music_helper.py

import math

def letter_note_as_number(letter):
    if letter == 'C':
        number = 0
    if letter == 'C#':
        number = 1
    if letter == 'D':
        number = 2
    if letter == 'D#':
        number = 3
    if letter == 'E':
        number = 4
    if letter == 'F':
        number = 5
    if letter == 'F#':
        number = 6
    if letter == 'G':
        number = 7
    if letter == 'G#':
        number = 8
    if letter == 'A':
        number = 9
    if letter == 'A#':
        number = 10
    if letter == 'B':
        number = 11
    return number

def get_scale_from_root(root, scale_type):
    steps = []
    scale_type = scale_type.upper()
    if scale_type == 'AEOLIAN':
       steps = [0, 2, 3, 5, 7, 8, 10] 
    if scale_type == 'BLUES':
       steps = [0, 2, 3, 4, 5, 7, 9, 10, 11] 
    if scale_type == 'CHROMATIC':
       steps = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]  
    if scale_type == 'DIATONIC_MINOR':
       steps = [0, 2, 3, 5, 7, 8, 10]  
    if scale_type == 'DORIAN':
       steps = [0, 2, 3, 5, 7, 9, 10]   
    if scale_type == 'HARMONIC_MINOR':
       steps = [0, 2, 3, 5, 7, 8, 11]  
    if scale_type == 'INDIAN':#since we get rid of any repeated value, we lose one of the INDIAN 1s. 
       steps = [0, 1, 1, 4, 5, 8, 10]
    if scale_type == 'LOCRIAN':
       steps = [0, 1, 3, 5, 6, 8, 10]
    if scale_type == 'LYDIAN':
       steps = [0, 2, 4, 6, 7, 9, 10]
    if scale_type == 'MAJOR':
       steps = [0, 2, 4, 5, 7, 9, 11]
    if scale_type == 'MELODIC_MINOR':
       steps = [0, 2, 3, 5, 7, 8, 9, 10, 11]
    if scale_type == 'MINOR':
       steps = [0, 2, 3, 5, 7, 8, 10]
    if scale_type == 'MIXOLYDIAN':
       steps = [0, 2, 4, 5, 7, 9, 10]
    if scale_type == 'NATURAL_MINOR':
       steps = [0, 2, 3, 5, 7, 8, 10] 
    if scale_type == 'PENTATONIC':
       steps = [0, 2, 4, 7, 9] 
    if scale_type == 'PHRYGIAN':
       steps = [0, 1, 3, 5, 7, 8, 10]  
    if scale_type == 'TURKISH':
       steps = [0, 1, 3, 5, 7, 10, 11]
    scale = []
    for s in steps:
        scale.append(root+s)
    scale.append(root+12)
    #print(scale)
    #print(steps)
    return scale  

def get_notes_in_scale(letter,octave,scale_type,chord_type):
    notes = []
    if octave == 'all':
      root = letter_note_as_number(letter)
      for i in range (0,9):
        notes.extend(get_scale_from_root(root+(i*12), scale_type))
    else:
      for c in octave:
        root = (c+1)*12+letter_note_as_number(letter)
        notes.extend(get_scale_from_root(root, scale_type))
    #print(get_scale_from_root(root, scale_type))
    notes = list(set(notes))
    notes = sorted(notes)
    return notes