chatbotTrainer.py

import os
import re
import numpy as np
import tensorflow
from keras.callbacks import Callback, ReduceLROnPlateau
from tensorflow.keras.preprocessing.text import Tokenizer
from tensorflow.keras.preprocessing.sequence import pad_sequences
from tensorflow.keras.layers import Input, LSTM, Dense, Embedding, Dropout, Flatten
from tensorflow.keras.regularizers import l2
from tensorflow.keras.models import Model, load_model, model_from_json
from tensorflow.keras.optimizers import Adam
import matplotlib.pyplot as plt
import logging
import heapq
import pickle
import time
import json
import pdb

tensorflow.keras.mixed_precision.set_global_policy('mixed_float16')


class BeamSearchHelper:
    def __init__(self, model, tokenizer, max_seq_length, encoder_filename, decoder_filename, top_k=5,

                 temperature=1.0, top_p=0.9, beam_width=3, scaling_factor=10, min_word=3):
        self.model = model
        self.tokenizer = tokenizer
        self.max_seq_length = max_seq_length
        self.top_k = top_k
        self.encoder_filename = encoder_filename
        self.decoder_filename = decoder_filename
        self.temperature = temperature
        self.scaling_factor = scaling_factor
        self.top_p = top_p
        self.beam_width = beam_width
        self.min_word = min_word
        self.logger = self.setup_logger()

    def setup_logger(self):
        logger = logging.getLogger("ChatbotBeamSearch")
        logger.setLevel(logging.DEBUG)
        console_handler = logging.StreamHandler()
        console_handler.setLevel(logging.INFO)
        console_formatter = logging.Formatter('%(levelname)s: %(message)s')
        console_handler.setFormatter(console_formatter)
        logger.addHandler(console_handler)
        file_handler = logging.FileHandler("chatbotBeam.log")
        file_handler.setLevel(logging.DEBUG)
        file_formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
        file_handler.setFormatter(file_formatter)
        logger.addHandler(file_handler)
        return logger

    def beam_search(self, input_text):
        # Load encoder and decoder models
        encoder_model = load_model(self.encoder_filename)
        decoder_model = load_model(self.decoder_filename)

        # Preprocess input
        input_seqs = self.tokenizer.texts_to_sequences([input_text])
        input_seqs = pad_sequences(input_seqs, maxlen=self.max_seq_length, padding='post')

        # Encode input sequence
        encoder_states = encoder_model.predict(input_seqs)
        state_h, state_c = encoder_states

        # Ensure batch size of 1
        state_h = state_h[0:1, :]
        state_c = state_c[0:1, :]

        # Initialize decoder with <start> token
        start_token_index = self.tokenizer.word_index.get('<start>', 1)
        target_seq = np.zeros((1, 1))
        target_seq[0, 0] = start_token_index

        # Initialize beam search candidates
        sequences = [(target_seq, state_h, state_c, 0.0, [])]  # (seq, h, c, score, decoded_words)

        for _ in range(self.max_seq_length):
            all_candidates = []

            for seq, state_h, state_c, score, decoded_words in sequences:
                # Predict the next token
                output_tokens, state_h, state_c = decoder_model.predict([seq, state_h, state_c])

                logits = output_tokens[0, -1, :] * self.scaling_factor
                logits = logits / self.temperature
                exp_logits = np.exp(logits - np.max(logits))  # Prevent overflow
                probabilities = exp_logits / np.sum(exp_logits)

                # Get the top beam_width candidate indices
                top_indices = np.argsort(probabilities)[-self.beam_width:]

                for idx in top_indices:
                    prob = probabilities[idx]
                    candidate_score = (score - np.log(prob + 1e-8)) / (len(decoded_words) + 1)  # Normalize by length

                    # Append predicted token
                    new_decoded_words = decoded_words + [idx]
                    new_seq = np.copy(seq)
                    new_seq[0, 0] = idx  # Set new token in sequence

                    # Enforce min_word before stopping at <end>
                    if idx == self.tokenizer.word_index.get('<end>', -1):
                        if len(new_decoded_words) < self.min_word:
                            continue  # Ignore <end> if min_word isn't reached
                        else:
                            return " ".join(self.tokenizer.index_word[i] for i in new_decoded_words if i in self.tokenizer.index_word)

