auto-stock/backend/app/api/endpoints/kis_credentials.py

"""사용자별 KIS(한국투자증권) 자격증명 관리 API (멀티테넌트 1단계, 설계문서 §5.3).

- 저장/삭제는 "조회 → upsert/삭제 → 응답"이 한 요청 안에서 원자적으로 끝나야 하므로
  auth.py 의 register/login 과 같은 성격으로 엔드포인트에서 직접 세션을 커밋한다
  (CLAUDE.md §3.2 예외 — 실시간 계층이 아님).
- 평문 app_key/app_secret/account_no 는 어떤 응답·로그에도 노출하지 않는다
  (app_key_hint·마스킹된 계좌번호만 노출).
- API 키(X-API-Key=SECRET_KEY) 호출자는 `get_current_user` 가 legacy owner 로
  매핑하므로(§5.4), legacy owner 도 없는 최초 상태(`user.id is None`)에서만 400을
  반환하고 그 외에는 정상적으로 legacy owner 본인의 자격증명을 다룬다.
"""
import asyncio
import hashlib
import logging
import time
from datetime import datetime

from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel, Field, field_validator
from sqlalchemy import select
from sqlalchemy.exc import IntegrityError
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.crypto import CredentialDecryptError, current_key_version, decrypt, encrypt, is_encryption_configured
from app.core.database import get_db
from app.core.tenant_auth import CurrentUser, get_current_user
from app.models.models import UserKisCredential
from app.services.korea_investment_api import KoreaInvestmentAPI
from app.services.tenant.registry import user_context_registry
from app.core.timeutil import now_kst

logger = logging.getLogger(__name__)
router = APIRouter()

_VERIFY_COOLDOWN_SEC = 60
# user_id -> 마지막 verify 시도 monotonic 시각 (인메모리, 프로세스 재시작 시 리셋되어도 무방)
_last_verify_attempt: dict[int, float] = {}


# ── 스키마 ────────────────────────────────────────────────────────────────
class CredentialsIn(BaseModel):
    mode: str
    app_key: str = Field(..., min_length=1)
    app_secret: str = Field(..., min_length=1)
    account_no: str = Field(..., min_length=1)

    @field_validator("mode")
    @classmethod
    def _mode_valid(cls, v: str) -> str:
        if v not in ("virtual", "real"):
            raise ValueError("mode는 virtual 또는 real 이어야 합니다.")
        return v

    @field_validator("account_no")
    @classmethod
    def _account_no_valid(cls, v: str) -> str:
        digits = v.replace("-", "")
        if not digits.isdigit() or len(digits) != 10:
            raise ValueError("계좌번호는 하이픈 제거 후 숫자 10자리(계좌 8자리+상품코드 2자리)여야 합니다.")
        return digits


class CredentialsOut(BaseModel):
    mode: str
    app_key_hint: str
    account_masked: str
    is_enabled: bool
    auto_trade_enabled: bool
    last_verified_at: datetime | None
    updated_at: datetime | None
    decrypt_error: bool = False


class AutoTradeIn(BaseModel):
    enabled: bool


class VerifyOut(BaseModel):
    ok: bool
    balance_summary: dict
    verified_at: datetime


# ── 헬퍼 ─────────────────────────────────────────────────────────────────
def _require_user_id(user: CurrentUser) -> int:
    if user.id is None:
        raise HTTPException(status_code=400, detail="관리자 계정을 먼저 생성하세요.")
    return user.id


async def _get_own(db: AsyncSession, user_id: int) -> UserKisCredential | None:
    result = await db.execute(select(UserKisCredential).where(UserKisCredential.user_id == user_id))
    return result.scalar_one_or_none()


def _mask_account(account_no_plain: str) -> str:
    """계좌 8자리 기준 마스킹: '******' + 뒤 2자리 (상품코드 제외)."""
    acct = account_no_plain[:8]
    return "******" + acct[-2:]


async def _to_out(cred: UserKisCredential) -> CredentialsOut:
    """계좌번호 마스킹 표시를 위해 복호화(M4: 스레드로 위임)한다.

