#!/usr/bin/env bash
#
# mangohud-logger — toggle MangoHud CSV logging on/off
#
# Just run it: if logging is off it gets switched on, if it's already on
# it gets switched off.
#
# What it manages on enable:
#   1. ~/.config/MangoHud/MangoHud.conf
#      → appends a marker block with output_folder, autostart_log, etc.
#      → keeps your existing keys; overrides `no_display` while logging
#        (autostart_log rides on the render hook that no_display disables).
#      → pins gpu_list to the GPU actually rendering games (see below), so the
#        gpu_* columns log real data instead of an idle second GPU.
#   2. ~/.config/environment.d/95-mangohud-logger.conf
#      → contains MANGOHUD=1 so the Vulkan layer auto-loads into every
#        game (gamescope sessions, Steam, native Vulkan apps).
#        Picked up by systemd-user at next session login.
#
# GPU selection (vendor-agnostic):
#   MangoHud logs stats for ONE GPU. On a hybrid box (an AMD/Intel iGPU beside a
#   discrete NVIDIA/AMD card) its default often picks the idle iGPU, so every
#   gpu_* column reads ~0. We auto-detect the render node that's the actual
#   gaming GPU — any vendor — and pin `gpu_list` to its index. Override with
#   MANGOHUD_LOGGER_GPU=<index> or =nvidia|amd|intel if the guess is wrong.
#
# Logs land in the user's Downloads folder under "mango-logs"
# (honours XDG_DOWNLOAD_DIR from ~/.config/user-dirs.dirs, else ~/Downloads).

set -euo pipefail

readonly MARKER_BEGIN="# >>> mangohud-logger BEGIN >>>"
readonly MARKER_END="# <<< mangohud-logger END <<<"

CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/MangoHud"
CONFIG_FILE="$CONFIG_DIR/MangoHud.conf"

ENV_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/environment.d"
ENV_FILE="$ENV_DIR/95-mangohud-logger.conf"

GS_SESSION_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/gamescope-session-plus/sessions.d"
GS_SESSION_FILE="$GS_SESSION_DIR/steam"
GS_OWNED_MARKER="# Written by mangohud-logger."

# Detect which gamescope (Game Mode) session manager is in use — this decides
# whether our env override is actually sourced at session start:
#   plus    → gamescope-session-plus sources ~/.config/gamescope-session-plus/
#             sessions.d/* after its own steam script, so our override works.
#   steamos → /usr/lib/steamos/gamescope-session hard-exports
#             STEAM_USE_MANGOAPP=1 and MANGOHUD_CONFIGFILE=<tmp>/no_display, and
#             sources NO user file. A global override is therefore impossible;
#             logging requires per-game Steam launch options instead.
#   none    → no gamescope session found (desktop-only machine).
detect_gs_flavor() {
  if [[ -e /usr/share/gamescope-session-plus/sessions.d/steam ]]; then
    printf 'plus\n'
  elif [[ -e /usr/lib/steamos/gamescope-session ]]; then
    printf 'steamos\n'
  else
    printf 'none\n'
  fi
}
GS_FLAVOR="$(detect_gs_flavor)"

# The per-game launch-option string that makes logging work on the steamos
# flavor (repoints MANGOHUD_CONFIGFILE back at our config so autostart_log fires).
LAUNCH_OPT="MANGOHUD_CONFIGFILE=$CONFIG_FILE mangohud %command%"

