#!/usr/bin/env bash
#==============================================================#
#
# AUTHOR:
#     Bryan Jenks
#         - www.bryanjenks.xyz
#         - https://github.com/tallguyjenks/flash.sh
#
# SOURCE:
#     This file is based off of the one presented in this YouTube Video by nixcasts:
#         - https://www.youtube.com/watch?v=lX8jqo70r1I
#
# PURPOSE:
#     To have a command line flash card tool with minimal code, plain text input and output
#
# VISION:
#     The goal i have for this script is a basic level emulation of ANKI to where i have a way to
#     keep track of a score for each item in each selected deck so that it can pick from a selection
#     of the lowest scoring items and shuf them to the user for reenforcement of active recall.
#
# DEPENDENCIES:
#     fzf - https://github.com/junegunn/fzf
#     bat - https://github.com/sharkdp/bat
#==============================================================#
PWD="$(pwd)" # Remember User's Starting Directory
DIR="$HOME/.local/share/flash" # Where Decks Are Located
EXAMPLE_DECK="$HOME/.local/share/flash/deck.csv"
COUNTER=0
DIR_MADE_MSG="
Your '~/.local/share/flash' directory has been made and
your 'deck.csv' file is ready for you to enter your flashcard data
"
NO_DECKS="
No decks were found, please make a new deck
using ':' as a delimiter in a '.csv' file in
the '.local/share/flash' directory.

An example of a card:
'Math:What is the square root of 4?:2:0'
"
DECK_TEMPLATE="History:When was the declaration of independence signed?:1776:0
Math:What is the square root of 4?:2:4
Science:What is the charge of a proton?:Positive:2
Philosophy:What was socrates known as?:The Gadfly of Athens:0
Programming:What is the typical starting value of an array?:0:5
History:What did Abraham Lincoln Typically Keep In his hat?:Mail:0
Math:what is the first 2 decimal places of PI:3.14:4
Science:What is the charge of an electron?:Negative:3
Programming:What does OOP stand for?:Object Oriented Programming:2
History:What did socrates drink to commit suicide?:Hemlock Tea:2
Math:What is the equation for a slope of a line?:y=mx+b:4
Science:What is the charge of a neutron?:Neutral:1
Programming:What is Vim?:God's Text Editor:999
History:What were the british known buy during the american revolution?:The redcoats:1
Math:What is the value of this equation - log10(100)?:2:0
Science:What are protons/neutrons/electrons made of?:quarks:5
Programming:What does RAM stand for?:Random Access Memory:1
History:What was the year 2000 also known as?:Y2K:0
Math:What is the formula for mean?:Sum/count:4
Science:What is cold?:The absense of heat:3
Programming:What languages are the worst?:Proprietary:999
History:When did man land on the moon?:1969:4
Math:10^3=?:1000:1
Science:The _____ ______ Project mapped all of man's genes.:Human Genome:3
Programming:What is the best computer to program on?:Thinkpad:999
History:When was flash.sh created?:April 2020:999
Math:What do you call a number only divisible by itself and 1?:Prime:0
Science:What is the distance between the Earth and Sol called?:An Astronomical Unit (AU):1
Programming:Best operating system?:Arch, because BTW i run Arch:999
"

if [ ! -d $DIR ];then # If Directory does NOT exist
    echo "No '.local/share/flash' directory, make it? y/n"
    read RESPONSE
        case "$RESPONSE" in
            [Nn]) exit ;;
            [Qq]) exit ;;
            [Yy]) mkdir "$DIR" && touch $EXAMPLE_DECK && echo "$DECK_TEMPLATE" >> $EXAMPLE_DECK && echo "$DIR_MADE_MSG" ;;
            *) echo "invalid choice, please select either 'y' or 'n'" ;;
        esac
fi

cd "$DIR"

if [ "$(find -maxdepth 999 -iname "*.csv" | wc -l)" = 0 ]; then # If there are no flashcard decks available
    echo "$NO_DECKS" && cd "$PWD" && exit
fi

# Show pretty FZF preview of decks using BAT
DECK="$(find -maxdepth 999 -iname "*.csv" | fzf --preview='bat --theme="Solarized (dark)" --style=numbers --color=always {} | head -500')"

main(){
    IFS=$':'; read -a q <<<$(sort "$DECK" -n --field-separator=: --key=4 | head | shuf -n 1)
    clear
    echo "===================================================="
    echo "Cards Reviewed: $COUNTER"
    echo "Category: ${q[0]}"
    echo "Question: ${q[1]}"
    echo ''
    read -sn 1 NEXT
    if [ "$NEXT" = q ]; then
        cd "$PWD" && exit
    fi
    echo "Answer: ${q[2]}"
    echo ''
    echo "===================================================="
    echo ''
    echo "How Difficult Was This Question?"
    echo ''
    echo "Hard [1]   Difficult [2]   Normal [3]   Mild [4]   Easy [5]"
    echo ''
    read -sn 1 DIFFICULTY_SCORE
    clear

    COUNTER="$(($COUNTER+1))" # Increment count for above test and card review count increment

    if [ "${q[3]}" = 0 ]; then
        NEW_ITEM_SCORE=0
        case "$DIFFICULTY_SCORE" in
            [123]) NEW_ITEM_SCORE=0 ;;#HARD DIFFICULTY & NORMAL
            4) NEW_ITEM_SCORE=1 ;;#MILD
            5) NEW_ITEM_SCORE=2 ;;#EASY
            *) NEW_ITEM_SCORE=0 ;;#INVALID
        esac

    elif [ "${q[3]}" = 1 ]; then
        case "$DIFFICULTY_SCORE" in
            1) NEW_ITEM_SCORE=0 ;;#HARD
            2) NEW_ITEM_SCORE=0 ;;#DIFFICULT
            3) NEW_ITEM_SCORE=1 ;;#NORMAL
            4) NEW_ITEM_SCORE=2 ;;#MILD
            5) NEW_ITEM_SCORE=3 ;;#EASY
            *) NEW_ITEM_SCORE=1 ;;#INVALID
        esac
    else
        case "$DIFFICULTY_SCORE" in
            1) NEW_ITEM_SCORE="$((${q[3]}-2))" ;;#HARD
            2) NEW_ITEM_SCORE="$((${q[3]}-1))" ;;#DIFFICULTY
            3) NEW_ITEM_SCORE="${q[3]}" ;;#NORMAL
            4) NEW_ITEM_SCORE="$((${q[3]}+1))" ;;#MILD
            5) NEW_ITEM_SCORE="$((${q[3]}+2))" ;;#EASY
            *) NEW_ITEM_SCORE="${q[3]}" ;;#INVALID
        esac
    fi

    # Update item score for each flashcard item
    sed -i "s/${q[0]}:${q[1]}:${q[2]}:${q[3]}/${q[0]}:${q[1]}:${q[2]}:$NEW_ITEM_SCORE/g" "$DECK"
}

while true; do
        main
done