using System;
using System.Configuration;

namespace Kreta.Naplo.Configuration
{
    public class CorsConfiguration : ConfigurationSection, ICorsConfiguration
    {
        const string SectionName = "CorsConfiguration";

        static Lazy<CorsConfiguration> instance;

        public static CorsConfiguration Instance
        {
            get
            {
                return instance.Value;
            }
        }

        [ConfigurationProperty(nameof(IsEnabled), IsRequired = true)]
        public bool IsEnabled => (bool)this[nameof(IsEnabled)];

        [ConfigurationProperty(nameof(Urls), IsRequired = true)]
        public string Urls => (string)this[nameof(Urls)];

        [ConfigurationProperty(nameof(Headers), IsRequired = true)]
        public string Headers => (string)this[nameof(Headers)];

        [ConfigurationProperty(nameof(Methods), IsRequired = true)]
        public string Methods => (string)this[nameof(Methods)];

        [ConfigurationProperty(nameof(SupportsCredentials), IsRequired = true)]
        public bool SupportsCredentials => (bool)this[nameof(SupportsCredentials)];

        static CorsConfiguration()
        {
            instance = new Lazy<CorsConfiguration>(() =>
            {
                var section = (CorsConfiguration)ConfigurationManager.GetSection(SectionName);

                if (section == null)
                {
                    throw new ConfigurationErrorsException($"{SectionName} configuration section was not found");
                }

                return section;
            });
        }
    }
}