import bcrypt from "bcrypt";
import type { FastifyInstance } from "fastify";
import { eq, roles, users, type Db } from "@parking/db";
import {
  clearAuthCookies,
  newCsrfToken,
  permissionsFor,
  requireAuth,
  setAuthCookies,
} from "../auth.js";

// Local auth: username + bcrypt password → signed JWT in an HttpOnly cookie.
// Fully offline; no external identity provider. See wiki/entities/local-jwt-auth.md.

interface LoginBody {
  username: string;
  password: string;
}

const LANGS = ["sq", "en"] as const;
type Lang = (typeof LANGS)[number];
interface LanguageBody {
  language: Lang;
}

const THEMES = ["dark", "light"] as const;
type Theme = (typeof THEMES)[number];
interface ThemeBody {
  theme: Theme;
}

/** The session shape the SPA bootstraps from: identity + role + its permission
 *  list (so the UI can gate nav/routes) + language. Role NAME is for display; the
 *  permissions are the source of truth. */
function sessionView(
  db: Db,
  user: {
    id: string;
    username: string;
    roleId: string;
    language: string;
    theme: string;
    fullName?: string | null;
  },
) {
  const role = db.select().from(roles).where(eq(roles.id, user.roleId)).get();
  const permissions = [...permissionsFor(user.roleId)];
  return {
    id: user.id,
    username: user.username,
    roleId: user.roleId,
    roleName: role?.name ?? user.roleId,
    permissions,
    language: user.language,
    theme: user.theme,
    fullName: user.fullName ?? null,
  };
}

export async function authRoutes(app: FastifyInstance, db: Db): Promise<void> {
  app.post<{ Body: LoginBody }>("/api/auth/login", async (req, reply) => {
    const { username, password } = req.body ?? {};
    if (!username || !password) {
      return reply.code(400).send({ error: "username and password required" });
    }

    const user = await db.select().from(users).where(eq(users.username, username)).get();

    // Always run a bcrypt compare to avoid leaking which usernames exist (timing).
    const hash = user?.passwordHash ?? "$2b$10$invalidinvalidinvalidinvalidinvalidinvalidinv";
    const ok = await bcrypt.compare(password, hash);
    if (!user || !ok) {
      return reply.code(401).send({ error: "invalid credentials" });
    }

    const csrf = newCsrfToken();
    // No expiresIn: the token is valid until explicit logout (see auth.ts). The
    // token carries roleId (not the permission list) — perms resolve per-request,
    // so a role edit applies immediately with no re-login.
    const token = await reply.jwtSign({
      sub: user.id,
      username: user.username,
      roleId: user.roleId,
      csrf,
    });
    setAuthCookies(reply, token, csrf);
    // `language` is NOT in the JWT (identity/role only) — it's a mutable preference
    // read from the DB, so changing it needs no token refresh.
    return sessionView(db, user);
  });

  app.post("/api/auth/logout", async (_req, reply) => {
    clearAuthCookies(reply);
    return { ok: true };
  });

  // Who am I — used by the SPA to bootstrap session state on load. Reads the live
  // `language` preference from the DB (not the token).
  app.get(
    "/api/auth/me",
    { preHandler: requireAuth },
    async (req, reply) => {
      const row = await db.select().from(users).where(eq(users.id, req.user.sub)).get();
      if (!row) {
        // The user was deleted while their cookie was still valid — clear it.
        clearAuthCookies(reply);
        return reply.code(401).send({ error: "session no longer valid" });
      }
      return sessionView(db, row);
    },
  );

  // Change MY own UI language preference (any signed-in user). Persisted to the
  // users row so it's restored on the next login, from any booth. See i18n.md.
  app.put<{ Body: LanguageBody }>(
    "/api/auth/language",
    { preHandler: requireAuth },
    async (req, reply) => {
      const language = req.body?.language;
      if (!language || !LANGS.includes(language)) {
        return reply.code(400).send({ error: `language must be one of: ${LANGS.join(", ")}` });
      }
      await db.update(users).set({ language }).where(eq(users.id, req.user.sub)).run();
      return { language };
    },
  );

  // Change MY own UI theme preference (any signed-in user). Persisted to the users
  // row like `language`, so it's restored on the next login from any booth.
  app.put<{ Body: ThemeBody }>(
    "/api/auth/theme",
    { preHandler: requireAuth },
    async (req, reply) => {
      const theme = req.body?.theme;
      if (!theme || !THEMES.includes(theme)) {
        return reply.code(400).send({ error: `theme must be one of: ${THEMES.join(", ")}` });
      }
      await db.update(users).set({ theme }).where(eq(users.id, req.user.sub)).run();
      return { theme };
    },
  );
}