#!/usr/bin/env bash

toduck() {
  local in=/dev/stdin
  local out=/dev/stdout
  local file="$1"
  if [[ -n $file ]];then
    in="$file"
    out="$(mktemp)"
  fi
  duck="https://lite.duckduckgo.com/lite?kd=-1&kp=-1&q=" # 🦆
  while IFS= read -r line; do
    if [[ $line =~ \[([^\]]+)\]\(\) ]]; then
      text="${BASH_REMATCH[1]}"
        line=${line/\[*\]\(\)/[$text]($duck$(urlencode "$text"))}
    fi
    echo "$line" >> $out
  done < "$in"
  if [[ -n $file ]]; then
    cp "$out" "$file"
    rm "$out"
  fi
}

toduck "$@"