#!/usr/bin/env bash
#
# Add a directory to the beginning of the PATH if it's not already there.
# Usage: x-path-append <dir>

# Set verbosity with VERBOSE=1
VERBOSE="${VERBOSE:-0}"

# Function to print usage information
usage()
{
  echo "Usage: $0 <dir>"
  exit 1
}

# Function to print messages if VERBOSE is enabled
# $1 - message (string)
msg()
{
  [[ "$VERBOSE" -eq 1 ]] && echo "$1"
}

# Function to remove a directory from PATH
# $1 - directory to remove (string)
remove_from_path()
{
  local dir=$1

  if echo "$PATH" | grep -qE "(^|:)$dir($|:)"; then
    export PATH=$(echo -n "$PATH" | awk -v RS=: -v ORS=: "\$0 != \"$dir\"" | sed 's/:$//')
    msg "Directory $dir has been removed from PATH"
  else
    msg "Directory $dir is not in PATH"
  fi
}

# Function to append a directory to PATH
# $1 - directory to append (string)
append_to_path()
{
  local dir=$1

  if [ ! -d "$dir" ]; then
    msg "(?) Directory $dir does not exist"
    exit 0
  fi

  if echo "$PATH" | grep -qE "(^|:)$dir($|:)"; then
    msg "(!) Directory $dir is already in PATH"
  else
    export PATH="${PATH:+"$PATH:"}$dir"
    msg "(!) Directory $dir has been added to the end of PATH"
  fi
}

# Main function
main()
{
  if [ "$#" -ne 1 ]; then
    usage
  fi

  remove_from_path "$1"
  append_to_path "$1"
}

main "$@"