# Resolve Downloads via xdg-user-dir if available, else the user-dirs.dirs file,
# else fall back to ~/Downloads. This makes the script work on non-English locales.
if command -v xdg-user-dir >/dev/null 2>&1; then
  DOWNLOADS_DIR="$(xdg-user-dir DOWNLOAD)"
elif [[ -f "${XDG_CONFIG_HOME:-$HOME/.config}/user-dirs.dirs" ]]; then
  # shellcheck disable=SC1090,SC1091
  source "${XDG_CONFIG_HOME:-$HOME/.config}/user-dirs.dirs"
  DOWNLOADS_DIR="${XDG_DOWNLOAD_DIR:-$HOME/Downloads}"
else
  DOWNLOADS_DIR="$HOME/Downloads"
fi
LOG_DIR="$DOWNLOADS_DIR/mango-logs"

err()  { printf '\033[31merror:\033[0m %s\n' "$*" >&2; }
info() { printf '\033[36m::\033[0m %s\n' "$*"; }
ok()   { printf '\033[32m✓\033[0m %s\n' "$*"; }
warn() { printf '\033[33m!\033[0m %s\n' "$*"; }

# PCI vendor IDs (as reported by /sys/class/drm/*/device/vendor).
readonly VENDOR_NVIDIA=0x10de
readonly VENDOR_AMD=0x1002
readonly VENDOR_INTEL=0x8086

# select_gpu — figure out which GPU MangoHud should log, vendor-agnostically.
#
# MangoHud enumerates DRM render nodes (renderD128, renderD129, …) in ascending
# order and `gpu_list=<n>` selects the n-th of them (verified: gpu_list=0 maps to
# renderD128). We pick the node that's the real gaming GPU and return its index.
#
# Selection order:
#   1. MANGOHUD_LOGGER_GPU override — a numeric index, or nvidia|amd|intel.
#   2. Single GPU → index 0 (covers every single-card machine, any vendor).
#   3. Multi-GPU → prefer a discrete NVIDIA; else the card with the most VRAM
#      (discrete AMD/Intel report mem_info_vram_total; iGPUs report far less/none).
#
# Sets globals: GPU_INDEX (may be ""), GPU_VENDOR, GPU_DESC.
select_gpu() {
  GPU_INDEX=""; GPU_VENDOR=""; GPU_DESC=""

  local nodes=()
  mapfile -t nodes < <(
    for n in /sys/class/drm/renderD*; do
      [[ -e "$n/device/vendor" ]] && basename "$n"
    done | sort   # ascending == MangoHud's gpu_list index order
  )

  local count=${#nodes[@]}
  if (( count == 0 )); then
    GPU_DESC="no DRM render node found (software renderer?) — gpu_list left unset"
    return
  fi

  # Index-aligned vendor + VRAM for each node.
  local vendors=() vrams=() i
  for i in "${!nodes[@]}"; do
    vendors[i]=$(cat "/sys/class/drm/${nodes[i]}/device/vendor" 2>/dev/null || echo unknown)
    vrams[i]=$(cat "/sys/class/drm/${nodes[i]}/device/mem_info_vram_total" 2>/dev/null || echo 0)
  done

  if [[ -n "${MANGOHUD_LOGGER_GPU:-}" ]]; then
    local ov="${MANGOHUD_LOGGER_GPU,,}"
    if [[ "$ov" =~ ^[0-9]+$ ]]; then
      GPU_INDEX="$ov"
    else
      local want=""
      case "$ov" in
        nvidia) want=$VENDOR_NVIDIA ;;
        amd)    want=$VENDOR_AMD ;;
        intel)  want=$VENDOR_INTEL ;;
      esac
      for i in "${!nodes[@]}"; do
        [[ "${vendors[i]}" == "$want" ]] && { GPU_INDEX="$i"; break; }
      done
      [[ -z "$GPU_INDEX" ]] && GPU_INDEX=0   # requested vendor absent → first GPU
    fi
  elif (( count == 1 )); then
    GPU_INDEX=0
  else
    # Prefer discrete NVIDIA (NVIDIA never populates mem_info_vram_total via DRM
    # sysfs, so the VRAM check below can't see it — hence this explicit pass).
    for i in "${!nodes[@]}"; do
      [[ "${vendors[i]}" == "$VENDOR_NVIDIA" ]] && { GPU_INDEX="$i"; break; }
    done
    if [[ -z "$GPU_INDEX" ]]; then
      local best=0 bestvram=-1
      for i in "${!nodes[@]}"; do
        if (( ${vrams[i]:-0} > bestvram )); then bestvram=${vrams[i]:-0}; best=$i; fi
      done
      GPU_INDEX="$best"
    fi
  fi

