#!/bin/bash
# gamemode-session — compositor-level gamemode for niri.
# Reference-counted over two sources (feral, manual). Applies effects on the
# first active source (0->1) and reverts on the last (1->0).
# Spec: docs/superpowers/specs/2026-07-15-niri-gamemode-design.md
set -u

STATE_DIR="${GAMEMODE_STATE_DIR:-${XDG_RUNTIME_DIR:-/run/user/$(id -u)}/gamemode}"
FAN_AUTO="${XDG_STATE_HOME:-$HOME/.local/state}/fan-profile-auto"
DRYRUN="${GAMEMODE_DRYRUN:-0}"

log() { printf 'gamemode: %s\n' "$*" >&2; }
run() { if [ "$DRYRUN" = 1 ]; then log "would: $*"; else "$@"; fi; }

is_active() {
    [ -n "$(find "$STATE_DIR" -maxdepth 1 -name 'src.*' -print -quit 2>/dev/null)" ]
}

snapshot_baseline() {
    mkdir -p "$STATE_DIR"
    powerprofilesctl get 2>/dev/null > "$STATE_DIR/baseline.profile" || : > "$STATE_DIR/baseline.profile"
    if pgrep -x waybar >/dev/null 2>&1; then echo 1; else echo 0; fi > "$STATE_DIR/baseline.waybar"
    if [ -f "$FAN_AUTO" ]; then echo 1; else echo 0; fi > "$STATE_DIR/baseline.fanauto"
}

# --- effects ------------------------------------------------------------------
effect_idle_on() {
    if [ "$DRYRUN" = 1 ]; then log "would: systemd-inhibit idle"; return; fi
    command -v systemd-inhibit >/dev/null 2>&1 || { log "no systemd-inhibit"; return; }
    systemd-inhibit --what=idle --who=gamemode --why="gaming session" --mode=block \
        sleep infinity >/dev/null 2>&1 &
    echo $! > "$STATE_DIR/idle.pid"
}
effect_idle_off() {
    local pid; pid=$(cat "$STATE_DIR/idle.pid" 2>/dev/null || echo "")
    [ -n "$pid" ] && run kill "$pid"
    rm -f "$STATE_DIR/idle.pid"
}

effect_dnd_on()  { command -v makoctl >/dev/null 2>&1 && run makoctl mode -a do-not-disturb; }
effect_dnd_off() { command -v makoctl >/dev/null 2>&1 && run makoctl mode -r do-not-disturb; }

# maps a power profile to the fw-fanctrl strategy (mirrors fan-profile.sh)
fan_for() { case "$1" in power-saver) echo lazy;; balanced) echo medium;; performance) echo agile;; *) return 1;; esac; }

effect_perf_on() {
    local base; base=$(cat "$STATE_DIR/baseline.profile" 2>/dev/null || echo "")
    if [ -n "$base" ] && [ "$base" != performance ]; then
        run powerprofilesctl set performance
        run pkill -RTMIN+8 waybar
    fi
    if [ "$(cat "$STATE_DIR/baseline.fanauto" 2>/dev/null)" = 1 ]; then
        run fw-fanctrl use agile
    fi
}
effect_perf_off() {
    local base; base=$(cat "$STATE_DIR/baseline.profile" 2>/dev/null || echo "")
    if [ -n "$base" ] && [ "$base" != performance ]; then
        run powerprofilesctl set "$base"
        run pkill -RTMIN+8 waybar
    fi
    if [ -n "$base" ] && [ "$(cat "$STATE_DIR/baseline.fanauto" 2>/dev/null)" = 1 ]; then
        local strat; strat=$(fan_for "$base") && run fw-fanctrl use "$strat"
    fi
}

effect_waybar_on() {  # hide
    pgrep -x waybar >/dev/null 2>&1 && run pkill -x waybar
}
effect_waybar_off() { # restore if it was running at entry
    [ "$(cat "$STATE_DIR/baseline.waybar" 2>/dev/null)" = 1 ] || return 0
    if [ "$DRYRUN" = 1 ]; then log "would: relaunch waybar"; else setsid waybar >/dev/null 2>&1 & fi
}

apply_effects()  { effect_idle_on;  effect_dnd_on;  effect_perf_on;  effect_waybar_on; }
revert_effects() { effect_idle_off; effect_dnd_off; effect_perf_off; effect_waybar_off; }

# --- state machine ------------------------------------------------------------
cmd_add() {
    local src="$1" was=0
    is_active && was=1
    mkdir -p "$STATE_DIR"
    touch "$STATE_DIR/src.$src"
    if [ "$was" = 0 ]; then
        snapshot_baseline
        apply_effects
        log "activated (source: $src)"
    else
        log "already active; +source: $src"
    fi
}

cmd_del() {
    local src="$1"
    rm -f "$STATE_DIR/src.$src"
    if ! is_active; then
        revert_effects
        rm -f "$STATE_DIR"/baseline.* "$STATE_DIR/idle.pid"
        log "deactivated (last source: $src)"
    else
        log "still active; -source: $src"
    fi
}

cmd_toggle() {
    if [ -e "$STATE_DIR/src.manual" ]; then cmd_del manual; else cmd_add manual; fi
}

cmd_status() { if is_active; then echo active; exit 0; else echo inactive; exit 1; fi; }

cmd_reset() {
    revert_effects 2>/dev/null || true
    rm -rf "$STATE_DIR"
    log "reset"
}

case "${1:-}" in
    add)    [ -n "${2:-}" ] || { log "add needs a source"; exit 2; }; cmd_add "$2" ;;
    del)    [ -n "${2:-}" ] || { log "del needs a source"; exit 2; }; cmd_del "$2" ;;
    toggle) cmd_toggle ;;
    status) cmd_status ;;
    reset)  cmd_reset ;;
    *)      log "usage: gamemode-session {add|del <source>|toggle|status|reset}"; exit 2 ;;
esac