using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using Nikse.SubtitleEdit.Core.DetectEncoding;

namespace Nikse.SubtitleEdit.Core
{
    public static class LanguageAutoDetect
    {

        private static int GetCount(string text, params string[] words)
        {
            var options = RegexOptions.CultureInvariant | RegexOptions.ExplicitCapture;
            var pattern = "\\b(" + string.Join("|", words) + ")\\b";
            return Regex.Matches(text, pattern, options).Count;
        }

        private static int GetCountContains(string text, params string[] words)
        {
            int count = 0;
            foreach (var w in words)
            {
                var regEx = new Regex(w);
                count += regEx.Matches(text).Count;
            }
            return count;
        }

        public static string AutoDetectGoogleLanguage(Encoding encoding)
        {
            switch (encoding.CodePage)
            {
                case 860:
                    return "pt"; // Portuguese
                case 28599:
                case 1254:
                    return "tr"; // Turkish
                case 28598:
                case 1255:
                    return "he"; // Hebrew
                case 28596:
                case 1256:
                    return "ar"; // Arabic
                case 1258:
                    return "vi"; // Vietnamese
                case 949:
                case 1361:
                case 20949:
                case 51949:
                case 50225:
                    return "ko"; // Korean
                case 1253:
                case 28597:
                    return "el"; // Greek
                case 50220:
                case 50221:
                case 50222:
                case 51932:
                case 20932:
                case 10001:
                    return "ja"; // Japanese
                case 20000:
                case 20002:
                case 20936:
                case 950:
                case 52936:
                case 54936:
                case 51936:
                    return "zh"; // Chinese
                default:
                    return null;
            }
        }

        private static readonly string[] AutoDetectWordsEnglish =
        {
            "we", "are", "and", "your", "what", "[TW]hat's", "You're", "(any|some|every)thing", "money", "because", "human", "because", "welcome", "really", "something", "confusing", "about", "know", "people", "other", "which", "would",
            "these", "could"
        };

        private static readonly string[] AutoDetectWordsDanish =
        {
            "vi", "han", "og", "jeg", "var", "men", "gider", "bliver", "virkelig", "kommer", "tilbage", "Hej", "længere", "gjorde", "dig", "havde", "[Uu]ndskyld", "arbejder", "vidste", "troede", "stadigvæk", "[Mm]åske", "første", "gik",
            "fortælle", "begyndt", "spørgsmål", "pludselig"
        };

        private static readonly string[] AutoDetectWordsNorwegian =
        {
            "vi", "og", "jeg", "var", "men", "igjen", "Nei", "Hei", "noen", "gjøre", "kanskje", "[Tt]renger", "tenker", "skjer", "møte", "veldig", "takk", "penger", "konsept", "hjelp", "forsvunnet", "skutt", "sterkt", "minste", "første",
            "fortsette", "inneholder", "gikk", "fortelle", "begynt", "spørsmål", "plutselig"
        };

        private static readonly string[] AutoDetectWordsSwedish =
        {
            "vi", "är", "och", "Jag", "inte", "för", "måste", "Öppna", "Förlåt", "nånting", "ingenting", "jävla", "Varför", "[Ss]nälla", "fattar", "själv", "säger", "öppna", "jävligt", "dörren", "göra", "behöver", "tillbaka", "Varför",
            "träffa", "kanske", "säga", "hände", "honom", "hennes", "veckor", "tänker", "själv", "pratar", "mycket", "mamma", "dödade", "Ursäkta", "säger", "senaste", "håller", "förstår", "veckan", "varför", "tycker", "första", "gick",
            "berätta", "börjat", "människor", "frågor", "fråga", "plötsligt", "skämt"
        };

        private static readonly string[] AutoDetectWordsSpanish =
        {
            "qué", "eso", "muy", "estoy?", "ahora", "hay", "tú", "así", "cuando", "cómo", "él", "sólo", "quiero", "gracias", "puedo", "bueno", "soy", "hacer", "fue", "eres", "usted", "tienes", "puede", "[Ss]eñor", "ese", "voy", "quién",
            "creo", "hola", "dónde", "sus", "verdad", "quieres", "mucho", "entonces", "estaba", "tiempo", "esa", "mejor", "hombre", "hace", "dios", "también", "están", "siempre", "hasta", "ahí", "siento", "puedes"
        };

        private static readonly string[] AutoDetectWordsItalian =
        {
            "Buongiorno", "Grazie", "Cosa", "quest[ao]", "quell[ao]", "tutt[io]", "[st]uo", "qualcosa", "ancora", "sono", "bene", "più", "andare", "essere", "venire", "abbiamo", "andiamo", "ragazzi", "signore", "numero", "giorno",
            "propriamente", "sensitivo", "negativo", "davvero", "faccio", "voglio", "vuole", "perché", "allora", "niente", "anche", "stai", "detto", "fatto", "hanno", "molto", "stato", "siamo", "così", "vuoi", "noi", "vero", "loro",
            "fare", "gli", "due"
        };

        private static readonly string[] AutoDetectWordsFrench =
        {
            "pas", "[vn]ous", "ça", "une", "pour", "[mt]oi", "dans", "elle", "tout", "plus", "[bmt]on", "suis", "avec", "oui", "fait", "ils", "être", "faire", "comme", "était", "quoi", "ici", "veux", "vouloir", "quelque", "pouvoir",
            "rien", "dit", "où", "votre", "pourquoi", "sont", "cette", "peux", "alors", "comment", "avez", "très", "même", "merci", "ont", "aussi", "chose", "voir", "allez", "tous", "ces", "deux", "avoir", " pouvoir", "même"
        };

        private static readonly string[] AutoDetectWordsPortuguese =
        {
            "[Nn]ão", "[Ee]ntão", "uma", "ele", "bem", "isso", "você", "sim", "meu", "muito", "estou", "ela", "fazer", "tem", "já", "minha", "tudo", "só", "tenho", "agora", "vou", "seu", "quem", "há", "lhe", "quero", "nós", "são", "ter",
            "coisa", "dizer", "eles", "pode", "bom", "mesmo", "mim", "estava", "assim", "estão", "até", "quer", "temos", "acho", "obrigado", "também", "tens", "deus", "quê", "ainda", "noite"
        };

        private static readonly string[] AutoDetectWordsGerman =
        {
            "und", "auch", "sich", "bin", "hast", "möchte", "müssen", "weiß", "[Vv]ielleicht", "Warum", "jetzt"
        };

