import torch

END_CHAR = '|'
all_letters = 'abcdefghijklmnopqrstuvwxyz ' + END_CHAR
NUM_LETTERS = len(all_letters)

def letter_to_index(letter):
    return all_letters.index(letter)

def letter_to_tensor(letter):
    idx = letter_to_index(letter)
    one_hot = torch.zeros((1, NUM_LETTERS))
    one_hot[0, idx] = 1
    return one_hot 

def name_to_tensor(name):
    letter_tensors = []
    for letter in name:
        letter_tensors.append(letter_to_tensor(letter))
    return torch.stack(letter_tensors)

# chi -> hi|
# woo -> oo|
def shift_name_right(name):
    return name[1:] + END_CHAR