#/bin/sh

set -e

main() {
    local machine_id_file="/etc/machine-id"

    if [ -f "$machine_id_file" ]; then
        echo "Machine ID already generated. Doing nothing."
        exit 0
    fi

    # Accumulate data to create unique machine id
    local mac_addresses=$(cat /sys/class/net/*/address | uniq | sort)
    local device_model=$(cat /sys/firmware/devicetree/base/model)

    # Ensure destination directory
    mkdir -p "$(dirname "$machine_id_file")"

    # Generate SHA256 hash of data and save it to $machine_id_file
    echo "$mac_adresses $device_model" | sha256sum | cut -d ' ' -f1 > "$machine_id_file"
}

main