# utils/tokenizer.py

class CharTokenizer:
    def __init__(self):
        self.chars = set()
        self.char2idx = {}
        self.idx2char = {}

    def fit(self, texts):
        for text in texts:
            self.chars.update(set(text))
        self.chars = sorted(list(self.chars))
        self.char2idx = {char: idx for idx, char in enumerate(self.chars)}
        self.idx2char = {idx: char for char, idx in self.char2idx.items()}

    def encode(self, text, max_length=None):
        encoded = [self.char2idx[char] for char in text if char in self.char2idx]
        if max_length:
            encoded = encoded[:max_length] + [0] * (max_length - len(encoded))
        return encoded

    def decode(self, tokens):
        return ''.join([self.idx2char[token] for token in tokens if token in self.idx2char])