#!/bin/bash
# Arch R — System Sleep Hook
# Installed to /usr/lib/systemd/system-sleep/archr-sleep
# Called by systemd before suspend (pre) and after wake (post).
#
# Pre-suspend: saves governors, sets powersave, unloads problem modules
# Post-wake: reloads modules, restores governors

MODULES_BAD="/etc/archr/modules.bad"
SAVED_MODULES="/tmp/archr-sleep-modules"
SAVED_CPU_GOV="/tmp/archr-sleep-cpu-gov"
SAVED_GPU_GOV="/tmp/archr-sleep-gpu-gov"

CPU_GOV="/sys/devices/system/cpu/cpufreq/policy0/scaling_governor"
GPU_GOV="/sys/devices/platform/ff400000.gpu/devfreq/ff400000.gpu/governor"
DMC_GOV="/sys/devices/platform/dmc/devfreq/dmc/governor"

log() { logger -t archr-sleep "$1"; }

pre_suspend() {
    log "Pre-suspend: saving state..."

    # Save current governors
    cat "$CPU_GOV" > "$SAVED_CPU_GOV" 2>/dev/null
    cat "$GPU_GOV" > "$SAVED_GPU_GOV" 2>/dev/null

    # Set powersave governors
    echo powersave > "$CPU_GOV" 2>/dev/null
    echo powersave > "$GPU_GOV" 2>/dev/null
    echo powersave > "$DMC_GOV" 2>/dev/null

    # Unload problem modules (USB, WiFi)
    if [ -f "$MODULES_BAD" ]; then
        rm -f "$SAVED_MODULES"
        while read -r line; do
            # Skip comments and empty lines
            [ -z "$line" ] && continue
            [[ "$line" == \#* ]] && continue

            for mod in $line; do
                if lsmod | grep -q "^${mod} "; then
                    echo "$mod" >> "$SAVED_MODULES"
                    modprobe -r "$mod" 2>/dev/null
                    log "Unloaded module: $mod"
                fi
            done
        done < "$MODULES_BAD"
    fi

    # Stop services that conflict with suspend
    systemctl stop archr-hotkeys.service 2>/dev/null
    systemctl stop battery-led.service 2>/dev/null

    log "Pre-suspend: done"
}

post_wake() {
    log "Post-wake: restoring state..."

    # Reload modules
    if [ -f "$SAVED_MODULES" ]; then
        tac "$SAVED_MODULES" | while read -r mod; do
            modprobe "$mod" 2>/dev/null
            log "Reloaded module: $mod"
        done
        rm -f "$SAVED_MODULES"
    fi

    # Restore governors
    if [ -f "$SAVED_CPU_GOV" ]; then
        cat "$SAVED_CPU_GOV" > "$CPU_GOV" 2>/dev/null
        rm -f "$SAVED_CPU_GOV"
    else
        echo schedutil > "$CPU_GOV" 2>/dev/null
    fi

    if [ -f "$SAVED_GPU_GOV" ]; then
        cat "$SAVED_GPU_GOV" > "$GPU_GOV" 2>/dev/null
        rm -f "$SAVED_GPU_GOV"
    else
        echo simple_ondemand > "$GPU_GOV" 2>/dev/null
    fi

    echo simple_ondemand > "$DMC_GOV" 2>/dev/null

    # Restart services
    systemctl start archr-hotkeys.service 2>/dev/null
    systemctl start battery-led.service 2>/dev/null

    log "Post-wake: done"
}

case "$1" in
    pre)  pre_suspend ;;
    post) post_wake ;;
esac