        private static readonly string[] AutoDetectWordsDutch =
        {
            "van", "een", "[Hh]et", "m(ij|ij)", "z(ij|ij)n", "hebben", "alleen", "Waarom"
        };

        private static readonly string[] AutoDetectWordsPolish =
        {
            "Czy", "ale", "ty", "siê", "się", "jest", "mnie", "Proszę", "życie", "statku", "życia", "Czyli", "Wszystko", "Wiem", "Przepraszam", "dobrze", "chciałam", "Dziękuję", "Żołnierzyk", "Łowca", "został", "stało", "dolarów",
            "wiadomości", "Dobrze", "będzie", "Dzień", "przyszłość", "Uratowałaś", "Cześć", "Trzeba", "zginąć", "walczyć", "ludzkość", "maszyny", "Jeszcze", "okrążenie", "wyścigu", "porządku", "detektywie",
            "przebieralni", "który"
        };

        private static readonly string[] AutoDetectWordsGreek =
        {
            "μου", "[Εε]ίναι", "αυτό", "Τόμπυ", "καλά", "Ενταξει", "πρεπει", "Λοιπον", "τιποτα", "ξερεις"
        };

        private static readonly string[] AutoDetectWordsRussian =
        {
            "[Ээч]?то", "[Нн]е", "[ТтМмбв]ы", "Да", "[Нн]ет", "Он", "его", "тебя", "как", "меня", "Но", "всё", "мне", "вас", "знаю", "ещё", "за", "нас", "чтобы", "был"
        };

        private static readonly string[] AutoDetectWordsBulgarian =
        {
            "[Кк]акво", "тук", "може", "Как", "Да", "Ваше", "нещо", "беше", "Добре", "трябва", "става", "Джоузи", "Защо", "дяволите", "Сиянието", "Трябва", "години", "Стивън", "Благодаря"
        };

        private static readonly string[] AutoDetectWordsUkrainian =
        {
            "[Нн]і", "[Пп]ривіт", "[Цц]е", "[Щщ]о", "[Йй]ого", "[Вв]ін", "[Яя]к", "[Гг]аразд", "[Яя]кщо", "[Мм]ені", "[Тт]вій", "[Її]х", "[Вв]ітаю", "[Дд]якую", "вже", "було", "був", "цього",
            "нічого", "немає", "може", "знову", "бо", "щось", "щоб", "цим", "тобі", "хотів", "твоїх", "мої", "мій", "має", "їм", "йому", "дуже"
        };

        private static readonly string[] AutoDetectWordsAlbanian =
        {
            "është", "këtë", "Unë", "mirë", "shumë", "Çfarë", "çfarë", "duhet", "Është", "mbrapa", "Faleminderit", "vërtet", "diçka", "gjithashtu", "gjithe", "eshte", "shume", "vetem", "tënde",
            "çmendur", "vullnetin", "vdekur"
        };

        private static readonly string[] AutoDetectWordsArabic =
        {
            "من", "هل", "لا", "في", "لقد", "ما", "ماذا", "يا", "هذا", "إلى", "على", "أنا", "أنت", "حسناً", "أيها", "كان", "كيف", "يكون", "هذه", "هذان", "الذي", "التي", "الذين", "هناك", "هنالك"
        };

        private static readonly string[] AutoDetectWordsFarsi =
        {
            "این", "برای", "اون", "سیب", "کال", "رو", "خيلي", "آره", "بود", "اون", "نيست", "اينجا", "باشه", "سلام", "ميکني", "داري", "چيزي", "چرا", "خوبه"
        };

        private static readonly string[] AutoDetectWordsHebrew =
        {
            "אתה", "אולי", "הוא", "בסדר", "יודע", "טוב"
        };

        private static readonly string[] AutoDetectWordsVietnamese =
        {
            "không", "[Tt]ôi", "anh", "đó", "ông", "tôi", "phải", "người", "được", "Cậu", "chúng", "chuyện", "muốn", "những", "nhiều"
        };

        private static readonly string[] AutoDetectWordsHungarian =
        {
            "hogy", "lesz", "tudom", "vagy", "mondtam", "még"
        };

        private static readonly string[] AutoDetectWordsTurkish =
        {
            "için", "Tamam", "Hayır", "benim", "daha", "deðil", "önce", "lazým", "çalýþýyor", "burada", "efendim"
        };

        private static readonly string[] AutoDetectWordsCroatianAndSerbian =
        {
            "sam", "ali", "nije", "Nije", "samo", "ovo", "kako", "dobro", "Dobro", "sve", "tako", "će", "mogu", "ću", "zašto", "nešto", "za", "misliš", "možeš", "možemo", "ništa", "znaš", "ćemo", "znam"
        };
        private static readonly string[] AutoDetectWordsCroatian =
        {
            "što", "ovdje", "gdje", "kamo", "tko", "prije", "uvijek", "vrijeme", "vidjeti", "netko", "vidio", "nitko", "bok", "lijepo", "oprosti", "htio", "mjesto", "oprostite", "čovjek", "dolje", "čovječe", "dvije", "dijete", "dio",
            "poslije", "događa", "vjerovati", "vjerojatno", "vjerujem", "točno", "razumijem", "vidjela", "cijeli", "svijet", "obitelj", "volio", "sretan", "dovraga", "svijetu", "htjela", "vidjeli", "negdje", "želio", "ponovno",
            "djevojka", "umrijeti", "čovjeka", "mjesta", "djeca", "osjećam", "uopće", "djecu", "naprijed", "obitelji", "doista", "mjestu", "lijepa", "također", "riječ", "tijelo"
        };
        private static readonly string[] AutoDetectWordsSerbian =
        {
            "šta", "ovde", "gde", "ko", "pre", "uvek", "vreme", "videti", "neko", "video", "niko", "ćao", "lepo", "izvini", "hteo", "mesto", "izvinite", "čovek", "dole", "čoveče", "dve", "dete", "deo", "posle", "dešava", "verovati",
            "verovatno", "verujem", "tačno", "razumem", "videla", "ceo", "svet", "porodica", "voleo", "srećan", "dođavola", "svetu", "htela", "videli", "negde", "želeo", "ponovo", "devojka", "umreti", "čoveka", "mesta", "deca", "osećam",
            "uopšte", "decu", "napred", "porodicu", "zaista", "mestu", "lepa", "takođe", "reč", "telo"
        };

