"""
A model worker executes the model.
"""
import argparse
import json
import uuid

from fastapi import FastAPI, Request
from fastapi.responses import StreamingResponse
from transformers import AutoModel, AutoTokenizer
import torch
import uvicorn

from transformers.generation.streamers import BaseStreamer
from threading import Thread
from queue import Queue


class TokenStreamer(BaseStreamer):
    def __init__(self, skip_prompt: bool = False, timeout=None):
        self.skip_prompt = skip_prompt

        # variables used in the streaming process
        self.token_queue = Queue()
        self.stop_signal = None
        self.next_tokens_are_prompt = True
        self.timeout = timeout

    def put(self, value):
        if len(value.shape) > 1 and value.shape[0] > 1:
            raise ValueError("TextStreamer only supports batch size 1")
        elif len(value.shape) > 1:
            value = value[0]

        if self.skip_prompt and self.next_tokens_are_prompt:
            self.next_tokens_are_prompt = False
            return

        for token in value.tolist():
            self.token_queue.put(token)

    def end(self):
        self.token_queue.put(self.stop_signal)

    def __iter__(self):
        return self

    def __next__(self):
        value = self.token_queue.get(timeout=self.timeout)
        if value == self.stop_signal:
            raise StopIteration()
        else:
            return value


class ModelWorker:
    def __init__(self, model_path, device='cuda'):
        self.device = device
        self.glm_model = AutoModel.from_pretrained(model_path, trust_remote_code=True,
                                                   device_map=device,low_cpu_mem_usage=True,load_in_4bit=True).eval()
        self.glm_tokenizer = AutoTokenizer.from_pretrained(model_path, trust_remote_code=True)

    @torch.inference_mode()
    def generate_stream(self, params):
        tokenizer, model = self.glm_tokenizer, self.glm_model

        prompt = params["prompt"]

        temperature = float(params.get("temperature", 1.0))
        top_p = float(params.get("top_p", 1.0))
        max_new_tokens = int(params.get("max_new_tokens", 256))

        inputs = tokenizer([prompt], return_tensors="pt")
        inputs = inputs.to(self.device)
        streamer = TokenStreamer(skip_prompt=True)
        thread = Thread(target=model.generate,
                        kwargs=dict(**inputs, max_new_tokens=int(max_new_tokens),
                                    temperature=float(temperature), top_p=float(top_p),
                                    streamer=streamer))
        thread.start()
        for token_id in streamer:
            yield (json.dumps({"token_id": token_id, "error_code": 0}) + "\n").encode()

    def generate_stream_gate(self, params):
        try:
            for x in self.generate_stream(params):
                yield x
        except Exception as e:
            print("Caught Unknown Error", e)
            ret = {
                "text": "Server Error",
                "error_code": 1,
            }
            yield (json.dumps(ret)+ "\n").encode()


app = FastAPI()


@app.post("/generate_stream")
async def generate_stream(request: Request):
    params = await request.json()

    generator = worker.generate_stream_gate(params)
    return StreamingResponse(generator)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--host", type=str, default="localhost")
    parser.add_argument("--port", type=int, default=10000)
    parser.add_argument("--model-path", type=str, default="glm-4-voice-9b-int4")
    args = parser.parse_args()

    worker = ModelWorker(args.model_path)
    uvicorn.run(app, host=args.host, port=args.port, log_level="info")