skip the rebuild")
    p.set_defaults(func=cmd_auto)

    sub.add_parser("validate", help="check state.json against the schema (read-only)").set_defaults(func=cmd_validate)

    sub.add_parser("wallpaper", help="apply the current wallpaper via swww").set_defaults(func=cmd_wallpaper)

    p = sub.add_parser("bg", help="wallpaper control: `bg next` cycles, `bg auto` resets")
    p.add_argument("action", choices=["next", "auto"], default="next", nargs="?")
    p.set_defaults(func=cmd_bg)

    args = parser.parse_args()
    QUIET = args.quiet
    try:
        args.func(args)
    except KeyboardInterrupt:
        sys.exit(130)


if __name__ == "__main__":
    main()