#!/usr/bin/env bash

cache_file="/tmp/tlds-alpha-by-domain.txt"
cache_duration=86400
tld_list_url="https://data.iana.org/TLD/tlds-alpha-by-domain.txt"

if [ -z "$1" ]; then
  echo "Usage: $0 <keyword>"
  exit 1
fi

keyword=$1

fetch_tlds() {
  if [[ -f "$cache_file" ]]; then
    last_modified=$(date -r "$cache_file" +%s)
    current_time=$(date +%s)
    if ((current_time - last_modified < cache_duration)); then
      cat "$cache_file"
      return
    fi
  fi

  curl -s "$tld_list_url" -o "$cache_file"
  cat "$cache_file"
}

tlds=$(fetch_tlds | tail -n +2 | tr '[:upper:]' '[:lower:]')

declare -A seen_tlds
declare -a all_tlds

generate_hacks() {
  local str=$1 full_domain
  for ((i=1; i<${#str}; i++)); do
    prefix=${str:0:i}
    suffix=${str:i}
    if echo "$tlds" | grep -q "^$suffix$"; then
      if [[ -z ${seen_tlds[$suffix]} ]]; then
        full_domain="$prefix.$suffix"
        echo "$full_domain"
        seen_tlds[$suffix]=1
        all_tlds+=("$full_domain")
      fi
    fi
  done
}

generate_path_hacks() {
  local str=$1 full_domain
  for ((i=1; i<${#str}; i++)); do
    subdomain=${str:0:i}
    remaining=${str:i}
    for ((j=1; j<${#subdomain}; j++)); do
      prefix=${subdomain:0:j}
      suffix=${subdomain:j}
      if echo "$tlds" | grep -q "^$suffix$"; then
        if [[ -z ${seen_tlds[$suffix]} ]]; then
          if [[ -n "$remaining" && -n "$subdomain" ]]; then
            echo "$prefix.$suffix/$remaining"
            seen_tlds[$suffix]=1
            all_tlds+=("$prefix.$suffix")
          fi
        fi
      fi
    done
  done
}

check_if_registered() {
  domain=$1
  result=$(dig +short "$domain")
  if [ -z "$result" ]; then
    echo "$domain ... AVAILABLE"
  else
    echo "$domain ... REGISTERED"
  fi
}


generate_hacks "$keyword"
keyword_with_s="${keyword}s"
generate_hacks "$keyword_with_s"
for ((i=0; i<${#keyword}; i++)); do
  modified_keyword="${keyword:0:i}${keyword:i+1}"
  generate_hacks "$modified_keyword"
done

generate_path_hacks "$keyword"
keyword_with_s="${keyword}s"
generate_path_hacks "$keyword_with_s"
for ((i=0; i<${#keyword}; i++)); do
  modified_keyword="${keyword:0:i}${keyword:i+1}"
  generate_path_hacks "$modified_keyword"
done

echo "Checking if generated domain hacks are registered:"
for domain in "${all_tlds[@]}"; do
  check_if_registered "$domain"
done