import { writable } from "svelte/store";

export interface Err {
  type: Failure;
  txHash?: string;
  message?: string;
}

export enum Failure {
  TransactionFailed = 1,
  NotAuthenticated = 2,
  InsufficientBalance = 3,
}

export const error = writable<Err | null>(null);

export class Unreachable extends Error {
  constructor(value?: never) {
    if (value) {
      super('unreachable value reached: ' + value);
    } else {
      super('unreachable code reached');
    }
  }
}

class AssertionError extends Error {
  constructor(message?: string) {
    if (message) {
      super(`assertion failed: ${message}`);
    } else {
      super(`assertion failed`);
    }
  }
}

export function assert(value: unknown, message?: string): asserts value {
  if (! value) {
    throw new AssertionError(message);
  }
}

export function assertEq(actual: unknown, expected: unknown, message?: string): void {
  if (actual !== expected) {
    throw new AssertionError(`assertion failed: expected '${expected}', got '${actual}': ${message}`);
  }
}