#! /bin/bash
#
# cassebriq.sh : Un cassebrique (sans briques) en bash 
#
# Edouard.Thiel@lif.univ-mrs.fr - 25/09/2014
#
# This program is free software under the terms of the 
# GNU Lesser General Public License (LGPL) version 2.1.


init_jeu ()
{
    ncols=$(tput cols)
    nlines=$(tput lines)
    raq_t="========="
    raq_l=${#raq_t}
    raq_x=$(( (ncols-raq_l)/2 ))
}

init_balle ()
{
    bal_x=$((ncols/2))
    bal_y=$((nlines/2))
    bal_dx=1
    bal_dy=-1
    continuer=true
}

deplacer_gauche ()
{
    ((raq_x-=2))
    if ((raq_x < 0)); then raq_x=0; fi
}

deplacer_droite ()
{
    ((raq_x+=2))
    if ((raq_x >= ncols-raq_l)); then raq_x=$((ncols-raq_l-1)); fi
}

afficher_raquette ()
{
    tput cup $((nlines-2)) $raq_x
    printf "%s" "$raq_t"
}

placer_curseur_en_bas ()
{
    tput cup $((nlines-1)) 0
}

afficher_balle ()
{
    tput cup $bal_y $bal_x
    printf "O"
}

afficher_aide ()
{
    tput cup 0 0
    printf "a: gauche  z: droite  n: nouveau jeu  q: quitter"
}

afficher_perdu ()
{
    tput cup $((nlines/2)) $((ncols/2-7))
    printf "PERDU !"
}

terminer ()
{
    echo
    echo "Merci d'avoir joué à ${0##*/}"
}

progresser_balle ()
{
    ((bal_x += bal_dx))
    ((bal_y += bal_dy))

    if ((bal_x < 0)); then
        bal_x=0; ((bal_dx = -bal_dx))
    elif ((bal_x >= ncols)); then
        bal_x=$((ncols-1)); ((bal_dx = -bal_dx))
    fi

    if ((bal_y < 0)); then
        bal_y=0; ((bal_dy = -bal_dy))
    elif ((bal_y == nlines-2)); then
        if ((bal_x >= raq_x && bal_x <= raq_x+raq_l)); then
            bal_y=$((nlines-3)); ((bal_dy = -bal_dy))
        else continuer=false
        fi
    fi
}

afficher_tout ()
{
    tput clear
    afficher_aide
    afficher_raquette
    afficher_balle
    if ! $continuer ; then afficher_perdu ; fi
    placer_curseur_en_bas
}

progresser_jeu ()
{
    if $continuer ; then progresser_balle ; fi
    afficher_tout
}

init_jeu
init_balle
trap terminer EXIT
trap progresser_jeu USR1

(
    while true ; do 
        kill -USR1 $$ >/dev/null 2>&1 || exit 0
        sleep 0.05
    done
) &

while read -n 1 -s c ; do
    case "$c" in
        a) deplacer_gauche ;;
        z) deplacer_droite ;;
        n) init_balle ;;
        q) break ;;
    esac
done

exit 0