Simple localization solution for Unity engine

POFile.cs

using UnityEngine;
using System.IO;
using System.Collections.Generic;
using System;
/// <summary>
///     Simple localization solution for Unity engine.
///     Loading and parsing language.po.txt file from streaming assets folder. 
///     
///     Author: Valery https://github.com/hww
///     
///     N.B. Do not support pluralization syntax with squared brackets msgstr[0].
///     Use instead two separated entries:
///     
///     msgid "singular id"
///     msgstr "singular text"
///     msgid "plural id 0"
///     msgstr "plurral text 0"
///     ...
///     msgid "plural id n"
///     msgstr "plurral text n"
///     
/// </summary>
/// <example>
///     var pofile = new POFile();
///     pofile.LoadLanguage("en");
///     
///     To get string:
///     
///     var msg1 = pofile.GetText("global.hello_world");
///     var msg2 = pofile.GetText("global.insert_x_coins", coinsCount);
///     
///     The last line is equivalent of:
///     
///     var key = pofile.GetPluralKey("global.insert_x_coins", coinsCount);
///     var msg2 = pofile.GetText(key);
///     
///     Example of string with pluralization:
///     
///     msgid "player.insert_x_coins_0"
///     msgstr "Insert {0} Coin"
///     msgid "player.insert_x_coins_1"
///     msgstr "Insert {0} Coins"
///     
///     The suffx _0 or _1 generated by method suffixMethod. The table suffixMethodsDictionary contains list
///     of suffixMethods for each language.
/// </example>
/// <see cref="https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html#PO-Files"/>

public class POFile
{
    /// <summary>
    ///     Read and parse .po file for selected language. 
    ///     The file path format is "Streming Assets/languages/{language}.po.txt"
    /// </summary>
    /// <param name="lang">language name aka: "en", "ru" or "en_US"</param>
    public void LoadLanguage(string lang)
    {
        SetLanguage(lang);

        string fullpath = Application.streamingAssetsPath + "/languages/" + lang + ".po.txt";
        var textAsset = File.ReadAllText(fullpath);
        if (textAsset == null)
        {
            Debug.LogError($"[POFile] '{fullpath}' file not found.");
        }
        else
        {
            Debug.Log($"[POFile] loading: '{fullpath}'");

            stringsDictionary.Clear();

            StringReader reader = new StringReader(textAsset);
            string key = null;
            string val = null;
            string line;
            while ((line = reader.ReadLine()) != null)
            {
                if (line.StartsWith("msgid \""))
                {
                    key = RemoveQuotes(line, 5);
                }
                else if (line.StartsWith("msgstr \""))
                {
                    val = RemoveQuotes(line, 6);

                    if (key != null && val != null)
                    {
                        // TODO: add error handling here in case of duplicate keys
                        stringsDictionary.Add(key, val);
                        key = val = null;
                    }
                    else
                        Debug.LogError($"[POFile] key or value is null key:'{key}' value:'{val}'.");
                }
            }
            reader.Close();
        }
    }
    // Set current language
    private void SetLanguage(string language)
    {
        currentLanguage = language;
        suffixMethod = suffixMethodsDictionary[language];
        Debug.Assert(suffixMethod != null);
    }
    // Remove spaces ' ' and quotes '"' from begin and endo of string
    private string RemoveQuotes(string str, int start)
    {
        Debug.Assert(str != null);
        Debug.Assert(start < str.Length);
        int startQuote = 0;
        int endQuote = 0;
        for (var i = start; i < str.Length; i++)
        {
            if (str[i] == ' ') continue;
            if (str[i] == '"')
            {
                startQuote = i;
                break;
            }
            Debug.LogError($"Text does not have start quote: '{str}'");
            return str;
        }

        for (var i = str.Length - 1; i >= startQuote; i--)
        {
            if (str[i] == ' ') continue;
            if (str[i] == '"')
            {
                endQuote = i;
                break;
            }
            Debug.LogError($"Text does not have end quote: '{str}'");
            return str;
        }
        Debug.Assert(endQuote > startQuote);
        return str.Substring(startQuote + 1, (endQuote - startQuote) - 1);
    }
	
    /// <summary>Find text value with the key</summary>
    public string GetText(string key)
    {
        Debug.Assert(key != null);
        string result = "";
        return stringsDictionary.TryGetValue(key, out result) ? result : null;
    }
	
