import { GristLoadConfig } from 'app/common/gristUrls';
import { FullUser, UserProfile } from 'app/common/UserAPI';
import { Document } from 'app/gen-server/entity/Document';
import { Organization } from 'app/gen-server/entity/Organization';
import { Workspace } from 'app/gen-server/entity/Workspace';
import { HomeDBManager } from 'app/gen-server/lib/HomeDBManager';
import { IAccessTokens } from 'app/server/lib/AccessTokens';
import { RequestWithLogin } from 'app/server/lib/Authorizer';
import { Comm } from 'app/server/lib/Comm';
import { create } from 'app/server/lib/create';
import { Hosts } from 'app/server/lib/extractOrg';
import { ICreate } from 'app/server/lib/ICreate';
import { IDocStorageManager } from 'app/server/lib/IDocStorageManager';
import { INotifier } from 'app/server/lib/INotifier';
import { IPermitStore } from 'app/server/lib/Permit';
import { ISendAppPageOptions } from 'app/server/lib/sendAppPage';
import { fromCallback } from 'app/server/lib/serverUtils';
import { Sessions } from 'app/server/lib/Sessions';
import * as express from 'express';
import { IncomingMessage } from 'http';

/**
 * Basic information about a Grist server.  Accessible in many
 * contexts, including request handlers and ActiveDoc methods.
 */
export interface GristServer {
  readonly create: ICreate;
  settings?: Readonly<Record<string, unknown>>;
  getHost(): string;
  getHomeUrl(req: express.Request, relPath?: string): string;
  getHomeUrlByDocId(docId: string, relPath?: string): Promise<string>;
  getOwnUrl(): string;
  getOrgUrl(orgKey: string|number): Promise<string>;
  getMergedOrgUrl(req: RequestWithLogin, pathname?: string): string;
  getResourceUrl(resource: Organization|Workspace|Document,
                 purpose?: 'api'|'html'): Promise<string>;
  getGristConfig(): GristLoadConfig;
  getPermitStore(): IPermitStore;
  getExternalPermitStore(): IPermitStore;
  getSessions(): Sessions;
  getComm(): Comm;
  getHosts(): Hosts;
  getHomeDBManager(): HomeDBManager;
  getStorageManager(): IDocStorageManager;
  getNotifier(): INotifier;
  getDocTemplate(): Promise<DocTemplate>;
  getTag(): string;
  sendAppPage(req: express.Request, resp: express.Response, options: ISendAppPageOptions): Promise<void>;
  getAccessTokens(): IAccessTokens;
}

export interface GristLoginSystem {
  getMiddleware(gristServer: GristServer): Promise<GristLoginMiddleware>;
  deleteUser(user: FullUser): Promise<void>;
}

export interface GristLoginMiddleware {
  getLoginRedirectUrl(req: express.Request, target: URL): Promise<string>;
  getSignUpRedirectUrl(req: express.Request, target: URL): Promise<string>;
  getLogoutRedirectUrl(req: express.Request, nextUrl: URL): Promise<string>;
  // Optional middleware for the GET /login, /signup, and /signin routes.
  getLoginOrSignUpMiddleware?(): express.RequestHandler[];
  // Optional middleware for the GET /logout route.
  getLogoutMiddleware?(): express.RequestHandler[];
  // Returns arbitrary string for log.
  addEndpoints(app: express.Express): Promise<string>;
  // Optionally, extract profile from request. Result can be a profile,
  // or null if anonymous (and other methods of determining profile such
  // as a cookie should not be used), or undefined to use other methods.
  getProfile?(req: express.Request|IncomingMessage): Promise<UserProfile|null|undefined>;
}

/**
 * Set the user in the current session.
 */
export async function setUserInSession(req: express.Request, gristServer: GristServer, profile: UserProfile) {
  const scopedSession = gristServer.getSessions().getOrCreateSessionFromRequest(req);
  // Make sure session is up to date before operating on it.
  // Behavior on a completely fresh session is a little awkward currently.
  const reqSession = (req as any).session;
  if (reqSession?.save) {
    await fromCallback(cb => reqSession.save(cb));
  }
  await scopedSession.updateUserProfile(req, profile);
}

export interface RequestWithGrist extends express.Request {
  gristServer?: GristServer;
}

export interface DocTemplate {
  page: string,
  tag: string,
}

/**
 * A very minimal GristServer object that throws an error if its bluff is
 * called.
 */
export function createDummyGristServer(): GristServer {
  return {
    create,
    settings: {},
    getHost() { return 'localhost:4242'; },
    getHomeUrl() { return 'http://localhost:4242'; },
    getHomeUrlByDocId() { return Promise.resolve('http://localhost:4242'); },
    getMergedOrgUrl() { return 'http://localhost:4242'; },
    getOwnUrl() { return 'http://localhost:4242'; },
    getPermitStore() { throw new Error('no permit store'); },
    getExternalPermitStore() { throw new Error('no external permit store'); },
    getGristConfig() { return { homeUrl: '', timestampMs: 0 }; },
    getOrgUrl() { return Promise.resolve(''); },
    getResourceUrl() { return Promise.resolve(''); },
    getSessions() { throw new Error('no sessions'); },
    getComm() { throw new Error('no comms'); },
    getHosts() { throw new Error('no hosts'); },
    getHomeDBManager() { throw new Error('no db'); },
    getStorageManager() { throw new Error('no storage manager'); },
    getNotifier() { throw new Error('no notifier'); },
    getDocTemplate() { throw new Error('no doc template'); },
    getTag() { return 'tag'; },
    sendAppPage() { return Promise.resolve(); },
    getAccessTokens() { throw new Error('no access tokens'); },
  };
}