                    # Add to candidate list
                    all_candidates.append((new_seq, state_h, state_c, candidate_score, new_decoded_words))

            # Select best beam_width sequences
            if not all_candidates:  # If no valid candidates, exit early
                break

            sequences = sorted(all_candidates, key=lambda x: x[3])[:self.beam_width]

        # Convert token indices back to words
        best_sequence = sequences[0][4]  # Get best decoded words
        return " ".join(self.tokenizer.index_word[idx] for idx in best_sequence if idx in self.tokenizer.index_word)

class BeamState:
    def __init__(self, sequence, score, state, logger):
        self.sequence = sequence
        self.score = score
        self.state = state
        self.logger = logger

    def __lt__(self, other):
        return self.score < other.score

    def log(self, message):
        self.logger.debug(message)



class MonitorEarlyStopping(Callback):
    def __init__(self, monitor='val_loss', patience=3, mode='min', restore_best_weights=True, verbose=1):
        super(MonitorEarlyStopping, self).__init__()
        self.monitor = monitor
        self.patience = patience
        self.mode = mode
        self.restore_best_weights = restore_best_weights
        self.verbose = verbose
        self.best_weights = None
        self.best_epoch = None
        self.wait = 0
        self.best_value = float('inf') if mode == 'min' else -float('inf')
        self.stopped_epoch_list = []  # List to track stopped epochs

    def on_epoch_end(self, epoch, logs=None):
        current_value = logs.get(self.monitor)
        if current_value is None:
            if self.verbose > 0:
                print(f"Warning: Metric '{self.monitor}' is not available in logs.")
            return

        # Check for improvement based on mode
        if (self.mode == 'min' and current_value < self.best_value) or (self.mode == 'max' and current_value > self.best_value):
            self.best_value = current_value
            self.best_weights = self.model.get_weights()
            self.best_epoch = epoch
            self.wait = 0
            if self.verbose > 0:
                print(f"Epoch {epoch + 1}: {self.monitor} improved to {self.best_value:.4f}")
        else:
            self.wait += 1
            if self.verbose > 0:
                print(f"Epoch {epoch + 1}: {self.monitor} did not improve. Patience: {self.wait}/{self.patience}")
                self.stopped_epoch_list.append(epoch + 1)

            # Stop training if patience is exceeded
            if self.wait >= self.patience:
                if self.verbose > 0:
                    print(f"Stopping early at epoch {epoch + 1}. Best {self.monitor}: {self.best_value:.4f} at epoch {self.best_epoch + 1}")
                self.model.stop_training = True
                if self.restore_best_weights:
                    if self.verbose > 0:
                        print(f"Restoring best model weights from epoch {self.best_epoch + 1}.")
                    self.model.set_weights(self.best_weights)


class ChatbotTrainer:
    def __init__(self):
        # Corpus Setup
        self.corpus = None
        self.all_vocab_size = 0

        # Model Setup
        self.model = None
        self.name = "Alex"
        self.model_filename = f"{self.name}_model.keras"
        self. encoder_filename = "encoder.keras"
        self.decoder_filename = "decoder.keras"
        self.tokenizer_save_path = "chatBotTokenizer.pkl"
        self.tokenizer = None
        self.reverse_tokenizer = None
        self.embedding_dim = 64
        self.max_seq_length = 64
        self.learning_rate = 0.0013
        self.optimizer = Adam(learning_rate=self.learning_rate, clipnorm=1.0)
        self.batch_size = 16
        self.epochs = 30
        self.early_patience = self.epochs // 2
        self.lstm_units = 128
        self.dropout = 0.1
        self.recurrent_dropout = 0.1
        self.test_size = 0.2
        self.max_vocabulary = 69000

        # Model but instantiated here but filled later
        self.encoder_model = None
        self.encoder_inputs = None
        self.decoder_inputs = None
        self.decoder_outputs = None
        self.decoder_model = None
        self.max_vocab_size = None
        self.config = None

