1class Tone:
  2
  3    TONES = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"]
  4    TONES_COUNT = len(TONES)
  5
  6    def __init__(self, name):
  7        self.name = name
  8        self.position = self.TONES.index(self.name)
  9
 10    def __eq__(self, other):
 11        return self.name == other.name
 12
 13    def __str__(self):
 14        return self.name
 15
 16    def __add__(self, other):
 17        if isinstance(other, Tone):
 18            return Chord(self, other)
 19        elif isinstance(other, Interval):
 20            result_tone_position = (self.position + other.number_of_semitones) % self.TONES_COUNT
 21            return Tone(self.TONES[result_tone_position])
 22
 23    def __sub__(self, other):
 24        if isinstance(other, Tone):
 25            return Interval(self.position - other.position)
 26        elif isinstance(other, Interval):
 27            result_tone_position = (self.position - other.number_of_semitones) % self.TONES_COUNT
 28            return Tone(self.TONES[result_tone_position])
 29
 30
 31class Interval:
 32
 33    POSSIBLE_INTERVALS = ["unison", "minor 2nd", "major 2nd",
 34         "minor 3rd", "major 3rd", "perfect 4th", "diminished 5th",
 35         "perfect 5th", "minor 6th", "major 6th", "minor 7th", "major 7th"
 36    ]
 37    INTERVALS_COUNT = len(POSSIBLE_INTERVALS)
 38
 39    def __init__(self, number_of_semitones):
 40        self.number_of_semitones = number_of_semitones % self.INTERVALS_COUNT
 41
 42    def __str__(self):
 43        return self.POSSIBLE_INTERVALS[self.number_of_semitones]
 44
 45    def __add__(self, other):
 46        if isinstance(other, Interval):
 47            return Interval(self.number_of_semitones + other.number_of_semitones)
 48        elif isinstance(other, Tone):
 49            raise TypeError("Invalid operation")
 50
 51    def __sub__(self, other):
 52        if isinstance(other, Tone):
 53            raise TypeError("Invalid operation")
 54
 55    def __neg__(self):
 56        return Interval(-self.number_of_semitones)
 57
 58
 59class Chord:
 60
 61    def __init__(self, root_tone, *args):
 62        self.tones = [root_tone]
 63        for tone in args:
 64            if tone.name not in [t.name for t in self.tones]:
 65                self.tones.append(tone)
 66        if len(self.tones) < 2:
 67            raise TypeError("Cannot have a chord made of only 1 unique tone")
 68
 69    def position_of_tone(self, tone):
 70        return (tone.position - self.tones[0].position) % Tone.TONES_COUNT
 71
 72    def __str__(self):
 73        sorted_tones = sorted(self.tones, key = lambda t: self.position_of_tone(t))
 74        return '-'.join(str(tone) for tone in sorted_tones)
 75
 76    def __add__(self, other):
 77        if isinstance(other, Tone):
 78            return Chord(*self.tones, other)
 79        if isinstance(other, Chord):
 80            return Chord(*self.tones, *other.tones)
 81
 82    def __sub__(self, other):
 83        """В тази функция приемам, че при премахване на root акорда, root става следващия акорд
 84        по реда на подаване в конструктора, а не следващия акорд спрямо "сортирания" вид."""
 85        if isinstance(other, Tone):
 86            if other not in self.tones:
 87                raise TypeError(f"Cannot remove tone {other.name} from chord {self}")
 88            if len(self.tones) <= 2:
 89                raise TypeError("Cannot have a chord made of only 1 unique tone")
 90            new_tones = [tone for tone in self.tones if tone != other]
 91            return Chord(*new_tones)
 92
 93    def is_minor(self):
 94        root_tone = self.tones[0]
 95        for tone in self.tones[1:]:
 96            if (tone.position - root_tone.position) % Tone.TONES_COUNT == 3:
 97                return True
 98        return False
 99
100    def is_major(self):
101        root_tone = self.tones[0]
102        for tone in self.tones[1:]:
103            if (tone.position - root_tone.position) % Tone.TONES_COUNT == 4:
104                return True
105        return False
106
107    def is_power_chord(self):
108        return not (self.is_minor() or self.is_major())
109
110    def transposed(self, interval):
111        transpose_by = interval.number_of_semitones
112        new_tones = []
113        for tone in self.tones:
114            if transpose_by >= 0:
115                new_tones.append(tone + interval)
116            else:
117                new_tones.append(tone + (-interval))
118        return Chord(*new_tones)