        private static readonly string[] AutoDetectWordsSerbianCyrillic =
        {
            "сам", "али", "није", "само", "ово", "како", "добро", "све", "тако", "ће", "могу", "ћу", "зашто", "нешто", "за", "шта", "овде", "бити", "чини", "учениче", "побегне", "остати", "Један", "Назад", "Молим"
        };

        private static readonly string[] AutoDetectWordsIndonesian =
        {
            "yang", "tahu", "bisa", "akan", "tahun", "tapi", "dengan", "untuk", "rumah", "dalam", "sudah", "bertemu"
        };

        private static readonly string[] AutoDetectWordsThai =
        {
            "โอ", "โรเบิร์ต", "วิตตอเรีย", "ดร", "คุณตำรวจ", "ราเชล", "ไม่", "เลดดิส", "พระเจ้า", "เท็ดดี้", "หัวหน้า", "แอนดรูว์",
            "คะ", "อิซานะ", "มจริง", "รับทราบ", "พอคะ", "ครับ", "อยาตขาป", "ยินดีทีดรูจักคะ", "ปลอดภัยดีนะ", "ทุกคน", "ตอนที", "ขอบคุณครับ", "ขอทษนะคะ", "ขอทษคะ"
        };

        private static readonly string[] AutoDetectWordsKorean =
        {
            "사루", "거야", "엄마", "그리고", "아니야", "하지만", "말이야", "그들은", "우리가", "엄마가", "괜찮아", "일어나", "잘했어", "뭐라고"
        };

        private static readonly string[] AutoDetectWordsMacedonian =
        {
            "господине", "Нема", "господине", "работа", "вселената", "Може", "треба", "Треба", "слетување", "капсулата", "време", "Френдшип", "Прием", "Добро", "пресметки", "Благодарам", "нешто", "Благодарам", "орбитата", "инженер",
            "Харисон", "Фала", "тоалет", "орбита", "знаеме", "Супервизор", "жени", "Добра", "требаат", "што", "дeкa", "eшe", "кучe", "Руиз", "кучeто", "кучињa", "Бјути", "имa", "многу", "кучињaтa", "AДЗЖ", "Животни", "моЖe", "мaчe",
            "мecто", "имaмe", "мaчињa", "пpвото", "пpaвaт", "нeшто", "колку"
        };

        private static readonly string[] AutoDetectWordsFinnish =
        {
            "että", "kuin", "minä", "mitään", "Mutta", "siitä", "täällä", "poika", "Kiitos", "enää", "vielä", "tässä", "sulkeutuu", "Soitetaan", "Soita", "Onnistui", "Mitä", "Etuovi", "tippiä", "antaa", "Onko", "Hidasta", "tuntia",
            "tilata", "päästä", "palolaitokselle", "hätänumeroon", "aikaa", "Tämä", "Sinulla", "Palauttaa", "Kiitos", "Arvostele", "Älä", "toimi", "televisiota", "takaisin", "reitin", "pitäisi", "palauttaa", "nopeamman", "mitään",
            "meidät", "maksaa", "kuullut", "kaikki", "jälkeen", "ihmiset", "hätäkeskukseen", "hiljaa", "haluat", "enää", "enemmän", "auttaa", "Tunkeilijahälytys", "Pysähdy", "Princen", "Käänny", "Kyllä", "Kiva", "Haluatko", "Haluan"
        };

        private static readonly string[] AutoDetectWordsRomanian =
        {
            "pentru", "oamenii", "decât", "[Vv]reau", "[Ss]înt", "Asteaptã", "Fãrã", "aici", "domnule", "trãiascã", "niciodatã", "înseamnã", "vorbesti", "fãcut", "spune", "făcut", "când", "aici", "Asta", "văzut", "dacă", "câteva",
            "amândoi", "Când", "totuși", "mașină", "aceeași", "întâmplat", "niște", "ziua", "noastră", "cunoscut", "decat", "[Tt]rebuie", "[Aa]cum", "Poate", "vrea", "soare", "nevoie", "daca", "echilibrul", "vorbesti", "zeului",
            "atunci", "memoria", "soarele"
        };

        // Czech and Slovak languages have many common words (especially when non flexed)
        private static readonly string[] AutoDetectWordsCzechAndSlovak =
        {
            "[Oo]n[ao]?", "[Jj]?si", "[Aa]le", "[Tt]en(to)?", "[Rr]ok", "[Tt]ak", "[Aa]by", "[Tt]am", "[Jj]ed(en|na|no)", "[Nn]ež", "[Aa]ni", "[Bb]ez", "[Dd]obr[ýáé]", "[Vv]šak", "[Cc]el[ýáé]", "[Nn]ov[ýáé]", "[Dd]ruh[ýáé]", "jsem",
            "poøádku", "Pojïme", "háje", "není", "Jdeme", "všecko", "jsme", "Prosím", "Vezmi", "když", "Takže", "Dìkuji", "prechádzku", "všetko", "Poïme", "potom", "Takže", "Neviem", "budúcnosti", "trochu"
        };
        // differences between Czech and Slovak languages / Czech words / please keep the words aligned between these languages for better comparison
        private static readonly string[] AutoDetectWordsCzech =
        {
            ".*[Řř].*", ".*[ůě].*", "[Bb]ýt", "[Jj]sem", "[Jj]si", "[Jj]á", "[Mm]ít", "[Aa]no", "[Nn]e",  "[Nn]ic", "[Dd]en", "[Jj]en", "[Cc]o", "[Jj]ak[o]?", "[Nn]ebo",  "[Pp]ři", "[Pp]ro", "[Pp]řed.*", "[Jj](ít|du|de|deme|dou)",
            "[Mm]ezi",  "[Jj]eště", "[Čč]lověk", "[Pp]odle", "[Dd]alší"
        };
        // differences between Czech and Slovak languages / Slovak words / please keep the words aligned between these languages for better comparison
        private static readonly string[] AutoDetectWordsSlovak =
        {
            ".*[Ôô].*", ".*[ä].*",  "[Bb]yť", "[Ss]om",  "[Ss]i",  "[Jj]a", "[Mm]ať", "[Áá]no", "[Nn]ie", "[Nn]ič", "[Dd]eň", "[Ll]en", "[Čč]o", "[Aa]ko", "[Aa]?[Ll]ebo", "[Pp]ri", "[Pp]re", "[Pp]red.*", "([Íí]sť|[Ii](dem|de|deme|dú))",
            "[Mm]edzi", "[Ee]šte",  "[Čč]lovek", "[Pp]odľa", "[Ďď]alš(í|ia|ie)"
        };