        # Training Setup
        self.vocabularyList = []
        self.troubleList = []
        self.running_trouble = []

        # Prediction Setup (Everything here will take priority)
        self.min_word = 10      # Only for generate_response
        self.temperature = 1
        self.scaling_factor = 1
        self.logger = self.setup_logger()  # Initialize your logger here
        self.beam_width = 9
        self.top_p = 0.7
        self.top_k = 3

        # Log Metrics...
        self.logger.info(f"""Metrics:\n

            Embedding/MaxSeqLength:({self.embedding_dim}, {self.max_seq_length})\n

            Batch Size: {self.batch_size}\n

            LSTM Units: {self.lstm_units}\n

            Epochs: {self.epochs}\n

            Dropout: ({self.dropout}, {self.recurrent_dropout})\n

            Test Split: {self.test_size}\n\n""")

       # Tokenizer setup & propagation
        if os.path.exists(self.tokenizer_save_path):
            with open(self.tokenizer_save_path, 'rb') as tokenizer_load_file:
                self.tokenizer = pickle.load(tokenizer_load_file)
                self.reverse_tokenizer = {index: word for word, index in self.tokenizer.word_index.items()}
                self.all_vocab_size = self.tokenizer.num_words
                for words, i in self.tokenizer.word_index.items():
                    if words not in self.vocabularyList:
                        self.vocabularyList.append(words)
                self.logger.info("Tokenizer loaded successfully.")
                # print(f"Number of words in loaded tokenizer: {len(self.tokenizer.word_index)}")
                # print(f"Number of words in the Vocab List: {len(self.vocabularyList)}")
        else:
            self.logger.warning("Tokenizer not found, making now...  ")
            self.tokenizer = Tokenizer(num_words=None, filters='!"#$%&()*+,-/.:;=?@[\\]^_`{|}~\t\n')

            # Save '<OOV>', '<start>', and '<end>' to word index
            self.tokenizer.num_words = 0
            self.vocabularyList = ['<start>', '<end>']
            for token in self.vocabularyList:
                if token not in self.tokenizer.word_index:
                    self.tokenizer.word_index[token] = self.tokenizer.num_words
                    self.tokenizer.index_word[self.tokenizer.num_words] = token
                    self.all_vocab_size += 1
                    self.tokenizer.num_words += 1

            # Set Tokenizer Values:
            self.tokenizer.num_words = len(self.tokenizer.word_index)
            self.tokenizer.oov_token = "<oov>"

            self.logger.info(f"New Tokenizer Index's:  {self.tokenizer.word_index}")

            # Debug Lines
            # for token in ['<start>', '<end>', '<oov>']:
            #     print(f"Index of {token}: {self.tokenizer.word_index.get(token)}")

        # Debug Line
        # print(list(self.tokenizer.word_index.keys()))

        if os.path.exists(self.model_filename) and os.path.exists(self.encoder_filename) and os.path.exists(self.decoder_filename):
            self.model, self.encoder_model, self.decoder_model =self.load_model_file()

    def save_full_weights(self, encoder_path="encoder.weights.h5", decoder_path="decoder.weights.h5"):
        if self.encoder_model is not None and self.decoder_model is not None:
            if os.path.exists(encoder_path):
                os.remove(encoder_path)
            if os.path.exists(decoder_path):
                os.remove(decoder_path)
            self.encoder_model.save_weights(encoder_path)
            self.decoder_model.save_weights(decoder_path)
            self.logger.info(f"Encoder weights saved at {encoder_path}.")
            self.logger.info(f"Decoder weights saved at {decoder_path}.")
        else:
            self.logger.warning(
                "Encoder or Decoder model does not exist. Ensure models are initialized before saving weights.")


    def load_corpus(self, corpus_path):
        import convokit
        self.logger.info("Loading and preprocessing corpus...")
        self.corpus = convokit.Corpus(filename=corpus_path)
        self.logger.info("Corpus loaded and preprocessed successfully.")

    def load_full_weights(self, encoder_path="encoder.weights.h5", decoder_path="decoder.weights.h5"):
        if self.encoder_model is not None and self.decoder_model is not None:
            self.encoder_model.load_weights(encoder_path)
            self.decoder_model.load_weights(decoder_path)
            self.logger.info(f"Encoder weights loaded from {encoder_path}.")
            self.logger.info(f"Decoder weights loaded from {decoder_path}.")
        else:
            self.logger.warning(
                "Encoder or Decoder model does not exist. Ensure models are initialized before loading weights.")