    /// <summary>Find text value with the key and quantity</summary>
    public string GetText(string key, int quantity)
    {
        Debug.Assert(key != null);
        string pluralKey = GetPluralKey(key, quantity);
        string result = "";
        return stringsDictionary.TryGetValue(pluralKey, out result) ? result : null;
    }
	
    /// <summary>
    ///     Get key for pluralized text value
    /// </summary>
    /// <param name="key"></param>
    /// <param name="quantity"></param>
    /// <returns></returns>
    public string GetPluralKey(string key, int quantity)
    {
        return $"{key}_{suffixMethod.Invoke(quantity)}";
    }

    /// <summary>Contains current language</summary>
    public string currentLanguage = "en";

    /// <summary>Keep the method for computing pluralization suffix</summary>
    private Func<int, int> suffixMethod;

    /// <summary>Key value pair from .po file</summary>
    private Dictionary<string, string> stringsDictionary = new Dictionary<string, string>(100);

    /// <summary>
    ///     Contains list of methos for each available language.
    /// </summary>
    private static readonly Dictionary<string, Func<int, int>> suffixMethodsDictionary = new Dictionary<string, Func<int, int>>()
    {
        { "ar", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "bg", (n) => n != 1 ? 1 : 0 }, // Bulgarian
		{ "ca", (n) => n != 1 ? 1 : 0 }, // Catalan
		{ "zh-CHS", (n) => 0 }, // Chinese
		{ "cs", (n) => (n == 1) ? 0 : (n >= 2 && n <= 4) ? 1 : 2 }, // Czech
		{ "da", (n) => n != 1 ? 1 : 0 }, // Danish
		{ "de", (n) => n != 1 ? 1 : 0 }, // German
		{ "el", (n) => n != 1 ? 1 : 0 }, // Greek
		{ "en", (n) => n != 1 ? 1 : 0 }, // English
		{ "es", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "fi", (n) => n != 1 ? 1 : 0 }, // Finnish
		{ "fr", (n) => n > 1 ? 1 : 0 }, // French
		{ "he", (n) => n != 1 ? 1 : 0 }, // Hebrew
		{ "hu", (n) => n != 1 ? 1 : 0 }, // Hungarian
		{ "is", (n) => (n % 10 != 1 || n % 100 == 11) ? 1 : 0 }, // Icelandic
		{ "it", (n) => n != 1 ? 1 : 0 }, // Italian
		{ "ja", (n) => 0 }, // Japanese
		{ "ko", (n) => 0 }, // Korean
		{ "nl", (n) => n != 1 ? 1 : 0 }, // Dutch
		{ "no", (n) => n != 1 ? 1 : 0 }, // Norwegian
		{ "pl", (n) => n == 1 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Polish
		{ "pt", (n) => n != 1 ? 1 : 0 }, // Portuguese
		{ "ro", (n) => n == 1 ? 0 : (n == 0 || (n % 100 > 0 && n % 100 < 20)) ? 1 : 2 }, // Romanian
		{ "ru", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Russian
		{ "hr", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Croatian
		{ "sk", (n) => (n == 1) ? 0 : (n >= 2 && n <= 4) ? 1 : 2 }, // Slovak
		{ "sq", (n) => n != 1 ? 1 : 0 }, // Albanian
		{ "sv", (n) => n != 1 ? 1 : 0 }, // Swedish
		{ "th", (n) => 0 }, // Thai
		{ "tr", (n) => n > 1 ? 1 : 0 }, // Turkish
		{ "id", (n) => 0 }, // Indonesian
		{ "uk", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Ukrainian
		{ "be", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Belarusian
		{ "sl", (n) => n % 100 == 1 ? 1 : n % 100 == 2 ? 2 : n % 100 == 3 || n % 100 == 4 ? 3 : 0 }, // Slovenian
		{ "et", (n) => n != 1 ? 1 : 0 }, // Estonian
		{ "lv", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n != 0 ? 1 : 2 }, // Latvian
		{ "lt", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Lithuanian
		{ "fa", (n) => 0 }, // Persian
		{ "vi", (n) => 0 }, // Vietnamese
		{ "hy", (n) => n != 1 ? 1 : 0 }, // Armenian
		{ "eu", (n) => n != 1 ? 1 : 0 }, // Basque
		{ "mk", (n) => (n == 1 || n % 10 == 1) ? 1 : (n == 2 || n % 10 == 2) ? 2 : 0 }, // Macedonian