    복호화 실패(L2, 키 로테이션 실패 등)는 500 대신 `decrypt_error=true`로 응답해
    마스킹 계좌 대신 원인 진단이 가능함을 알린다.
    """
    try:
        account_masked = _mask_account(
            await asyncio.to_thread(decrypt, cred.account_no_enc, cred.key_version)
        )
        decrypt_error = False
    except CredentialDecryptError as e:
        logger.error("[KISCredentials] 계좌번호 복호화 실패 user_id=%s: %s", cred.user_id, e)
        account_masked = "******"
        decrypt_error = True

    return CredentialsOut(
        mode=cred.mode,
        app_key_hint=(cred.app_key_hint or "") + "…",
        account_masked=account_masked,
        is_enabled=cred.is_enabled,
        auto_trade_enabled=cred.auto_trade_enabled,
        last_verified_at=cred.last_verified_at,
        updated_at=cred.updated_at,
        decrypt_error=decrypt_error,
    )


def _pick_float(d: dict, keys: list[str]) -> float:
    for k in keys:
        v = d.get(k)
        if v not in (None, ""):
            try:
                return float(v)
            except (TypeError, ValueError):
                continue
    return 0.0


# ── 엔드포인트 ────────────────────────────────────────────────────────────
@router.get("/credentials", response_model=CredentialsOut)
async def get_credentials(
    user: CurrentUser = Depends(get_current_user), db: AsyncSession = Depends(get_db)
):
    user_id = _require_user_id(user)
    cred = await _get_own(db, user_id)
    if cred is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="등록된 KIS 자격증명이 없습니다.")
    return await _to_out(cred)


@router.put("/credentials", response_model=CredentialsOut)
async def put_credentials(
    body: CredentialsIn,
    user: CurrentUser = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    user_id = _require_user_id(user)
    if not is_encryption_configured():
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="CREDENTIALS_ENCRYPTION_KEY/SECRET_KEY 미설정 또는 기본값 — 자격증명 암호화 저장 불가",
        )

    app_key_hash = hashlib.sha256(body.app_key.encode()).hexdigest()
    dup = await db.execute(
        select(UserKisCredential).where(
            UserKisCredential.app_key_hash == app_key_hash,
            UserKisCredential.user_id != user_id,
        )
    )
    if dup.scalar_one_or_none() is not None:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="이미 다른 사용자가 등록한 앱키입니다.")

    now = now_kst()
    cred = await _get_own(db, user_id)
    is_new = cred is None
    if is_new:
        cred = UserKisCredential(user_id=user_id, auto_trade_enabled=False)
        db.add(cred)

    cred.mode = body.mode
    cred.app_key_enc = encrypt(body.app_key)
    cred.app_secret_enc = encrypt(body.app_secret)
    cred.account_no_enc = encrypt(body.account_no)
    cred.account_product_code = body.account_no[8:10]
    cred.app_key_hash = app_key_hash
    cred.app_key_hint = body.app_key[:6]
    cred.is_enabled = False
    cred.last_verified_at = None
    cred.key_version = current_key_version()
    cred.updated_at = now

    try:
        await db.commit()
    except IntegrityError:
        await db.rollback()
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="이미 다른 사용자가 등록한 앱키입니다.")
    await db.refresh(cred)

    await user_context_registry.invalidate(user_id)
    logger.info(
        "[KISCredentials] 자격증명 %s user_id=%s mode=%s app_key=%s…",
        "생성" if is_new else "교체", user_id, body.mode, body.app_key[:6],
    )
    return await _to_out(cred)


@router.delete("/credentials", status_code=status.HTTP_204_NO_CONTENT)
async def delete_credentials(
    user: CurrentUser = Depends(get_current_user), db: AsyncSession = Depends(get_db)
):
    user_id = _require_user_id(user)
    cred = await _get_own(db, user_id)
    if cred is not None:
        await db.delete(cred)
        await db.commit()
    await user_context_registry.invalidate(user_id)
    logger.info("[KISCredentials] 자격증명 삭제 user_id=%s", user_id)


