OnPlayerLanguageChanged

using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using Oxide.Core;
using UnityEngine;

namespace Oxide.Plugins
{
    [Info("Player Language Tracker", "RustPluginGenerator", "1.0.0")]
    [Description("Stores the language each player selects and answers a chat command in it")]
    public class PlayerLanguageTracker : RustPlugin
    {
        private const string PermAdmin = "playerlanguagetracker.admin";

        private PluginConfig config;
        private Dictionary<string, string> languages = new Dictionary<string, string>();

        private class PluginConfig
        {
            [JsonProperty("Announce language change in chat")]
            public bool AnnounceChange { get; set; } = true;
        }

        protected override void LoadDefaultConfig() => config = new PluginConfig();

        protected override void LoadConfig()
        {
            base.LoadConfig();
            try
            {
                config = Config.ReadObject<PluginConfig>();
                if (config == null) throw new Exception();
            }
            catch
            {
                PrintWarning("Configuration file is invalid, using defaults");
                LoadDefaultConfig();
            }
            SaveConfig();
        }

        protected override void SaveConfig() => Config.WriteObject(config);

        protected override void LoadDefaultMessages()
        {
            lang.RegisterMessages(new Dictionary<string, string>
            {
                ["LanguageSaved"] = "Your language is now set to {0}.",
                ["LanguageQuery"] = "The server has your language on record as {0}.",
                ["ListHeader"] = "Recorded player languages:",
                ["NoData"] = "No language data has been recorded yet."
            }, this);
        }

        private string Msg(string key, string userId = null, params object[] args) =>
            string.Format(lang.GetMessage(key, this, userId), args);

        private void Init()
        {
            permission.RegisterPermission(PermAdmin, this);
            LoadData();
        }

        private void LoadData()
        {
            languages = Interface.Oxide.DataFileSystem.ReadObject<Dictionary<string, string>>(Name)
                        ?? new Dictionary<string, string>();
        }

        private void OnPlayerLanguageChanged(BasePlayer player, string val)
        {
            if (player == null || string.IsNullOrEmpty(val)) return;

            languages[player.UserIDString] = val;

            if (config.AnnounceChange)
            {
                player.ChatMessage(Msg("LanguageSaved", player.UserIDString, val));
            }
        }

        [ChatCommand("lang")]
        private void CmdLang(BasePlayer player, string command, string[] args)
        {
            if (player == null) return;

            string stored;
            string current = languages.TryGetValue(player.UserIDString, out stored) ? stored : "unknown";
            player.ChatMessage(Msg("LanguageQuery", player.UserIDString, current));
        }

        [ChatCommand("langlist")]
        private void CmdLangList(BasePlayer player, string command, string[] args)
        {
            if (player == null || !permission.UserHasPermission(player.UserIDString, PermAdmin)) return;

            if (languages.Count == 0)
            {
                player.ChatMessage(Msg("NoData", player.UserIDString));
                return;
            }

            player.ChatMessage(Msg("ListHeader", player.UserIDString));
            foreach (KeyValuePair<string, string> entry in languages)
            {
                string name = BasePlayer.FindByID(ulong.Parse(entry.Key))?.displayName ?? entry.Key;
                player.ChatMessage(name + " - " + entry.Value);
            }
        }

        private void Unload()
        {
            Interface.Oxide.DataFileSystem.WriteObject(Name, languages);
        }
    }
}