"""
This script creates a CLI demo with transformers backend for the glm-4-9b model,
allowing users to interact with the model through a command-line interface.

Usage:
- Run the script to start the CLI demo.
- Interact with the model by typing questions and receiving responses.

Note: The script includes a modification to handle markdown to plain text conversion,
ensuring that the CLI interface displays formatted text correctly.
"""

import os
import torch
from threading import Thread
from typing import Union
from pathlib import Path
from peft import AutoPeftModelForCausalLM, PeftModelForCausalLM
from transformers import (
    AutoModelForCausalLM,
    AutoTokenizer,
    PreTrainedModel,
    PreTrainedTokenizer,
    PreTrainedTokenizerFast,
    StoppingCriteria,
    StoppingCriteriaList,
    TextIteratorStreamer
)

ModelType = Union[PreTrainedModel, PeftModelForCausalLM]
TokenizerType = Union[PreTrainedTokenizer, PreTrainedTokenizerFast]

MODEL_PATH = os.environ.get('MODEL_PATH', 'THUDM/glm-4-9b-chat')


def load_model_and_tokenizer(
        model_dir: Union[str, Path], trust_remote_code: bool = True
) -> tuple[ModelType, TokenizerType]:
    model_dir = Path(model_dir).expanduser().resolve()
    if (model_dir / 'adapter_config.json').exists():
        model = AutoPeftModelForCausalLM.from_pretrained(
            model_dir, trust_remote_code=trust_remote_code, device_map='auto')
        tokenizer_dir = model.peft_config['default'].base_model_name_or_path
    else:
        model = AutoModelForCausalLM.from_pretrained(model_dir, trust_remote_code=trust_remote_code, device_map='auto')
        tokenizer_dir = model_dir

    tokenizer = AutoTokenizer.from_pretrained(
        tokenizer_dir, trust_remote_code=trust_remote_code, encode_special_tokens=True, use_fast=False
    )
    return model, tokenizer


model, tokenizer = load_model_and_tokenizer(MODEL_PATH, trust_remote_code=True)


class StopOnTokens(StoppingCriteria):
    def __call__(self, input_ids: torch.LongTensor, scores: torch.FloatTensor, **kwargs) -> bool:
        stop_ids = model.config.eos_token_id
        for stop_id in stop_ids:
            if input_ids[0][-1] == stop_id:
                return True
        return False


if __name__ == "__main__":
    history = []
    max_length = 8192
    top_p = 0.8
    temperature = 0.6
    stop = StopOnTokens()

    print("Welcome to the GLM-4-9B CLI chat. Type your messages below.")
    while True:
        user_input = input("\nYou: ")
        if user_input.lower() in ["exit", "quit"]:
            break
        history.append([user_input, ""])

        messages = []
        for idx, (user_msg, model_msg) in enumerate(history):
            if idx == len(history) - 1 and not model_msg:
                messages.append({"role": "user", "content": user_msg})
                break
            if user_msg:
                messages.append({"role": "user", "content": user_msg})
            if model_msg:
                messages.append({"role": "assistant", "content": model_msg})
        model_inputs = tokenizer.apply_chat_template(
            messages,
            add_generation_prompt=True,
            tokenize=True,
            return_tensors="pt"
        ).to(model.device)
        streamer = TextIteratorStreamer(
            tokenizer=tokenizer,
            timeout=60,
            skip_prompt=True,
            skip_special_tokens=True
        )
        generate_kwargs = {
            "input_ids": model_inputs,
            "streamer": streamer,
            "max_new_tokens": max_length,
            "do_sample": True,
            "top_p": top_p,
            "temperature": temperature,
            "stopping_criteria": StoppingCriteriaList([stop]),
            "repetition_penalty": 1.2,
            "eos_token_id": model.config.eos_token_id,
        }
        t = Thread(target=model.generate, kwargs=generate_kwargs)
        t.start()
        print("GLM-4:", end="", flush=True)
        for new_token in streamer:
            if new_token:
                print(new_token, end="", flush=True)
                history[-1][1] += new_token

        history[-1][1] = history[-1][1].strip()
