#!/bin/bash

# =================================================================
# CONFIGURATION – EDIT THESE TWO LINES
# =================================================================
SINK_G435="alsa_output.usb-Logitech_G_series_G435_Wireless_Gaming_Headset_202105190004-00.analog-stereo"
SINK_FALLBACK="alsa_output.pci-0000_03_00.1.hdmi-surround-extra3"

# Rapid‑volume‑up detection
RAPID_THRESHOLD=10      # number of VOLUMEUP events in the window
RAPID_WINDOW=3          # seconds

# =================================================================
# Find the G435 Consumer Control input device automatically
# =================================================================
find_g435_event() {
    for link in /dev/input/by-id/*G435*event*; do
        if [ -e "$link" ]; then
            readlink -f "$link"
            return 0
        fi
    done
    return 1
}

DEVICE=""
while [ -z "$DEVICE" ]; do
    DEVICE=$(find_g435_event)
    if [ -z "$DEVICE" ]; then
        echo "G435 input device not found – retrying in 2s..." >&2
        sleep 2
    fi
done
echo "Found G435 device: $DEVICE"

# =================================================================
# Switch function
# =================================================================
switch_to_sink() {
    local target="$1"
    pactl set-default-sink "$target"
    for id in $(pactl list short sink-inputs | awk '{print $1}'); do
        pactl move-sink-input "$id" "$target" 2>/dev/null
    done
    echo "Switched to: $target"
}

# =================================================================
# Event loop – grab the device exclusively
# =================================================================
up_timestamps=()

exec 3< <(stdbuf -oL evtest  "$DEVICE")

while read -u 3 line; do
    # Volume UP press (115)
    if [[ "$line" == *"code 115 (KEY_VOLUMEUP)"*"value 1"* ]]; then
        now=$(date +%s)
        up_timestamps+=("$now")
        # prune timestamps older than window
        cutoff=$((now - RAPID_WINDOW))
        new_ts=()
        for ts in "${up_timestamps[@]}"; do
            [ "$ts" -ge "$cutoff" ] && new_ts+=("$ts")
        done
        up_timestamps=("${new_ts[@]}")
        count=${#up_timestamps[@]}

        if [ "$count" -gt "$RAPID_THRESHOLD" ]; then
            echo "Rapid VOLUMEUP ($count presses) – switching to FALLBACK"
            switch_to_sink "$SINK_FALLBACK"
        else
            echo "Normal VOLUMEUP – switching to G435"
            switch_to_sink "$SINK_G435"
        fi

    # Volume DOWN press (114) – always switch to G435
    elif [[ "$line" == *"code 114 (KEY_VOLUMEDOWN)"*"value 1"* ]]; then
        echo "VOLUMEDOWN – switching to G435"
        switch_to_sink "$SINK_G435"
    fi
done