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background/bash2048.sh

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+#!/usr/bin/env bash
+
+#important variables
+declare -ia board    # array that keeps track of game status
+declare -i pieces    # number of pieces present on board
+declare -i score=0   # score variable
+declare -i flag_skip # flag that prevents doing more than one operation on
+                     # single field in one step
+declare -i moves     # stores number of possible moves to determine if player lost 
+                     # the game
+declare ESC=$'\e'    # escape byte
+declare header="Bash 2048 v1.1 (https://github.com/mydzor/bash2048)"
+
+declare -i start_time=$(date +%s)
+
+#default config
+declare -i board_size=4
+declare -i target=2048
+declare -i reload_flag=0
+declare config_dir="$HOME/.bash2048"
+
+#for colorizing numbers
+declare -a colors
+colors[2]=33         # yellow text
+colors[4]=32         # green text
+colors[8]=34         # blue text
+colors[16]=36        # cyan text
+colors[32]=35        # purple text
+colors[64]="33m\033[7"        # yellow background
+colors[128]="32m\033[7"       # green background
+colors[256]="34m\033[7"       # blue background
+colors[512]="36m\033[7"       # cyan background
+colors[1024]="35m\033[7"      # purple background
+colors[2048]="31m\033[7"      # red background (won with default target)
+
+exec 3>/dev/null     # no logging by default
+
+trap "end_game 0 1" INT #handle INT signal
+
+#simplified replacement of seq command
+function _seq {
+  local cur=1
+  local max
+  local inc=1
+  case $# in
+    1) let max=$1;;
+    2) let cur=$1
+       let max=$2;;
+    3) let cur=$1
+       let inc=$2
+       let max=$3;;
+  esac
+  while test $max -ge $cur; do
+    printf "$cur "
+    let cur+=inc
+  done
+}
+
+# print currect status of the game, last added pieces are marked red
+function print_board {
+  clear
+  printf "$header pieces=$pieces target=$target score=$score\n"
+  printf "Board status:\n" >&3
+  printf "\n"
+  printf '/------'
+  for l in $(_seq 1 $index_max); do
+    printf '+------'
+  done
+  printf '\\\n'
+  for l in $(_seq 0 $index_max); do
+    printf '|'
+    for m in $(_seq 0 $index_max); do
+      if let ${board[l*$board_size+m]}; then
+        if let '(last_added==(l*board_size+m))|(first_round==(l*board_size+m))'; then
+          printf '\033[1m\033[31m %4d \033[0m|' ${board[l*$board_size+m]}
+        else
+          printf "\033[1m\033[${colors[${board[l*$board_size+m]}]}m %4d\033[0m |" ${board[l*$board_size+m]}
+        fi
+        printf " %4d |" ${board[l*$board_size+m]} >&3
+      else
+        printf '      |'
+        printf '      |' >&3
+      fi
+    done
+    let l==$index_max || {
+      printf '\n|------'
+      for l in $(_seq 1 $index_max); do
+        printf '+------'
+      done
+      printf '|\n'
+      printf '\n' >&3
+    }
+  done
+  printf '\n\\------'
+  for l in $(_seq 1 $index_max); do
+    printf '+------'
+  done
+  printf '/\n'
+}
+
+# Generate new piece on the board
+# inputs:
+#         $board  - original state of the game board
+#         $pieces - original number of pieces
+# outputs:
+#         $board  - new state of the game board
+#         $pieces - new number of pieces
+function generate_piece {
+  while true; do
+    let pos=RANDOM%fields_total
+    let board[$pos] || {
+      let value=RANDOM%10?2:4
+      board[$pos]=$value
+      last_added=$pos
+      printf "Generated new piece with value $value at position [$pos]\n" >&3
+      break;
+    }
+  done
+  let pieces++
+}
+
+# perform push operation between two pieces
+# inputs:
+#         $1 - push position, for horizontal push this is row, for vertical column
+#         $2 - recipient piece, this will hold result if moving or joining
+#         $3 - originator piece, after moving or joining this will be left empty
+#         $4 - direction of push, can be either "up", "down", "left" or "right"
+#         $5 - if anything is passed, do not perform the push, only update number 
+#              of valid moves
+#         $board - original state of the game board
+# outputs:
+#         $change    - indicates if the board was changed this round
+#         $flag_skip - indicates that recipient piece cannot be modified further
+#         $board     - new state of the game board
+function push_pieces {
+  case $4 in
+    "up")
+      let "first=$2*$board_size+$1"
+      let "second=($2+$3)*$board_size+$1"
+      ;;
+    "down")
+      let "first=(index_max-$2)*$board_size+$1"
+      let "second=(index_max-$2-$3)*$board_size+$1"
+      ;;
+    "left")
+      let "first=$1*$board_size+$2"
+      let "second=$1*$board_size+($2+$3)"
+      ;;
+    "right")
+      let "first=$1*$board_size+(index_max-$2)"
+      let "second=$1*$board_size+(index_max-$2-$3)"
+      ;;
+  esac
+  let ${board[$first]} || { 
+    let ${board[$second]} && {
+      if test -z $5; then
+        board[$first]=${board[$second]}
+        let board[$second]=0
