import numpy as np
import matplotlib.pyplot as plt

notes = ["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"]

keys = {f"{notes[i % 12]}{int(i / 12)}": 440 * pow(2, (1 / 12) * (i - 57))
        for i in range(9, 8 * 12 + 1)}

h_freq = 3579545

print(keys)

def note_error(note_freq: float):
    x = round(h_freq / note_freq)
    real_freq = h_freq / x
    error_in_cent = np.log2(real_freq / note_freq) * 1200
    return error_in_cent

errors = {key_name: note_error(freq) for (key_name, freq) in keys.items()}

print(errors)

plt.figure(figsize=(18, 6))
plt.xticks(rotation=90)
plt.xlabel("key")
plt.ylabel("error in cents")
plt.plot(list(errors.keys()), list(errors.values()),
         marker='o', linestyle="dotted")
plt.axhline(y=0.2, color='red', linestyle="dashed")
plt.axhline(y=-0.2, color='red', linestyle="dashed")
plt.show()