feat(utils): add utility to reset active personas to defaults

src/lib/utils/personaDefaults.ts

@@ -0,0 +1,38 @@
+import type { Persona } from "$lib/types/Persona";
+
+export function resolveDefaultPersonaIds(personas: Persona[]): string[] {
+	const defaults = personas
+		.filter((persona) => persona.isDefault && !persona.archived)
+		.map((persona) => persona.id);
+
+	if (defaults.length > 0) {
+		return defaults;
+	}
+
+	return personas.filter((persona) => !persona.archived).map((persona) => persona.id);
+}
+
+function haveSameMembers(a: string[], b: string[]): boolean {
+	if (a.length !== b.length) return false;
+
+	const setB = new Set(b);
+	return a.every((value) => setB.has(value));
+}
+
+export async function resetActivePersonasToDefaults(
+	settings: { instantSet: (settings: { activePersonas: string[] }) => Promise<void> },
+	personas: Persona[],
+	currentActive: string[]
+): Promise<void> {
+	const targetIds = resolveDefaultPersonaIds(personas);
+
+	if (targetIds.length === 0) {
+		return;
+	}
+
+	if (haveSameMembers(currentActive, targetIds)) {
+		return;
+	}
+
+	await settings.instantSet({ activePersonas: targetIds });
+}