  # Describe the choice (guard against an out-of-range manual override).
  local node="${nodes[$GPU_INDEX]:-?}" vsel="${vendors[$GPU_INDEX]:-unknown}" name
  case "$vsel" in
    "$VENDOR_NVIDIA") name=NVIDIA ;;
    "$VENDOR_AMD")    name=AMD ;;
    "$VENDOR_INTEL")  name=Intel ;;
    *)                name="vendor $vsel" ;;
  esac
  GPU_VENDOR="$vsel"
  GPU_DESC="gpu_list=$GPU_INDEX → $node ($name), $count GPU(s) detected"
}

# libnvidia-ml (NVML) is what lets MangoHud read NVIDIA load/power/clocks.
have_nvml() {
  ldconfig -p 2>/dev/null | grep -q 'libnvidia-ml' \
    || [[ -e /usr/lib/libnvidia-ml.so.1 || -e /usr/lib64/libnvidia-ml.so.1 ]]
}

# ── CPU telemetry (vendor-neutral: works on AMD *and* Intel) ────────────────
#
# MangoHud reads CPU temperature from hwmon and CPU package power from the RAPL
# powercap energy counters. Both paths are the same regardless of CPU vendor:
#   • temp  → hwmon driver: k10temp/zenpower (AMD), coretemp (Intel)
#   • power → /sys/class/powercap/intel-rapl:* — despite the "intel" name this is
#     the powercap *framework*; on AMD it's fed by intel_rapl_msr from the Zen
#     RAPL MSRs. Since CVE-2020-8694 the energy_uj files are root-only (0400),
#     so user-mode MangoHud can't read them and cpu_power logs as 0.

readonly RAPL_UDEV_FILE=/etc/udev/rules.d/60-mangohud-logger-rapl.rules

# cpu_vendor → AMD | Intel | <raw string>
cpu_vendor() {
  local v; v=$(awk -F': ' '/^vendor_id/{print $2; exit}' /proc/cpuinfo 2>/dev/null)
  case "$v" in
    AuthenticAMD) echo AMD ;;
    GenuineIntel) echo Intel ;;
    *)            echo "${v:-unknown}" ;;
  esac
}

# First RAPL package energy counter (enough to gate on), else empty.
rapl_energy_file() { compgen -G '/sys/class/powercap/*rapl*/energy_uj' 2>/dev/null | head -1; }

# rapl_state → readable | denied | absent
rapl_state() {
  local f; f=$(rapl_energy_file)
  [[ -z "$f" ]] && { echo absent; return; }
  if cat "$f" >/dev/null 2>&1; then echo readable; else echo denied; fi
}

# cpu_temp_source → hwmon 'name' providing CPU temp (any vendor), else empty.
cpu_temp_source() {
  local h n
  for h in /sys/class/hwmon/hwmon*; do
    n=$(cat "$h/name" 2>/dev/null) || continue
    case "$n" in
      k10temp|zenpower|zenpower3|coretemp|k8temp) echo "$n"; return ;;
    esac
  done
  echo ""
}

# do_fix_cpu_power — install a udev rule making RAPL energy counters readable so
# MangoHud can log cpu_power. Vendor-neutral (same RAPL path on AMD and Intel).
do_fix_cpu_power() {
  local vend; vend=$(cpu_vendor)
  info "CPU power ($vend) comes from RAPL energy counters, root-only since CVE-2020-8694."
  info "This installs a udev rule so they're user-readable and MangoHud can log cpu_power."
  warn "Security note: re-exposes the low-severity PLATYPUS power side-channel."
  warn "Fine for a personal gaming/benchmark box; skip on shared/multi-user machines."
  echo

