import { IAction, IUser, IUserData, UserKey } from "@etsoo/appscript";
import { Utils } from "@etsoo/shared";
import { IProviderProps, IUpdate } from "./IState";
import { State } from "./State";

/**
 * User action type
 * Style like 'const enum' will remove definition of the enum and cause module errors
 */
export enum UserActionType {
  // Login
  Login = "LOGIN",

  // Logout
  Logout = "LOGOUT",

  // Update
  Update = "UPDATE",

  // Unauthorized
  Unauthorized = "UNAUTHORIZED"
}

/**
 * User action to manage the user
 */
export interface UserAction<D extends IUser> extends IAction {
  /**
   * Action type
   */
  type: UserActionType;

  /**
   * User data
   */
  user?: IUserData;

  /**
   * User update callback
   */
  update?: (state: D) => void;
}

/**
 * User provider props
 */
export type UserProviderProps<D extends IUser> = IProviderProps<UserAction<D>>;

/**
 * Users calls with the state
 */
export interface UserCalls<D extends IUser> extends IUpdate<D, UserAction<D>> {}

/**
 * User state
 */
export class UserState<D extends IUser> {
  /**
   * Context
   */
  readonly context;

  /**
   * Provider
   */
  readonly provider;

  /**
   * Constructor
   */
  constructor() {
    const { context, provider } = State.create<
      D,
      UserAction<D>,
      UserCalls<D>,
      UserProviderProps<D>
    >(
      (state, action) => {
        // User reducer
        switch (action.type) {
          case UserActionType.Login:
            const lastChangedFields =
              state.authorized && action.user
                ? this.getChangedFields(action.user, state)
                : undefined;
            return {
              ...action.user!,
              authorized: true,
              lastChangedFields
            } as D;
          case UserActionType.Logout:
            return {
              ...state, // Keep other user data
              lastChangedFields: undefined,
              token: undefined, // Remove token
              authorized: false // Flag as unauthorized
            };
          case UserActionType.Update:
            if (action.update) {
              var newState = { ...state };
              action.update(newState);
              newState.lastChangedFields = this.getChangedFields(
                newState,
                state
              );
              return newState;
            }
            return state;
          case UserActionType.Unauthorized:
            // Avoid multiple updates (For example, multiple API calls failed with 405)
            if (state.authorized === false) return state;

            return {
              ...state, // Keep other user data and token for refresh
              lastChangedFields: undefined,
              authorized: false // Flag as unauthorized
            };
          default:
            return state;
        }
      },
      {} as D,
      {} as UserCalls<D>
    );

    this.context = context;
    this.provider = provider;
  }

  private getChangedFields(input: object, init: object) {
    return Utils.objectUpdated(input, init, [
      "authorized",
      "seconds",
      "lastChangedFields"
    ]) as UserKey[];
  }
}