using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Web;
using VAR.Json;

namespace VAR.WebForms.Common.Code
{
    public class MultiLang
    {
        private static string GetLocalPath(string path)
        {
            string currentDir = Path.GetDirectoryName((new System.Uri(Assembly.GetExecutingAssembly().CodeBase)).AbsolutePath);
            return string.Format("{0}/{1}", Directory.GetParent(currentDir), path);
        }

        private static Dictionary<string, Dictionary<string, object>> _literals = null;

        private static void InitializeLiterals()
        {
            _literals = new Dictionary<string, Dictionary<string, object>>();

            JsonParser jsonParser = new JsonParser();
            foreach (string lang in new string[] { "en", "es" })
            {
                string filePath = GetLocalPath(string.Format("Resources/Literals.{0}.json", lang));
                if (File.Exists(filePath) == false) { continue; }

                string strJsonLiteralsLanguage = File.ReadAllText(filePath);
                object result = jsonParser.Parse(strJsonLiteralsLanguage);
                _literals.Add(lang, result as Dictionary<string, object>);
            }
        }

        private const string _defaultLanguage = "en";

        private static string GetUserLanguage()
        {
            HttpContext ctx = HttpContext.Current;
            if (ctx != null)
            {
                if (ctx.Items["UserLang"] != null)
                {
                    return (string)ctx.Items["UserLang"];
                }

                IEnumerable<string> userLanguages = ctx.Request.UserLanguages
                    .Select(lang =>
                    {
                        if (lang.Contains(";"))
                        {
                            lang = lang.Split(';')[0];
                        }
                        if (lang.Contains("-"))
                        {
                            lang = lang.Split('-')[0];
                        }
                        return lang.ToLower();
                    })
                    .Where(lang => _literals.ContainsKey(lang));
                string userLang = userLanguages.FirstOrDefault() ?? _defaultLanguage;

                ctx.Items["UserLang"] = userLang;
                return userLang;
            }
            return _defaultLanguage;
        }

        public static string GetLiteral(string resource, string culture = null)
        {
            if (_literals == null) { InitializeLiterals(); }
            if (culture == null) { culture = GetUserLanguage(); }

            if (_literals == null || _literals.ContainsKey(culture) == false) { return resource; }
            Dictionary<string, object> _literalCurrentCulture = _literals[culture];

            if (_literalCurrentCulture == null || _literalCurrentCulture.ContainsKey(resource) == false) { return resource; }
            return (_literalCurrentCulture[resource] as string) ?? resource;
        }
    }
}