        private static readonly string[] AutoDetectWordsLatvian =
        {
            "Paldies", "neesmu ", "nezinu", "viòð", "viņš", "viņu", "kungs", "esmu", "Viņš", "Velns", "viņa", "dievs", "Pagaidi", "varonis", "agrāk", "varbūt"
        };

        private static readonly string[] AutoDetectWordsLithuanian =
        {
            "tavęs", "veidai", "apie", "jums", "Veidai", "Kaip", "kaip", "reikia", "Šūdas", "frensis", "Ačiū", "vilsonai", "Palauk", "Veidas", "viskas", "Tikrai", "manęs", "Tačiau", "žmogau", "Flagai", "Prašau", "Džiune", "Nakties",
            "šviesybe", "Supratau", "komanda", "reikia", "apie", "Kodėl", "mūsų", "Ačiū", "vyksta"
        };

        private static readonly string[] AutoDetectWordsHindi =
        {
            "एक", "और", "को", "का", "यह", "सकते", "लिए", "करने", "भारतीय", "सकता", "भारत", "तकनीक", "कंप्यूटिंग", "उपकरण", "भाषाओं", "भाषा", "कंप्यूटर", "आप", "आपको", "अपने", "लेकिन", "करना", "सकता", "बहुत", "चाहते", "अच्छा", "वास्तव",
            "लगता", "इसलिए", "शेल्डन", "धन्यवाद।", "तरह", "करता", "चाहता", "कोशिश", "करते", "किया", "अजीब", "सिर्फ", "शुरू"
        };

        private static readonly string[] AutoDetectWordsUrdu =
        {
            "نہیں", "ایک", "ہیں", "کیا", "اور", "لئے", "ٹھیک", "ہوں", "مجھے", "تھا", "کرنے", "صرف", "ارے", "یہاں", "بہت", "لیکن", "ساتھ", "اپنے", "اچھا", "میرے", "چاہتا", "انہوں", "تمہیں"
        };

        private static readonly string[] AutoDetectWordsSinhalese =
        {
            "කරන්න", "නැහැ", "කියල", "මගේ", "එයා", "ඔයාට", "කැප්ටන්", "ඔයාගේ", "පුළුවන්", "හැම", "වගේ", "වෙන්න", "ඕනා", "නෙමේ", "තියෙන්නේ", "වගේම", "දන්නවා", "වෙනවා", "එහෙම", "හිතන්නේ", "කියලා", "කරනවා", "යන්න", "දෙයක්", "තියනවා",
            "හොදයි", "දෙන්න", "එකක්", "මොනාද", "කියන්න", "කරන්නේ", "වෙන්නේ", "රොජර්ස්", "දාන්න", "කරලා", "ඔයාව", "වෙලා", "කොහොමද", "කිවුවා", "ඔබට", "රාවුල්"
        };

        private static string AutoDetectGoogleLanguage(string text, int bestCount)
        {
            int count = GetCount(text, AutoDetectWordsEnglish);
            if (count > bestCount)
            {
                int dutchCount = GetCount(text, AutoDetectWordsDutch);
                if (dutchCount < count)
                {
                    return "en";
                }
            }

            count = GetCount(text, AutoDetectWordsDanish);
            if (count > bestCount)
            {
                int norwegianCount = GetCount(text, "ut", "deg", "meg", "merkelig", "mye", "spørre");
                int dutchCount = GetCount(text, AutoDetectWordsDutch);
                int swedishCount = GetCount(text, AutoDetectWordsSwedish);
                if (norwegianCount < 2 && dutchCount < count && swedishCount < count)
                {
                    return "da";
                }
            }

            count = GetCount(text, AutoDetectWordsNorwegian);
            if (count > bestCount)
            {
                int danishCount = GetCount(text, "siger", "dig", "mig", "mærkelig", "tilbage", "spørge");
                int dutchCount = GetCount(text, AutoDetectWordsDutch);
                int swedishCount = GetCount(text, AutoDetectWordsSwedish);
                if (danishCount < 2 && dutchCount < count && swedishCount < count)
                {
                    return "no";
                }
            }

            count = GetCount(text, AutoDetectWordsSwedish);
            if (count > bestCount)
            {
                return "sv";
            }

            count = GetCount(text, AutoDetectWordsSpanish);
            if (count > bestCount)
            {
                int frenchCount = GetCount(text, "[Cc]'est", "pas", "vous", "pour", "suis", "Pourquoi", "maison", "souviens", "quelque"); // not spanish words
                int portugueseCount = GetCount(text, "[NnCc]ão", "Então", "h?ouve", "pessoal", "rapariga", "tivesse", "fizeste",
                                                     "jantar", "conheço", "atenção", "foste", "milhões", "devias", "ganhar", "raios"); // not spanish words
                if (frenchCount < 2 && portugueseCount < 2)
                {
                    return "es";
                }
            }

            count = GetCount(text, AutoDetectWordsItalian);
            if (count > bestCount)
            {
                int frenchCount = GetCount(text, "[Cc]'est", "pas", "vous", "pour", "suis", "Pourquoi", "maison", "souviens", "quelque"); // not italian words
                if (frenchCount < 2)
                {
                    return "it";
                }
            }

            count = GetCount(text, AutoDetectWordsFrench);
            if (count > bestCount)
            {
                int romanianCount = GetCount(text, "[Vv]reau", "[Ss]înt", "[Aa]cum", "pentru", "domnule", "aici");
                if (romanianCount < 5)
                {
                    return "fr";
                }
            }

            count = GetCount(text, AutoDetectWordsPortuguese);
            if (count > bestCount)
            {
                return "pt"; // Portuguese
            }

            count = GetCount(text, AutoDetectWordsGerman);
            if (count > bestCount)
            {
                return "de";
            }

            count = GetCount(text, AutoDetectWordsDutch);
            if (count > bestCount)
            {
                return "nl";
            }

            count = GetCount(text, AutoDetectWordsPolish);
            if (count > bestCount)
            {
                return "pl";
            }

            count = GetCount(text, AutoDetectWordsGreek);
            if (count > bestCount)
            {
                return "el"; // Greek
            }

