private void InsertFriend(Friend friend)
{
var friends = ReadFromFile();
var maxFriendId = friends.Count == 0 ? 0 : friends.Max(f => f.Id);
friend.Id = maxFriendId + 1;
friends.Add(friend);
SaveToFile(friends);
}
private void UpdateFriend(Friend friend)
{
var friends = ReadFromFile();
var existing = friends.Single(f => f.Id == friend.Id);
var indexOfExisting = friends.IndexOf(existing);
friends.Insert(indexOfExisting, friend);
friends.Remove(existing);
SaveToFile(friends);
}
public void SaveFriend(Friend friend)
{
if (friend.Id <= 0)
{
InsertFriend(friend);
}
else
{
UpdateFriend(friend);
}
}