    def plot_and_save_training_metrics(self, history, speaker):
        # Plot training metrics such as loss and accuracy
        plt.figure(figsize=(10, 6))

        # Plot training loss
        plt.subplot(1, 2, 1)
        plt.plot(history.history['loss'], label='Training Loss')
        plt.plot(history.history['val_loss'], label='Validation Loss')
        plt.title('Training and Validation Loss')
        plt.xlabel('Epoch')
        plt.ylabel('Loss')
        plt.legend()

        # Plot training accuracy
        plt.subplot(1, 2, 2)
        plt.plot(history.history['accuracy'], label='Training Accuracy')
        plt.plot(history.history['val_accuracy'], label='Validation Accuracy')
        plt.title('Training and Validation Accuracy')
        plt.xlabel('Epoch')
        plt.ylabel('Accuracy')
        plt.legend()

        # Save the plot as an image file
        # plot_filename = f"{speaker}_training_metrics.png"
        # plt.tight_layout()
        # plt.savefig(plot_filename)  # Save the plot as an image
        # plt.close()  # Close the plot to free up memory

        return "Did Not Save in Jupyter Notebook. See plot_and_save_training_metrics"


    def setup_logger(self):
        logger = logging.getLogger("ChatbotTrainer")
        logger.setLevel(logging.DEBUG)

        # Create console handler and set level to INFO for progress reports
        console_handler = logging.StreamHandler()
        console_handler.setLevel(logging.INFO)
        console_formatter = logging.Formatter('%(levelname)s: %(message)s')
        console_handler.setFormatter(console_formatter)
        logger.addHandler(console_handler)

        # Create a file handler and set level to DEBUG for progress reports and ERROR for error notifications
        file_handler = logging.FileHandler("chatbot.log")
        file_handler.setLevel(logging.DEBUG)  # Set level to DEBUG to capture progress reports
        file_formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
        file_handler.setFormatter(file_formatter)
        logger.addHandler(file_handler)

        return logger

    # This function allows to reformat the embedding weights to a new max_vocabulary
    # If max_vocabulary(defined in build_model) is changed incrementally (or set large to begin with; this is N/A)
    def redo_embeddings(self):
        # Get current embedding weights
        old_embedding_weights = self.model.get_layer("embedding").get_weights()[0]

        # Define new max vocabulary size
        new_vocab_size = self.max_vocabulary  # Set this to the updated size
        embedding_dim = old_embedding_weights.shape[1]

        # Expand the embedding matrix
        new_embedding_weights = np.random.normal(size=(new_vocab_size, embedding_dim))  # Initialize new words randomly
        new_embedding_weights[:old_embedding_weights.shape[0], :] = old_embedding_weights  # Keep old weights

        # Replace the embedding layer
        self.model.get_layer("embedding").set_weights([new_embedding_weights])

    def save_tokenizer(self, texts=None):
        if self.tokenizer:
            if texts:
                for token in texts:
                    if token not in self.tokenizer.word_index and self.tokenizer.num_words < self.max_vocabulary:
                        self.tokenizer.word_index[token] = self.tokenizer.num_words
                        self.all_vocab_size += 1
                        self.tokenizer.num_words += 1
                        # Debug Line
                        # print(f"Word: {token}\nIndex: {self.tokenizer.num_words}")
                        self.max_vocab_size = self.tokenizer.num_words

                self.tokenizer.fit_on_texts(texts)

            with open(self.tokenizer_save_path, 'wb') as tokenizer_save_file:
                pickle.dump(self.tokenizer, tokenizer_save_file)

            self.tokenizer.num_words = len(self.tokenizer.word_index)

        elif self.tokenizer == None:
            self.logger.warning("No tokenizer to save.")

    def save_embedding_weights(self, filepath="embedding_weights.npy"):
        if self.model is not None:
            embedding_layer = self.model.get_layer('embedding')

            # Extract the weights
            embedding_weights = embedding_layer.get_weights()[0]  # Weights are stored as a list, take the first element

