How to make a Rust barrel scrap bonus plugin (Oxide/Carbon)

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

namespace Oxide.Plugins
{
    [Info("Barrel Scrap Bonus", "RustPluginGenerator", "1.0.0")]
    [Description("Awards configurable bonus scrap when a player destroys a loot barrel, with a VIP multiplier.")]
    public class BarrelScrapBonus : RustPlugin
    {
        private const string PermUse = "barrelscrapbonus.use";
        private const string PermAdmin = "barrelscrapbonus.admin";
        private const string PermVip = "barrelscrapbonus.vip";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Bonus Chance Percent")]
            public float BonusChance { get; set; } = 15f;

            [JsonProperty("Min Scrap")]
            public int MinScrap { get; set; } = 10;

            [JsonProperty("Max Scrap")]
            public int MaxScrap { get; set; } = 25;

            [JsonProperty("VIP Multiplier")]
            public float VipMultiplier { get; set; } = 2f;

            [JsonProperty("Notify Player")]
            public bool NotifyPlayer { get; set; } = true;

            [JsonProperty("Barrel Name Fragments")]
            public List<string> BarrelFragments { get; set; } = new List<string>
            {
                "loot-barrel",
                "loot-barrel-1",
                "loot-barrel-2",
                "loot_barrel"
            };
        }

        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>
            {
                ["Bonus"] = "You found {0} bonus scrap in the barrel.",
                ["Status"] = "Chance: {0}%, Scrap: {1}-{2}, VIP multiplier: x{3}",
                ["Reloaded"] = "Barrel scrap bonus configuration reloaded.",
                ["NoPermission"] = "You do not have permission to use this command.",
                ["Usage"] = "Usage: /barrelscrap <status|reload>"
            }, 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(PermUse, this);
            permission.RegisterPermission(PermAdmin, this);
            permission.RegisterPermission(PermVip, this);
        }

        private void OnEntityDeath(BaseCombatEntity entity, HitInfo info)
        {
            if (entity == null || info == null) return;

            var container = entity as LootContainer;
            if (container == null) return;

            var player = info.InitiatorPlayer;
            if (player == null || player.IsNpc || !player.IsConnected) return;

            var prefab = container.ShortPrefabName ?? string.Empty;
            if (!IsBarrel(prefab)) return;

            if (UnityEngine.Random.Range(0f, 100f) > config.BonusChance) return;

            int rolled = UnityEngine.Random.Range(config.MinScrap, config.MaxScrap + 1);
            if (rolled <= 0) return;

            if (permission.UserHasPermission(player.UserIDString, PermVip) && config.VipMultiplier > 0f)
            {
                rolled = Mathf.FloorToInt(rolled * config.VipMultiplier);
            }

            if (rolled <= 0) return;

            var scrap = ItemManager.CreateByName("scrap", rolled);
            if (scrap == null) return;

            player.GiveItem(scrap);

            if (config.NotifyPlayer)
            {
                player.ChatMessage(Msg("Bonus", player.UserIDString, rolled));
            }
        }

        private bool IsBarrel(string prefabName)
        {
            if (string.IsNullOrEmpty(prefabName) || config.BarrelFragments == null) return false;
            foreach (var fragment in config.BarrelFragments)
            {
                if (string.IsNullOrEmpty(fragment)) continue;
                if (prefabName.IndexOf(fragment, StringComparison.OrdinalIgnoreCase) >= 0) return true;
            }
            return false;
        }

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

            if (args == null || args.Length == 0)
            {
                player.ChatMessage(Msg("Usage", player.UserIDString));
                return;
            }

            var sub = args[0].ToLowerInvariant();

            if (sub == "status")
            {
                if (!permission.UserHasPermission(player.UserIDString, PermUse))
                {
                    player.ChatMessage(Msg("NoPermission", player.UserIDString));
                    return;
                }

                player.ChatMessage(Msg("Status", player.UserIDString,
                    config.BonusChance, config.MinScrap, config.MaxScrap, config.VipMultiplier));
                return;
            }

            if (sub == "reload")
            {
                if (!permission.UserHasPermission(player.UserIDString, PermAdmin))
                {
                    player.ChatMessage(Msg("NoPermission", player.UserIDString));
                    return;
                }

                LoadConfig();
                player.ChatMessage(Msg("Reloaded", player.UserIDString));
                return;
            }

            player.ChatMessage(Msg("Usage", player.UserIDString));
        }

        private void Unload()
        {
            SaveConfig();
        }
    }
}