#!/usr/bin/env python3
import os
import vertexai
import logging
from fastapi import FastAPI
from fastapi.responses import StreamingResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel
from vertexai.generative_models import ChatSession, GenerativeModel, Part, SafetySetting
from cachetools import LRUCache
from dotenv import load_dotenv


load_dotenv()
PROJECT_ID = os.environ.get('PROJECT_ID')
SESSION_CACHE = LRUCache(15)

logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.DEBUG)


def generate():
  vertexai.init(project=PROJECT_ID, location="us-central1")
  model = GenerativeModel(
    "gemini-1.5-flash-001",
    system_instruction=[textsi_1]
  )

  return model.start_chat()

textsi_1 = """你要用中文回答一个德语刚入门的新手的回答，先用德语回答然后在用中文解释这个回答并给出建议"""

generation_config = {
    "max_output_tokens": 1024,
    "temperature": 0.2,
    "top_p": 0,
}

safety_settings = [
    SafetySetting(
        category=SafetySetting.HarmCategory.HARM_CATEGORY_HATE_SPEECH,
        threshold=SafetySetting.HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE
    ),
    SafetySetting(
        category=SafetySetting.HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT,
        threshold=SafetySetting.HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE
    ),
    SafetySetting(
        category=SafetySetting.HarmCategory.HARM_CATEGORY_SEXUALLY_EXPLICIT,
        threshold=SafetySetting.HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE
    ),
    SafetySetting(
        category=SafetySetting.HarmCategory.HARM_CATEGORY_HARASSMENT,
        threshold=SafetySetting.HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE
    ),
]


def stream_chat(model : ChatSession, _input):
  responses = model.send_message(
      [_input],
      generation_config=generation_config,
      safety_settings=safety_settings,
      stream=True,
  )

  for chunk in responses:
      yield chunk.text


app = FastAPI(
    title="AAII",
    version="0.0.1"
)


class ChatRequest(BaseModel):
    prompt: str
    session_uuid: str


@app.post("/generate_text_stream")
async def generate_text(request: ChatRequest):
    if model := SESSION_CACHE.get(request.session_uuid):
        return StreamingResponse(stream_chat(model, request.prompt),media_type="text/plain")

    model = generate()

    SESSION_CACHE[request.session_uuid] = model
    logging.info(f"Buid new session: {request.session_uuid}")
    return StreamingResponse(stream_chat(model, request.prompt),media_type="text/plain")

app.mount("/", StaticFiles(directory="static", html=True), name="static")