            count = GetCount(text, AutoDetectWordsRussian);
            if (count > bestCount)
            {
                var bulgarianCount = GetCount(text, AutoDetectWordsBulgarian);
                if (bulgarianCount > count)
                {
                    return "bg"; // Bulgarian
                }

                var ukranianCount = GetCount(text, AutoDetectWordsUkrainian);
                if (ukranianCount > count)
                {
                    return "uk"; // Ukrainian
                }

                return "ru"; // Russian
            }

            count = GetCount(text, AutoDetectWordsUkrainian);
            if (count > bestCount)
            {
                return "uk"; // Ukrainian
            }

            count = GetCount(text, AutoDetectWordsBulgarian);
            if (count > bestCount)
            {
                return "bg"; // Bulgarian
            }

            count = GetCount(text, AutoDetectWordsAlbanian);
            if (count > bestCount)
            {
                return "sq"; // Albanian
            }

            count = GetCount(text, AutoDetectWordsArabic);
            if (count > bestCount)
            {
                int hebrewCount = GetCount(text, AutoDetectWordsHebrew);
                int farsiCount = GetCount(text, AutoDetectWordsFarsi);
                if (hebrewCount < count && farsiCount < count)
                {
                    return "ar"; // Arabic
                }
            }

            count = GetCount(text, AutoDetectWordsHebrew);
            if (count > bestCount)
            {
                return "he"; // Hebrew
            }

            count = GetCount(text, AutoDetectWordsFarsi);
            if (count > bestCount)
            {
                return "fa"; // Farsi (Persian)
            }

            count = GetCount(text, AutoDetectWordsCroatianAndSerbian);
            if (count > bestCount)
            {
                int croatianCount = GetCount(text, AutoDetectWordsCroatian);
                int serbianCount = GetCount(text, AutoDetectWordsSerbian);
                if (croatianCount > serbianCount)
                {
                    return "hr"; // Croatian
                }

                return "sr"; // Serbian
            }

            count = GetCount(text, AutoDetectWordsVietnamese);
            if (count > bestCount)
            {
                return "vi"; // Vietnamese
            }

            count = GetCount(text, AutoDetectWordsHungarian);
            if (count > bestCount)
            {
                return "hu"; // Hungarian
            }

            count = GetCount(text, AutoDetectWordsTurkish);
            if (count > bestCount)
            {
                return "tr"; // Turkish
            }

            count = GetCount(text, AutoDetectWordsIndonesian);
            if (count > bestCount)
            {
                return "id"; // Indonesian
            }

            count = GetCount(text, AutoDetectWordsThai);
            if (count > 10 || count > bestCount)
            {
                return "th"; // Thai
            }

            count = GetCount(text, AutoDetectWordsKorean);
            if (count > 10 || count > bestCount)
            {
                return "ko"; // Korean
            }

            count = GetCount(text, AutoDetectWordsFinnish);
            if (count > bestCount)
            {
                return "fi"; // Finnish
            }

            count = GetCount(text, AutoDetectWordsRomanian);
            if (count > bestCount)
            {
                return "ro"; // Romanian
            }

            count = GetCountContains(text, "シ", "ュ", "シン", "シ", "ン", "ユ");
            count += GetCountContains(text, "イ", "ン", "チ", "ェ", "ク", "ハ");
            count += GetCountContains(text, "シ", "ュ", "う", "シ", "ン", "サ");
            count += GetCountContains(text, "シ", "ュ", "シ", "ン", "だ", "う");
            if (count > bestCount * 2)
            {
                return "ja"; // Japanese - not tested...
            }

            count = GetCountContains(text, "是", "是早", "吧", "的", "爱", "上好");
            count += GetCountContains(text, "的", "啊", "好", "好", "亲", "的");
            count += GetCountContains(text, "谢", "走", "吧", "晚", "上", "好");
            count += GetCountContains(text, "来", "卡", "拉", "吐", "滚", "他");
            if (count > bestCount * 2)
            {
                return "zh"; // Chinese (simplified) - not tested...
            }

            count = GetCount(text, AutoDetectWordsCzechAndSlovak);
            if (count > bestCount)
            {
                var lithuanianCount = GetCount(text, AutoDetectWordsLithuanian);
                int finnishCount = GetCount(text, AutoDetectWordsFinnish);
                if (lithuanianCount <= count && finnishCount < count)
                {
                    int czechWordsCount = GetCount(text, AutoDetectWordsCzech);
                    int slovakWordsCount = GetCount(text, AutoDetectWordsSlovak);
                    if (czechWordsCount >= slovakWordsCount)
                    {
                        return "cs"; // Czech
                    }

                    return "sk"; // Slovak
                }
            }

            count = GetCount(text, AutoDetectWordsLatvian);
            if (count > bestCount * 1.2)
            {
                return "lv";
            }

            count = GetCount(text, AutoDetectWordsLithuanian);
            if (count > bestCount)
            {
                return "lt";
            }

            count = GetCount(text, AutoDetectWordsHindi);
            if (count > bestCount)
            {
                return "hi";
            }

            count = GetCount(text, AutoDetectWordsUrdu);
            if (count > bestCount)
            {
                return "ur";
            }

            count = GetCount(text, AutoDetectWordsSinhalese);
            if (count > bestCount)
            {
                return "sl";
            }

            count = GetCount(text, AutoDetectWordsMacedonian);
            if (count > bestCount)
            {
                return "mk";
            }

            return string.Empty;
        }

        public static string AutoDetectGoogleLanguage(Subtitle subtitle)
        {
            return AutoDetectGoogleLanguageOrNull(subtitle) ?? "en";
        }

        public static string AutoDetectGoogleLanguageOrNull(Subtitle subtitle)
        {
            var s = new Subtitle(subtitle);
            s.RemoveEmptyLines();
            string languageId = AutoDetectGoogleLanguage(s.GetAllTexts(), s.Paragraphs.Count / 14);
            if (string.IsNullOrEmpty(languageId))
            {
                languageId = null;
            }

            return languageId;
        }

        public static string AutoDetectLanguageName(string languageName, Subtitle subtitle)
        {
            if (string.IsNullOrEmpty(languageName))
            {
                languageName = "en_US";
            }

            int bestCount = subtitle.Paragraphs.Count / 14;

            string text = subtitle.GetAllTexts();
            List<string> dictionaryNames = Utilities.GetDictionaryLanguages();