		{ "af", (n) => n != 1 ? 1 : 0 }, // Afrikaans
		{ "ka", (n) => 0 }, // Georgian
		{ "fo", (n) => n != 1 ? 1 : 0 }, // Faroese
		{ "hi", (n) => n != 1 ? 1 : 0 }, // Hindi
		{ "sw", (n) => n != 1 ? 1 : 0 }, // Swahili
		{ "gu", (n) => n != 1 ? 1 : 0 }, // Gujarati
		{ "ta", (n) => n != 1 ? 1 : 0 }, // Tamil
		{ "te", (n) => n != 1 ? 1 : 0 }, // Telugu
		{ "kn", (n) => n != 1 ? 1 : 0 }, // Kannada
		{ "mr", (n) => n != 1 ? 1 : 0 }, // Marathi
		{ "gl", (n) => n != 1 ? 1 : 0 }, // Gallegan -------------------------------
		{ "kok", (n) => n != 1 ? 1 : 0 }, // Konkani -------------------------------
		{ "ar-SA", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "bg-BG", (n) => n != 1 ? 1 : 0 }, // Bulgarian
		{ "ca-ES", (n) => n != 1 ? 1 : 0 }, // Catalan
		{ "zh-TW", (n) => 0 }, // Chinese
		{ "cs-CZ", (n) => (n == 1) ? 0 : (n >= 2 && n <= 4) ? 1 : 2 }, // Czech
		{ "da-DK", (n) => n != 1 ? 1 : 0 }, // Danish
		{ "de-DE", (n) => n != 1 ? 1 : 0 }, // German
		{ "el-GR", (n) => n != 1 ? 1 : 0 }, // Greek
		{ "en-US", (n) => n != 1 ? 1 : 0 }, // English
		{ "fi-FI", (n) => n != 1 ? 1 : 0 }, // Finnish
		{ "fr-FR", (n) => n > 1 ? 1 : 0 }, // French
		{ "he-IL", (n) => n != 1 ? 1 : 0 }, // Hebrew
		{ "hu-HU", (n) => n != 1 ? 1 : 0 }, // Hungarian
		{ "is-IS", (n) => (n % 10 != 1 || n % 100 == 11) ? 1 : 0 }, // Icelandic
		{ "it-IT", (n) => n != 1 ? 1 : 0 }, // Italian
		{ "ja-JP", (n) => 0 }, // Japanese
		{ "ko-KR", (n) => 0 }, // Korean
		{ "nl-NL", (n) => n != 1 ? 1 : 0 }, // Dutch
		{ "nb-NO", (n) => n != 1 ? 1 : 0 }, // Norwegian
		{ "pl-PL", (n) => n == 1 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Polish
		{ "pt-BR", (n) => n > 1 ? 1 : 0 }, // Portuguese
		{ "ro-RO", (n) => n == 1 ? 0 : (n == 0 || (n % 100 > 0 && n % 100 < 20)) ? 1 : 2 }, // Romanian
		{ "ru-RU", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Russian
		{ "hr-HR", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Croatian
		{ "sk-SK", (n) => (n == 1) ? 0 : (n >= 2 && n <= 4) ? 1 : 2 }, // Slovak
		{ "sq-AL", (n) => n != 1 ? 1 : 0 }, // Albanian
		{ "sv-SE", (n) => n != 1 ? 1 : 0 }, // Swedish
		{ "th-TH", (n) => 0 }, // Thai
		{ "tr-TR", (n) => n > 1 ? 1 : 0 }, // Turkish
		{ "id-ID", (n) => 0 }, // Indonesian
		{ "uk-UA", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Ukrainian
		{ "be-BY", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Belarusian
		{ "sl-SI", (n) => n % 100 == 1 ? 1 : n % 100 == 2 ? 2 : n % 100 == 3 || n % 100 == 4 ? 3 : 0 }, // Slovenian
		{ "et-EE", (n) => n != 1 ? 1 : 0 }, // Estonian
		{ "lv-LV", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n != 0 ? 1 : 2 }, // Latvian
		{ "lt-LT", (n) => n % 10 == 1 && n % 100 != 11 ? 0 : n % 10 >= 2 && (n % 100 < 10 || n % 100 >= 20) ? 1 : 2 }, // Lithuanian
		{ "fa-IR", (n) => 0 }, // Persian
		{ "vi-VN", (n) => 0 }, // Vietnamese
		{ "hy-AM", (n) => n != 1 ? 1 : 0 }, // Armenian
		{ "eu-ES", (n) => n != 1 ? 1 : 0 }, // Basque
		{ "mk-MK", (n) => (n == 1 || n % 10 == 1) ? 1 : (n == 2 || n % 10 == 2) ? 2 : 0}, // Macedonian
		{ "af-ZA", (n) => n != 1 ? 1 : 0 }, // Afrikaans
		{ "ka-GE", (n) => 0 }, // Georgian
		{ "fo-FO", (n) => n != 1 ? 1 : 0 }, // Faroese
		{ "hi-IN", (n) => n != 1 ? 1 : 0 }, // Hindi
		{ "sw-KE", (n) => n != 1 ? 1 : 0 }, // Swahili
		{ "gu-IN", (n) => n != 1 ? 1 : 0 }, // Gujarati
		{ "ta-IN", (n) => n != 1 ? 1 : 0 }, // Tamil
		{ "te-IN", (n) => n != 1 ? 1 : 0 }, // Telugu
		{ "kn-IN", (n) => n != 1 ? 1 : 0 }, // Kannada
		{ "mr-IN", (n) => n != 1 ? 1 : 0 }, // Marathi