            # Save weights to a file
            if os.path.exists(filepath):
                os.remove(filepath)

            np.save(filepath, embedding_weights)
            self.logger.info(f"Embedding weights saved successfully at {filepath}.")
        else:
            self.logger.warning("No model exists to extract embedding weights.")

    def load_embedding_weights(self, filepath="embedding_weights.npy"):
        if self.model is not None:
            embedding_layer = self.model.get_layer('embedding')

            # Load weights from the file
            embedding_weights = np.load(filepath)

            # Ensure the weights shape matches the layer's expected shape
            if embedding_layer.input_dim == embedding_weights.shape[0] and embedding_layer.output_dim == \
                    embedding_weights.shape[1]:
                embedding_layer.set_weights([embedding_weights])
                self.logger.info(f"Embedding weights loaded successfully from {filepath}.")
            else:
                self.logger.error("Mismatch in embedding weights shape. Ensure the model and weights are compatible.")
        else:
            self.logger.warning("No model exists to load embedding weights into.")

    def clean_text(self, text):
        txt = text.lower().strip()

        # Contraction mapping (expanded)
        contractions = {
            "i'm": "i am", "he's": "he is", "she's": "she is", "that's": "that is",
            "what's": "what is", "where's": "where is", "who's": "who is", "how's": "how is",
            "it's": "it is", "let's": "let us", "they're": "they are", "we're": "we are",
            "you're": "you are", "i've": "i have", "you've": "you have", "we've": "we have",
            "they've": "they have", "i'd": "i would", "you'd": "you would", "he'd": "he would",
            "she'd": "she would", "we'd": "we would", "they'd": "they would", "i'll": "i will",
            "you'll": "you will", "he'll": "he will", "she'll": "she will", "we'll": "we will",
            "they'll": "they will", "don't": "do not", "doesn't": "does not", "didn't": "did not",
            "won't": "will not", "wouldn't": "would not", "can't": "cannot", "couldn't": "could not",
            "shouldn't": "should not", "mightn't": "might not", "mustn't": "must not",
            "isn't": "is not", "aren't": "are not", "wasn't": "was not", "weren't": "were not",
            "haven't": "have not", "hasn't": "has not", "hadn't": "had not"
        }

        # Expand contractions
        for contraction, expansion in contractions.items():
            txt = re.sub(r"\b" + re.escape(contraction) + r"\b", expansion, txt)

        # Remove unwanted characters but keep apostrophes
        txt = re.sub(r"[^a-zA-Z0-9' ]", " ", txt)  # Keep words, numbers, and apostrophes
        txt = re.sub(r"\s+", " ", txt).strip()  # Remove extra spaces

        # Preserve words in vocabulary list
        for word in txt.split():
            if word not in self.vocabularyList:
                self.vocabularyList.append(word)

        self.save_tokenizer(self.vocabularyList)

        return txt

    # Training
    def preprocess_texts(self, input_texts, target_texts):
        input_texts = [self.clean_text(text) for text in input_texts.split(" ")]
        target_texts = [self.clean_text(text) for text in target_texts.split(" ")]

        # Initialize lists to store processed inputs and targets
        input_texts = [f"<start> {texts} <end>" for texts in input_texts if input_texts and input_texts != ""]
        target_texts = [f"<start> {texts} <end>" for texts in target_texts if target_texts and target_texts != ""]

        input_sequences = self.tokenizer.texts_to_sequences(input_texts)
        target_sequences = self.tokenizer.texts_to_sequences(target_texts)

        input_sequences = pad_sequences(input_sequences, maxlen=self.max_seq_length, padding='post')
        target_sequences = pad_sequences(target_sequences, maxlen=self.max_seq_length, padding='post')

        # Ensure target_sequences has enough samples
        if target_sequences.shape[0] != input_sequences.shape[0]:
            print(f"Padding mismatch! Input: {input_sequences.shape}, Target: {target_sequences.shape}")
            if target_sequences.shape[0] < input_sequences.shape[0]:
                target_sequences = np.resize(target_sequences, input_sequences.shape)
            if target_sequences.shape[0] > input_sequences.shape[0]:
                target_sequences = np.resize(input_sequences, target_sequences.shape)

        return input_sequences, target_sequences

    # Prediction
    def preprocess_input(self, texts):
        preprocessed_input = ["<start>"]
        texts = self.clean_text(texts)

        preprocessed_text = texts.lower().split(" ")
        preprocessed_input.extend(preprocessed_text)
        preprocessed_input.append("<end>")

