#!/usr/bin/env bash

# Color definitions
# RED
# BLUE
# GREEN
# YELLOW

get_term_size() {
    # POSIX alternative to 'checkwinsize'.
    read -r LINES COLUMNS < <(stty size)
}

display() {
    # Hides the cursor.
    printf '\e[?25l'
    # Clear the screen.
    printf '\e[2J'
    # Move the cursor to the center.
    get_term_size
    ((l=$LINES/2))
    ((c=$COLUMNS/2))
    printf '\e[%s;%sH' "$l" "$c"
    while IFS= read -r line; do
        # Print the contents of the slide file, line by line.
        printf '%s' "$line"
        # Move one row down after each print.
        printf '\e[B'
    done <<< "$1"
    # Change slide on space.
    read -rsn1 input
    [[ "$input" = " " ]] && 
        continue
}

main() {
    slide_dir="$1"
    for f in $slide_dir/*.txt; do
        f_contents="$(<$f)"
        display "$f_contents"
    done
    # Return the cursor.
    printf '\e[?25h'
}

main "$@"