using JetBrains.Annotations;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using UnityEngine;

namespace NEG.Localization
{
    [PublicAPI]
    public class LocalizationManager
    {
        private class AvailableLanguages
        {
            public List<string> Languages { get; set; }
        }
        
        public const string LanguageResourcePath = "Localization";
        public const string ResourcesFolderPath = "Data/Resources";
        public const string AvailableLanguagesFile = "Languages";

        public static LocalizationManager Instance => instance ??= new LocalizationManager();
        
        public IEnumerable<string> Languages => languages;

        private static LocalizationManager instance;
        private List<string> languages;
        private HashSet<Action<LocalizationProvider>> actions = new();
        private LocalizationProvider provider;
        
        public LocalizationManager()
        {
            var file = Resources.Load<TextAsset>($"{LanguageResourcePath}/{AvailableLanguagesFile}");
            var available = JsonConvert.DeserializeObject<AvailableLanguages>(file.text);
            languages = available.Languages;
        }

        public void SelectLanguage(string languageCode)
        {
            if (!languages.Contains(languageCode))
            {
                Debug.LogError($"Localization {languageCode} not found in files");
                return;
            }

            provider = new LocalizationProvider($"{LanguageResourcePath}/{languageCode}");
            
            foreach (var item in actions)
            {
                item?.Invoke(provider);
            }
        }

        /// <summary>
        /// Register action for localization. Always fire provided action
        /// </summary>
        /// <param name="action">action to call on localization change</param>
        public static void Register(Action<LocalizationProvider> action)
        {
            if (!Instance.actions.Contains(action))
            {
                Instance.actions.Add(action);
            }

            action.Invoke(Instance.provider);
        }
        
        /// <summary>
        /// Unregister action from localization.
        /// </summary>
        /// <param name="action">action to unregister</param>
        public static void Unregister(Action<LocalizationProvider> action) => Instance.actions.Remove(action);

    }
}