#!/usr/bin/env bash
set -euo pipefail

# Script Name: nato
# Description: Convert strings to NATO phonetic alphabet
# Source: Inspired by https://evanhahn.com/scripts-i-wrote-that-i-use-all-the-time/
# Usage: nato bar        # Output: Bravo Alfa Romeo
#        nato "hello 123"

if [[ $# -eq 0 ]]; then
  echo "Usage: nato <string>" >&2
  exit 1
fi

# NATO phonetic alphabet mapping
declare -A nato_map=(
  [a]="Alfa" [b]="Bravo" [c]="Charlie" [d]="Delta" [e]="Echo"
  [f]="Foxtrot" [g]="Golf" [h]="Hotel" [i]="India" [j]="Juliett"
  [k]="Kilo" [l]="Lima" [m]="Mike" [n]="November" [o]="Oscar"
  [p]="Papa" [q]="Quebec" [r]="Romeo" [s]="Sierra" [t]="Tango"
  [u]="Uniform" [v]="Victor" [w]="Whiskey" [x]="Xray" [y]="Yankee"
  [z]="Zulu"
  [0]="Zero" [1]="One" [2]="Two" [3]="Three" [4]="Four"
  [5]="Five" [6]="Six" [7]="Seven" [8]="Eight" [9]="Niner"
)

# Convert all arguments to lowercase and process each character
input="$(echo "$*" | tr '[:upper:]' '[:lower:]')"

result=()
while IFS= read -r -n1 char; do
  # Skip empty characters
  [[ -z "$char" ]] && continue

  if [[ -n "${nato_map[$char]:-}" ]]; then
    result+=("${nato_map[$char]}")
  elif [[ "$char" == " " ]]; then
    result+=("/")  # Use / as space separator
  fi
done <<< "$input"

# Output with spaces between words
echo "${result[*]}"