type EditorUI = {
	getEditorComponent(): unknown;
	setEditorComponent(factory: unknown): void;
};

export type EditorInstallResult = "installed" | "occupied" | "incompatible" | "failed";

function asEditorUI(value: unknown): EditorUI | undefined {
	if (typeof value !== "object" || value === null) return undefined;
	const ui = value as Partial<EditorUI>;
	return typeof ui.getEditorComponent === "function" && typeof ui.setEditorComponent === "function"
		? ui as EditorUI
		: undefined;
}

/** Installs a replacement editor without displacing an existing one. */
export function installEditorComponent(ui: unknown, factory: unknown): EditorInstallResult {
	const editorUI = asEditorUI(ui);
	if (!editorUI || typeof factory !== "function") return "incompatible";

	try {
		if (editorUI.getEditorComponent()) return "occupied";
	} catch {
		return "incompatible";
	}

	try {
		editorUI.setEditorComponent(factory);
		return "installed";
	} catch {
		clearOwnedEditorComponent(editorUI, factory);
		return "failed";
	}
}

/** Restores the stock editor only when this factory is still installed. */
export function clearOwnedEditorComponent(ui: unknown, factory: unknown): boolean {
	const editorUI = asEditorUI(ui);
	if (!editorUI || typeof factory !== "function") return false;

	try {
		if (editorUI.getEditorComponent() !== factory) return false;
	} catch {
		return false;
	}

	try {
		editorUI.setEditorComponent(undefined);
		return true;
	} catch {
		return false;
	}
}