import os
# Set the KMP_DUPLICATE_LIB_OK environment variable to handle a known issue with PyTorch
os.environ['KMP_DUPLICATE_LIB_OK'] = 'TRUE'
import sys
import torch
from transformers import GPT2Tokenizer, GPT2LMHeadModel, TextDataset, DataCollatorForLanguageModeling, Trainer, TrainingArguments, get_linear_schedule_with_warmup

class GPT2Assistant:
    def __init__(self):
        # Load the GPT-2 tokenizer from the specified path
        self.tokenizer = GPT2Tokenizer.from_pretrained("/Users/migueldeguzman/Desktop/gpt2xl_algos/RLLMv13/layer4/")

    def fine_tune(self, answer_file_path, model_output_dir, epochs=1.0):
        # Load the pre-trained GPT-2 model from the specified path
        self.model = GPT2LMHeadModel.from_pretrained("/Users/migueldeguzman/Desktop/gpt2xl_algos/RLLMv13/layer4/")
        # Create a text dataset from the specified file path and tokenizer, with a block size of 128
        train_dataset = TextDataset(
            tokenizer=self.tokenizer,
            file_path=answer_file_path,
            block_size=128
        )

        # Create a data collator for language modeling tasks
        data_collator = DataCollatorForLanguageModeling(
            tokenizer=self.tokenizer,
            mlm=False
        )
        
         # Calculate the total number of training steps based on the dataset length and number of epochs
        total_steps = len(train_dataset) * epochs
        # Set the number of warmup steps for the learning rate scheduler
        warmup_steps = 0.1 * total_steps

        # Create an Adam optimizer with specified learning rate and weight decay
        optimizer = torch.optim.Adam(self.model.parameters(), lr=42e-6, weight_decay=0.005)
        # Create a linear learning rate scheduler with warmup steps
        scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps=warmup_steps, num_training_steps=total_steps)

        # Define the training arguments
        training_args = TrainingArguments(
            output_dir=model_output_dir,
            overwrite_output_dir=True,
            num_train_epochs=epochs,
            per_device_train_batch_size=4,
            save_steps=10_000,
            save_total_limit=2,
            gradient_accumulation_steps=8,
            lr_scheduler_type='cosine',
            warmup_steps=500
        )

         # Create a Trainer instance with the specified model, arguments, data collator, dataset, and optimizers
        trainer = Trainer(
            model=self.model,
            args=training_args,
            data_collator=data_collator,
            train_dataset=train_dataset,
            optimizers=(optimizer, scheduler)
        )

        # Fine-tune the model using the Trainer
        trainer.train()
        # Save the fine-tuned model and tokenizer to the specified output directory
        self.model.save_pretrained(model_output_dir)
        self.tokenizer.save_pretrained(model_output_dir)

    def generate_answer(self, prompt, max_length=1000):
        # Encode the input prompt using the tokenizer
        input_ids = self.tokenizer.encode(prompt, return_tensors="pt")
        
        # Check if the tokenizer has a pad token and set it if not
        if self.tokenizer.pad_token_id is None:
            self.tokenizer.pad_token = self.tokenizer.eos_token

        # Create an attention mask for the input ids
        attention_mask = (input_ids != self.tokenizer.pad_token_id).long()

        # Generate text using the fine-tuned model with the specified parameters
        output = self.model.generate(
            input_ids,
            attention_mask=attention_mask,
            max_length=max_length,
            num_return_sequences=1,
            no_repeat_ngram_size=2,
            do_sample=True,
            top_k=50,
            top_p=0.95,
            temperature=0.0000000000000000000000000001
        )

        # Decode the generated output using the tokenizer, skipping special tokens
        answer = self.tokenizer.decode(output[0], skip_special_tokens=True)
        # Return the generated answer, excluding the original prompt
        return answer[len(prompt):]

    def query(self, prompt):
        # Generate an answer for the given prompt
        generated_answer = self.generate_answer(prompt)
        print(generated_answer)
        return generated_answer

def main():
    # Set the file path for the text file to fine-tune on
    text_file_path = "/Users/migueldeguzman/Desktop/gpt2xl_algos/RLLMv13/layer5/animus.text"
    # Set the output directory path for the fine-tuned model
    model_output_dir = "/Users/migueldeguzman/Desktop/gpt2xl_algos/RLLMv13/layer5/"

    assistant = GPT2Assistant()
    # Prompt the user to choose whether to fine-tune a new model or load an existing one
    choice = input("Do you want to fine-tune a new model (n) or load an existing one (e)? (n/e): ")

    if choice.lower() == "n":
        # Fine-tune the model if the user chooses 'n'
        print("Fine-tuning the model...")
        assistant.fine_tune(text_file_path, model_output_dir)
        print("Model fine-tuning complete.")
    elif choice.lower() == "e":
        print("Loading the existing model...")
        # Load the existing fine-tuned model if the user chooses 'e'
        assistant.model = GPT2LMHeadModel.from_pretrained(model_output_dir)
        print("Existing model loaded.")
    else:
        print("Invalid choice. Exiting the program.")
        sys.exit()

    while True:
        # Prompt the user for a question# Prompt the user for a question
        prompt = input("Enter your question (or type 'exit' to stop): ")
        if prompt.lower() == "exit":
            break

        print("Answering in progress...")
        # Generate an answer for the user's prompt
        generated_answer = assistant.query(prompt)

        print("\n")

if __name__ == "__main__":
    main()