  case "$(rapl_state)" in
    absent)
      err "no RAPL powercap interface found."
      info "try:  sudo modprobe intel_rapl_msr   (then re-run)"
      return 1 ;;
    readable)
      ok "RAPL energy counters are already user-readable — nothing to do."
      return 0 ;;
  esac

  local chmod_bin; chmod_bin=$(command -v chmod || echo /usr/bin/chmod)
  # KERNEL match covers the package (intel-rapl:0) and its subzones (intel-rapl:0:0).
  # %S%p resolves to the node's /sys path; we chmod its energy_uj attribute.
  local rule="SUBSYSTEM==\"powercap\", KERNEL==\"intel-rapl:*\", RUN+=\"$chmod_bin 0444 %S%p/energy_uj\""

  info "writing $RAPL_UDEV_FILE (sudo)…"
  if ! printf '%s\n' \
        "# Installed by mangohud-logger: make RAPL energy_uj user-readable for CPU-power logging." \
        "# Remove this file to revert. See: mangohud-logger help" \
        "$rule" | sudo tee "$RAPL_UDEV_FILE" >/dev/null; then
    err "failed to write $RAPL_UDEV_FILE"; return 1
  fi

  sudo udevadm control --reload-rules 2>/dev/null || true
  sudo udevadm trigger --subsystem-match=powercap 2>/dev/null || true
  # Apply to already-present nodes now (udev 'add' won't re-fire for existing ones).
  sudo "$chmod_bin" -f 0444 /sys/class/powercap/*rapl*/energy_uj 2>/dev/null || true

  if [[ "$(rapl_state)" == readable ]]; then
    ok "done — cpu_power will now be logged (persists across reboots)."
  else
    warn "rule installed but counters still not readable; a reboot should apply it."
  fi
}

# do_doctor — report cross-vendor telemetry readiness; makes no changes.
do_doctor() {
  info "mangohud-logger doctor — telemetry readiness (read-only)"
  echo
  if command -v mangohud >/dev/null 2>&1; then
    ok "mangohud: $(mangohud --version 2>/dev/null | head -1)"
  else
    err "mangohud: NOT installed"
  fi
  info "session flavor: $GS_FLAVOR"
  echo

  # GPUs — list every render node, then the one that will be logged.
  info "GPUs (DRM render nodes):"
  local n vend name
  for n in $(compgen -G '/sys/class/drm/renderD*' 2>/dev/null | sort); do
    [[ -e "$n/device/vendor" ]] || continue
    vend=$(cat "$n/device/vendor" 2>/dev/null)
    case "$vend" in
      "$VENDOR_NVIDIA") name=NVIDIA ;; "$VENDOR_AMD") name=AMD ;;
      "$VENDOR_INTEL")  name=Intel  ;; *) name="vendor $vend" ;;
    esac
    printf '     %s  (%s)\n' "$(basename "$n")" "$name"
  done
  select_gpu
  if [[ -n "$GPU_INDEX" ]]; then ok "will log: $GPU_DESC"
  else warn "will log: $GPU_DESC"; fi
  if [[ "$GPU_VENDOR" == "$VENDOR_NVIDIA" ]]; then
    if have_nvml; then ok "  NVML present → NVIDIA load/power/clocks will log"
    else err "  NVML missing → NVIDIA gpu_* columns will be 0 (install nvidia-utils)"; fi
  fi
  echo

  # CPU — temp + power, vendor-neutral.
  info "CPU: $(cpu_vendor)"
  local ts; ts=$(cpu_temp_source)
  if [[ -n "$ts" ]]; then ok "  temp source: hwmon '$ts' → cpu_temp will log"
  else warn "  temp: no known sensor (k10temp/zenpower/coretemp) → cpu_temp may be 0"; fi
  case "$(rapl_state)" in
    readable) ok   "  power (RAPL): readable → cpu_power will log" ;;
    denied)   warn "  power (RAPL): root-only → cpu_power = 0.  Fix:  $(basename "$0") fix-cpu-power" ;;
    absent)   warn "  power (RAPL): no powercap interface → cpu_power = 0 (modprobe intel_rapl_msr)" ;;
  esac
  echo

  if [[ -f "$CONFIG_FILE" ]] && grep -qF "$MARKER_BEGIN" "$CONFIG_FILE"; then
    ok "logging is currently ENABLED (log folder: $LOG_DIR)"
  else
    info "logging is currently disabled — run '$(basename "$0")' to enable"
  fi
}

usage() {
  cat <<EOF
mangohud-logger — toggle MangoHud CSV logging, with cross-vendor telemetry setup

