horserace.sh

#!/bin/bash
# horserace.sh: Very simple horserace simulation.
# Author: Stefano Palmeri
# Used with permission.

################################################################
#  Goals of the script:
#  playing with escape sequences and terminal colors.
#
#  Exercise:
#  Edit the script to make it run less randomly,
#+ set up a fake betting shop . . .
#  Um . . . um . . . it's starting to remind me of a movie . . .
#
#  The script gives each horse a random handicap.
#  The odds are calculated upon horse handicap
#+ and are expressed in European(?) style.
#  E.g., odds=3.75 means that if you bet $1 and win,
#+ you receive $3.75.
#
#  The script has been tested with a GNU/Linux OS,
#+ using xterm and rxvt, and konsole.
#  On a machine with an AMD 900 MHz processor,
#+ the average race time is 75 seconds.
#  On faster computers the race time would be lower.
#  So, if you want more suspense, reset the USLEEP_ARG variable.
#
#  Script by Stefano Palmeri.
################################################################

E_RUNERR=65

# Check if md5sum and bc are installed.
if ! which bc &> /dev/null; then
   echo bc is not installed.
   echo "Can\'t run . . . "
   exit $E_RUNERR
fi
if ! which md5sum &> /dev/null; then
   echo md5sum is not installed.
   echo "Can\'t run . . . "
   exit $E_RUNERR
fi

#  Set the following variable to slow down script execution.
#  It will be passed as the argument for usleep (man usleep)
#+ and is expressed in microseconds (500000 = half a second).
SLEEP_ARG=0

#  Clean up the temp directory, restore terminal cursor and
#+ terminal colors -- if script interrupted by Ctl-C.
trap 'echo -en "\E[?25h"; echo -en "\E[0m"; stty echo;\
tput cup 20 0; rm -fr  $HORSE_RACE_TMP_DIR'  TERM EXIT
#  See the chapter on debugging for an explanation of 'trap.'

# Set a unique (paranoid) name for the temp directory the script needs.
HORSE_RACE_TMP_DIR=$HOME/.horserace-`date +%s`-`head -c10 /dev/urandom \
| md5sum | head -c30`

# Create the temp directory and move right in.
mkdir $HORSE_RACE_TMP_DIR
cd $HORSE_RACE_TMP_DIR


#  This function moves the cursor to line $1 column $2 and then prints $3.
#  E.g.: "move_and_echo 5 10 linux" is equivalent to
#+ "tput cup 4 9; echo linux", but with one command instead of two.
#  Note: "tput cup" defines 0 0 the upper left angle of the terminal,
#+ echo defines 1 1 the upper left angle of the terminal.
move_and_echo() {
          echo -ne "\E[${1};${2}H""$3"
}

# Function to generate a pseudo-random number between 1 and 9.
random_1_9 ()
{
    head -c10 /dev/urandom | md5sum | tr -d [a-z] | tr -d 0 | cut -c1
}

#  Two functions that simulate "movement," when drawing the horses.
draw_horse_one() {
               echo -n " "//$MOVE_HORSE//
}
draw_horse_two(){
              echo -n " "\\\\$MOVE_HORSE\\\\
}


# Define current terminal dimension.
N_COLS=`tput cols`
N_LINES=`tput lines`

# Need at least a 20-LINES X 80-COLUMNS terminal. Check it.
if [ $N_COLS -lt 80 ] || [ $N_LINES -lt 20 ]; then
   echo "`basename $0` needs a 80-cols X 20-lines terminal."
   echo "Your terminal is ${N_COLS}-cols X ${N_LINES}-lines."
   exit $E_RUNERR
fi


# Start drawing the race field.

# Need a string of 80 chars. See below.
BLANK80=`seq -s "" 100 | head -c80`

clear

# Set foreground and background colors to white.
echo -ne '\E[37;47m'

# Move the cursor on the upper left angle of the terminal.
tput cup 0 0

# Draw six white lines.
for n in `seq 5`; do
      echo $BLANK80   # Use the 80 chars string to colorize the terminal.
done

