from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from kafka import KafkaProducer, KafkaAdminClient
from kafka.admin import NewTopic
import uuid
import json

from AiService.Config.Config import KAFKA_TOPIC, KAFKA_BOOTSTRAP_SERVERS
from AiService.Model.TaskModel import *

# 定义请求体模型
class TaskRequest(BaseModel):
    prompt: str  # 用户输入的提示词

# 初始化 FastAPI 应用
app = FastAPI()

# 创建 Kafka 生产者
producer = KafkaProducer(
    bootstrap_servers=KAFKA_BOOTSTRAP_SERVERS,
    value_serializer=lambda v: json.dumps(v).encode('utf-8')  # 将消息序列化为 JSON
)

# 检查并创建主题
def ensure_topic_exists():
    try:
        # 创建 Kafka AdminClient
        admin_client = KafkaAdminClient(bootstrap_servers=KAFKA_BOOTSTRAP_SERVERS)

        # 获取所有主题
        existing_topics = admin_client.list_topics()

        # 如果主题不存在，则创建
        if KAFKA_TOPIC not in existing_topics:
            topic = NewTopic(
                name=KAFKA_TOPIC,
                num_partitions=1,  # 分区数
                replication_factor=1  # 副本数
            )
            admin_client.create_topics([topic])
            print(f"Topic '{KAFKA_TOPIC}' created successfully.")
        else:
            print(f"Topic '{KAFKA_TOPIC}' already exists.")

        # 关闭 AdminClient
        admin_client.close()
    except Exception as e:
        print(f"Failed to ensure topic exists: {str(e)}")

# 查询任务状态接口
@app.get("/task-status/{task_id}")
def get_task_status(task_id: str):
    try:
        tm = TaskModel()
        task_status = tm.get_task_status(task_id)
        tm.close()

        if task_status:
            return task_status
        else:
            raise HTTPException(status_code=404, detail="Task not found")
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to get task status: {str(e)}")

# 定义 Lifespan 事件
@asynccontextmanager
async def lifespan(app: FastAPI):
    # 应用启动时检查并创建主题
    ensure_topic_exists()
    yield
    # 应用关闭时清理资源（可选）
    print("Application shutdown.")

# 定义接口
@app.post("/create-task")
def create_task(task_request: TaskRequest):
    try:
        # 生成唯一的 task_id
        task_id = str(uuid.uuid4())

        # 构造任务信息
        task_data = {
            "task_id": task_id,
            "prompt": task_request.prompt
        }

        # 将任务信息写入 Kafka
        producer.send(KAFKA_TOPIC, value=task_data)
        producer.flush()  # 确保消息发送完成

        # 将任务信息写入 MySQL
        tm = TaskModel()
        tm.insert_task(task_id, task_request.prompt)
        tm.close()

        # 返回 task_id
        return {"task_id": task_id}
    except Exception as e:
        # 处理异常
        raise HTTPException(status_code=500, detail=f"Failed to create task: {str(e)}")

# 启动应用
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)