# -*- coding: utf-8 -*-
"""
自然写手写识别与AI分析引擎软件 V1.0

版权所有 (C) 2026
软件全称：自然写手写识别与AI分析引擎软件
版本号：V1.0

主启动文件 - FastAPI 服务入口
负责服务初始化、路由注册、中间件配置
"""

from fastapi import FastAPI, Request, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from contextlib import asynccontextmanager
import uvicorn
import logging
import time
from typing import Dict, Any

# 导入各业务模块路由
from api.ocr_api import router as ocr_router
from api.math_api import router as math_router
from api.stroke_order_api import router as stroke_order_router
from api.essay_api import router as essay_router
from service.model_manager import ModelManager
from config.settings import Settings

# 日志配置
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(name)s: %(message)s"
)
logger = logging.getLogger("writech-ai-engine")

# 全局配置
settings = Settings()

# 全局模型管理器实例
model_manager = ModelManager(settings)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    应用生命周期管理
    启动时加载所有AI模型到GPU/CPU内存
    关闭时释放模型资源
    """
    logger.info("自然写AI引擎启动中，加载模型...")
    # 启动时加载所有模型
    await model_manager.load_all_models()
    logger.info("所有模型加载完成，服务就绪")
    yield
    # 关闭时释放资源
    logger.info("服务关闭中，释放模型资源...")
    model_manager.release_all_models()
    logger.info("模型资源已释放")


# 创建 FastAPI 应用实例
app = FastAPI(
    title="自然写手写识别与AI分析引擎",
    description="对智能点阵笔采集的笔迹数据进行OCR识别、数学列式识别、笔顺分析及AI智能批改",
    version="1.0.0",
    lifespan=lifespan
)

# 跨域中间件配置
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.middleware("http")
async def request_logging_middleware(request: Request, call_next):
    """
    请求日志与性能监控中间件
    记录每个请求的处理时间、状态码、推理耗时
    """
    start_time = time.time()
    request_id = request.headers.get("X-Request-ID", str(time.time()))

    # 输入数据大小校验（防恶意攻击，最大10MB）
    content_length = request.headers.get("content-length")
    if content_length and int(content_length) > 10 * 1024 * 1024:
        return JSONResponse(
            status_code=413,
            content={"code": 413, "msg": "请求数据过大，最大支持10MB", "data": None}
        )

    response = await call_next(request)

    # 记录请求处理时间
    process_time = time.time() - start_time
    response.headers["X-Process-Time"] = f"{process_time:.4f}"
    response.headers["X-Request-ID"] = request_id

    logger.info(
        f"{request.method} {request.url.path} "
        f"status={response.status_code} "
        f"time={process_time:.4f}s"
    )

    return response


@app.middleware("http")
async def mtls_authentication_middleware(request: Request, call_next):
    """
    mTLS 双向认证中间件
    内部服务间通信需携带有效的客户端证书
    
    安全设计：
    - 服务鉴权：内部服务间 mTLS 双向认证
    - 请求校验：输入数据格式校验与大小限制（防恶意攻击）
    """
    # 检查是否为内部服务调用
    client_cert = request.headers.get("X-Client-Cert")
    api_key = request.headers.get("X-API-Key")

    # 白名单路径不需要认证
    whitelist_paths = ["/health", "/docs", "/openapi.json"]
    if request.url.path in whitelist_paths:
        return await call_next(request)

    # 验证API Key或客户端证书
    if not api_key and not client_cert:
        return JSONResponse(
            status_code=401,
            content={"code": 401, "msg": "缺少认证凭据", "data": None}
        )

    if api_key and api_key != settings.api_key:
        return JSONResponse(
            status_code=403,
            content={"code": 403, "msg": "API Key无效", "data": None}
        )

    return await call_next(request)


# 注册各业务路由
app.include_router(ocr_router, prefix="/api/v1/ocr", tags=["OCR识别"])
app.include_router(math_router, prefix="/api/v1/math", tags=["数学识别"])
app.include_router(stroke_order_router, prefix="/api/v1/stroke-order", tags=["笔顺评分"])
app.include_router(essay_router, prefix="/api/v1/essay", tags=["作文批改"])


@app.get("/health")
async def health_check():
    """健康检查端点"""
    model_status = model_manager.get_all_status()
    return {
        "code": 200,
        "msg": "success",
        "data": {
            "status": "healthy",
            "models": model_status,
            "version": "1.0.0"
        }
    }


@app.get("/api/v1/model/status")
async def get_model_status():
    """
    查询各模型加载状态与版本
    GET /api/v1/model/status
    """
    status = model_manager.get_all_status()
    return {
        "code": 200,
        "msg": "success",
        "data": status
    }


@app.exception_handler(HTTPException)
async def http_exception_handler(request: Request, exc: HTTPException):
    """统一HTTP异常处理"""
    return JSONResponse(
        status_code=exc.status_code,
        content={
            "code": exc.status_code,
            "msg": exc.detail,
            "data": None
        }
    )


@app.exception_handler(Exception)
async def general_exception_handler(request: Request, exc: Exception):
    """统一异常处理"""
    logger.error(f"未处理异常: {str(exc)}", exc_info=True)
    return JSONResponse(
        status_code=500,
        content={
            "code": 500,
            "msg": "AI引擎内部错误",
            "data": None
        }
    )


if __name__ == "__main__":
    uvicorn.run(
        "main:app",
        host="0.0.0.0",
        port=8001,
        workers=4,
        log_level="info"
    )