artcraft-services/packages/components/src/session/SessionWrapper.ts

import { GetSessionInfo, GetSessionInfoIsOk, SessionInfoSuccessResponse } from '../api/session/GetSessionInfo'

// A lot of the APIs return null or leave values absent. 
// I need to pick a single strategy and stick with it.
type MaybeString = string | null | undefined;

/**
 * SessionWrapper can wrap each of the following states:
 * 
 *   1) logged-in session
 *   2) non-existing session (logged out)
 *   3) lookup errors, server errors, 401, etc. (logged out)
 * 
 * It then makes frontend permission checking simple.
 */
export class SessionWrapper {
  sessionStateResponse?: SessionInfoSuccessResponse;

  private constructor(sessionStateResponse?: SessionInfoSuccessResponse) {
    if (sessionStateResponse !== undefined) {
      this.sessionStateResponse = sessionStateResponse;
    }
  }

  // Perform lookup and return a wrapper of a valid, inval
  public static async lookupSession() : Promise<SessionWrapper> {
    let response = await GetSessionInfo();
    if (GetSessionInfoIsOk(response)) {
      return SessionWrapper.wrapResponse(response);
    } else {
      return SessionWrapper.emptySession();
    }
  }

  public static emptySession() : SessionWrapper {
    return new SessionWrapper();
  }

  public static wrapResponse(sessionStateResponse: SessionInfoSuccessResponse) : SessionWrapper {
    return new SessionWrapper(sessionStateResponse);
  }

  public isLoggedIn() : boolean {
    return this.sessionStateResponse?.logged_in || false;
  }

  public getUsername() : string | undefined {
    return this.sessionStateResponse?.user?.username;
  }

  public getDisplayName() : string | undefined {
    return this.sessionStateResponse?.user?.display_name;
  }

  public getEmailGravatarHash() : string | undefined {
    return this.sessionStateResponse?.user?.email_gravatar_hash;
  }

  public canEditUserProfile(username: string) : boolean {
    if (this.getUsername() === username) {
      return true;
    }
    return this.canEditOtherUsersProfiles();
  }

  public canEditTtsModelByUserToken(userToken: MaybeString) : boolean {
    return this.canEditOtherUsersTtsModels() || this.userTokenMatches(userToken);
  }

  public canDeleteTtsModelByUserToken(userToken: MaybeString) : boolean {
    return this.canDeleteOtherUsersTtsModels() || this.userTokenMatches(userToken);
  }

  public canDeleteTtsResultByUserToken(userToken: MaybeString) : boolean {
    return this.canDeleteOtherUsersTtsResults() || this.userTokenMatches(userToken);
  }

  public canDeleteW2lTemplateByUserToken(userToken: MaybeString) : boolean {
    return this.canDeleteOtherUsersW2lTemplates() || this.userTokenMatches(userToken);
  }

  public canDeleteW2lResultByUserToken(userToken: MaybeString) : boolean {
    return this.canDeleteOtherUsersW2lResults() || this.userTokenMatches(userToken);
  }

  public canUseTts() : boolean {
    return this.sessionStateResponse?.user?.can_use_tts || true; // NB: Default true.
  }

  public canUseW2l() : boolean {
    return this.sessionStateResponse?.user?.can_use_w2l || true; // NB: Default true
  }

  public canUploadTtsModels() : boolean {
    return this.sessionStateResponse?.user?.can_upload_tts_models || false;
  }

  public canUploadW2lTemplates() : boolean {
    return this.sessionStateResponse?.user?.can_upload_w2l_templates || false;
  }

  public canBanUsers() : boolean {
    return this.sessionStateResponse?.user?.can_ban_users || false;
  }

  public canEditCategories() : boolean {
    // TODO / NB: There aren't fine-grained controls over categories.
    return this.canBanUsers();
  }

  public canApproveW2lTemplates() : boolean {
    return this.sessionStateResponse?.user?.can_approve_w2l_templates || false;
  }

  public canEditOtherUsersProfiles() : boolean {
    return this.sessionStateResponse?.user?.can_edit_other_users_profiles || false;
  }

  public canEditOtherUsersTtsModels() : boolean {
    return this.sessionStateResponse?.user?.can_edit_other_users_tts_models || false;
  }

  public canDeleteOtherUsersTtsModels() : boolean {
    return this.sessionStateResponse?.user?.can_delete_other_users_tts_models || false;
  }

  public canDeleteOtherUsersTtsResults() : boolean {
    return this.sessionStateResponse?.user?.can_delete_other_users_tts_results || false;
  }

  public canDeleteOtherUsersW2lTemplates() : boolean {
    return this.sessionStateResponse?.user?.can_delete_other_users_w2l_templates || false;
  }

  public canDeleteOtherUsersW2lResults() : boolean {
    return this.sessionStateResponse?.user?.can_delete_other_users_w2l_results || false;
  }
  
  public canEditTtsResultAsUserOrMod(creatorUserToken: MaybeString) : boolean {
    if (this.userTokenMatches(creatorUserToken)) {
      return true;
    }
    return this.canDeleteOtherUsersTtsResults(); // TODO: There is no granular permission for this yet.
  }

  public deleteTtsResultAsMod(creatorUserToken: MaybeString) : boolean {
    if (this.userTokenMatches(creatorUserToken)) {
      return true;
    }
    return this.canDeleteOtherUsersTtsResults();
  }

  public deleteTtsModelAsMod(creatorUserToken: MaybeString) : boolean {
    if (this.userTokenMatches(creatorUserToken)) {
      return true;
    }
    return this.canDeleteOtherUsersTtsModels();
  }

  public canEditW2lResultAsUserOrMod(creatorUserToken: MaybeString) : boolean {
    if (this.userTokenMatches(creatorUserToken)) {
      return true;
    }
    return this.canDeleteOtherUsersW2lResults(); // TODO: There is no granular permission for this yet.
  }

  public canDeleteW2lResultAsUserOrMod(creatorUserToken: MaybeString) : boolean {
    if (this.userTokenMatches(creatorUserToken)) {
      return true;
    }
    return this.canDeleteOtherUsersW2lResults();
  }

  public userTokenMatches(otherUserToken: MaybeString) : boolean {
    // Default to false if user token on either side is falsey. 
    if (!otherUserToken) {
      return false;
    }
    const ourUserToken = this.sessionStateResponse?.user?.user_token;
    if (!ourUserToken) {
      return false;
    }
    return ourUserToken === otherUserToken;
  }
}