config.cs

using Newtonsoft.Json;
using PipeGuard.Data.Code;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace PipeGuard.Data.Services
{
    public class ConfigService
    {
        private class Config
        {
            public string ConnectionString { get; set; }
            public List<Unit> Units { get; set; }
        }

        private class Unit
        {
            public string Dev { get; set; }
            public int HwAddr { get; set; }
        }

        public string ConnectionString => _config.ConnectionString;

        public readonly Dictionary<string, int> UnitsByDev;

        private readonly Config _config;

        public ConfigService(string configPath)
        {
            var text = File.ReadAllText(configPath);
            var json = JsonConvert.DeserializeObject<Config>(text);
            Validate(json);
            UnitsByDev = json.Units.ToDictionary(u => u.Dev, u => u.HwAddr);

            _config = json;
        }

        private static void Validate(Config config)
        {
            if (string.IsNullOrEmpty(config.ConnectionString))
                throw new ConfigException("Connection string is null or empty");

            if (!config.Units.AreDistinct(d => d.Dev))
                throw new ConfigException("Duplicite dev in unit array");

            if (!config.Units.AreDistinct(d => d.HwAddr))
                throw new ConfigException("Duplicite hwAddr in unit array");

            if (config.Units.Any(d => string.IsNullOrEmpty(d.Dev)))
                throw new ConfigException("Dev is null or empty string");

            if (config.Units.Any(d => d.HwAddr < 1))
                throw new ConfigException("HwAddr is less than 1");
        }


    }

    public class ConfigException : Exception
    {
        public ConfigException(string msg) : base(msg)
        {
        }
    }
}