from __future__ import annotations

import logging
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from .api import router as api_router
from .config import get_settings
from .models.db import Database, set_db
from .strategy import StrategyEngine, set_engine
from .strategy.session import bootstrap_session

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(levelname)s [%(name)s] %(message)s",
)
logger = logging.getLogger("eth_hedge_sim")


def resolve_frontend_dist() -> Path:
    here = Path(__file__).resolve()
    repo_root = here.parents[2]
    return repo_root / "frontend" / "dist"


@asynccontextmanager
async def lifespan(app: FastAPI):
    db = Database()
    set_db(db)
    # 必须在 set_db 之后读 DB 覆盖，否则会按 .env 默认 okx 起会话，
    # 而 health 显示 DB 里的 binance → 合约号/盘口错乱（期权一直 -/-）
    from .exchange.runtime import load_runtime_settings

    settings = load_runtime_settings()
    engine = StrategyEngine()
    set_engine(engine)
    engine.ensure_loop()

    session = bootstrap_session(settings)
    try:
        await session.start()
        logger.info(
            "exchange=%s strategy session started mode=%s",
            settings.exchange,
            "SIM" if get_settings().is_sim else "LIVE",
        )
    except Exception:
        logger.exception("strategy session failed to start")

    yield

    await engine.pause()
    if engine._task and not engine._task.done():
        engine._task.cancel()
        try:
            await engine._task
        except Exception:
            pass
    await session.stop()
    from .exchange import set_exchange
    from .strategy.session import set_session

    set_session(None)
    set_exchange(None)
    set_engine(None)
    db.close()
    set_db(None)


app = FastAPI(
    title="比特骆驼自动化对冲系统",
    version="0.3.0",
    description="比特骆驼自动化对冲系统（eth_hedge_sim）",
    lifespan=lifespan,
)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)
app.include_router(api_router)


@app.get("/health")
async def health() -> dict:
    from .strategy import get_engine
    from .strategy.session import get_session

    settings = get_settings()
    try:
        from .exchange.runtime import load_runtime_settings

        rt = load_runtime_settings()
        exchange_name = rt.exchange
    except Exception:
        exchange_name = settings.exchange
    sess = get_session()
    snap = sess.snapshot()
    try:
        st = get_engine().state()
    except Exception:
        st = None
    return {
        "ok": True,
        "mode": settings.mode,
        "env_name": settings.env_name,
        "exchange": exchange_name,
        "sim": settings.is_sim,
        "market_connected": snap.connected,
        "pair": snap.pair.to_dict() if snap.pair else None,
        "updated_at_ms": snap.updated_at_ms,
        "strategy": {
            "running": st.get("running") if st else None,
            "phase": st.get("phase") if st else None,
            "rounds_done": st.get("rounds_done") if st else None,
        },
    }


_DIST = resolve_frontend_dist()
if (_DIST / "assets").is_dir():
    app.mount("/assets", StaticFiles(directory=str(_DIST / "assets")), name="assets")

_ICONS = _DIST / "icons"
if _ICONS.is_dir():
    app.mount("/icons", StaticFiles(directory=str(_ICONS)), name="icons")


def _dist_file(name: str) -> Path:
    return _DIST / name


@app.get("/manifest.webmanifest")
async def web_manifest():
    path = _dist_file("manifest.webmanifest")
    if not path.exists():
        raise HTTPException(status_code=404, detail="manifest missing")
    return FileResponse(
        path,
        media_type="application/manifest+json",
        headers={"Cache-Control": "no-cache"},
    )


@app.get("/sw.js")
async def service_worker():
    path = _dist_file("sw.js")
    if not path.exists():
        raise HTTPException(status_code=404, detail="service worker missing")
    return FileResponse(
        path,
        media_type="application/javascript",
        headers={
            "Cache-Control": "no-cache",
            "Service-Worker-Allowed": "/",
        },
    )


@app.get("/")
async def index_page():
    index = _DIST / "index.html"
    if index.exists():
        return FileResponse(index)
    return {
        "ok": True,
        "msg": "frontend not built yet; run: cd frontend && npm ci && npm run build",
        "health": "/health",
    }


@app.get("/app/{full_path:path}")
@app.get("/plan")
@app.get("/trades")
@app.get("/stats")
@app.get("/settings")
@app.get("/login")
async def spa_pages(full_path: str = ""):
    index = _DIST / "index.html"
    if not index.exists():
        raise HTTPException(status_code=404, detail="frontend not built")
    return FileResponse(index)