## library of useful functions, usually prefixed with '_'

##
## ARRAY Functions
##

function _array_contains {
    local -n array=$1
    local element=$2
    [[ " ${array[@]} " =~ " ${element} " ]] && return 0 || return 1
}

function _array_intersect {
    local -n arr1=$1
    local -n arr2=$2
    local -n result=$3

    declare -A include
    for item in "${arr2[@]}"; do include["$item"]=1; done

    result=()
    for item in "${arr1[@]}"; do [[ -n ${include["$item"]} ]] && result+=("$item"); done
}

function _array_subtract {
    local -n arr1=$1   # First array
    local -n arr2=$2   # Array to subtract
    local -n result=$3 # Output array

    [[ ${#arr2[@]} == 0 ]] && result=("${arr1[@]}") && return

    declare -A exclude
    for item in "${arr2[@]}"; do exclude["$item"]=1; done

    result=()
    for item in "${arr1[@]}"; do [[ -z ${exclude["$item"]} ]] && result+=("$item"); done
}

##
## TEXT Functions
##

function _pluralize_simple {
    echo -n "$1 "
    [[ $1 -eq 1 || $1 -eq -1 ]] && echo ${2} || echo ${2}s
}

##
## READ Functions
##

function _confirm_destructive {
    local message="${1:-This cannot be undone!}"
    echo "⚠️  WARNING: $message"
    read -p "Type YES to confirm: " response
    case "$response" in
        [yY][eE][sS] | [yY]) return 0 ;;
        *) echo "canceled!" && return 1 ;;
    esac
}