        # Convert words to token IDs
        preprocessed_input = self.tokenizer.texts_to_sequences([preprocessed_input])
        preprocessed_input = [item for sublist in preprocessed_input for item in sublist]  # Flatten

        preprocessed_input = np.array(preprocessed_input).reshape(1, -1)  # (1, length)

        preprocessed_input = pad_sequences(preprocessed_input, maxlen=self.max_seq_length, padding='post')

        # ("Final Input Shape:", preprocessed_input.shape)  # Debugging
        return preprocessed_input

    def build_model(self):
        if not self.model:
            # Encoder
            self.encoder_inputs = Input(shape=(self.max_seq_length,))
            encoder_embedding = Embedding(
                input_dim=self.max_vocabulary,
                output_dim=self.embedding_dim,
                mask_zero=True,
                embeddings_regularizer=l2(0.01)
            )(self.encoder_inputs)
            encoder_lstm = LSTM(
                self.lstm_units,
                return_state=True,
                return_sequences=False,
                dropout=self.dropout,
                recurrent_dropout=self.recurrent_dropout
            )
            _, state_h, state_c = encoder_lstm(encoder_embedding)
            encoder_states = [state_h, state_c]
            self.encoder_model = Model(self.encoder_inputs, encoder_states)

            # Decoder
            self.decoder_inputs = Input(shape=(None,), name='decoder_input')
            decoder_embedding = Embedding(
                input_dim=self.max_vocabulary,
                output_dim=self.embedding_dim,
                mask_zero=True
            )(self.decoder_inputs)
            decoder_lstm = LSTM(
                self.lstm_units,
                return_sequences=True,
                return_state=True,
                dropout=self.dropout,
                recurrent_dropout=self.recurrent_dropout,
                kernel_regularizer=l2(0.001)
            )
            decoder_state_input_h = Input(shape=(self.lstm_units,))
            decoder_state_input_c = Input(shape=(self.lstm_units,))
            decoder_states_inputs = [decoder_state_input_h, decoder_state_input_c]
            decoder_lstm_output, state_h, state_c = decoder_lstm(decoder_embedding, initial_state=decoder_states_inputs)
            decoder_states = [state_h, state_c]
            decoder_dense = Dense(self.max_vocabulary, activation='softmax', kernel_regularizer=l2(0.001), bias_regularizer=l2(0.001))
            self.decoder_outputs = decoder_dense(decoder_lstm_output)
            self.decoder_model = Model([self.decoder_inputs] + decoder_states_inputs,
                                       [self.decoder_outputs] + decoder_states)

            # Combine encoder and decoder into the full model
            decoder_lstm_output, _, _ = decoder_lstm(decoder_embedding, initial_state=encoder_states)
            self.decoder_outputs = decoder_dense(decoder_lstm_output)
            self.model = Model([self.encoder_inputs, self.decoder_inputs], self.decoder_outputs)
            self.model.compile(
                optimizer=self.optimizer,
                loss='sparse_categorical_crossentropy',
                metrics=['accuracy']
            )
            return self.model, self.encoder_model, self.decoder_model

    def load_model_config(self, config_filename="model_config.json"):
        if os.path.exists(config_filename):
            with open(config_filename, "r", encoding="utf-8") as f:
                data = json.load(f)
            self.logger.info(f"Loading model config from {config_filename}")

            # Rebuild model from config
            self.model = model_from_json(data["model_config"])

            # Rebuild optimizer
            self.optimizer = Adam.from_config(data["optimizer"])

            # Compile model with restored optimizer
            self.model.compile(
                optimizer=self.optimizer,
                loss='sparse_categorical_crossentropy',
                metrics=['accuracy']
            )
            self.logger.info("Model compiled successfully after loading config.")
            return self.model
        return None

    def train_model(self, input_texts, target_texts, conversation_id, speaker):
        #  We Define running_trouble at the start of a new training
        self.running_trouble = []

