namespace Core.Blueprint.Storage
{
    public class TrieNode
    {
        public Dictionary<char, TrieNode> Children { get; private set; }
        public bool IsEndOfWord { get; set; }

        public TrieNode()
        {
            Children = [];
            IsEndOfWord = false;
        }
    }
    public class Trie
    {
        private readonly TrieNode _root;

        public Trie()
        {
            _root = new TrieNode();
        }

        public void Insert(string word)
        {
            var node = _root;
            foreach (var ch in word)
            {
                if (!node.Children.ContainsKey(ch))
                {
                    node.Children[ch] = new TrieNode();
                }
                node = node.Children[ch];
            }
            node.IsEndOfWord = true;
        }

        public List<string> SearchByPrefix(string? prefix)
        {
            var results = new List<string>();
            var node = _root;
            foreach (var ch in prefix)
            {
                if (!node.Children.ContainsKey(ch))
                {
                    return results;
                }
                node = node.Children[ch];
            }
            SearchByPrefixHelper(node, prefix, results);
            return results;
        }

        private void SearchByPrefixHelper(TrieNode node, string currentPrefix, List<string> results)
        {
            if (node.IsEndOfWord)
            {
                results.Add(currentPrefix);
            }
            foreach (var kvp in node.Children)
            {
                SearchByPrefixHelper(kvp.Value, currentPrefix + kvp.Key, results);
            }
        }
    }
}