#!/bin/sh

# The application supplies its own PID. Refuse broad or malformed targets.
TARGET_PID="$1"
LASER_DEVICE="${2:-/dev/ttyS1}"
LASER_BAUD="${3:-9600}"

turn_off_laser() {
    if [ ! -c "$LASER_DEVICE" ]; then
        echo "[CHARGE] laser serial device not found: $LASER_DEVICE" >&2
        return 1
    fi

    stty -F "$LASER_DEVICE" "$LASER_BAUD" raw -echo 2>/dev/null || return 1
    printf '\252\000\001\276\000\001\000\000\300' > "$LASER_DEVICE"
}

case "$TARGET_PID" in
    ''|*[!0-9]*)
        echo "[CHARGE] invalid application pid: $TARGET_PID" >&2
        exit 2
        ;;
esac

if [ "$TARGET_PID" -le 1 ]; then
    echo "[CHARGE] refusing to terminate pid: $TARGET_PID" >&2
    exit 2
fi

# First request laser-off while the application still owns the initialized UART.
turn_off_laser || true

kill -TERM "$TARGET_PID" 2>/dev/null || true

# Wait up to two seconds for a graceful exit, then force termination.
WAIT_COUNT=0
while kill -0 "$TARGET_PID" 2>/dev/null && [ "$WAIT_COUNT" -lt 20 ]; do
    sleep 0.1
    WAIT_COUNT=$((WAIT_COUNT + 1))
done
if kill -0 "$TARGET_PID" 2>/dev/null; then
    kill -KILL "$TARGET_PID" 2>/dev/null || true
    sleep 0.1
fi

# Send laser-off again after the application releases the UART.
turn_off_laser || true