"""
This script creates an interactive web demo for the GLM-4-9B model using Gradio,
a Python library for building quick and easy UI components for machine learning models.
It's designed to showcase the capabilities of the GLM-4-9B model in a user-friendly interface,
allowing users to interact with the model through a chat-like interface.
"""

import os
from pathlib import Path
from threading import Thread
from typing import Union

import gradio as gr
import torch
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')
TOKENIZER_PATH = os.environ.get("TOKENIZER_PATH", MODEL_PATH)


def _resolve_path(path: Union[str, Path]) -> Path:
    return Path(path).expanduser().resolve()


def load_model_and_tokenizer(
        model_dir: Union[str, Path], trust_remote_code: bool = True
) -> tuple[ModelType, TokenizerType]:
    model_dir = _resolve_path(model_dir)
    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, 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


def predict(history, prompt, max_length, top_p, temperature):
    stop = StopOnTokens()
    messages = []
    if prompt:
        messages.append({"role": "system", "content": prompt})
    for idx, (user_msg, model_msg) in enumerate(history):
        if prompt and idx == 0:
            continue
        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(next(model.parameters()).device)
    streamer = TextIteratorStreamer(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()
    for new_token in streamer:
        if new_token:
            history[-1][1] += new_token
        yield history


with gr.Blocks() as demo:
    gr.HTML("""<h1 align="center">GLM-4-9B Gradio Simple Chat Demo</h1>""")
    chatbot = gr.Chatbot()

    with gr.Row():
        with gr.Column(scale=3):
            with gr.Column(scale=12):
                user_input = gr.Textbox(show_label=False, placeholder="Input...", lines=10, container=False)
            with gr.Column(min_width=32, scale=1):
                submitBtn = gr.Button("Submit")
        with gr.Column(scale=1):
            prompt_input = gr.Textbox(show_label=False, placeholder="Prompt", lines=10, container=False)
            pBtn = gr.Button("Set Prompt")
        with gr.Column(scale=1):
            emptyBtn = gr.Button("Clear History")
            max_length = gr.Slider(0, 32768, value=8192, step=1.0, label="Maximum length", interactive=True)
            top_p = gr.Slider(0, 1, value=0.8, step=0.01, label="Top P", interactive=True)
            temperature = gr.Slider(0.01, 1, value=0.6, step=0.01, label="Temperature", interactive=True)


    def user(query, history):
        return "", history + [[query, ""]]


    def set_prompt(prompt_text):
        return [[prompt_text, "成功设置prompt"]]


    pBtn.click(set_prompt, inputs=[prompt_input], outputs=chatbot)

    submitBtn.click(user, [user_input, chatbot], [user_input, chatbot], queue=False).then(
        predict, [chatbot, prompt_input, max_length, top_p, temperature], chatbot
    )
    emptyBtn.click(lambda: (None, None), None, [chatbot, prompt_input], queue=False)

demo.queue()
demo.launch(server_name="127.0.0.1", server_port=8000, inbrowser=True, share=True)
