#! /bin/bash

set -e

BASE_DIR=$(dirname "$0")
PROG_NAME=$(basename "$0")

difference=12
freq_base=880
freq_var=220
min_diff=1
wave_func=sine

usage() {
    echo 1>&2 "usage: $PROG_NAME [-d <initial difference>] [-b <frequency base>] [-v <frequency variation>] [-m <minimum difference>] [-w <wave function>]"
    exit $1
}

while [[ $# -gt 0 ]]; do
    case "$1" in
        -h) usage 0 ;;
        -d)
            if ! [[ "$2" =~ [1-9][0-9]* ]]; then
                echo 1>&2 "-d option must be followed by a positive integer"
                usage 1
            fi
            shift
            difference=$1
            ;;
        -b)
            if ! [[ "$2" =~ [1-9][0-9]* ]]; then
                echo 1>&2 "-b option must be followed by a positive integer"
                usage 1
            fi
            shift
            freq_base=$1
            ;;
        -v)
            if ! [[ "$2" =~ [1-9][0-9]* ]]; then
                echo 1>&2 "-v option must be followed by a positive integer"
                usage 1
            fi
            shift
            freq_var=$1
            ;;
        -m)
            if ! [[ "$2" =~ [0-9]*(\.[0-9]+)? ]]; then
                echo 1>&2 "-m option must be followed by a non-zero number"
                usage 1
            fi
            shift
            min_diff=$1
            ;;
        -w)
            if ! [[ "$2" =~ sine|square|triangle|sawtooth|point|circle ]]; then
                echo 1>&2 "-w option must be followed by valid wave function"
                usage 1
            fi
            shift
            wave_func=$1
            ;;
        *)
            echo 1>&2 "unrecognized option: '$1'"
            usage 1
            ;;
    esac
    shift
done

playtones() {
    if [[ $answer = y ]]; then
        "$BASE_DIR/playsound" -w $wave_func $high
        "$BASE_DIR/playsound" -w $wave_func $low
    else
        "$BASE_DIR/playsound" -w $wave_func $low
        "$BASE_DIR/playsound" -w $wave_func $high
    fi
}

while true; do
    echo "The current difference is $difference cents"
    low=$(python3 -c "from random import randrange; print($freq_base + randrange($freq_var))")
    high=$(python3 -c "print($low * (2 ** ($difference / 1200)))")
    if [[ $((RANDOM % 2)) = 0 ]]; then
        answer=y
    else
        answer=n
    fi
    playtones
    read -p 'Was the higher note first? (y/n/r) ' response
    while [[ "$response" != y ]] && [[ "$response" != n ]]; do
        if [[ "$response" = r ]]; then
            playtones
        else
            echo "Response must be either 'y', 'n', or 'r' (case sensitive)"
        fi
        read -p 'Was the higher note first? (y/n/r) ' response
    done
    if [[ $response != $answer ]]; then
        echo 'Incorrect.'
        break
    fi
    echo 'Correct!'
    difference=$(python3 -c "print(max($min_diff, round($difference * 0.9, 2)))")
    sleep 1
done