#!/usr/bin/env bash

set -euo pipefail

ASPELL_LANG='en_GB'
ASPELL_PERSONAL_WORDLIST='./.aspell/.aspell.en.pws'
DEFAULT_OUTPUT='aspell_output'

RED='\033[1;31m'
AMBER='\033[1;33m'
GREEN='\033[1;32m'
NC='\033[0m'

inputFile=''
outputFile=''

usage () {
echo "Usage:"
echo "spellcheck [OPTION]..."
echo
echo "Description:"
echo -e "\tspellcheck is a wrapper script that uses aspell to check the spelling of"
echo -e "\tall words in a file. Any detected spelling errors are printed to screen"
echo -e "\tand to an output file."
echo
echo "Options:"
echo -e "\t-i\tinput file for spell checking."
echo -e "\t-o\toutput file where list of spelling errors are written to."
echo -e "\t\tThe default output file is ${DEFAULT_OUTPUT}."
echo -e "\t-h\tprints usage."
echo
echo -e "Examples:"
echo -e "\tspellcheck -i my_file.txt -o output.txt"
echo -e "\tspellcheck -i my_file"
}

validate_args() {
  if [ -z "$inputFile" ]; then
    echo -e "${RED}ERROR: ${NC}Option '-i' is not set or is empty."
    usage
    return 1
  fi

  if [ -z "$outputFile" ]; then
    echo -e "${AMBER}WARNING: ${NC}Option '-o' is not set or is empty. The output file will be set to ${DEFAULT_OUTPUT}"
    outputFile=${DEFAULT_OUTPUT}
  fi

  return 0
}

spellcheck() {
  cat ${inputFile} | aspell -d ${ASPELL_LANG} -p ${ASPELL_PERSONAL_WORDLIST} list > ${outputFile}

  let spellingErrors=$( cat ${outputFile} | wc -l )
  if [ $spellingErrors -gt 0 ]; then
    echo
    echo -e "${RED}ERROR: ${NC}The following spelling errors were found in ${inputFile}:"
    cat ${outputFile}
    return 1
  else
    echo
    echo -e "${GREEN}INFO: ${NC}No spelling errors found."
  fi

  return 0
}

while getopts 'i:o:h' flag; do
  case "${flag}" in
    i) inputFile=${OPTARG} ;;
    o) outputFile=${OPTARG} ;;
    h) usage && exit 0 ;;
    *) usage && exit 2 ;;
  esac
done

validate_args || exit 1
spellcheck || exit 1