import { appDatabase, AppDatabaseKey, appStorage, AppStorageKey } from '../storage/local';
import { API_URL } from '../constants/api-url';
import { WEB_URL } from '../constants/web-url';
import { clientReplace, notifySessionEnd, notifySessionStart } from './client-navigation';
import { mapUserPrivileges } from './map-user-privileges';
import { safeInternalPath } from './safe-internal-path';
import type { AuthUser, TokenPair } from './auth.types';

interface TerminateOptions {
  /** When true, appends ?redirect= so the user returns to their page after re-login.
   *  Defaults to false (intended for 401 / expired token).
   *  Set to false for manual logout so the user lands on a clean login page. */
  preserveRedirect?: boolean;
}

export async function persistTokenPair(tokens: TokenPair): Promise<void> {
  await appDatabase.setItem(AppDatabaseKey.ACCESS_TOKEN, tokens.accessToken);
  await appDatabase.setItem(AppDatabaseKey.REFRESH_TOKEN, tokens.refreshToken);
}

export async function persistUserSession(me: AuthUser): Promise<void> {
  const label = me.isSuperadmin ? 'Superadmin' : (me.privilege?.name ?? me.username);

  await appStorage.setItem(AppStorageKey.USER_ID, me.id);
  await appDatabase.setItem(AppDatabaseKey.USER_PROFILE, {
    id: me.id,
    username: me.username,
    isSuperadmin: me.isSuperadmin,
    privilege: me.privilege,
    name: me.username,
    label,
  });
  await appDatabase.setItem(AppDatabaseKey.USER_PRIVILEGE, mapUserPrivileges(me.permissions, me.isSuperadmin));
}

export async function terminateAuthSession(options: TerminateOptions = {}): Promise<void> {
  const { preserveRedirect = false } = options;

  await appDatabase.removeItem(AppDatabaseKey.USER_PRIVILEGE);
  await appDatabase.removeItem(AppDatabaseKey.USER_PROFILE);
  await appDatabase.removeItem(AppDatabaseKey.ACCESS_TOKEN);
  await appDatabase.removeItem(AppDatabaseKey.REFRESH_TOKEN);
  await appStorage.removeItem(AppStorageKey.USER_ID);

  let loginUrl = WEB_URL.LOGIN;
  const isLoginPage =
    window.location.pathname === WEB_URL.LOGIN || window.location.pathname.startsWith(`${WEB_URL.LOGIN}/`);

  if (!isLoginPage) {
    if (preserveRedirect) {
      loginUrl += `?redirect=${encodeURIComponent(window.location.pathname)}`;
    }

    notifySessionEnd();
    clientReplace(loginUrl);
  }
}

export async function initiateAuthSession(tokens: TokenPair, me: AuthUser): Promise<void> {
  if (!tokens.accessToken) {
    throw new Error('Login response missing access token');
  }

  await persistTokenPair(tokens);
  await persistUserSession(me);
  notifySessionStart();

  const params = new URLSearchParams(window.location.search);
  clientReplace(safeInternalPath(params.get('redirect'), WEB_URL.APP));
}

let refreshInFlight: Promise<TokenPair> | null = null;

export async function refreshAuthSession(): Promise<TokenPair> {
  if (!refreshInFlight) {
    refreshInFlight = rotateRefreshToken().finally(() => {
      refreshInFlight = null;
    });
  }

  return refreshInFlight;
}

async function rotateRefreshToken(): Promise<TokenPair> {
  const refreshToken = await appDatabase.getItem<string>(AppDatabaseKey.REFRESH_TOKEN);
  if (!refreshToken) {
    throw new Error('Missing refresh token');
  }

  const { apiClient } = await import('./api-client');
  const response = await apiClient.request<TokenPair>({
    url: API_URL.AUTH_REFRESH,
    method: 'POST',
    data: { refreshToken },
    skipAuthRefresh: true,
  });
  const tokens: TokenPair = {
    accessToken: response.data.accessToken,
    refreshToken: response.data.refreshToken,
  };

  await persistTokenPair(tokens);
  return tokens;
}

export async function logoutAuthSession(): Promise<void> {
  const refreshToken = await appDatabase.getItem<string>(AppDatabaseKey.REFRESH_TOKEN);

  try {
    if (refreshToken) {
      const { apiClient } = await import('./api-client');
      await apiClient.request({
        url: API_URL.AUTH_REVOKE,
        method: 'POST',
        data: { refreshToken },
        skipAuthRefresh: true,
      });
    }
  } catch {
    // Always clear the local session, even if the server revoke call fails.
  }

  await terminateAuthSession({ preserveRedirect: false });
}