# Sets foreground color to black.
echo -ne '\E[30m'

move_and_echo 3 1 "START  1"
move_and_echo 3 75 FINISH
move_and_echo 1 5 "|"
move_and_echo 1 80 "|"
move_and_echo 2 5 "|"
move_and_echo 2 80 "|"
move_and_echo 4 5 "|  2"
move_and_echo 4 80 "|"
move_and_echo 5 5 "V  3"
move_and_echo 5 80 "V"

# Set foreground color to red.
echo -ne '\E[31m'

# Some ASCII art.
move_and_echo 1 8 "..@@@..@@@@@...@@@@@.@...@..@@@@..."
move_and_echo 2 8 ".@...@...@.......@...@...@.@......."
move_and_echo 3 8 ".@@@@@...@.......@...@@@@@.@@@@...."
move_and_echo 4 8 ".@...@...@.......@...@...@.@......."
move_and_echo 5 8 ".@...@...@.......@...@...@..@@@@..."
move_and_echo 1 43 "@@@@...@@@...@@@@..@@@@..@@@@."
move_and_echo 2 43 "@...@.@...@.@.....@.....@....."
move_and_echo 3 43 "@@@@..@@@@@.@.....@@@@...@@@.."
move_and_echo 4 43 "@..@..@...@.@.....@.........@."
move_and_echo 5 43 "@...@.@...@..@@@@..@@@@.@@@@.."


# Set foreground and background colors to green.
echo -ne '\E[32;42m'

# Draw  eleven green lines.
tput cup 5 0
for n in `seq 11`; do
      echo $BLANK80
done

# Set foreground color to black.
echo -ne '\E[30m'
tput cup 5 0

# Draw the fences.
echo "++++++++++++++++++++++++++++++++++++++\
++++++++++++++++++++++++++++++++++++++++++"

tput cup 15 0
echo "++++++++++++++++++++++++++++++++++++++\
++++++++++++++++++++++++++++++++++++++++++"

# Set foreground and background colors to white.
echo -ne '\E[37;47m'

# Draw three white lines.
for n in `seq 3`; do
      echo $BLANK80
done

# Set foreground color to black.
echo -ne '\E[30m'

# Create 9 files to stores handicaps.
for n in `seq 10 7 68`; do
      touch $n
done

# Set the first type of "horse" the script will draw.
HORSE_TYPE=2

#  Create position-file and odds-file for every "horse".
#+ In these files, store the current position of the horse,
#+ the type and the odds.
for HN in `seq 9`; do
      touch horse_${HN}_position
      touch odds_${HN}
      echo \-1 > horse_${HN}_position
      echo $HORSE_TYPE >>  horse_${HN}_position
      # Define a random handicap for horse.
       HANDICAP=`random_1_9`
      # Check if the random_1_9 function returned a good value.
      while ! echo $HANDICAP | grep [1-9] &> /dev/null; do
                HANDICAP=`random_1_9`
      done
      # Define last handicap position for horse.
      LHP=`expr $HANDICAP \* 7 + 3`
      for FILE in `seq 10 7 $LHP`; do
            echo $HN >> $FILE
      done

      # Calculate odds.
      case $HANDICAP in
              1) ODDS=`echo $HANDICAP \* 0.25 + 1.25 | bc`
                                 echo $ODDS > odds_${HN}
              ;;
              2 | 3) ODDS=`echo $HANDICAP \* 0.40 + 1.25 | bc`
                                       echo $ODDS > odds_${HN}
              ;;
              4 | 5 | 6) ODDS=`echo $HANDICAP \* 0.55 + 1.25 | bc`
                                             echo $ODDS > odds_${HN}
              ;;
              7 | 8) ODDS=`echo $HANDICAP \* 0.75 + 1.25 | bc`
                                       echo $ODDS > odds_${HN}
              ;;
              9) ODDS=`echo $HANDICAP \* 0.90 + 1.25 | bc`
                                  echo $ODDS > odds_${HN}
      esac


done


# Print odds.
print_odds() {
tput cup 6 0
echo -ne '\E[30;42m'
for HN in `seq 9`; do
      echo "#$HN odds->" `cat odds_${HN}`
done
}

# Draw the horses at starting line.
draw_horses() {
tput cup 6 0
echo -ne '\E[30;42m'
for HN in `seq 9`; do
      echo /\\$HN/\\"                               "
done
}

print_odds

echo -ne '\E[47m'
# Wait for a enter key press to start the race.
# The escape sequence '\E[?25l' disables the cursor.
tput cup 17 0
echo -e '\E[?25l'Press [enter] key to start the race...
read -s

