"""外网网关 — FastAPI 应用。

薄反向代理层：对外保持 HTTPS 接口不变，对内转发到 worker 池。
不跑任何算法（无 torch/mediapipe/opencv 依赖）。
"""

import asyncio
import logging
import time
from contextlib import asynccontextmanager
from pathlib import Path
from fastapi import FastAPI, Request
from fastapi.staticfiles import StaticFiles

from gateway.config import load_config

# ---------------------------------------------------------------------------
# 日志
# ---------------------------------------------------------------------------

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
)
logger = logging.getLogger("gateway")


# ---------------------------------------------------------------------------
# 应用生命周期
# ---------------------------------------------------------------------------

@asynccontextmanager
async def lifespan(app: FastAPI):
    """启动：加载配置、初始化健康池；关闭：清理资源。"""
    # 启动
    cfg = load_config()
    logger.info("网关启动中... workers=%s", cfg["workers"])

    # 初始化健康池（阶段二实现）
    try:
        from gateway.pool import init_pool, shutdown_pool as _pool_shutdown
        _has_pool = True
    except ImportError:
        logger.warning("pool 模块未就绪，跳过健康池初始化")
        _has_pool = False

    if _has_pool:
        await init_pool(cfg)
        app.state._pool_shutdown = _pool_shutdown
    else:
        app.state._pool_shutdown = None

    # 确保标注图目录存在
    static_dir = Path(cfg["static_dir"])
    static_dir.mkdir(parents=True, exist_ok=True)
    logger.info("标注图目录: %s", static_dir)

    # 启动定期清理任务（阶段四）
    cleanup_shutdown = asyncio.Event()
    cleanup_task = asyncio.create_task(
        _cleanup_loop(static_dir, cfg, cleanup_shutdown)
    )
    app.state._cleanup_shutdown = cleanup_shutdown
    app.state._cleanup_task = cleanup_task

    yield

    # 关闭
    logger.info("网关关闭中...")
    # 停止清理任务
    if app.state._cleanup_shutdown:
        app.state._cleanup_shutdown.set()
    if app.state._cleanup_task:
        app.state._cleanup_task.cancel()
        try:
            await app.state._cleanup_task
        except asyncio.CancelledError:
            pass
    if app.state._pool_shutdown:
        await app.state._pool_shutdown()
    logger.info("网关已关闭")


# ---------------------------------------------------------------------------
# 创建应用
# ---------------------------------------------------------------------------

app = FastAPI(
    title="旷视五接口 — 网关",
    version="0.1.0",
    description="外网网关：反向代理 5 个接口到高性能 worker 池。",
    lifespan=lifespan,
)

# 静态文件托管（阶段四完善）
static_root = Path(__file__).resolve().parent.parent / "static"
static_root.mkdir(parents=True, exist_ok=True)
(static_root / "annotations").mkdir(parents=True, exist_ok=True)
app.mount("/static", StaticFiles(directory=str(static_root)), name="static")


# ---------------------------------------------------------------------------
# 健康检查（网关自身）
# ---------------------------------------------------------------------------

def _get_pool_status_safe():
    """安全获取池状态（pool 未就绪时返回占位值）。"""
    try:
        from gateway.pool import get_pool_status
        return get_pool_status()
    except ImportError:
        return {"total": 0, "healthy": 0, "busy": 0}


async def _cleanup_loop(annotations_dir: Path, cfg: dict, shutdown: asyncio.Event):
    """定期清理 static/annotations/ 中过期的标注图文件。

    配置项（可选，在 config.json 中设定）：
    - cleanup.interval_minutes: 清理间隔，默认 60
    - cleanup.max_age_hours: 文件保留时长（小时），默认 24
    """
    cleanup_cfg = cfg.get("cleanup", {})
    interval_s = cleanup_cfg.get("interval_minutes", 60) * 60
    max_age_s = cleanup_cfg.get("max_age_hours", 24) * 3600

    logger.info(
        "清理任务启动 | 间隔=%dmin | 保留=%dh | 目录=%s",
        interval_s // 60, max_age_s // 3600, annotations_dir,
    )

