using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Deltares.Authorization;

namespace Deltares.Dam.Data.License
{
    /// <summary>
    /// License class to chekout and checkin licenses
    /// </summary>
    public class DamLicense
    {
        private const string dAuthFeature = "DGS_26_00_V";

        private static DAuthClient dAuthClient;
        private static DamLicenseType damLicenseType = DamLicenseType.None;
        private static string checkedOutFeature;

        /// <summary>
        /// Gets the type of the dam license.
        /// </summary>
        /// <value>
        /// The type of the dam license.
        /// </value>
        public static DamLicenseType DamLicenseType
        {
            get
            {
                return damLicenseType;
            }
        }

        /// <summary>
        /// Checkouts the license.
        /// Look up all features starting with the specified string
        /// See if any of them has the correct license version, according to the version we get from the Application version info
        /// </summary>
        public static void CheckoutLicense(string version)
        {
            IEnumerable<string> featureNames = GetAllFeaturesStartingWith(dAuthFeature);
            if (featureNames == null)
            {
                checkedOutFeature = null;
                damLicenseType = DamLicenseType.None;
                return;
            }
            int majorVersion = GetMajorVersionFromVersionString(version);
            string versionString = majorVersion.ToString(CultureInfo.InvariantCulture);
            damLicenseType = DamLicenseType.None;
            foreach (var featureName in featureNames)
            {
                if (DAuthClient.CheckOut(featureName, versionString))
                {
                    damLicenseType = DamLicenseType.LFM;
                    checkedOutFeature = featureName;
                    break;
                }
            }
        }

        /// <summary>
        /// Checks in the license.
        /// </summary>
        public static void CheckinLicense()
        {
            if (!String.IsNullOrEmpty(checkedOutFeature))
            {
                DAuthClient.CheckIn(checkedOutFeature);
            }
        }

        /// <summary>
        /// Gets all features starting with the specified feature string
        /// </summary>
        /// <param name="feature">the feature string to look up</param>
        /// <returns>all the feature names thta start with the specified feature string</returns>
        public static IEnumerable<string> GetAllFeaturesStartingWith(string feature)
        {
            string[] features = null;
            DAuthClient.GetAvailableFeatures(ref features);
            if (features == null)
            {
                return null;
            }
            IEnumerable<string> featureNames = features.Where(s => s.StartsWith(feature));
            return featureNames;
        }

        private static DAuthClient DAuthClient
        {
            get
            {
                if (dAuthClient != null)
                {
                    return dAuthClient;
                }
                dAuthClient = new DAuthClient(false, true);
                return dAuthClient;
            }
        }

        private static int GetMajorVersionFromVersionString(string version)
        {
            var seperator = new[]
            {
                '.'
            };
            var versionNumbers = version.Split(seperator);
            int majorVersion;
            int.TryParse(versionNumbers[0], out majorVersion);
            return majorVersion;
        }
    }
}