#  Disable normal echoing in the terminal.
#  This avoids key presses that might "contaminate" the screen
#+ during the race.
stty -echo

# --------------------------------------------------------
# Start the race.

draw_horses
echo -ne '\E[37;47m'
move_and_echo 18 1 $BLANK80
echo -ne '\E[30m'
move_and_echo 18 1 Starting...
sleep 1

# Set the column of the finish line.
WINNING_POS=74

# Define the time the race started.
START_TIME=`date +%s`

# COL variable needed by following "while" construct.
COL=0

while [ $COL -lt $WINNING_POS ]; do

          MOVE_HORSE=0

          # Check if the random_1_9 function has returned a good value.
          while ! echo $MOVE_HORSE | grep [1-9] &> /dev/null; do
                MOVE_HORSE=`random_1_9`
          done

          # Define old type and position of the "randomized horse".
          HORSE_TYPE=`cat  horse_${MOVE_HORSE}_position | tail -n 1`
          COL=$(expr `cat  horse_${MOVE_HORSE}_position | head -n 1`)

          ADD_POS=1
          # Check if the current position is an handicap position.
          if seq 10 7 68 | grep -w $COL &> /dev/null; then
                if grep -w $MOVE_HORSE $COL &> /dev/null; then
                      ADD_POS=0
                      grep -v -w  $MOVE_HORSE $COL > ${COL}_new
                      rm -f $COL
                      mv -f ${COL}_new $COL
                      else ADD_POS=1
                fi
          else ADD_POS=1
          fi
          COL=`expr $COL + $ADD_POS`
          echo $COL >  horse_${MOVE_HORSE}_position  # Store new position.

         # Choose the type of horse to draw.
          case $HORSE_TYPE in
                1) HORSE_TYPE=2; DRAW_HORSE=draw_horse_two
                ;;
                2) HORSE_TYPE=1; DRAW_HORSE=draw_horse_one
          esac
          echo $HORSE_TYPE >>  horse_${MOVE_HORSE}_position
          # Store current type.

          # Set foreground color to black and background to green.
          echo -ne '\E[30;42m'

          # Move the cursor to new horse position.
          tput cup `expr $MOVE_HORSE + 5` \
      `cat  horse_${MOVE_HORSE}_position | head -n 1`

          # Draw the horse.
          $DRAW_HORSE
           sleep $SLEEP_ARG

           # When all horses have gone beyond field line 15, reprint odds.
           touch fieldline15
           if [ $COL = 15 ]; then
             echo $MOVE_HORSE >> fieldline15
           fi
           if [[ `wc -l fieldline15 | cut -f1 -d " "` = 9 ]]; then
               print_odds
               : > fieldline15
           fi

          # Define the leading horse.
          HIGHEST_POS=`cat *position | sort -n | tail -1`

          # Set background color to white.
          echo -ne '\E[47m'
          tput cup 17 0
          echo -n Current leader: `grep -w $HIGHEST_POS *position | cut -c7`\
      "                              "

done

# Define the time the race finished.
FINISH_TIME=`date +%s`

# Set background color to green and enable blinking text.
echo -ne '\E[30;42m'
echo -en '\E[5m'

# Make the winning horse blink.
tput cup `expr $MOVE_HORSE + 5` \
`cat  horse_${MOVE_HORSE}_position | head -n 1`
$DRAW_HORSE

# Disable blinking text.
echo -en '\E[25m'

# Set foreground and background color to white.
echo -ne '\E[37;47m'
move_and_echo 18 1 $BLANK80

# Set foreground color to black.
echo -ne '\E[30m'

# Make winner blink.
tput cup 17 0
echo -e "\E[5mWINNER: $MOVE_HORSE\E[25m""  Odds: `cat odds_${MOVE_HORSE}`"\
"  Race time: `expr $FINISH_TIME - $START_TIME` secs"

# Restore cursor and old colors.
echo -en "\E[?25h"
echo -en "\E[0m"

# Restore echoing.
stty echo

# Remove race temp directory.
rm -rf $HORSE_RACE_TMP_DIR

tput cup 19 0

exit 0