Best practices for implementing services with internal state and static dependencies

export type Scheduler<R, U extends User> = {
    start: () => Effect<R, SchedulerStartupError, void>;

    stop: () => Effect<R, ProgramError, void>;

    addHandler: (jobHandler: Job.AnyHandler) => void;

    schedule: <A extends JsonObject>(
        job: Job.Descriptor<A, U>,
    ) => Effect<R, SchedulerError, Job.Job<A, U>>;
};

export class DefaultScheduler<R> implements Scheduler<R> {
    private state: "stopped" | "running" | "uninitialized" = "uninitialized";

    constructor(
        private jobRepository: JobRepository<R>,
        private handlers: Map<string, AnyJobHandler>,
        private timer: Timer,
        private idProvider: IdProvider<string>,
        private jobCheckInterval: Duration,
        private retryInterval: Duration,
        private logger: Logger<unknown>
    ) {}

    public start() {
        // ...
    }

    public addHandler(jobHandler: AnyJobHandler) {
        // ...
    }

    public stop() {
        // ...
    }

    public schedule<D extends JsonObject>(
        job: JobDescriptor<D>
    ): ReaderTaskEither<R, SchedulingError, Job<D>> {
        // ...
    }
}