OnLootSpawn

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

namespace Oxide.Plugins
{
    [Info("CustomLootSpawn", "RustPluginGenerator", "1.0.0")]
    [Description("Replaces loot in matching containers with a configurable item list.")]
    public class CustomLootSpawn : RustPlugin
    {
        private const string PermBypass = "customlootspawn.bypass";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Prefab shortnames (leave a match to override loot)")]
            public List<string> Prefabs = new List<string> { "crate_normal", "crate_basic" };

            [JsonProperty("Items to give (shortname amount)")]
            public List<string> Items = new List<string> { "rifle.ak 1", "ammo.rifle 90", "bandage 5" };

            [JsonProperty("Log each override to console")]
            public bool LogOverrides = false;
        }

        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);

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

        private object OnLootSpawn(object source)
        {
            if (source == null) return null;

            var container = source as LootContainer;
            if (container == null) return null;
            if (container.inventory == null) return null;
            if (string.IsNullOrEmpty(container.ShortPrefabName)) return null;
            if (!config.Prefabs.Contains(container.ShortPrefabName)) return null;

            FillContainer(container);

            if (config.LogOverrides)
                Puts($"Seeded {container.ShortPrefabName} at {container.transform.position}");

            return true;
        }

        private void FillContainer(LootContainer container)
        {
            var inv = container.inventory;
            inv.Clear();

            foreach (var line in config.Items)
            {
                if (string.IsNullOrEmpty(line)) continue;
                var parts = line.Split(' ');
                if (parts.Length < 1) continue;

                string shortname = parts[0];
                int amount = 1;
                if (parts.Length >= 2) int.TryParse(parts[1], out amount);
                if (amount <= 0) continue;

                var item = ItemManager.CreateByName(shortname, amount, 0UL);
                if (item == null)
                {
                    PrintWarning($"Unknown item shortname in config: {shortname}");
                    continue;
                }

                if (!item.MoveToContainer(inv))
                {
                    item.Remove();
                }
            }

            inv.MarkDirty();
        }
    }
}