    while not shutdown.is_set():
        try:
            await asyncio.wait_for(shutdown.wait(), timeout=interval_s)
            break  # shutdown
        except asyncio.TimeoutError:
            pass  # 正常到时，执行清理

        now = time.time()
        deleted = 0
        for f in annotations_dir.iterdir():
            if f.name == ".gitkeep":
                continue
            if not f.is_file():
                continue
            try:
                age_s = now - f.stat().st_mtime
                if age_s > max_age_s:
                    f.unlink()
                    deleted += 1
                    logger.debug("清理过期文件: %s (age=%.1fh)", f.name, age_s / 3600)
            except Exception:
                logger.warning("清理文件失败: %s", f.name, exc_info=True)

        if deleted:
            logger.info("清理完成: 删除 %d 个过期文件", deleted)

    logger.info("清理任务已停止")


@app.get("/gateway-health", include_in_schema=False)
async def gateway_health():
    """网关自身健康检查（区别于 worker 的 /health）。"""
    status = _get_pool_status_safe()
    return {
        "status": "ok",
        "service": "gateway",
        "workers_total": status["total"],
        "workers_healthy": status["healthy"],
        "workers_busy": status["busy"],
    }


@app.get("/health", include_in_schema=False)
async def health():
    """兼容旧 /health 路径，返回网关状态。"""
    return await gateway_health()


@app.get("/", include_in_schema=False)
async def index():
    cfg = load_config()
    return {
        "service": "旷视五接口 — 网关",
        "version": "0.1.0",
        "docs": f"{cfg['public_base_url']}/docs",
    }


# ---------------------------------------------------------------------------
# 代理路由
# ---------------------------------------------------------------------------
# 所有接口统一走「选 worker → 转发 → 改写 base64 → 返回」链路。
# 使用 Request 对象直接读取并转发，不做业务入参解析（解析在 worker 侧完成）。
# Form/File 声明保留在 OpenAPI extra 中以便文档生成。


def _proxy(request: Request, path: str):
    """延迟导入 proxy_request。"""
    from gateway.forward import proxy_request
    return proxy_request(request, path)


# 声明各接口的 form 参数用于 OpenAPI schema（实际转发直接读 Request）
_MEASURE_FORMS = {
    "image_file": {"type": "file", "description": "上传图片文件（JPG/PNG，≤ 1 MB）"},
    "image_url": {"type": "string", "description": "图片 URL"},
    "image_base64": {"type": "string", "description": "图片 base64（需带前缀）"},
}

_GROW_FORMS = {
    **_MEASURE_FORMS,
    "beauty_enabled": {"type": "boolean", "description": "是否开启美颜效果"},
}

_GROW_B_FORMS = {
    "marked_image_file": {"type": "file", "description": "划线图片文件"},
    "marked_image_url": {"type": "string", "description": "划线图片 URL"},
    "marked_image_base64": {"type": "string", "description": "划线图片 base64"},
    "original_image_file": {"type": "file", "description": "原始用户照片文件"},
    "original_image_url": {"type": "string", "description": "原始用户照片 URL"},
    "original_image_base64": {"type": "string", "description": "原始用户照片 base64"},
}


@app.post("/api/v1/face/measure", tags=["人脸分析"])
async def face_measure(request: Request):
    """接口1：四庭七眼测量标注"""
    return await _proxy(request, "/api/v1/face/measure")


@app.post("/api/v1/hair/grow", tags=["生发"])
async def hair_grow(request: Request):
    """接口2：C端生发"""
    return await _proxy(request, "/api/v1/hair/grow")


@app.post("/api/v1/hair/grow-b", tags=["生发"])
async def hair_grow_b(request: Request):
    """接口3：B端生发"""
    return await _proxy(request, "/api/v1/hair/grow-b")


@app.post("/api/v1/face/features", tags=["人脸分析"])
async def face_features(request: Request):
    """接口4：用户特征分析"""
    return await _proxy(request, "/api/v1/face/features")


@app.post("/api/v1/hairline/generate", tags=["人脸分析"])
async def hairline_generate(request: Request):
    """接口5：发际线PNG生成"""
    return await _proxy(request, "/api/v1/hairline/generate")