from __future__ import annotations

import hashlib
from typing import Optional

import aiosqlite
from fastapi import APIRouter, Depends, Request
from fastapi.responses import JSONResponse

from api.deps import error_response, get_db
from common import ApiModel
from security import JwtConfig, create_jwt
from settings import settings
from users import repository as users_db
from users.models import User

router = APIRouter(prefix="/auth", tags=["auth-v2"])


class RegisterBody(ApiModel):
    email: str
    password: str
    display_name: str


class LoginBody(ApiModel):
    email: str
    password: str


class TokenResponse(ApiModel):
    access_token: str
    token_type: str = "bearer"
    user: User


def _hash_pw(pw: str) -> str:
    # Placeholder; replace with proper hashing (bcrypt/argon2) later
    return hashlib.sha256(pw.encode("utf-8")).hexdigest()


def _jwt_config() -> JwtConfig:
    # Secrets can be provided base64-encoded via env; fallback to deterministic dev defaults (NOT for prod)
    import base64

    if settings.access_secret_b64:
        access = base64.b64decode(settings.access_secret_b64)
    else:
        access = b"dev-access-secret-change-me-32bytes!!"[:32]
    if settings.refresh_secret_b64:
        refresh = base64.b64decode(settings.refresh_secret_b64)
    else:
        refresh = b"dev-refresh-secret-change-me-32bytes!!"[:32]
    return JwtConfig(
        issuer=settings.jwt_issuer,
        audience=settings.jwt_audience,
        access_secret=access,
        refresh_secret=refresh,
        access_ttl_seconds=settings.access_ttl_seconds,
        refresh_ttl_seconds=settings.refresh_ttl_seconds,
    )


def _token_pair_for_user(user: User) -> tuple[str, str]:
    cfg = _jwt_config()
    sub = str(user.id)
    access = create_jwt(cfg, sub, kind="access", extra={"user_id": user.id, "email": user.email})
    refresh = create_jwt(cfg, sub, kind="refresh")
    return access, refresh


@router.post("/register", response_model=TokenResponse, operation_id="register")
async def register(request: Request, body: RegisterBody, conn: aiosqlite.Connection = Depends(get_db)):
    existing = await users_db.get_by_email(conn, body.email)
    if existing:
        return error_response(request, 400, "Email already registered")
    uid = await users_db.insert_user(conn, body.email, body.display_name)
    await users_db.set_local_credentials(conn, uid, _hash_pw(body.password))
    user = await users_db.get_by_email(conn, body.email)
    assert user is not None
    access, refresh = _token_pair_for_user(user)
    resp = JSONResponse(TokenResponse(access_token=access, user=user).model_dump(by_alias=True))
    # HttpOnly refresh cookie
    resp.set_cookie(
        key="refresh_token",
        value=refresh,
        httponly=True,
        secure=False,
        samesite="lax",
        max_age=settings.refresh_ttl_seconds,
        path="/api/v1/auth/refresh",
    )
    return resp


@router.post("/login", response_model=TokenResponse, operation_id="loginV2")
async def login(request: Request, body: LoginBody, conn: aiosqlite.Connection = Depends(get_db)):
    user: Optional[User] = await users_db.get_by_email(conn, body.email)
    if not user:
        return error_response(request, 401, "Invalid credentials")
    stored = await users_db.get_local_password_hash(conn, user.id)
    if not stored or stored != _hash_pw(body.password):
        return error_response(request, 401, "Invalid credentials")
    access, refresh = _token_pair_for_user(user)
    resp = JSONResponse(TokenResponse(access_token=access, user=user).model_dump(by_alias=True))
    resp.set_cookie(
        key="refresh_token",
        value=refresh,
        httponly=True,
        secure=False,
        samesite="lax",
        max_age=settings.refresh_ttl_seconds,
        path="/api/v1/auth/refresh",
    )
    return resp


class RefreshResponse(ApiModel):
    access_token: str
    token_type: str = "bearer"


@router.post("/refresh", response_model=RefreshResponse, operation_id="refreshV2")
async def refresh(request: Request):
    token = request.cookies.get("refresh_token")
    if not token:
        return error_response(request, 401, "Unauthorized")
    from security import verify_jwt

    try:
        _h, payload = verify_jwt(_jwt_config(), token, expected_kind="refresh")
    except Exception:
        return error_response(request, 401, "Unauthorized")
    user_id = str(payload.get("sub"))
    access = create_jwt(_jwt_config(), user_id, kind="access")
    return RefreshResponse(access_token=access)


@router.post("/logout", operation_id="logoutV2")
async def logout():
    resp = JSONResponse({"ok": True})
    resp.delete_cookie("refresh_token", path="/api/v1/auth/refresh")
    return resp