@router.post("/credentials/verify", response_model=VerifyOut)
async def verify_credentials(
    user: CurrentUser = Depends(get_current_user), db: AsyncSession = Depends(get_db)
):
    user_id = _require_user_id(user)
    cred = await _get_own(db, user_id)
    if cred is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="등록된 KIS 자격증명이 없습니다.")

    now_mono = time.monotonic()
    last = _last_verify_attempt.get(user_id)
    if last is not None:
        remaining = _VERIFY_COOLDOWN_SEC - (now_mono - last)
        if remaining > 0:
            raise HTTPException(
                status_code=status.HTTP_429_TOO_MANY_REQUESTS,
                detail=f"{int(remaining) + 1}초 후 다시 시도하세요.",
            )
    _last_verify_attempt[user_id] = now_mono

    try:
        app_key = await asyncio.to_thread(decrypt, cred.app_key_enc, cred.key_version)
        app_secret = await asyncio.to_thread(decrypt, cred.app_secret_enc, cred.key_version)
        account_no = await asyncio.to_thread(decrypt, cred.account_no_enc, cred.key_version)
    except CredentialDecryptError as e:
        logger.error("[KISCredentials] verify 복호화 실패 user_id=%s: %s", user_id, e)
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="자격증명 복호화 실패 — 서버 키 변경 여부 확인")

    temp_kis = KoreaInvestmentAPI.for_user(
        user_id=user_id, app_key=app_key, app_secret=app_secret, account_no=account_no, mode=cred.mode,
    )
    try:
        balance = await temp_kis.get_balance()
    except Exception as e:
        # L5: KIS 예외 원문 대신 예외 타입명만 노출(방어적 — 현재 KIS 오류 본문에 키는 없음).
        logger.warning("[KISCredentials] verify 실패 user_id=%s: %s", user_id, e)
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"KIS 연결 확인 실패: {type(e).__name__} — 연결 실패",
        )
    finally:
        await temp_kis.close()

    if balance.get("rt_cd") != "0":
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=balance.get("msg1") or "KIS 잔고 조회 실패",
        )

    output2 = balance.get("output2") or {}
    if isinstance(output2, list):
        output2 = output2[0] if output2 else {}

    balance_summary = {
        "available_cash": _pick_float(output2, ["dnca_tot_amt", "d2_deposit", "nass_amt"]),
        "total_assets": _pick_float(output2, ["tot_evlu_amt", "tot_evlu_amt_smtl"]),
        "stock_value": _pick_float(output2, ["scts_evlu_amt", "evlu_amt_smtl_amt"]),
    }

    now = now_kst()
    cred.last_verified_at = now
    cred.is_enabled = True
    cred.updated_at = now
    await db.commit()

    logger.info("[KISCredentials] verify 성공 user_id=%s mode=%s", user_id, cred.mode)
    return VerifyOut(ok=True, balance_summary=balance_summary, verified_at=now)


@router.patch("/auto-trade", response_model=CredentialsOut)
async def patch_auto_trade(
    body: AutoTradeIn,
    user: CurrentUser = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    user_id = _require_user_id(user)
    cred = await _get_own(db, user_id)
    if cred is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="등록된 KIS 자격증명이 없습니다.")

    if body.enabled and not cred.is_enabled:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="먼저 연결 테스트(verify)를 통과해야 자동매매를 활성화할 수 있습니다.",
        )

    cred.auto_trade_enabled = body.enabled
    cred.updated_at = now_kst()
    await db.commit()
    # H3: 캐시된 UserContext.auto_trade_enabled 스냅샷이 갱신되도록 무효화(다음 호출에서 재조립).
    await user_context_registry.invalidate(user_id)
    logger.info("[KISCredentials] auto_trade_enabled=%s user_id=%s", body.enabled, user_id)
    return await _to_out(cred)