using System;
using System.Collections.Generic;

namespace PKHeX.Core
{
    public static class GameInfo
    {
        private static readonly string[] ptransp = { "ポケシフター", "Poké Transfer", "Poké Fret", "Pokétrasporto", "Poképorter", "Pokétransfer", "포케시프터", "宝可传送", "寶可傳送" };
        private static readonly string[] lang_val = { "ja", "en", "fr", "it", "de", "es", "ko", "zh", "zh2" };
        private static readonly string[] lang_geo = { "ja", "en", "fr", "de", "it", "es", "zh", "ko" };
        private const string DefaultLanguage = "en";
        public static string CurrentLanguage { get; set; } = DefaultLanguage;
        public static int Language(string lang = null) => Array.IndexOf(lang_val, lang ?? CurrentLanguage);
        public static string Language2Char(uint lang) => lang > lang_val.Length ? DefaultLanguage : lang_val[lang];
        private static readonly GameStrings[] Languages = new GameStrings[lang_val.Length];

        // Lazy fetch implementation
        private static int DefaultLanguageIndex => Array.IndexOf(lang_val, DefaultLanguage);
        private static int GetLanguageIndex(string lang)
        {
            int l = Array.IndexOf(lang_val, lang);
            return l < 0 ? DefaultLanguageIndex : l;
        }
        public static GameStrings GetStrings(string lang)
        {
            int index = GetLanguageIndex(lang);
            return GetStrings(index);
        }
        public static GameStrings GetStrings(int index)
        {
            return Languages[index] ?? (Languages[index] = new GameStrings(lang_val[index]));
        }
        public static string GetTransporterName(string lang)
        {
            int index = GetLanguageIndex(lang);
            if (index >= ptransp.Length)
                index = DefaultLanguageIndex;
            return ptransp[index];
        }

        public static GameStrings Strings { get; set; } = GetStrings(DefaultLanguage);
        public static string[] GetStrings(string ident, string lang, string type = "text")
        {
            string[] data = Util.GetStringList(ident, lang, type);
            if (data == null || data.Length == 0)
                data = Util.GetStringList(ident, DefaultLanguage, type);

            return data;
        }

        // DataSource providing
        public static IReadOnlyList<ComboItem> ItemDataSource => Strings.ItemDataSource;
        public static IReadOnlyList<ComboItem> SpeciesDataSource => Strings.SpeciesDataSource;
        public static IReadOnlyList<ComboItem> BallDataSource => Strings.BallDataSource;
        public static IReadOnlyList<ComboItem> NatureDataSource => Strings.NatureDataSource;
        public static IReadOnlyList<ComboItem> AbilityDataSource => Strings.AbilityDataSource;
        public static IReadOnlyList<ComboItem> VersionDataSource => Strings.VersionDataSource;
        public static IReadOnlyList<ComboItem> LegalMoveDataSource => Strings.LegalMoveDataSource;
        public static IReadOnlyList<ComboItem> HaXMoveDataSource => Strings.HaXMoveDataSource;
        public static IReadOnlyList<ComboItem> MoveDataSource => Strings.MoveDataSource;
        public static IReadOnlyList<ComboItem> LanguageDataSource(int gen) => GameStrings.LanguageDataSource(gen);


        /// <summary>
        /// Gets Country and Region strings for corresponding IDs and language.
        /// </summary>
        /// <param name="country">Country ID</param>
        /// <param name="region">Region ID</param>
        /// <param name="language">Language ID</param>
        /// <returns></returns>
        public static Tuple<string, string> GetCountryRegionText(int country, int region, string language)
        {
            // Get Language we're fetching for
            int lang = Array.IndexOf(lang_geo, language);
            string c = GetCountryString(country, lang);
            string r = GetRegionString(country, region, lang);
            return new Tuple<string, string>(c, r); // country, region
        }

        /// <summary>
        /// Gets the Country string for a given Country ID
        /// </summary>
        /// <param name="country">Country ID</param>
        /// <param name="language">Language ID</param>
        /// <returns>Country ID string</returns>
        private static string GetCountryString(int country, int language)
        {
            string c;
            // Get Country Text
            try
            {
                string[] inputCSV = Util.GetStringList("countries");
                // Set up our Temporary Storage
                string[] unsortedList = new string[inputCSV.Length - 1];
                int[] indexes = new int[inputCSV.Length - 1];