USAGE:
  $(basename "$0")                  Toggle logging on/off (default action)
  $(basename "$0") doctor           Report GPU/CPU telemetry readiness (no changes)
  $(basename "$0") fix-cpu-power    Make RAPL CPU-power counters user-readable (sudo)
  $(basename "$0") help             Show this help

ENVIRONMENT:
  MANGOHUD_LOGGER_GPU=<index|nvidia|amd|intel>
                                    Force which GPU MangoHud logs (default: auto —
                                    prefers the discrete gaming GPU, any vendor)

Works across AMD/Intel CPUs and NVIDIA/AMD/Intel GPUs, single- or multi-GPU.
EOF
}

# do_toggle — the original enable/disable behavior (default action).
do_toggle() {
  if ! command -v mangohud >/dev/null 2>&1; then
    err "mangohud is not installed — install it first (e.g. 'sudo pacman -S mangohud lib32-mangohud')."
    exit 1
  fi

  mkdir -p "$CONFIG_DIR"
  [[ -f "$CONFIG_FILE" ]] || : > "$CONFIG_FILE"

  if grep -qF "$MARKER_BEGIN" "$CONFIG_FILE"; then
  # Currently enabled → strip the block and remove the env file.
  tmp=$(mktemp)
  awk -v b="$MARKER_BEGIN" -v e="$MARKER_END" '
    $0 == b { skip = 1; next }
    $0 == e { skip = 0; next }
    !skip   { print }
  ' "$CONFIG_FILE" > "$tmp"
  # Trim trailing blank lines the block may have left behind.
  sed -i -e :a -e '/^\s*$/{$d;N;ba' -e '}' "$tmp"
  mv "$tmp" "$CONFIG_FILE"

  env_removed=0
  if [[ -f "$ENV_FILE" ]]; then
    rm -f "$ENV_FILE"
    env_removed=1
  fi

  # Only remove the gamescope session override if WE wrote it.
  gs_removed=0
  if [[ -f "$GS_SESSION_FILE" ]] && head -1 "$GS_SESSION_FILE" | grep -qF "$GS_OWNED_MARKER"; then
    rm -f "$GS_SESSION_FILE"
    gs_removed=1
  fi

  ok "MangoHud logging disabled"
  info "existing logs kept in: $LOG_DIR"
  if (( env_removed )); then
    info "removed: $ENV_FILE"
    info "MANGOHUD env var stays set in the *current* session until logout"
  fi
  if (( gs_removed )); then
    info "removed: $GS_SESSION_FILE"
  fi
else
  # Currently disabled → append the config block + write the env file.
  # Check for pre-existing manual log keys *before* we write, so the warning is accurate.
  manual_log_keys=0
  if grep -qE '^\s*(output_folder|autostart_log|log_duration|log_interval|toggle_logging|gpu_list)\s*=' "$CONFIG_FILE"; then
    manual_log_keys=1
  fi

  # Work out which GPU to log (any vendor, single- or multi-GPU) before writing.
  select_gpu

  mkdir -p "$LOG_DIR"
  {
    [[ -s "$CONFIG_FILE" ]] && printf '\n'
    printf '%s\n' "$MARKER_BEGIN"
    printf '# Added by mangohud-logger — remove this block to disable logging.\n'
    printf 'output_folder=%s\n' "$LOG_DIR"
    printf 'autostart_log=1\n'
    printf 'log_duration=0\n'
    printf 'log_interval=100\n'
    printf 'toggle_logging=Shift_L+F2\n'
    # Override any earlier `no_display` — MangoHud's autostart_log rides on the
    # render hook, which `no_display` disables. Without this, logs never start.
    printf 'no_display=0\n'
    # Pin the GPU MangoHud logs to the actual gaming GPU (see select_gpu). Omitted
    # only when no render node was found, so MangoHud keeps its own default.
    [[ -n "$GPU_INDEX" ]] && printf 'gpu_list=%s\n' "$GPU_INDEX"
    printf '%s\n' "$MARKER_END"
  } >> "$CONFIG_FILE"