+        let change=1
+        printf "move piece with value ${board[$first]} from [$second] to [$first]\n" >&3
+      else
+        let moves++
+      fi
+      return
+    }
+    return
+  }
+  let ${board[$second]} && let flag_skip=1
+  let "${board[$first]}==${board[second]}" && { 
+    if test -z $5; then
+      let board[$first]*=2
+      let "board[$first]==$target" && end_game 1
+      let board[$second]=0
+      let pieces-=1
+      let change=1
+      let score+=${board[$first]}
+      printf "joined piece from [$second] with [$first], new value=${board[$first]}\n" >&3
+    else
+      let moves++
+    fi
+  }
+}
+
+function apply_push {
+  printf "\n\ninput: $1 key\n" >&3
+  for i in $(_seq 0 $index_max); do
+    for j in $(_seq 0 $index_max); do
+      flag_skip=0
+      let increment_max=index_max-j
+      for k in $(_seq 1 $increment_max); do
+        let flag_skip && break
+        push_pieces $i $j $k $1 $2
+      done 
+    done
+  done
+}
+
+function check_moves {
+  let moves=0
+  apply_push up fake
+  apply_push down fake
+  apply_push left fake
+  apply_push right fake
+}
+
+function key_react {
+  let change=0
+  read -d '' -sn 1
+  test "$REPLY" = "$ESC" && {
+    read -d '' -sn 1 -t1
+    test "$REPLY" = "[" && {
+      read -d '' -sn 1 -t1
+      case $REPLY in
+        A) apply_push up;;
+        B) apply_push down;;
+        C) apply_push right;;
+        D) apply_push left;;
+      esac
+    }
+  } || {
+    case $REPLY in
+      k) apply_push up;;
+      j) apply_push down;;
+      l) apply_push right;;
+      h) apply_push left;;
+
+      w) apply_push up;;
+      s) apply_push down;;
+      d) apply_push right;;
+      a) apply_push left;;
+    esac
+  }
+}
+
+function save_game {
+  rm -rf "$config_dir"
+  mkdir "$config_dir"
+  echo "${board[@]}" > "$config_dir/board"
+  echo "$board_size" > "$config_dir/board_size"
+  echo "$pieces" > "$config_dir/pieces"
+  echo "$target" > "$config_dir/target"
+#  echo "$log_file" > "$config_dir/log_file"
+  echo "$score" > "$config_dir/score"
+  echo "$first_round" > "$config_dir/first_round"
+}
+
+function reload_game {
+  printf "Loading saved game...\n" >&3
+
+  if test ! -d "$config_dir"; then
+    return
+  fi
+  board=(`cat "$config_dir/board"`)
+  board_size=(`cat "$config_dir/board_size"`)
+  board=(`cat "$config_dir/board"`)
+  pieces=(`cat "$config_dir/pieces"`)
+  first_round=(`cat "$config_dir/first_round"`)
+  target=(`cat "$config_dir/target"`)
+  score=(`cat "$config_dir/score"`)
+
+  fields_total=board_size*board_size
+  index_max=board_size-1
+}
+
+function end_game {
+  # count game duration
+  end_time=$(date +%s) 
+  let total_time=end_time-start_time
+
+  print_board
+  printf "Your score: $score\n"
+
+  printf "This game lasted "
+
+  `date --version > /dev/null 2>&1`
+  if [[ "$?" -eq 0 ]]; then
+      date -u -d @${total_time} +%T
+  else
+      date -u -r ${total_time} +%T
+  fi
+
+  stty echo
+  let $1 && {
+    printf "Congratulations you have achieved $target\n"
+    exit 0
+  }
+  let test -z $2 && {
+    read -n1 -p "Do you want to overwrite saved game? [y|N]: "
+    test "$REPLY" = "Y" || test "$REPLY" = "y" && {
+      save_game
+      printf "\nGame saved. Use -r option next to load this game.\n"
+      exit 0
+    }
+    test "$REPLY" = "" && {
+      printf "\nGame not saved.\n"
+      exit 0
+    }
+  }
+  printf "\nYou have lost, better luck next time.\033[0m\n"
+  exit 0
+}
+
+function help {
+  cat <<END_HELP
+Usage: $1 [-b INTEGER] [-t INTEGER] [-l FILE] [-r] [-h]
+
+  -b			specify game board size (sizes 3-9 allowed)
+  -t			specify target score to win (needs to be power of 2)
+  -l			log debug info into specified file
+  -r			reload the previous game
+  -h			this help
+
+END_HELP
+}
+
+
+#parse commandline options
+while getopts "b:t:l:rh" opt; do
+  case $opt in
+    b ) board_size="$OPTARG"
+      let '(board_size>=3)&(board_size<=9)' || {
+        printf "Invalid board size, please choose size between 3 and 9\n"
+        exit -1 
+      };;
+    t ) target="$OPTARG"
+      printf "obase=2;$target\n" | bc | grep -e '^1[^1]*$'
+      let $? && {
+        printf "Invalid target, has to be power of two\n"
+        exit -1 
+      };;
+    r ) reload_flag="1";;
+    h ) help $0
+        exit 0;;
+    l ) exec 3>$OPTARG;;
+    \?) printf "Invalid option: -"$opt", try $0 -h\n" >&2
+            exit 1;;
+    : ) printf "Option -"$opt" requires an argument, try $0 -h\n" >&2
+            exit 1;;
+  esac
+done
+
+#init board
+let fields_total=board_size*board_size
+let index_max=board_size-1
+for i in $(_seq 0 $fields_total); do board[$i]="0"; done
+let pieces=0
+generate_piece
+first_round=$last_added
+generate_piece
+
+#load saved game if flag is set
+if test $reload_flag = "1"; then
+  reload_game
+fi
+
+while true; do
+  print_board
+  key_react
+  let change && generate_piece
+  first_round=-1
+  let pieces==fields_total && {
+   check_moves
+   let moves==0 && end_game 0 #lose the game
+  }
+done