using System;
using System.Configuration;
using Validators = Kreta.Core.Configuration.Validators;

namespace Kreta.Naplo.Configuration.Kreta
{
    /// <summary>
    /// Authorization configuration section
    /// </summary>
    /// <seealso cref="System.Configuration.ConfigurationSection" />
    public class KretaNaploApiConfiguration : ConfigurationSection, IKretaNaploApiConfiguration
    {
        /// <summary>
        /// Name of section
        /// </summary>
        const string SectionName = "KretaNaploApi";

        /// <summary>
        /// The instance
        /// </summary>
        static Lazy<KretaNaploApiConfiguration> instance;

        /// <summary>
        /// Gets the instance.
        /// </summary>
        /// <value>
        /// The instance.
        /// </value>
        public static KretaNaploApiConfiguration Instance
        {
            get
            {
                return instance.Value;
            }
        }

        /// <summary>
        /// Gets the kreta API key.
        /// </summary>
        /// <value>
        /// The kreta API key.
        /// </value>
        /// <remarks>.NET ConfigurationProperty constructor is buggy: it sets the default value of string type to string.Empty (not null), then
        /// calls all validator for default value too. So in normal way you can't configure e.g. "MinLength" constaint, wihtout explicitly set "Default"
        /// to a string with length larger than "MinLength". The workaround is to write a custom valitor and set "DefaultValue" to a special
        /// string that theese validators knows, in order to skip validations when ConfigurationProperty calls them for default values.
        /// This is a known issue in .NET framework.</remarks>
        [ConfigurationProperty(nameof(ApiKey), IsRequired = true, DefaultValue = Validators.StringValidator.SkipValidationForDefaultValue)]
        [Validators.StringValidator(false, MinLength = 36, MaxLength = 256)]
        public string ApiKey
        {
            get
            {
                return (string)this[nameof(ApiKey)];
            }
        }

        /// <summary>
        /// Gets the base URL.
        /// </summary>
        /// <value>
        /// The base URL.
        /// </value>
        /// <remarks>.NET ConfigurationProperty constructor is buggy: it sets the default value of string type to string.Empty (not null), then
        /// calls all validator for default value too. So in normal way you can't configure e.g. "MinLength" constaint, wihtout explicitly set "Default"
        /// to a string with length larger than "MinLength". The workaround is to write a custom valitor and set "DefaultValue" to a special
        /// string that theese validators knows, in order to skip validations when ConfigurationProperty calls them for default values.
        /// This is a known issue in .NET framework.</remarks>
        [ConfigurationProperty(nameof(BaseUrl), IsRequired = true, DefaultValue = Validators.StringValidator.SkipValidationForDefaultValue)]
        [Validators.UrlValidator(Validators.UrlType.HttpBaseUrl)]
        public string BaseUrl
        {
            get
            {
                return (string)this[nameof(BaseUrl)];
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="KretaNaploApiConfiguration"/> class.
        /// </summary>
        static KretaNaploApiConfiguration()
        {
            instance = new Lazy<KretaNaploApiConfiguration>(() =>
            {
                var section = (KretaNaploApiConfiguration)ConfigurationManager.GetSection(SectionName);

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

                return section;
            });
        }
    }
}