Circle Progression in Music Theory

circle_progression.py

#!/usr/bin/python3

from termcolor import colored
from time import sleep as wait_a_few_seconds_between_chords

scales = {
    "C" : ["C" , "D" , "E" , "F" , "G" , "A" , "B" ],
    "Db": ["Db", "Eb", "F" , "Gb", "Ab", "Bb", "C" ],
    "D" : ["D" , "E" , "Gb", "G" , "A" , "B" , "Db"],
    "Eb": ["Eb", "F" , "G" , "Ab", "Bb", "C" , "D" ],
    "E" : ["E" , "Gb", "Ab", "A" , "B" , "Db", "Eb"],
    "F" : ["F" , "G" , "A" , "Bb", "C" , "D" , "E" ],
    "Gb": ["Gb", "Ab", "Bb", "B" , "Db", "Eb", "F" ],
    "G" : ["G" , "A" , "B" , "C" , "D" , "E" , "Gb"],
    "Ab": ["Ab", "Bb", "C" , "Db", "Eb", "F" , "G" ],
    "A" : ["A" , "B" , "Db", "D" , "E" , "Gb", "Ab"],
    "Bb": ["Bb", "C" , "D" , "Eb", "F" , "G" , "A" ],
    "B" : ["B" , "Db", "Eb", "E" , "Gb", "Ab", "Bb"]
}

circle_progression_roman_numerals = {
    "I"   : 1 , "IV" : 4,
    "viiº": 7 , "iii": 3,
    "vi"  : 6 , "ii" : 2,
    "V"   : 5
}


def append_quality(scale_degree):
    if scale_degree in {1, 4, 5}:
        return " Maj"
    elif scale_degree in {2, 3, 6}:
        return " min"
    else:
        return " dim"


def attribute_color(scale_degree):
    if scale_degree in {1, 4, 5}:
        return "green"
    elif scale_degree in {2, 3, 6}:
        return "blue"
    else:
        return "red"


def main():
    print() # initial separator
    for key in scales:
        print("----------------- Circle Progression in the Key of", key, "-----------------" )
        for chord in circle_progression_roman_numerals:
            print(colored(scales[key][circle_progression_roman_numerals[chord] - 1] +
                        append_quality(circle_progression_roman_numerals[chord]), color=attribute_color(circle_progression_roman_numerals[chord])), end=" | ")
        print(colored(scales[key][circle_progression_roman_numerals["I"] - 1] +
                        append_quality(circle_progression_roman_numerals["I"]), color=attribute_color(circle_progression_roman_numerals["I"])), end=" | \n")
        print() # separator
        wait_a_few_seconds_between_chords(5)


if __name__ == "__main__":
    main()