import {
	type DomainError,
	type Encounter,
	isDomainError,
	undo,
} from "@initiative/domain";
import type { EncounterStore, UndoRedoStore } from "./ports.js";

export function undoUseCase(
	encounterStore: EncounterStore,
	undoRedoStore: UndoRedoStore,
): Encounter | DomainError {
	const current = encounterStore.get();
	const state = undoRedoStore.get();
	const result = undo(state, current);

	if (isDomainError(result)) {
		return result;
	}

	encounterStore.save(result.encounter);
	undoRedoStore.save(result.state);
	return result.encounter;
}