import { db, shoppingLists, shoppingListMembers, eq, and } from "@epicure/db";

export type ShoppingListRole = "owner" | "editor" | "viewer";

export type ShoppingListAccess = {
  list: typeof shoppingLists.$inferSelect;
  role: ShoppingListRole;
};

/** Resolves a user's access to a shopping list — owner, or member with their assigned role. Null if no access. */
export async function getShoppingListAccess(
  listId: string,
  userId: string
): Promise<ShoppingListAccess | null> {
  const list = await db.query.shoppingLists.findFirst({ where: eq(shoppingLists.id, listId) });
  if (!list) return null;
  if (list.userId === userId) return { list, role: "owner" };

  const member = await db.query.shoppingListMembers.findFirst({
    where: and(eq(shoppingListMembers.listId, listId), eq(shoppingListMembers.userId, userId)),
  });
  if (!member) return null;

  return { list, role: member.role };
}

export function canWriteShoppingList(role: ShoppingListRole): boolean {
  return role === "owner" || role === "editor";
}