Rock Paper Scissors Lizard Spock

rpsls.sh

#!/bin/sh

CHOICES="Rock Paper Scissors Lizard Spock"

check_rule() {
        user="$1"; computer="$2"; draw="yes"
        while read rulestr ; do
                rule="$rulestr"
                winner="${rule%% *}"; rule="${rule#* }"
                verb="${rule%% *}"; rule="${rule#* }"
                loser="${rule%% *}"; rule="${rule#* }"
                if [ \( "$user" = "$winner" \) -a \( "$computer" = "$loser" \) ]; then
                        echo "$rulestr. You win!"
                        USER_WINS=$(($USER_WINS+1))
                        draw=""
                elif [ \( "$user" = "$loser" \) -a \( "$computer" = "$winner" \) ]; then
                        echo "$rulestr. You lose!"
                        COMPUTER_WINS=$(($COMPUTER_WINS+1))
                        draw=""
                fi
        done <<RULEZ
Scissors cuts Paper
Paper covers Rock
Rock crushes Lizard
Lizard poisons Spock
Spock smashes Scissors
Scissors decapitates Lizard
Lizard eats Paper
Paper disproves Spock
Spock vaporizes Rock
Rock crushes Scissors
RULEZ
        if [ -n "$draw" ]; then
                echo "It's a draw."
                DRAW_COUNT=$(($DRAW_COUNT+1))
        fi
}

ask_user_choice() {
        i=0
        for choice in $CHOICES; do
                i=$((i+1))
                echo "$i. $choice"
        done
        choice=""
        while [ -z "$choice" ]; do
                echo -n "Choose your choice [1-5]: "
                read choice_index
                get_choice_by_index "$choice_index"
        done
        user_choice="$choice"
}

get_choice_by_index() {
        choice_index="$1"
        i=0
        for choice in $CHOICES; do
                i=$(($i+1))
                if [ "$i" -eq "$choice_index" ]; then
                        return
                fi
        done
        choice=""
}

random_choice() {
        rand=`awk 'BEGIN{srand();print int(rand()*5)+1}'`
        get_choice_by_index "$rand"
}

show_stats_and_exit() {
        echo ""
        echo "*** STATISTICS ***"
        echo "You played $GAME_COUNT times"
        echo "You won $USER_WINS times"
        echo "Computer won $COMPUTER_WINS times"
        echo "We had $DRAW_COUNT draws"
        echo ""
        echo "Bye."
        exit 0
}


GAME_COUNT=0; COMPUTER_WINS=0; USER_WINS=0; DRAW_COUNT=0

trap show_stats_and_exit INT

echo "Welcome to $CHOICES"
echo "Enter your choice to play, press CTRL+C to exit."
echo ""

while true; do
        random_choice; computer_choice="$choice"
        ask_user_choice
        GAME_COUNT=$(($GAME_COUNT+1))
        echo ""
        echo "You chose $user_choice, computer chose $computer_choice."
        check_rule "$user_choice" "$computer_choice"
        echo ""
done