        # We make sure everything to do with the model is loaded properly, or generated if it doesn't exist
        loaded_model = self.load_model_config(config_filename="model_config.json")
        if os.path.exists(self.model_filename) and os.path.exists(self.encoder_filename) and os.path.exists(
                self.decoder_filename):
            self.model, self.encoder_model, self.decoder_model = self.load_model_file()
            self.logger.info("Loaded full model from saved files.")

        elif not os.path.exists(self.model_filename) and not os.path.exists(self.encoder_filename) and not os.path.exists(
                self.decoder_filename) and loaded_model:
            self.model = loaded_model
        elif not self.model and not self.encoder_model and not self.decoder_model:
            self.logger.info("Building new model...")
            self.model, self.encoder_model, self.decoder_model = self.build_model()

        # Once everything loads properly we start training:
        self.logger.info(f"Training Model for ConversationID: {conversation_id}")

        if self.corpus is None or self.tokenizer is None:
            raise ValueError("Corpus or tokenizer is not initialized.")

        # Preprocess the texts into sequences
        input_sequences, target_sequences = self.preprocess_texts(input_texts, target_texts)

        # Debug Lines
        # for token in ['<start>', '<end>', '<oov>']:
        #     print(f"Index of {token}: {self.tokenizer.word_index.get(token)}")

        # Stats
        self.logger.info(f"Num Words: {self.tokenizer.num_words}")
        self.logger.info(f"Vocabulary Size: {len(self.tokenizer.word_index)}")
        self.logger.info(f"Length of Vocabulary List: {len(self.vocabularyList)}")

        # Prepare training data
        encoder_input_data = input_sequences
        decoder_input_data = target_sequences[:, :-1]
        decoder_target_data = target_sequences[:, 1:]

        self.logger.info(f"Encoder Input Data Shape: {encoder_input_data.shape}")
        self.logger.info(f"Decoder Input Data Shape: {decoder_input_data.shape}")
        self.logger.info(f"Decoder Target Data Shape: {decoder_target_data.shape}")

        # Instantiate the callback
        early_stopping = MonitorEarlyStopping(
            monitor='val_loss',
            patience=self.early_patience,
            mode='min',
            restore_best_weights=True,
            verbose=1
        )

        lr_patience = self.early_patience // 3
        lr_scheduler = ReduceLROnPlateau(monitor='val_loss', factor=0.3, patience=lr_patience, verbose=1)

        # Train the model
        history = self.model.fit(
            [encoder_input_data, decoder_input_data],
            np.expand_dims(decoder_target_data, -1),
            batch_size=self.batch_size,
            epochs=self.epochs,
            validation_split=self.test_size,
            callbacks=[early_stopping, lr_scheduler]
        )

        # Log any early stopping events
        if len(early_stopping.stopped_epoch_list) > 0:
                self.troubleList.append(speaker)

        # Reset stopped epoch list & save to running trouble
        self.running_trouble = [item for item in early_stopping.stopped_epoch_list]
        early_stopping.stopped_epoch_list = []

        # Evaluate the model on the training data
        test_loss, test_accuracy = self.model.evaluate(
            [encoder_input_data, decoder_input_data],
            np.expand_dims(decoder_target_data, -1),
            batch_size=self.batch_size
        )

        # Save training metrics as a plot
        plot_filename = self.plot_and_save_training_metrics(history, speaker)
        self.logger.info(f"Training metrics plot saved as {plot_filename}")
        self.logger.info(f"Test loss for Conversation {speaker}: {test_loss}")
        self.logger.info(f"Test accuracy for Conversation {speaker}: {test_accuracy}")
        self.logger.info(f"Model trained and saved successfully for speaker: {speaker}")

        # Compile the model before saving
        self.model.compile(
            optimizer=self.optimizer,
            loss='sparse_categorical_crossentropy',
            metrics=['accuracy']
        )

        # Save the model after training
        self.save_tokenizer(self.vocabularyList)
        self.save_model(self.model, self.encoder_model, self.decoder_model)

    def save_model(self, model, encoder_model, decoder_model):
        self.logger.info("Saving Model...")
        if model:
            self.encoder_model.save(self.encoder_filename)
            self.logger.info("Encoder saved.")
            time.sleep(1)
            self.decoder_model.save(self.decoder_filename)
            self.logger.info("Decoder saved.")
            time.sleep(1)
            self.model.save(self.model_filename)
            self.logger.info("Model saved.")
            time.sleep(1)
            self.save_full_weights()
            self.save_embedding_weights()

        else:
            self.logger.warning("No model to save.")

    def load_model_file(self):
        self.logger.info("Loading Model and Tokenizer...")

