import asyncio
import json
from threading import Lock
from typing import List

from fastapi import APIRouter, Request, status, HTTPException
from sse_starlette.sse import EventSourceResponse
from pydantic import BaseModel
from utils.rwkv import *
import global_var

router = APIRouter()


class Message(BaseModel):
    role: str
    content: str


class ChatCompletionBody(ModelConfigBody):
    messages: List[Message]
    model: str = "rwkv"
    stream: bool = False
    stop: str = None


completion_lock = Lock()


@router.post("/v1/chat/completions")
@router.post("/chat/completions")
async def chat_completions(body: ChatCompletionBody, request: Request):
    model: RWKV = global_var.get(global_var.Model)
    if model is None:
        raise HTTPException(status.HTTP_400_BAD_REQUEST, "model not loaded")

    question = body.messages[-1]
    if question.role == "user":
        question = question.content
    else:
        raise HTTPException(status.HTTP_400_BAD_REQUEST, "no question found")

    completion_text = ""
    for message in body.messages:
        if message.role == "user":
            completion_text += (
                "Bob: "
                + message.content.replace("\\n", "\n")
                .replace("\r\n", "\n")
                .replace("\n\n", "\n")
                .strip()
                + "\n\n"
            )
        elif message.role == "assistant":
            completion_text += (
                "Alice: "
                + message.content.replace("\\n", "\n")
                .replace("\r\n", "\n")
                .replace("\n\n", "\n")
                .strip()
                + "\n\n"
            )
    completion_text += "Alice:"

    async def eval_rwkv():
        while completion_lock.locked():
            await asyncio.sleep(0.1)
        else:
            completion_lock.acquire()
            set_rwkv_config(model, global_var.get(global_var.Model_Config))
            set_rwkv_config(model, body)
            if body.stream:
                for response, delta in rwkv_generate(
                    model,
                    completion_text,
                    stop="\n\nBob" if body.stop is None else body.stop,
                ):
                    if await request.is_disconnected():
                        break
                    yield json.dumps(
                        {
                            "response": response,
                            "model": "rwkv",
                            "choices": [
                                {
                                    "delta": {"content": delta},
                                    "index": 0,
                                    "finish_reason": None,
                                }
                            ],
                        }
                    )
                if await request.is_disconnected():
                    completion_lock.release()
                    return
                yield json.dumps(
                    {
                        "response": response,
                        "model": "rwkv",
                        "choices": [
                            {
                                "delta": {},
                                "index": 0,
                                "finish_reason": "stop",
                            }
                        ],
                    }
                )
                yield "[DONE]"
            else:
                response = None
                for response, delta in rwkv_generate(
                    model,
                    completion_text,
                    stop="\n\nBob" if body.stop is None else body.stop,
                ):
                    if await request.is_disconnected():
                        break
                if await request.is_disconnected():
                    completion_lock.release()
                    return
                yield {
                    "response": response,
                    "model": "rwkv",
                    "choices": [
                        {
                            "message": {
                                "role": "assistant",
                                "content": response,
                            },
                            "index": 0,
                            "finish_reason": "stop",
                        }
                    ],
                }
            # torch_gc()
            completion_lock.release()

    if body.stream:
        return EventSourceResponse(eval_rwkv())
    else:
        return await eval_rwkv().__anext__()


class CompletionBody(ModelConfigBody):
    prompt: str
    model: str = "rwkv"
    stream: bool = False
    stop: str = None


@router.post("/v1/completions")
@router.post("/completions")
async def completions(body: CompletionBody, request: Request):
    model: RWKV = global_var.get(global_var.Model)
    if model is None:
        raise HTTPException(status.HTTP_400_BAD_REQUEST, "model not loaded")

    async def eval_rwkv():
        while completion_lock.locked():
            await asyncio.sleep(0.1)
        else:
            completion_lock.acquire()
            set_rwkv_config(model, global_var.get(global_var.Model_Config))
            set_rwkv_config(model, body)
            if body.stream:
                for response, delta in rwkv_generate(
                    model, body.prompt, stop=body.stop
                ):
                    if await request.is_disconnected():
                        break
                    yield json.dumps(
                        {
                            "response": response,
                            "model": "rwkv",
                            "choices": [
                                {
                                    "text": delta,
                                    "index": 0,
                                    "finish_reason": None,
                                }
                            ],
                        }
                    )
                if await request.is_disconnected():
                    completion_lock.release()
                    return
                yield json.dumps(
                    {
                        "response": response,
                        "model": "rwkv",
                        "choices": [
                            {
                                "text": "",
                                "index": 0,
                                "finish_reason": "stop",
                            }
                        ],
                    }
                )
                yield "[DONE]"
            else:
                response = None
                for response, delta in rwkv_generate(
                    model, body.prompt, stop=body.stop
                ):
                    if await request.is_disconnected():
                        break
                if await request.is_disconnected():
                    completion_lock.release()
                    return
                yield {
                    "response": response,
                    "model": "rwkv",
                    "choices": [
                        {
                            "text": response,
                            "index": 0,
                            "finish_reason": "stop",
                        }
                    ],
                }
            # torch_gc()
            completion_lock.release()

    if body.stream:
        return EventSourceResponse(eval_rwkv())
    else:
        return await eval_rwkv().__anext__()