/** 
 * ============================================================================
 * Copyright(C) Skitourenguru GmbH. All Rights Reserved. 
 * ============================================================================
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Globalization;

namespace TopoMap.AvalancheUtilities
{
    public class RouteIdentifiers
    {
        /// <summary>
        /// Converts a route id from the 'old region specific scheme' to the 'new generalized scheme'
        /// </summary>
        /// <param name="countryCollection"></param>
        /// <param name="countryId">A route id in the 'old region specific scheme'</param>
        /// <param name="alpsId">A route id in the 'new generalized scheme'</param>
        /// <returns></returns>
        public static bool getAlpsRouteIdentifier(string countryCollection, int countryId, out int alpsId)
        {
            alpsId = INVALID_ROUTE_ID;
            if (!REGION_ASSIGNMENT.ContainsKey(countryCollection))
            {
                return false;
            }

            alpsId = 10 * countryId;

            Region region = REGION_ASSIGNMENT[countryCollection];

            if (region == Region.IE)
            {
                // Last digit will be 6=IT
                alpsId += (int)Region.IT;
                return true;
            }

            if (region == Region.IW)
            {
                // Last digit will be 6=IT
                alpsId += (int)Region.IT;
                alpsId += 1000;
                return true;
            }

            int countryCode = (int)REGION_ASSIGNMENT[countryCollection];

            alpsId += countryCode;
            return true;
        }

        /// <summary>
        /// Converts a route id from the 'new generalized scheme' to the 'old region specific scheme'
        /// </summary>
        /// <param name="alpsId">A route id in the 'new generalized scheme'</param>
        /// <param name="countryCollection"></param>
        /// <param name="countryId">A route id in the 'old region specific scheme'</param>
        /// <returns></returns>
        public static bool getCountryRouteIdentifier(int alpsId, out string countryCollection, out int countryId)
        {
            countryCollection = null;
            countryId = alpsId / 10;

            string countrIdString = alpsId.ToString(CultureInfo.InvariantCulture);

            int countryCode = alpsId % 10;
            if (!Enum.IsDefined(typeof(Region), countryCode))
            {
                countryId = INVALID_ROUTE_ID;
                return false;
            }

            Region region = (Region)countryCode;
            if (region == Region.DE)
            {
                // Germany got a new numbering scheme starting with winter 2025/2026
                countryId = INVALID_ROUTE_ID;
                return false;
            }

            if (region == Region.AP)
            {
                // Impossible: We want to convert to an id relative to a country
                countryId = INVALID_ROUTE_ID;
                return false;
            }

            countryCollection = COLLECTION_ASSIGNMENT[region];
            if (region == Region.IT)
            {
                if (countryId >= 5000)
                {
                    // Theoretically these are Routes of South Tyrol. This case can never happen as IE would be deduced by countryCode
                    countryId = INVALID_ROUTE_ID;
                    return false;
                }

                if (countryId < 1000)
                {
                    countryCollection = COLLECTION_ASSIGNMENT[Region.IE];
                    return true;
                }

                if (countryId < 2000)
                {
                    countryCollection = COLLECTION_ASSIGNMENT[Region.IW];
                    countryId -= 1000;
                    return true;
                }

            }
            return true;
        }

        public enum Region
        {
            AP = 0,

            CH = 1,
            AT = 2,
            FR = 3,

            IT = 6,
            DE = 7,
            SI = 8,
            PY = 9,

            /// <summary>
            /// Legacy definition
            /// </summary>
            IE = 4,

            /// <summary>
            /// Legacy definition
            /// </summary>
            IW = 5,

        }

        public static readonly Dictionary<Region, string> COLLECTION_ASSIGNMENT = new Dictionary<Region, string>()
        {
            { Region.AP, "Alps" },
            { Region.CH, "Switzerland" },
            { Region.AT, "Austria" },
            { Region.FR, "France" },
            { Region.IT, "Italy" },
            { Region.DE, "Germany" },
            { Region.SI, "Slovenia" },
            { Region.PY, "Pyrenees" },

            /// Legacy definition
            { Region.IE, "ItalyEast" },

            /// Legacy definition
            { Region.IW, "ItalyWest" },
        };


        public static readonly Dictionary<string, Region> REGION_ASSIGNMENT = COLLECTION_ASSIGNMENT.ToDictionary(kv => kv.Value, kv => kv.Key);

        public readonly static int INVALID_ROUTE_ID = 0;


        public readonly static string ALPS_COLLECTION = COLLECTION_ASSIGNMENT[Region.AP];
    }
}