1from collections import OrderedDict
  2
  3class Tone:
  4    TONES_ORDER = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
  5    TONES_TOTAL = len(TONES_ORDER)
  6
  7    def __init__(self, name):
  8        if name not in Tone.TONES_ORDER:
  9           raise Exception(f'{name} is not a valid tone!')
 10        self.name = name
 11
 12    def __str__(self):
 13        return self.name
 14    
 15    def __eq__(self, other):
 16        if not isinstance(other, Tone):
 17
 18            return False
 19        return self.name == other.name
 20
 21    def __add__(self, other):
 22        if isinstance(other, Tone):
 23            return Chord(self, other)
 24        elif isinstance(other, Interval):
 25            current_tone_idx = Tone.TONES_ORDER.index(self.name)
 26            new_tone_idx = (current_tone_idx + other.num_semitones) % Tone.TONES_TOTAL
 27
 28            new_tone = Tone.TONES_ORDER[new_tone_idx]
 29            return Tone(new_tone)
 30    
 31    def __sub__(self, other):
 32        if isinstance(other, Tone):
 33            self_tone_idx = Tone.TONES_ORDER.index(self.name)
 34            other_tone_idx = Tone.TONES_ORDER.index(other.name)
 35
 36            num_semitones = (self_tone_idx - other_tone_idx) % Tone.TONES_TOTAL
 37            return Interval(num_semitones)
 38        elif isinstance(other, Interval):
 39            return self + (-other)
 40    
 41    def __hash__(self):
 42        return hash(self.name)
 43
 44
 45class Interval:
 46    INTERVAL_NAMES = (
 47            'unison', 'minor 2nd', 'major 2nd', 'minor 3rd', 'major 3rd', 'perfect 4th', 
 48            'diminished 5th', 'perfect 5th', 'minor 6th', 'major 6th', 'minor 7th', 'major 7th'
 49                     )
 50    def __init__(self, num_semitones):
 51        if not isinstance(num_semitones, int):
 52            raise TypeError('Number of semitones must be an integer! :)')
 53        self.num_semitones = num_semitones % Tone.TONES_TOTAL
 54    
 55    def __str__(self):
 56        return Interval.INTERVAL_NAMES[self.num_semitones]
 57    
 58    def __add__(self, other):
 59        if isinstance(other, Interval):
 60            new_interval = self.num_semitones + other.num_semitones
 61            return Interval(new_interval)
 62        raise TypeError ('Invalid operation')
 63
 64    def __sub__(self, other):
 65        if isinstance(other, Tone):
 66            raise TypeError ('Invalid operation')
 67        
 68    def __neg__(self):
 69        return Interval(-self.num_semitones)
 70
 71
 72class Chord:
 73    def __init__(self, *args):
 74        if any(not isinstance(t, Tone) for t in args):
 75            raise TypeError('One or more arguments are not of type Tone!')
 76
 77        ordered_tones_set = OrderedDict.fromkeys(args)
 78
 79        self.distinct_tones = list(ordered_tones_set.keys())
 80
 81        if len(self.distinct_tones) == 1:
 82            raise TypeError("Cannot have a chord made of only 1 unique tone")
 83
 84    def __str__(self):
 85        root_tone = self.distinct_tones[0]
 86        root_tone_idx = Tone.TONES_ORDER.index(root_tone.name)
 87        
 88        final_order_tones = []
 89
 90        for i in range(Tone.TONES_TOTAL):
 91            current_tone_idx = (i + root_tone_idx) % Tone.TONES_TOTAL 
 92            current_tone = Tone.TONES_ORDER[current_tone_idx]
 93            if Tone(current_tone) in self.distinct_tones:
 94                final_order_tones.append(Tone.TONES_ORDER[current_tone_idx])
 95        return '-'.join(final_order_tones)
 96    
 97    def is_minor(self):
 98        root_tone = self.distinct_tones[0]
 99        root_tone_idx = Tone.TONES_ORDER.index(root_tone.name)
100
101        minor_3rd_idx =  (root_tone_idx + 3) % Tone.TONES_TOTAL
102        minor_3rd_tone = Tone(Tone.TONES_ORDER[minor_3rd_idx])
103
104        return minor_3rd_tone in self.distinct_tones
105
106    def is_major(self): 
107        root_tone = self.distinct_tones[0]
108        root_tone_idx = Tone.TONES_ORDER.index(root_tone.name)
109
110        major_3rd_idx =  (root_tone_idx + 4) % Tone.TONES_TOTAL
111        major_3rd_tone = Tone(Tone.TONES_ORDER[major_3rd_idx])
112
113        return major_3rd_tone in self.distinct_tones
114
115    def is_power_chord(self):
116        return not self.is_minor() and not self.is_major()
117    
118    def __add__(self, other):
119        if isinstance(other, Tone):
120            if other in self.distinct_tones:
121                return self 
122            
123            new_distinct_tones = self.distinct_tones[:]
124            new_distinct_tones.append(other)  
125            return Chord(*new_distinct_tones)
126        
127        elif isinstance(other, Chord):
128            combined_tones = self.distinct_tones + other.distinct_tones
129            return Chord(*combined_tones) 
130        
131    def __sub__(self, other):
132        if isinstance(other, Tone):
133            if other not in self.distinct_tones:
134                raise TypeError(f'Cannot remove tone {other.name} from chord {self}')
135            
136            new_distinct_tones = self.distinct_tones[:]
137            new_distinct_tones.remove(other)
138            return Chord(*new_distinct_tones)
139    
140    def transposed(self, interval):
141        if isinstance(interval, Interval):
142            transposed_tones = [tone + interval for tone in self.distinct_tones]
143
144            return Chord(*transposed_tones)
145