task.exceptions.ts

import {
  BadRequestException,
  ConflictException,
  NotFoundException,
} from '@nestjs/common';
import { ErrorCode, HasErrorCode } from '../../common/exceptions/error-codes';
import { TaskStatus } from '../entities/task-status.enum';

/** Task id did not resolve to a stored task. */
export class TaskNotFoundException
  extends NotFoundException
  implements HasErrorCode
{
  readonly code = ErrorCode.TaskNotFound;

  constructor(id: string) {
    super(`Task ${id} not found`);
  }
}

/** A status change that the transition state machine forbids. */
export class IllegalStatusTransitionException
  extends ConflictException
  implements HasErrorCode
{
  readonly code = ErrorCode.IllegalStatusTransition;

  constructor(from: TaskStatus, to: TaskStatus) {
    super(`Illegal status transition: ${from} → ${to}`);
  }
}

/** A partial update that carried no updatable fields. */
export class EmptyUpdateException
  extends BadRequestException
  implements HasErrorCode
{
  readonly code = ErrorCode.EmptyUpdate;

  constructor() {
    super('Update payload must contain at least one field');
  }
}

/** Attempt to mutate a task that has been archived (read-only). */
export class TaskArchivedException
  extends ConflictException
  implements HasErrorCode
{
  readonly code = ErrorCode.TaskArchivedReadonly;

  constructor() {
    super('Archived tasks are read-only');
  }
}

/** Pagination cursor that does not match any task in the result set. */
export class InvalidCursorException
  extends BadRequestException
  implements HasErrorCode
{
  readonly code = ErrorCode.InvalidCursor;

  constructor() {
    super('Invalid pagination cursor');
  }
}