#!/bin/bash

# Antonio Álvarez Feijoo
#
# Utility to edit the environment variables

script_name="envedit"
#profile=".profile" # login shell?
profile=".bashrc" # non-login shell?
menu_size=10
tmp="/tmp/"
d_main=$tmp"."$$"_main"
d_list=$tmp"."$$"_list"
d_edit=$tmp"."$$"_edit"
d_new=$tmp"."$$"_new"

trap "{ rm -f $d_main $d_list $d_edit $d_new; }" EXIT SIGINT SIGTERM

edit() {
    if [ $1 -eq 1 ]; then
        var=$2
        var_val=""
        backtitle="$script_name - Environment variables editor"
    else
        var=${vars[$2]}
        var_val=${!var}
        backtitle="$script_name - List of environment variables"
    fi

    dialog --title "$"$var \
           --backtitle "$backtitle" \
           --inputbox "Enter its value:" \
           8 100 \
           "$var_val" 2> $d_edit

    ret=$?
    if [ $ret -eq 1 -o $ret -eq 255 ]; then
        return 0
    fi

    new_val=`cat $d_edit`
    export $var="$new_val"

    if [ -e ~/$profile ]; then
        dialog --yesno "Do you want to update your $profile?" \
               0 0

        case $? in
            0)
                sed "/^export\ $var=/d" ~/$profile > $tmp$profile"_tmp"
                mv $tmp$profile"_tmp" ~/$profile

                echo "export $var=\"$new_val\"" >> ~/$profile

                dialog --infobox "$profile updated" \
                       3 20
                sleep 1
                ;;
        esac
    fi
}

list() {
    vars=(`env | cut -d '=' -f 1 | sort`)
    vars_num=${#vars[*]}

    for i in `seq 0 $(($vars_num - 1))`; do
        var=${vars[$i]}
        vars_list=$vars_list$(($i + 1))" "$var" "
    done

    while :; do
        dialog --title "List of environment variables" \
               --backtitle "$script_name - Main menu" \
               --menu "Select one:" \
               17 50 $menu_size \
               $vars_list 2> $d_list

        ret=$?
        if [ $ret -eq 1 -o $ret -eq 255 ]; then
            return 0
        fi

        op=`cat $d_list`
        edit 0 $(($op - 1))
    done
}

new() {
    while :; do
        dialog --title "New environment variable" \
               --backtitle "$script_name - Main menu" \
               --inputbox "Enter its name:" \
               8 30 2> $d_new

        ret=$?
        if [ $ret -eq 1 -o $ret -eq 255 ]; then
            return 0
        fi

        new_var_name=`cat $d_new`
        if [ -z $new_var_name ]; then
            dialog --infobox "The variable must have a name" \
                   3 34
            sleep 1
        else
            edit 1 $new_var_name
            return 0
        fi
    done
}

quit() {
    rm -f $d_main $d_list $d_edit $d_new
    clear
    bash -i # just to preserve exports in this terminal :P
    exit 0
}

main() {
    dialog_installed=`which dialog`
    if [ -z $dialog_installed ]; then
        echo "To be able to execute this script, you have to install 'dialog'"
        if [ -e "/etc/lsb-release" ]; then
            distro=`cat /etc/lsb-release | grep DISTRIB_ID | cut -d '=' -f 2`
            if [ $distro = "Ubuntu" -o $distro = "Debian" ]; then
                echo "Execute: sudo apt-get install dialog"
            fi
        fi
        exit 1
    fi

    while :; do
        dialog --title "Main menu" \
               --backtitle "$script_name - Environment variables editor" \
               --menu "Options:" \
               10 50 3 \
               1 "Show list" \
               2 "Create new" \
               0 "Return to shell" 2> $d_main

        ret=$?
        if [ $ret -eq 1 -o $ret -eq 255 ]; then
            quit
        fi

        op=`cat $d_main`
        case $op in
            1)
                list
                ;;
            2)
                new
                ;;
            0)
                quit
                ;;
        esac
    done
}

main