#!/usr/bin/env bash

clear() {
  printf '\x1b\x5b\x48\x1b\x5b\x32\x4a'
}

red() {
  if (( $# )); then
    local red=$'\x1b\x5b\x33\x31\x6d'
    local rst=$'\x1b\x28\x42\x1b\x5b\x6d'
    printf %s%s%s "$red" "$1" "$rst"
  fi
}

render() {
  local pce=${pcs[$pos-1]}

  if [[ $pce = " " ]]; then
    pcs[$pos-1]=$(red "*")
  else
    pcs[$pos-1]=$(red "$pce")
  fi

  clear
  printf "%s\n" "${brd[0]}"
  printf "${brd[1]}\n" "${pcs[@]:0:3}"
  printf "%s\n" "${brd[2]}"
  printf "%s\n" "${brd[0]}"
  printf "${brd[1]}\n" "${pcs[@]:3:3}"
  printf "%s\n" "${brd[2]}"
  printf "%s\n" "${brd[0]}"
  printf "${brd[1]}\n" "${pcs[@]:6:3}"
  printf "%s\n" "${brd[0]}"

  pcs[$pos-1]=$pce
}

place() {
  if (( $# )); then
    local chr=$1 plc=$2 row win col
    pcs[$plc]=$chr

    for (( row = 0; row < 7; row += 3 )); do
      if [[ ${pcs[*]:$row:3} = @(x x x|o o o) ]]; then
        win=${pcs[$row]}
        break
      fi
    done

    if [[ -z $win ]]; then
      for col in {0..2}; do
        if [[ ${pcs[$col]}${pcs[$col+3]}${pcs[$col+6]} = @(xxx|ooo) ]]; then
          win=${pcs[$col]}
          break
        fi
      done
    fi

    if [[ -z $win ]]; then
      if [[ ${pcs[0]}${pcs[4]}${pcs[8]} = @(xxx|ooo) ]]; then
        win=${pcs[0]}
      elif [[ ${pcs[2]}${pcs[4]}${pcs[6]} = @(xxx|ooo) ]]; then
        win=${pcs[2]}
      fi
    fi

    (( pld += 1 ))

    if [[ -n $win ]]; then
      case $win in
      x)
        res=1
        ;;
      o)
        res=2
      esac
    elif (( pld == 9 )); then
      res=3
    else
      res=0
    fi

    return "$res"
  fi

  return 4
}

win=0 pld=0 pos=1

pcs=(
  " " " " " "
  " " " " " "
  " " " " " "
)

brd=(
  '   |   |'
  ' %s | %s | %s'
  '___|___|___'
)

while ! (( win )); do
  render

  while true; do
    read -rsn 1 key
    dir=

    case $key in
    "")
      if [[ ${pcs[$pos-1]} = " " ]]; then
        break
      fi
      ;;
    $'\x1b')
      read -rsn 2 arrow

      case $arrow in
      $'\x4f\x41'|$'\x5b\x41')
        dir=up
        ;;
      $'\x4f\x42'|$'\x5b\x42')
        dir=down
        ;;
      $'\x4f\x43'|$'\x5b\x43')
        dir=right
        ;;
      $'\x4f\x44'|$'\x5b\x44')
        dir=left
        ;;
      esac
      ;;
    w|W)
      dir=up
      ;;
    s|S)
      dir=down
      ;;
    d|D)
      dir=right
      ;;
    a|A)
      dir=left
      ;;
    esac

    if [[ -n $dir ]]; then
      case $dir in
      up)
        if (( pos > 3 )); then
          (( pos -= 3 ))
        fi
        ;;
      down)
        if (( pos < 7 )); then
          (( pos += 3 ))
        fi
        ;;
      right)
        if (( pos % 3 )); then
          (( pos += 1 ))
        fi
        ;;
      left)
        if (( (pos % 3) != 1 )); then
          (( pos -= 1 ))
        fi
      esac
    fi

    render
  done

  place x "$(( pos - 1 ))"

  if ! (( res )); then
    unu=( )

    for (( cnt = 0; cnt < 9; ++cnt )); do
      if [[ ${pcs[$cnt]} = " " ]]; then
        unu+=( "$cnt" )
      fi
    done

    ops=$(( RANDOM % ${#unu[@]} ))
    place o "${unu[$ops]}"
  fi

  if (( $res )); then
    render

    case $res in
    1)
      printf 'x wins\n'
      ;;
    2)
      printf 'o wins\n'
      ;;
    3)
      printf 'tie game\n'
    esac

    exit
  fi
done