  # Inline config string mirroring the MangoHud.conf block. MANGOHUD_CONFIG takes
  # precedence over MANGOHUD_CONFIGFILE, so this is what makes logging work GLOBALLY
  # in SteamOS Game Mode — that session forces MANGOHUD_CONFIGFILE=<tmp>/no_display,
  # but it never sets MANGOHUD_CONFIG, so ours (from environment.d) wins for every game.
  # NOTE: relies on output_folder having no commas/spaces (true for the default path).
  MH_INLINE="output_folder=$LOG_DIR,autostart_log=1,log_duration=0,log_interval=100,toggle_logging=Shift_L+F2,no_display=0"
  [[ -n "$GPU_INDEX" ]] && MH_INLINE+=",gpu_list=$GPU_INDEX"

  mkdir -p "$ENV_DIR"
  cat > "$ENV_FILE" <<EOF
$GS_OWNED_MARKER Delete this file (or re-run the script) to remove.
# MANGOHUD=1 makes the Vulkan loader inject the MangoHud layer into every game.
MANGOHUD=1
# MANGOHUD_CONFIG (inline) OVERRIDES MANGOHUD_CONFIGFILE. SteamOS Game Mode forces
# MANGOHUD_CONFIGFILE=<tmp>/no_display, which would otherwise suppress our config and
# stop logging. This inline config wins over it, so autostart_log/output_folder take
# effect for every game with NO per-game launch options. Verified: MANGOHUD_CONFIG
# beats a no_display configfile (vkcube CSV log produced).
MANGOHUD_CONFIG=$MH_INLINE
EOF

  # Game Mode handling depends on which session manager is installed (see
  # detect_gs_flavor). Only gamescope-session-plus sources our override file;
  # the steamos flavor needs per-game launch options instead.
  gs_action=""
  if [[ "$GS_FLAVOR" == "plus" ]]; then
    # gamescope-session-plus override — only write if file is absent or already
    # ours, so we never trample a user-written override.
    if [[ ! -f "$GS_SESSION_FILE" ]] || head -1 "$GS_SESSION_FILE" | grep -qF "$GS_OWNED_MARKER"; then
      mkdir -p "$GS_SESSION_DIR"
      cat > "$GS_SESSION_FILE" <<EOF
$GS_OWNED_MARKER
# Sourced AFTER /usr/share/gamescope-session-plus/sessions.d/steam (last wins).
#
# Without this:
#   1. The system steam session script exports MANGOHUD_CONFIGFILE pointing to a
#      temp file containing only "no_display", which suppresses our user
#      ~/.config/MangoHud/MangoHud.conf and so autostart_log/output_folder
#      never take effect. Unsetting the var falls back to the user file.
#   2. STEAM_USE_MANGOAPP=1 makes Steam ask gamescope to use the mangoapp
#      compositor overlay instead of the in-game MangoHud Vulkan layer.
#      The Vulkan layer is the one that writes CSV logs.

