A simple version of Wordle game

wordle.sh

#!/bin/bash

#
# Uses ripgrep (rg)
#

length=${length:-5}
tries=${tries:-6}

# All words of given length from a dictionary
declare -a words
declare -A words_dict

words=( $(rg --color=never --no-line-number '^\w{'"${length}"'}$' /usr/share/dict/words) )

# Generate random position in the dictionary by reading
# 8-byte integer from system random generator
random_pos=$(( $(od --output-duplicates --address-radix=n --read-bytes=8 --format=u8 < /dev/urandom) % ${#words[@]} ))

# Select the secret word and convert to upper case
secret=${words[$random_pos]^^}

# Prepare fast search dictionary in upper case and empty the raw array
for word in ${words[@]}; do
  words_dict[${word^^}]=""
done
words=()

function validate_word() {
  local word="$1"

  if (( ${#word} != $length )); then
    echo "You have to use ${length}-letter word!"
    false
    return
  fi

  if ! [ -v words_dict["${word^^}"] ]; then
    echo "${word} is not recognized, try again!"
    false
    return
  fi

  true
}

clr_no=$(printf "\x1b[0m")
clr_green_bg=$(printf "\x1b[48;2;83;140;78m")
clr_yellow_bg=$(printf "\x1b[48;2;181;159;59m")
clr_gray_bg=$(printf "\x1b[48;2;58;58;60m")
clr_white_fg=$(printf "\x1b[1;38;2;215;218;220m")

function process_guess() {
  local guess="${1^^}"
  local secret="$2"

  # Important values to calculate for a specific letter:
  #   ${secret_letter_total[$letter]} - number of appearances of the letter in the secret.
  #   ${guess_letter_correct[$letter]} - number of correct guessed positions for the letter (green).
  #   ${secret_letter_total[$letter]} - ${guess_letter_correct[$letter]} = number of maximum possible mismatched
  # guessed letters to be shown (yellow).
  # All guesses that exceed ${secret_letter_total[$letter]} - ${guess_letter_correct[$letter]} even if that letter
  # was found somewhere will be shown as misses (gray).

  local -A secret_letter_total=()
  local -A guess_letter_correct=()
  local -A guess_letter_mismatches=()
  local letter
  local guessed_letters=0

  # Secret letter frequencies
  for ((i = 0; i < ${#secret}; i++)); do
    letter=${secret:$i:1}
    if ! [ -v "${secret_letter_total[$letter]}" ]; then
      secret_letter_total[$letter]=1
    else
      (( secret_letter_total[$letter]++ ))
    fi
  done

  # First pass - exact matches.
  for ((i = 0; i < ${#guess}; i++)); do
    letter=${guess:$i:1}

    if [[ "$letter" == "${secret:$i:1}" ]]; then
      (( guessed_letters++ ))

      if ! [ -v "${guess_letter_correct[$letter]}" ] || (( guess_letter_correct[$letter] == 0 )); then
        guess_letter_correct[$letter]=1
      else
       (( guess_letter_correct[$letter]++ ))
      fi
    elif ! [ -v "${guess_letter_correct[$letter]}" ]; then
      guess_letter_correct[$letter]=0
    fi
  done

  # Second pass - completing the markup
  printf "${clr_white_fg}"
  for ((i = 0; i < ${#guess}; i++)); do
    letter=${guess:$i:1}

    # exact match
    if [[ "$letter" == "${secret:$i:1}" ]]; then
      printf "${clr_green_bg} ${letter} "
      continue
    fi

    # miss
    if ! [ -v "${secret_letter_total[$letter]}" ]; then
      printf "${clr_gray_bg} ${letter} "
      continue
    fi

    # mismatch
    # update the frequency of that mismatch
    if ! [ -v "${guess_letter_mismatches[$letter]}" ]; then
      guess_letter_mismatches[$letter]=1
    else
     (( guess_letter_mismatches[$letter]++ ))
    fi

    if (( ${guess_letter_mismatches[$letter]} <= ${secret_letter_total[$letter]} - ${guess_letter_correct[$letter]} )); then
       printf "${clr_yellow_bg} ${letter} "
    else
       printf "${clr_gray_bg} ${letter} "
    fi
  done
  printf "${clr_no}"

  if ((guessed_letters == length)); then
    return 1
  fi

  return 0
}

rc=0
while (( (tries > 0 ) && (rc == 0) )); do
  printf "Enter your guess (${tries} tries left): "
  read guess

  if ! validate_word "$guess"; then
    continue
  fi

  hints=$(process_guess "$guess" "$secret")
  rc=$?
  printf "${hints}\n"
  ((--tries))
done

if ((rc != 0)); then
  echo "You win!"
else
  echo "You lose!"
  echo "The word was: ${secret}"
fi