import asyncio
import torch
from datetime import datetime
from services.model_visitor import ModelVisitor
from utils.logger import Logger

logger = Logger.get_logger(__name__)


class IbmTextGenerator(ModelVisitor):

    async def visit(self, model_generator, input_text, max_length_per_chunk=50):
        return await self._generate_text(model_generator, input_text, max_length_per_chunk)

    async def _generate_text_chunk(self, model_generator, input_ids, max_length_per_chunk):
        with torch.no_grad():
            outputs = await asyncio.to_thread(model_generator.model.generate, input_ids, max_new_tokens=max_length_per_chunk)
            continuation = model_generator.tokenizer.decode(
                outputs[0], skip_special_tokens=False)

            logger.info('Chunk generated: {}'.format(continuation))

            return continuation

    async def _generate_text(self, model_generator, input_text, max_length_per_chunk):
        """
            Generates the text based on input provided
            Args:
                input_text (str): The input string containing text blocks.
                max_length_per_chunk: Max length per chunk (Default: 50 / Optional)
        """
        try:
            start_time = datetime.now()

            logger.info('Started at: {}'.format(
                start_time.strftime(model_generator._format_data_time)))

            input_ids = model_generator.tokenizer.encode(
                input_text, return_tensors='pt').to(model_generator.device)

            output_text = input_text
            while True:
                continuation = await self._generate_text_chunk(
                    model_generator, input_ids, max_length_per_chunk)

                new_text = continuation[len(model_generator.tokenizer.decode(
                    input_ids[0], skip_special_tokens=False)):]
                output_text += new_text
                input_ids = model_generator.tokenizer.encode(
                    output_text, return_tensors='pt').to(model_generator.device)
                if "<|endoftext|>" in new_text or new_text.count('```') > 1:
                    break

            end_time = datetime.now()

            logger.info('Output generated at: {}'.format(
                end_time.strftime(model_generator._format_data_time)))

            logger.info('Time taken: {}'.format(end_time - start_time))

            return output_text
        except asyncio.CancelledError:
            logger.error(
                'Cancelling model generation due to disconnection in network.')
            return ""