using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Extensions.Configuration;

namespace BTCPayServer
{
    public class SelectedChains
    {
        HashSet<string> chains = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
        bool all = false;
        public SelectedChains(IConfiguration configuration)
        {
            foreach (var chain in (configuration["chains"] ?? string.Empty)
                .Split(',', StringSplitOptions.RemoveEmptyEntries)
                    .Select(t => t.ToUpperInvariant()))
            {
                if (chain == "*")
                {
                    all = true;
                    continue;
                }
                chains.Add(chain);
            }
            if (chains.Count == 0 && !(GetBool(configuration["nodefaultchain"]) ?? false))
                chains.Add("BTC");
            if (all)
                chains.Clear();
        }

        private bool? GetBool(string val)
        {
            if (string.IsNullOrWhiteSpace(val))
                return null;
            return val.ToLowerInvariant() switch
            {
                "1" or "true" => true,
                "0" or "false" => false,
                _ => (bool?)null
            };
        }

        public bool Contains(string cryptoCode)
        {
            return all || chains.Contains(cryptoCode);
        }
        public void Add(string cryptoCode)
        {
            chains.Add(cryptoCode);
        }
        public IEnumerable<string> ExplicitlySelected => chains;
    }
}