            bool containsEnGb = false;
            bool containsEnUs = false;
            bool containsHrHr = false;
            bool containsSrLatn = false;
            foreach (string name in dictionaryNames)
            {
                if (name.Contains("[en_GB]"))
                {
                    containsEnGb = true;
                }

                if (name.Contains("[en_US]"))
                {
                    containsEnUs = true;
                }

                if (name.Contains("[hr_HR]"))
                {
                    containsHrHr = true;
                }

                if (name.Contains("[sr_Latn]"))
                {
                    containsSrLatn = true;
                }
            }

            foreach (string name in dictionaryNames)
            {
                string shortName = string.Empty;
                int start = name.IndexOf('[');
                int end = name.IndexOf(']');
                if (start > 0 && end > start)
                {
                    start++;
                    shortName = name.Substring(start, end - start);
                }

                int count;
                switch (shortName.Replace("-", "_").ToLowerInvariant())
                {
                    case "da_dk":
                        count = GetCount(text, AutoDetectWordsDanish);
                        if (count > bestCount)
                        {
                            int norwegianCount = GetCount(text, "ut", "deg", "meg", "merkelig", "mye", "spørre");
                            int dutchCount = GetCount(text, AutoDetectWordsDutch);
                            if (norwegianCount < 2 && dutchCount < count)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "nb_no":
                        count = GetCount(text, AutoDetectWordsNorwegian);
                        if (count > bestCount)
                        {
                            int danishCount = GetCount(text, "siger", "dig", "mig", "mærkelig", "tilbage", "spørge");
                            int dutchCount = GetCount(text, AutoDetectWordsDutch);
                            if (danishCount < 2 && dutchCount < count)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "sv_se":
                        count = GetCount(text, AutoDetectWordsSwedish);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "en_us":
                        count = GetCount(text, AutoDetectWordsEnglish);
                        if (count > bestCount)
                        {
                            int dutchCount = GetCount(text, AutoDetectWordsDutch);
                            if (dutchCount < count)
                            {
                                languageName = shortName;
                                bestCount = count;
                                if (containsEnGb)
                                {
                                    int usCount = GetCount(text, "color", "flavor", "honor", "humor", "neighbor", "honor");
                                    int gbCount = GetCount(text, "colour", "flavour", "honour", "humour", "neighbour", "honour");
                                    if (gbCount > usCount)
                                    {
                                        languageName = "en_GB";
                                    }
                                }
                            }
                        }
                        break;
                    case "en_gb":
                        count = GetCount(text, AutoDetectWordsEnglish);
                        if (count > bestCount)
                        {
                            int dutchCount = GetCount(text, AutoDetectWordsDutch);
                            if (dutchCount < count)
                            {
                                languageName = shortName;
                                bestCount = count;
                                if (containsEnUs)
                                {
                                    int usCount = GetCount(text, "color", "flavor", "honor", "humor", "neighbor", "honor");
                                    int gbCount = GetCount(text, "colour", "flavour", "honour", "humour", "neighbour", "honour");
                                    if (gbCount < usCount)
                                    {
                                        languageName = "en_US";
                                    }
                                }
                            }
                        }
                        break;
                    case "es_any":
                    case "es_es":
                        count = GetCount(text, AutoDetectWordsSpanish);
                        if (count > bestCount)
                        {
                            int frenchCount = GetCount(text, "[Cc]'est", "pas", "vous", "pour", "suis", "Pourquoi", "maison", "souviens", "quelque"); // not spanish words
                            int portugueseCount = GetCount(text, "[NnCc]ão", "Então", "h?ouve", "pessoal", "rapariga", "tivesse", "fizeste",
                                "jantar", "conheço", "atenção", "foste", "milhões", "devias", "ganhar", "raios"); // not spanish words
                            if (frenchCount < 2 && portugueseCount < 2)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "it_it":
                        count = GetCount(text, AutoDetectWordsItalian);
                        if (count > bestCount)
                        {
                            int frenchCount = GetCount(text, "[Cc]'est", "pas", "vous", "pour", "suis", "Pourquoi", "maison", "souviens", "quelque"); // not italian words
                            int spanishCount = GetCount(text, "Hola", "nada", "Vamos", "pasa", "los", "como"); // not italian words
                            if (frenchCount < 2 && spanishCount < 2)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "fr_fr":
                        count = GetCount(text, AutoDetectWordsFrench);
                        if (count > bestCount)
                        {
                            int romanianCount = GetCount(text, "[Vv]reau", "[Ss]înt", "[Aa]cum", "pentru", "domnule", "aici");
                            int spanishCount = GetCount(text, "Hola", "nada", "Vamos", "pasa", "los", "como"); // not french words
                            int italianCount = GetCount(text, AutoDetectWordsItalian);
                            if (romanianCount < 5 && spanishCount < 2 && italianCount < 2)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "de_de":
                        count = GetCount(text, AutoDetectWordsGerman);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "nl_nl":
                        count = GetCount(text, AutoDetectWordsDutch);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "pl_pl":
                        count = GetCount(text, AutoDetectWordsPolish);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "el_gr":
                        count = GetCount(text, AutoDetectWordsGreek);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "ru_ru":
                        count = GetCount(text, AutoDetectWordsRussian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "uk_ua":
                        count = GetCount(text, AutoDetectWordsUkrainian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "ro_ro":
                        count = GetCount(text, AutoDetectWordsRomanian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "hr_hr": // Croatian
                        count = GetCount(text, AutoDetectWordsCroatianAndSerbian);
                        if (count > bestCount)
                        {
                            bestCount = count;
                            languageName = shortName;
                            if (containsSrLatn)
                            {
                                int croatianCount = GetCount(text, AutoDetectWordsCroatian);
                                int serbianCount = GetCount(text, AutoDetectWordsSerbian);
                                if (serbianCount > croatianCount)
                                {
                                    languageName = "sr-Latn";
                                }
                            }
                        }
                        break;
                    case "sr_latn": // Serbian (Latin)
                        count = GetCount(text, AutoDetectWordsCroatianAndSerbian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                            if (containsHrHr)
                            {
                                int croatianCount = GetCount(text, AutoDetectWordsCroatian);
                                int serbianCount = GetCount(text, AutoDetectWordsSerbian);
                                if (serbianCount < croatianCount)
                                {
                                    languageName = "hr_HR";
                                }
                            }
                        }
                        break;
                    case "sr": // Serbian (Cyrillic)
                        count = GetCount(text, AutoDetectWordsSerbianCyrillic);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "pt_pt": // Portuguese Portugal
                    case "pt_br": // Portuguese Brazil
                        count = GetCount(text, AutoDetectWordsPortuguese);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "hu_hu": // Hungarian
                        count = GetCount(text, AutoDetectWordsHungarian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "cs_cz": // Czech
                        count = GetCount(text, AutoDetectWordsCzech);
                        if (count > bestCount)
                        {
                            var lithuanianCount = GetCount(text, AutoDetectWordsLithuanian);
                            if (count > lithuanianCount)
                            {
                                languageName = shortName;
                                bestCount = count;
                            }
                        }
                        break;
                    case "sk_sk": // Slovak
                        count = GetCount(text, AutoDetectWordsSlovak);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "lv_lv": // Latvian
                        count = GetCount(text, AutoDetectWordsLatvian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "lt_lt": // Lithuanian
                    case "lt":    // Lithuanian (Neutral)
                        count = GetCount(text, AutoDetectWordsLithuanian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "hi_in": // Hindi
                    case "hi":
                        count = GetCount(text, AutoDetectWordsHindi);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "ur_ur": // Urdu
                    case "ur":
                        count = GetCount(text, AutoDetectWordsUrdu);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "sl_sl": // Sinhalese
                    case "sl":
                        count = GetCount(text, AutoDetectWordsSinhalese);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "tr_tr": // Turkish
                        count = GetCount(text, AutoDetectWordsTurkish);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "he_il": // Hebrew
                        count = GetCount(text, AutoDetectWordsHebrew);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "vi_vn": // Vietnamese
                        count = GetCount(text, AutoDetectWordsVietnamese);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "ar": // Arabic
                    case "ar_ar":
                        count = GetCount(text, AutoDetectWordsArabic);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "sq_al": // Albanian
                        count = GetCount(text, AutoDetectWordsAlbanian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "id_id": // Indonesian
                        count = GetCount(text, AutoDetectWordsIndonesian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "ko_kr": // Korean
                        count = GetCount(text, AutoDetectWordsKorean);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "mk_mk": // Macedonian
                        count = GetCount(text, AutoDetectWordsMacedonian);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                    case "fa": // Farsi (Persian)
                    case "fa_ir":
                        count = GetCount(text, AutoDetectWordsFarsi);
                        if (count > bestCount)
                        {
                            languageName = shortName;
                            bestCount = count;
                        }
                        break;
                }
            }
            return languageName;
        }

