#!/bin/bash

if [ "$FINALS_VAR" != "proglang" ]; then
    echo "ERROR: FINALS_VAR must be set to 'proglang'."
    echo "Current value: '${FINALS_VAR}'"
    exit 1
fi

if [ "$1" != "dsc31" ]; then
    echo "ERROR: The first argument must be 'dsc31'."
    echo "Usage: $0 dsc31"
    exit 1
fi

LENGTH=500
USER_NAME=$(whoami)

USER_LEN=${#USER_NAME}

RANDOM_LEN=$((LENGTH - USER_LEN))

RANDOM_PART=$(tr -dc 'A-Za-z0-9' < /dev/urandom | head -c $RANDOM_LEN)

INSERT_POS=$((RANDOM_LEN / 2))

FINAL_STRING="${RANDOM_PART:0:$INSERT_POS}${USER_NAME}${RANDOM_PART:$INSERT_POS}"

echo "$FINAL_STRING"