from datetime import datetime, timezone
from fastapi import APIRouter, Depends, HTTPException, Request, status
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.database import get_db
from app.core.security import verify_password, hash_password, create_access_token, get_current_user
from app.models.user import User
from app.schemas.auth import LoginRequest, TokenResponse, UserBrief

router = APIRouter(prefix="/auth", tags=["认证"])


async def _try_ldap_auth(username: str, password: str):
    """尝试 LDAP 认证，成功返回用户信息 dict，失败返回 None"""
    from app.core.database import async_session
    from app.models.ldap_config import LdapConfig
    from app.core.crypto import decrypt_password
    import json

    async with async_session() as db:
        result = await db.execute(select(LdapConfig).limit(1))
        ldap = result.scalar_one_or_none()
        if not ldap or not ldap.ldap_host:
            return None

    try:
        import ldap as _ldap
        protocol = "ldaps" if ldap.use_ldaps else "ldap"
        uri = f"{protocol}://{ldap.ldap_host}:{ldap.ldap_port}"
        conn = _ldap.initialize(uri)
        conn.protocol_version = 3
        if ldap.use_ldaps:
            conn.set_option(_ldap.OPT_X_TLS_REQUIRE_CERT, _ldap.OPT_X_TLS_NEVER)
        conn.set_option(_ldap.OPT_NETWORK_TIMEOUT, 10)

        # Admin bind to search user
        conn.simple_bind_s(ldap.admin_dn, decrypt_password(ldap.admin_password))

        # Search with uid filter
        base_filter = ldap.search_filter or "(objectClass=inetOrgPerson)"
        if "%s" in base_filter:
            user_filter = base_filter.replace("%s", username)
        else:
            user_filter = f"(&{base_filter}(uid={username}))"

        results = conn.search_s(
            ldap.base_dn, _ldap.SCOPE_SUBTREE, user_filter,
            ["uid", "cn", "mail", "telephoneNumber"],
        )
        if not results or not results[0][0]:
            conn.unbind_s()
            return None

        user_dn, user_attrs = results[0]

        # Verify password by binding as user
        try:
            conn.simple_bind_s(user_dn, password)
        except Exception:
            conn.unbind_s()
            return None

        # Extract info
        def _attr(key):
            vals = user_attrs.get(key, [])
            return vals[0].decode("utf-8", errors="ignore") if vals else ""

        user_mapping = json.loads(ldap.user_mapping) if ldap.user_mapping else {}
        info = {
            "username": _attr(user_mapping.get("username", "uid")) or username,
            "display_name": _attr(user_mapping.get("display_name", "cn")) or username,
            "email": _attr(user_mapping.get("email", "mail")) or None,
        }
        conn.unbind_s()
        return info
    except Exception:
        return None


@router.post("/login", response_model=TokenResponse)
async def login(req: LoginRequest, request: Request, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(User).where(User.username == req.username))
    user = result.scalar_one_or_none()

    auth_source = "local"

    if user:
        # 本地用户存在，用本地密码验证
        if not verify_password(req.password, user.hashed_password):
            # 本地密码不对，记录失败
            from app.services.audit_logger import log_operation
            await log_operation(db, action="login_failed", username=req.username,
                                detail="登录失败: 用户名或密码错误", request=request)
            await db.commit()
            raise HTTPException(status_code=401, detail="用户名或密码错误")
    else:
        # 本地没有该用户，尝试 LDAP 认证
        ldap_info = await _try_ldap_auth(req.username, req.password)
        if not ldap_info:
            from app.services.audit_logger import log_operation
            await log_operation(db, action="login_failed", username=req.username,
                                detail="登录失败: 本地和LDAP均未通过", request=request)
            await db.commit()
            raise HTTPException(status_code=401, detail="用户名或密码错误")

        # LDAP 认证成功，自动创建本地用户
        user = User(
            username=ldap_info["username"],
            display_name=ldap_info["display_name"],
            email=ldap_info.get("email"),
            hashed_password=hash_password(req.password),
            role="developer",
            is_active=True,
        )
        db.add(user)
        await db.flush()
        auth_source = "ldap"

    if not user.is_active:
        raise HTTPException(status_code=403, detail="用户已禁用")

    user.last_login = datetime.now(timezone.utc)

    from app.services.audit_logger import log_operation
    await log_operation(db, action="login", user_id=user.id, username=user.username,
                        detail=f"登录成功 ({auth_source})", request=request)
    await db.commit()

    token = create_access_token(data={"sub": str(user.id), "role": user.role})

    return TokenResponse(
        access_token=token,
        user=UserBrief(
            id=user.id,
            username=user.username,
            display_name=user.display_name,
            role=user.role,
            email=user.email,
        ),
    )


@router.get("/me", response_model=UserBrief)
async def get_me(current_user: User = Depends(get_current_user)):
    return UserBrief(
        id=current_user.id,
        username=current_user.username,
        display_name=current_user.display_name,
        role=current_user.role,
        email=current_user.email,
    )


@router.post("/logout")
async def logout():
    return {"message": "已登出"}