        public static Encoding DetectAnsiEncoding(byte[] buffer)
        {
            try
            {
                var greekEncoding = Encoding.GetEncoding(1253); // Greek
                if (GetCount(greekEncoding.GetString(buffer), AutoDetectWordsGreek) > 5)
                {
                    return greekEncoding;
                }

                var russianEncoding = Encoding.GetEncoding(1251); // Cyrillic
                if (GetCount(russianEncoding.GetString(buffer), "что", "быть", "весь", "этот", "один", "такой") > 5) // Russian
                {
                    return russianEncoding;
                }

                if (GetCount(russianEncoding.GetString(buffer), AutoDetectWordsSerbianCyrillic) > buffer.Length / 1500)
                {
                    return russianEncoding;
                }

                if (GetCount(russianEncoding.GetString(buffer), "Какво", "тук", "може", "Как", "Ваше", "какво") > 5) // Bulgarian
                {
                    return russianEncoding;
                }

                if (GetCount(russianEncoding.GetString(buffer), AutoDetectWordsSerbianCyrillic) > buffer.Length / 300) // Serbian
                {
                    return russianEncoding;
                }

                var encoding1250 = Encoding.GetEncoding(1250); // Central European/Eastern European: Polish, Czech, Slovak, Hungarian, Slovene, Bosnian, Croatian, Serbian (Latin script), Romanian (before 1993 spelling reform) and Albanian
                if (GetCount(encoding1250.GetString(buffer), AutoDetectWordsCroatianAndSerbian) > buffer.Length / 300)
                {
                    return encoding1250;
                }

                if (GetCount(encoding1250.GetString(buffer), AutoDetectWordsCzechAndSlovak) > buffer.Length / 300)
                {
                    return encoding1250;
                }

                var encoding1252 = Encoding.GetEncoding(1252); // Latin - English and some other Western languages
                var pol1252Count = GetCount(encoding1252.GetString(buffer), AutoDetectWordsPolish);
                var pol1250Count = GetCount(encoding1250.GetString(buffer), AutoDetectWordsPolish);
                var encoding28592 = Encoding.GetEncoding(28592);
                var pol28592Count = GetCount(encoding28592.GetString(buffer), AutoDetectWordsPolish);
                if (pol1252Count > buffer.Length / 300 || pol1250Count > buffer.Length / 300)
                {
                    if (pol28592Count > pol1250Count && pol28592Count > pol1252Count)
                    {
                        return encoding28592;
                    }

                    return pol1252Count > pol1250Count ? encoding1252 : encoding1250;
                }

                russianEncoding = Encoding.GetEncoding(28595); // Russian
                if (GetCount(russianEncoding.GetString(buffer), "что", "быть", "весь", "этот", "один", "такой") > 5) // Russian
                {
                    return russianEncoding;
                }

                var thaiEncoding = Encoding.GetEncoding(874); // Thai
                if (GetCount(thaiEncoding.GetString(buffer), "โอ", "โรเบิร์ต", "วิตตอเรีย", "ดร", "คุณตำรวจ", "ราเชล", "ไม่", "เลดดิส", "พระเจ้า", "เท็ดดี้", "หัวหน้า", "แอนดรูว์") > 5)
                {
                    return thaiEncoding;
                }

                var arabicEncoding = Encoding.GetEncoding(1256); // Arabic
                var hebrewEncoding = Encoding.GetEncoding(28598); // Hebrew
                if (GetCount(arabicEncoding.GetString(buffer), AutoDetectWordsArabic) > 5)
                {
                    if (GetCount(hebrewEncoding.GetString(buffer), AutoDetectWordsHebrew) > 10)
                    {
                        return hebrewEncoding;
                    }

                    return arabicEncoding;
                }
                if (GetCount(hebrewEncoding.GetString(buffer), AutoDetectWordsHebrew) > 5)
                {
                    return hebrewEncoding;
                }