                // Gather our data from the input file
                for (int i = 1; i < inputCSV.Length; i++)
                {
                    string[] countryData = inputCSV[i].Split(',');
                    if (countryData.Length <= 1) continue;
                    indexes[i - 1] = Convert.ToInt32(countryData[0]);
                    unsortedList[i - 1] = countryData[language + 1];
                }

                int countrynum = Array.IndexOf(indexes, country);
                c = unsortedList[countrynum];
            }
            catch { c = "Illegal"; }

            return c;
        }

        /// <summary>
        /// Gets the Region string for a specified country ID.
        /// </summary>
        /// <param name="country">Country ID</param>
        /// <param name="region">Region ID</param>
        /// <param name="language">Language ID</param>
        /// <returns>Region ID string</returns>
        private static string GetRegionString(int country, int region, int language)
        {
            // Get Region Text
            try
            {
                string[] inputCSV = Util.GetStringList($"sr_{country:000}");
                // Set up our Temporary Storage
                string[] unsortedList = new string[inputCSV.Length - 1];
                int[] indexes = new int[inputCSV.Length - 1];

                // Gather our data from the input file
                for (int i = 1; i < inputCSV.Length; i++)
                {
                    string[] countryData = inputCSV[i].Split(',');
                    if (countryData.Length <= 1) continue;
                    indexes[i - 1] = Convert.ToInt32(countryData[0]);
                    unsortedList[i - 1] = countryData[language + 1];
                }

                int regionnum = Array.IndexOf(indexes, region);
                return unsortedList[regionnum];
            }
            catch { return "Illegal"; }
        }

        /// <summary>
        /// Gets the location names array for a specified generation.
        /// </summary>
        /// <param name="gen">Generation to get location names for.</param>
        /// <param name="bankID">BankID used to choose the text bank.</param>
        /// <returns>List of location names.</returns>
        private static IReadOnlyList<string> GetLocationNames(int gen, int bankID)
        {
            switch (gen)
            {
                case 2: return Strings.metGSC_00000;
                case 3: return Strings.metRSEFRLG_00000;
                case 4:
                    switch (bankID)
                    {
                        case 0: return Strings.metHGSS_00000;
                        case 2: return Strings.metHGSS_02000;
                        case 3: return Strings.metHGSS_03000;
                        default: return null;
                    }
                case 5:
                    switch (bankID)
                    {
                        case 0: return Strings.metBW2_00000;
                        case 3: return Strings.metBW2_30000;
                        case 4: return Strings.metBW2_40000;
                        case 6: return Strings.metBW2_60000;
                        default: return null;
                    }
                case 6:
                    switch (bankID)
                    {
                        case 0: return Strings.metXY_00000;
                        case 3: return Strings.metXY_30000;
                        case 4: return Strings.metXY_40000;
                        case 6: return Strings.metXY_60000;
                        default: return null;
                    }
                case 7:
                    switch (bankID)
                    {
                        case 0: return Strings.metSM_00000;
                        case 3: return Strings.metSM_30000;
                        case 4: return Strings.metSM_40000;
                        case 6: return Strings.metSM_60000;
                        default: return null;
                    }
                default:
                    return null;
            }
        }

        /// <summary>
        /// Gets the location name for the specified parameters.
        /// </summary>
        /// <param name="eggmet">Location is from the <see cref="PKM.Egg_Location"/></param>
        /// <param name="locval">Location value</param>
        /// <param name="format">Current <see cref="PKM.Format"/></param>
        /// <param name="generation"><see cref="PKM.GenNumber"/> of origin</param>
        /// <returns>Location name</returns>
        public static string GetLocationName(bool eggmet, int locval, int format, int generation)
        {
            int gen = -1;
            int bankID = 0;

            if (format == 2)
                gen = 2;
            else if (format == 3)
                gen = 3;
            else if (generation == 4 && (eggmet || format == 4)) // 4
            {
                const int size = 1000;
                bankID = locval / size;
                gen = 4;
                locval %= size;
            }
            else // 5-7+
            {
                const int size = 10000;
                bankID = locval / size;

                int g = generation;
                if (g >= 5)
                    gen = g;
                else if (format >= 5)
                    gen = format;

                locval %= size;
                if (bankID >= 3)
                    locval--;
            }

            var bank = GetLocationNames(gen, bankID);
            if (bank == null || bank.Count <= locval)
                return string.Empty;
            return bank[locval];
        }

        /// <summary>
        /// Gets the location list for a specific version, which can retrieve either met locations or egg locations.
        /// </summary>
        /// <param name="version">Version to retrieve for</param>
        /// <param name="pkmFormat">Generation to retrieve for</param>
        /// <param name="egg">Egg Locations are to be retrieved instead of regular Met Locations</param>
        /// <returns>Consumable list of met locations</returns>
        public static IReadOnlyList<ComboItem> GetLocationList(GameVersion version, int pkmFormat, bool egg = false)
        {
            return Strings.GetLocationList(version, pkmFormat, egg);
        }
    }
}