		{ "gl-ES", (n) => n != 1 ? 1 : 0 }, // Gallegan -------------------------------
		{ "kok-IN", (n) => n != 1 ? 1 : 0 }, // Konkani -------------------------------
		{ "ar-IQ", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "zh-CN", (n) => 0 }, // Chinese
		{ "de-CH", (n) => n != 1 ? 1 : 0 }, // German
		{ "en-GB", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-MX", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "fr-BE", (n) => n > 1 ? 1 : 0 }, // French
		{ "it-CH", (n) => n != 1 ? 1 : 0 }, // Italian
		{ "nl-BE", (n) => n != 1 ? 1 : 0 }, // Dutch
		{ "nn-NO", (n) => n != 1 ? 1 : 0 }, // Norwegian
		{ "pt-PT", (n) => n != 1 ? 1 : 0 }, // Portuguese
		{ "sv-FI", (n) => n != 1 ? 1 : 0 }, // Swedish
		{ "ar-EG", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "zh-HK", (n) => 0 }, // Chinese
		{ "de-AT", (n) => n != 1 ? 1 : 0 }, // German
		{ "en-AU", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-ES", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "fr-CA", (n) => n > 1 ? 1 : 0 }, // French
		{ "ar-LY", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "zh-SG", (n) => 0 }, // Chinese
		{ "de-LU", (n) => n != 1 ? 1 : 0 }, // German
		{ "en-CA", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-GT", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "fr-CH", (n) => n > 1 ? 1 : 0 }, // French
		{ "ar-DZ", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "zh-MO", (n) => 0 }, // Chinese
		{ "en-NZ", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-CR", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "fr-LU", (n) => n > 1 ? 1 : 0 }, // French
		{ "ar-MA", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "en-IE", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-PA", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-TN", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "en-ZA", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-DO", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-OM", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-VE", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-YE", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-CO", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-SY", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-PE", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-JO", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "en-TT", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-AR", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-LB", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "en-ZW", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-EC", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-KW", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "en-PH", (n) => n != 1 ? 1 : 0 }, // English
		{ "es-CL", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-AE", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-UY", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-BH", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-PY", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "ar-QA", (n) => n == 0 ? 0 : n == 1 ? 1 : n == 2 ? 2 : n % 100 >= 3 && n % 100 <= 10 ? 3 : n % 100 >= 11 ? 4 : 5 }, // Arabic
		{ "es-BO", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "es-SV", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "es-HN", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "es-NI", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "es-PR", (n) => n != 1 ? 1 : 0 }, // Spanish
		{ "zh-CHT", (n) => 0 }, // Chinese
		{ "ms", (n) => 0 } // Malaysia
    };
}