bashtutor_helper

#!/bin/bash

function bashtutor_greet() {
    echo -n -e "\033[32m"
    echo "Welcome! You are running bashtutor ${BASHTUTOR_VERSION}."
    echo "The currently loaded module is '$1' with ${#BASHTUTOR_TASK_FILE_LIST[@]} tasks."
    echo "You may run 'task' or 'hint' anytime to display" \
         "the current task again or a help message respectably." 
    echo -e "\033[0m"
}

function bashtutor_completed() {
    echo -n -e "\033[32m"
    echo "Module completed. Thanks for flying bashtutor!"
    echo -n -e "\033[0m"
    exit
}

function bashtutor_wrap() {
    source $BASHTUTOR_MODULE_DIRNAME/${BASHTUTOR_TASK_FILE_LIST[$BASHTUTOR_PROGRESS]}

    $@
    r=$?

    unset description
    unset hint
    unset validate

    return $r
}

if [ $# -ne 0 ]; then # Initial call
    set -o errexit
        if [ -d "$1" ]
            then BASHTUTOR_TASK_FILE_LIST_FILE="$1/task_list.sh"
            else BASHTUTOR_TASK_FILE_LIST_FILE="$1"
        fi

        declare -a BASHTUTOR_TASK_FILE_LIST
        source "$BASHTUTOR_TASK_FILE_LIST_FILE" ||
            (echo "'$BASHTUTOR_TASK_FILE_LIST' does not seem like a module. Exiting..." && exit 1)
        ! [ -v BASHTUTOR_TASK_FILE_LIST ] &&
            echo "Module sourced, but no tasks were specified. Exiting..." &&
            exit 1
        BASHTUTOR_MODULE_DIRNAME=$(realpath "$(dirname "$BASHTUTOR_TASK_FILE_LIST_FILE")")

        BASHTUTOR_TMPDIR=$(mktemp -d)
        cp bashtutor_helper ${BASHTUTOR_TMPDIR}
        cd ${BASHTUTOR_TMPDIR}

        alias task='bashtutor_wrap description'
        alias hint='bashtutor_wrap hint'

        BASHTUTOR_PROGRESS=0
        BASHTUTOR_PS1='(bashtutor) $ '
        PS1=$BASHTUTOR_PS1
        PROMPT_COMMAND=()
        PROMPT_COMMAND="BASHTUTOR_R=\$?; source ${PWD}/bashtutor_helper"
        IGNOREEOF=3 # We dont want the user to be able to quit by mistake
        BASHTUTOR_VERSION="v1.2"

        NORMAL="\033[0m"
        BOLD="\033[1m"
        ITALICS="\033[3m"
        RED="\033[31m"
        GREEN="\033[32m"
        YELLOW="\033[33m"
        BLUE="\033[34m"
        MAGENTA="\033[35m"
        CYAN="\033[36m"

        bashtutor_greet $1

        bashtutor_wrap description
    set +o errexit
else # Event callback
    LAST_CMD="$(history | tail -n 1 | cut -c 8-)"

    bashtutor_wrap validate $LAST_CMD
    if [ $? == 1 ]; then
        BASHTUTOR_PROGRESS=$(expr $BASHTUTOR_PROGRESS + 1)

        [ -z "${BASHTUTOR_TASK_FILE_LIST[$BASHTUTOR_PROGRESS]}" ] && bashtutor_completed

        echo ""
        echo -e "${GREEN}($((${BASHTUTOR_PROGRESS}))/$((${#BASHTUTOR_TASK_FILE_LIST[@]})))${NORMAL}"
        echo ""
        task
    fi
fi