lnk

#!/bin/bash
LOCAL_CONFIG="$HOME/.vanityURLs.conf"
STATIC_FILE="static.lnk"
MAX_ATTEMPTS=100

function print_usage() {
  echo "There are two valid ways to call this script:"
  echo -e "1) A random shortcode will be generated automatically:\n\t./scripts/lnk [LONG_URL]"
  echo -e "2) Specify the shortcode you want:\n\t./scripts/lnk [LONG_URL] [SHORTCODE]"
  exit 1
}

# Function to generate a random character from a given set
function random_char() {
  # Potentially ambiguous characters (e.g. '1', 'I', and 'l') are
  # ignored.
  local characters="34789abcdefghijmnpqrstwxyABCDEFHJLMNPQRTUVWXY"
  local N_CHARS=${#characters}
  local index=$((RANDOM % $N_CHARS))
  echo -n "${characters:index:1}"
}

function generate_shortcode() {
  # Generate a random string
  random_string=""
  for i in $(seq 1 $SHORTCODE_LENGTH); do
    random_string="${random_string}$(random_char)"
  done

  # Check if "/$random_string is already in the file
  counter=0  # Initialize the counter
  while [ "$counter" -le $MAX_ATTEMPTS ]; do
    if grep -q "^/$random_string" "$STATIC_FILE"; then
      ((counter++))
    else
      echo $random_string
      break
    fi
  done
}

if [ -f "$LOCAL_CONFIG" ]; then
  source $LOCAL_CONFIG
else
  echo "Error: $LOCAL_CONFIG not found."
  echo "Hint: Did you do \`cp $(basename $LOCAL_CONFIG) $HOME\` and set your values?"
  exit 1
fi

# Expand REPO_DIR in case it starts with '~/'
eval REPO_DIR=$REPO_DIR
cd $REPO_DIR

case "$#" in
  0)
    print_usage
    ;;
  1)
    LONG_URL="$1"
    SHORTCODE=$(generate_shortcode)
    if [ "$SHORTCODE" = "" ]; then
      echo "Error: $MAX_ATTEMPTS attempts were made to find a unique random string for your URL in $STATIC_FILE, but no success.
      Aborting. Consider raising the value of SHORTCODE_LENGTH in '$LOCAL_CONFIG'."
      exit 1
    fi
    ;;
  2)
    LONG_URL="$1"
    SHORTCODE="$2"
    if grep -q "^/$SHORTCODE" "$STATIC_FILE"; then
      echo "Error: /$SHORTCODE is already taken in $STATIC_FILE."
      exit 1
    fi
    ;;
  *)
    print_usage
    ;;
esac

# If the long URL is already being redirected, notify the user
if grep -q -P "$LONG_URL( |$)" $STATIC_FILE; then
  echo "This URL is already being redirected:"
  grep -P "$LONG_URL( |$)" $STATIC_FILE
  exit 1
fi

# Validate long URL given by user
$REPO_DIR/scripts/validateURL $LONG_URL
if [ "$?" -ne 0 ]; then
  exit 1
fi



if [ "$DRY_RUN" = true ]; then
  echo "Dry run, files will not be modified."
else
  git fetch; git pull origin $(git branch --show-current)
  echo "/$SHORTCODE $LONG_URL" >> $STATIC_FILE
  git add $STATIC_FILE
  git commit -m "add redirect /$SHORTCODE --> $LONG_URL"
  git push origin main
fi

echo "Your shortened URL is https://$MY_DOMAIN/$SHORTCODE"
echo "Please give ~15 seconds for your link to become valid"

cd - > /dev/null