        # Load model without the optimizer first
        model = load_model(self.model_filename, compile=False)

        # Manually recompile with a fresh Adam optimizer
        self.optimizer = Adam(learning_rate=self.learning_rate, clipnorm=1.0)
        model.compile(optimizer=self.optimizer, loss='sparse_categorical_crossentropy', metrics=['accuracy'])

        print("Model Loaded... \nNow loading encoder/decoder models...  ")

        encoder_model = load_model(self.encoder_filename)
        decoder_model = load_model(self.decoder_filename)

        print("Decoder and Encoder Loaded...  ")

        self.load_full_weights()
        self.load_embedding_weights()

        return model, encoder_model, decoder_model

    def beam_search(self, input_text):
        # Preprocess input to match generate_response format
        input_seq = self.preprocess_input(input_text)

        # Perform beam search using the BeamSearchHelper class
        beam_search_helper = BeamSearchHelper(
            model=self.model,
            tokenizer=self.tokenizer,
            max_seq_length=self.max_seq_length,
            encoder_filename=self.encoder_filename,
            decoder_filename=self.decoder_filename,
            top_k=self.top_k,
            temperature=self.temperature,
            top_p=self.top_p,
            beam_width=self.beam_width,
            scaling_factor=self.scaling_factor
        )

        # Perform beam search
        output_seq = beam_search_helper.beam_search(input_seq)

        # Convert token indices back to words
        output_words = [self.tokenizer.index_word[idx] for idx in output_seq if idx in self.tokenizer.index_word]

        return " ".join(output_words)

    def generate_response(self, input_seq):
        try:
            # Clean and tokenize input text
            input_seqs = self.preprocess_input(input_seq)

            # Encode the input sequence using the encoder model
            encoder_states = self.encoder_model.predict(input_seqs)
            state_h, state_c = encoder_states
            state_h = state_h[0:1, :]  # Ensure batch size 1
            state_c = state_c[0:1, :]

            # Initialize the decoder input with the <start> token
            start_token_index = self.tokenizer.word_index.get('<start>', 1)
            target_seq = np.zeros((1, 1))
            target_seq[0, 0] = start_token_index

            # Debugging before passing to the decoder
            # print(f"Initial Target Seq Shape: {target_seq.shape}, state_h Shape: {state_h.shape}, state_c Shape: {state_c.shape}")

            # Decode the sequence
            decoded_sentence = []

            for _ in range(self.max_seq_length):
                output_tokens, state_h, state_c = self.decoder_model.predict([target_seq, state_h, state_c])

                # Scale logits immediately after getting output_tokens
                logits = output_tokens[0, -1, :] * self.scaling_factor
                logits = logits / self.temperature
                logits = np.clip(logits, -50, 50)

                # Compute softmax
                exp_logits = np.exp(logits - np.max(logits))  # Prevent overflow
                probabilities = exp_logits / np.sum(exp_logits)
                probabilities = exp_logits / (np.sum(exp_logits) + 1e-8)

                predicted_token_index = np.random.choice(len(probabilities), p=probabilities)
                predicted_word = self.reverse_tokenizer.get(predicted_token_index, '<oov>')

                print(f"Logits: {logits[:10]}")  # Debugging (First 10 values)
                print(f"Softmax Probabilities: {probabilities[:10]}")  # Debugging

                if predicted_word == "<end>" and len(
                        decoded_sentence) < self.min_word:
                    continue

                elif predicted_word == "<end>":
                    break

                if predicted_word not in ["<oov>", "<start>", "<end>"]:
                    decoded_sentence.append(predicted_word)

                # Update target sequence for the next iteration
                target_seq[0, 0] = predicted_token_index

            return " ".join(decoded_sentence).strip()

        except Exception as e:
            self.logger.error(f"Error in generate_response: {str(e)}")
            return "Error"