                if (GetCount(encoding1250.GetString(buffer), "să", "şi", "văzut", "regulă", "găsit", "viaţă") > 99)
                {
                    return encoding1250;
                }

                var koreanEncoding = Encoding.GetEncoding(949); // Korean
                if (GetCount(koreanEncoding.GetString(buffer), "그리고", "아니야", "하지만", "말이야", "그들은", "우리가") > 5)
                {
                    return koreanEncoding;
                }

                return EncodingTools.DetectInputCodepage(buffer);
            }
            catch
            {
                return Encoding.Default;
            }
        }

        public static Encoding GetEncodingFromFile(string fileName, bool skipAnsiAuto = false)
        {
            var encoding = Encoding.Default;

            try
            {
                foreach (var enc in Configuration.AvailableEncodings)
                {
                    if (enc.WebName == Configuration.Settings.General.DefaultEncoding && enc.WebName != Encoding.Unicode.WebName && enc.WebName != Encoding.UTF8.WebName)
                    {
                        encoding = enc;
                        break;
                    }
                }

                using (var file = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
                {
                    var bom = new byte[12]; // Get the byte-order mark, if there is one
                    file.Position = 0;
                    file.Read(bom, 0, bom.Length);
                    if (bom[0] == 0xef && bom[1] == 0xbb && bom[2] == 0xbf)
                    {
                        encoding = Encoding.UTF8;
                    }
                    else if (bom[0] == 0xff && bom[1] == 0xfe && bom[2] == 0 && bom[3] == 0)
                    {
                        encoding = Encoding.GetEncoding(12000); // UTF-32 (LE)
                    }
                    else if (bom[0] == 0xff && bom[1] == 0xfe)
                    {
                        encoding = Encoding.Unicode;
                    }
                    else if (bom[0] == 0xfe && bom[1] == 0xff) // utf-16 and ucs-2
                    {
                        encoding = Encoding.BigEndianUnicode;
                    }
                    else if (bom[0] == 0 && bom[1] == 0 && bom[2] == 0xfe && bom[3] == 0xff) // ucs-4
                    {
                        encoding = Encoding.GetEncoding(12001); // UTF-32 (BE)
                    }
                    else if (bom[0] == 0x2b && bom[1] == 0x2f && bom[2] == 0x76 && (bom[3] == 0x38 || bom[3] == 0x39 || bom[3] == 0x2b || bom[3] == 0x2f)) // utf-7
                    {
                        encoding = Encoding.UTF7;
                    }
                    else if (file.Length > bom.Length)
                    {
                        long length = file.Length;
                        if (length > 500000)
                        {
                            length = 500000;
                        }

                        file.Position = 0;
                        var buffer = new byte[length];
                        file.Read(buffer, 0, buffer.Length);

                        if (IsUtf8(buffer, out var couldBeUtf8))
                        {
                            encoding = Encoding.UTF8;
                        }
                        else if (couldBeUtf8 && Configuration.Settings.General.DefaultEncoding.StartsWith("UTF-8", StringComparison.Ordinal))
                        { // keep utf-8 encoding if it's default
                            encoding = Encoding.UTF8;
                        }
                        else if (couldBeUtf8 && fileName.EndsWith(".xml", StringComparison.OrdinalIgnoreCase) && Encoding.Default.GetString(buffer).ToLowerInvariant().Replace('\'', '"').Contains("encoding=\"utf-8\""))
                        { // keep utf-8 encoding for xml files with utf-8 in header (without any utf-8 encoded characters, but with only allowed utf-8 characters)
                            encoding = Encoding.UTF8;
                        }
                        else if (Configuration.Settings.General.AutoGuessAnsiEncoding && !skipAnsiAuto)
                        {
                            return DetectAnsiEncoding(buffer);
                        }
                    }
                }
            }
            catch
            {
                // ignored
            }
            return encoding;
        }

        /// <summary>
        /// Will try to determine if buffer is utf-8 encoded or not.
        /// If any non-utf8 sequences are found then false is returned, if no utf8 multibytes sequences are found then false is returned.
        /// </summary>
        private static bool IsUtf8(byte[] buffer, out bool couldBeUtf8)
        {
            couldBeUtf8 = false;
            int utf8Count = 0;
            int i = 0;
            while (i < buffer.Length - 3)
            {
                byte b = buffer[i];
                if (b > 127)
                {
                    if (b >= 194 && b <= 223 && buffer[i + 1] >= 128 && buffer[i + 1] <= 191)
                    { // 2-byte sequence
                        utf8Count++;
                        i++;
                    }
                    else if (b >= 224 && b <= 239 && buffer[i + 1] >= 128 && buffer[i + 1] <= 191 &&
                                                     buffer[i + 2] >= 128 && buffer[i + 2] <= 191)
                    { // 3-byte sequence
                        utf8Count++;
                        i += 2;
                    }
                    else if (b >= 240 && b <= 244 && buffer[i + 1] >= 128 && buffer[i + 1] <= 191 &&
                                                     buffer[i + 2] >= 128 && buffer[i + 2] <= 191 &&
                                                     buffer[i + 3] >= 128 && buffer[i + 3] <= 191)
                    { // 4-byte sequence
                        utf8Count++;
                        i += 3;
                    }
                    else
                    {
                        return false;
                    }
                }
                i++;
            }
            couldBeUtf8 = true;
            if (utf8Count == 0)
            {
                return false; // not utf-8 (no characters utf-8 encoded...)
            }

            return true;
        }

        private static readonly char[] RightToLeftLetters = string.Join(string.Empty, AutoDetectWordsArabic.Concat(AutoDetectWordsHebrew).Concat(AutoDetectWordsFarsi).Concat(AutoDetectWordsUrdu)).Distinct().ToArray();

        public static bool CouldBeRightToLeftLanguage(Subtitle subtitle)
        {
            var text = subtitle.GetAllTexts();
            if (text.Length > 1000)
            {
                return GetCount(text, AutoDetectWordsArabic.Concat(AutoDetectWordsHebrew).Concat(AutoDetectWordsFarsi).Concat(AutoDetectWordsUrdu).ToArray()) > 1;
            }
            foreach (var letter in RightToLeftLetters)
            {
                if (text.Contains(letter))
                {
                    return true;
                }
            }
            return false;
        }

    }
}