unset MANGOHUD_CONFIGFILE
export STEAM_USE_MANGOAPP=0
export STEAM_MANGOAPP_PRESETS_SUPPORTED=0
EOF
      gs_action="written"
    else
      gs_action="left alone (you have a custom override at $GS_SESSION_FILE)"
    fi
  elif [[ "$GS_FLAVOR" == "steamos" ]]; then
    # This build uses /usr/lib/steamos/gamescope-session, which hard-exports
    # MANGOHUD_CONFIGFILE=<tmp>/no_display and STEAM_USE_MANGOAPP=1 with no user
    # hook — so a global override is impossible. Remove any stale override we
    # wrote on a previous (plus-flavor) run so it doesn't mislead.
    if [[ -f "$GS_SESSION_FILE" ]] && head -1 "$GS_SESSION_FILE" | grep -qF "$GS_OWNED_MARKER"; then
      rm -f "$GS_SESSION_FILE"
    fi
    gs_action="n/a — using MANGOHUD_CONFIG (global, no override file needed)"
  else
    gs_action="no gamescope session detected (desktop only)"
  fi

  if (( manual_log_keys )); then
    warn "pre-existing log-related keys found in config — they may override ours."
  fi

  # NVIDIA GPU stats come from NVML; without it every gpu_* column logs as 0.
  if [[ "$GPU_VENDOR" == "$VENDOR_NVIDIA" ]] && ! have_nvml; then
    warn "selected an NVIDIA GPU but libnvidia-ml (NVML) not found — GPU load/power"
    warn "won't be logged. Install the NVIDIA userspace (e.g. 'nvidia-utils')."
  fi

  # CPU power/temp readiness (same checks on AMD and Intel).
  rapl=$(rapl_state)
  if [[ "$rapl" == denied ]]; then
    warn "cpu_power won't log — RAPL counters are root-only. Enable it with:"
    warn "    $(basename "$0") fix-cpu-power"
  elif [[ "$rapl" == absent ]]; then
    warn "cpu_power won't log — no RAPL powercap interface (try: sudo modprobe intel_rapl_msr)."
  fi
  [[ -z "$(cpu_temp_source)" ]] && warn "no known CPU temp sensor found — cpu_temp may read 0."

  ok "MangoHud logging enabled"
  info "log folder:   $LOG_DIR"
  info "toggle key:   Shift+F2 (during a game)"
  info "config file:  $CONFIG_FILE"
  info "env file:     $ENV_FILE  (MANGOHUD=1)"
  info "gpu logged:   ${GPU_DESC:-MangoHud default}"
  if [[ -n "$GPU_INDEX" ]]; then
    info "              (override with MANGOHUD_LOGGER_GPU=<index|nvidia|amd|intel>)"
  fi
  info "cpu ($( cpu_vendor )):    temp=$( [[ -n "$(cpu_temp_source)" ]] && echo ok || echo none )  power(RAPL)=$rapl"
  info "session type: $GS_FLAVOR  (gamescope override: $gs_action)"
  info "note: while logging is on, the HUD becomes visible during games"
  info "      (autostart_log needs the render hook that no_display disables)"

  if [[ "$GS_FLAVOR" == "steamos" ]]; then
    # SteamOS Game Mode forces MANGOHUD_CONFIGFILE=<tmp>/no_display, but our
    # MANGOHUD_CONFIG (set above in environment.d) overrides it for every game —
    # so logging IS global here, no per-game launch options needed.
    info "→ logging is GLOBAL via MANGOHUD_CONFIG — no per-game launch options needed."
    warn "log out and back into Game Mode (or reboot) so environment.d takes effect."
    info "while logging, the in-game MangoHud overlay will be visible (autostart_log"
    info "needs the render hook that no_display disables) — that's expected."
    info "fallback for a single game (e.g. if you don't want to restart the session):"
    printf '    \033[1m%s\033[0m\n' "$LAUNCH_OPT"
  else
    warn "log out and back in (or restart your gamescope session) so the env var takes effect."
  fi
fi
}

# ── Command dispatch ────────────────────────────────────────────────────────
case "${1:-toggle}" in
  toggle|"")                     do_toggle ;;
  doctor|check|--check|-c)       do_doctor ;;
  fix-cpu-power|fix|--fix-cpu-power) do_fix_cpu_power ;;
  -h|--help|help)                usage ;;
  *) err "unknown command: $1"; echo; usage; exit 1 ;;
esac