How to make a Rust first blood plugin (announce + reward first kill)

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

namespace Oxide.Plugins
{
    [Info("First Blood", "RustPluginGenerator", "1.0.0")]
    [Description("Announces the first player kill after a restart and rewards the killer.")]
    public class FirstBlood : RustPlugin
    {
        private const string PermAdmin = "firstblood.admin";
        private const string PermReset = "firstblood.reset";
        private const string DataFile = "FirstBlood";

        private PluginConfig config;
        private FirstBloodData data;

        private class PluginConfig
        {
            [JsonProperty("Announce First Blood")]
            public bool Announce { get; set; } = true;

            [JsonProperty("Reward Enabled")]
            public bool RewardEnabled { get; set; } = true;

            [JsonProperty("Reward Items")]
            public List<RewardItem> RewardItems { get; set; } = new List<RewardItem>
            {
                new RewardItem { Shortname = "scrap", Amount = 250, Skin = 0 },
                new RewardItem { Shortname = "supply.signal", Amount = 1, Skin = 0 }
            };

            [JsonProperty("Claimed")]
            public bool Claimed { get; set; } = false;

            [JsonProperty("Killer Id")]
            public string KillerId { get; set; } = string.Empty;

            [JsonProperty("Killer Name")]
            public string KillerName { get; set; } = string.Empty;

            [JsonProperty("Timestamp")]
            public int Timestamp { get; set; } = 0;
        }

        private class RewardItem
        {
            [JsonProperty("Shortname")]
            public string Shortname { get; set; } = "scrap";

            [JsonProperty("Amount")]
            public int Amount { get; set; } = 1;

            [JsonProperty("Skin")]
            public ulong Skin { get; set; } = 0;
        }

        private class FirstBloodData
        {
            [JsonProperty("Claimed")]
            public bool Claimed { get; set; } = false;

            [JsonProperty("Killer Id")]
            public string KillerId { get; set; } = string.Empty;

            [JsonProperty("Killer Name")]
            public string KillerName { get; set; } = string.Empty;

            [JsonProperty("Timestamp")]
            public int Timestamp { get; set; } = 0;
        }

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

        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>
            {
                ["FirstBlood.Broadcast"] = "FIRST BLOOD: {0} killed {1} with {2} ({3}m)",
                ["FirstBlood.Reward"] = "You received the first blood reward: {0}",
                ["FirstBlood.Status.Claimed"] = "First blood claimed by {0} at {1}.",
                ["FirstBlood.Status.Open"] = "First blood is still open.",
                ["FirstBlood.Reset"] = "First blood claim cleared.",
                ["FirstBlood.NoPermission"] = "You do not have permission to use this command."
            }, this);
        }

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

        private void OnServerInitialized()
        {
            data = Interface.Oxide.DataFileSystem.ReadObject<FirstBloodData>(DataFile) ?? new FirstBloodData();
            if (data.Claimed)
                Puts($"First blood already claimed by {data.KillerName} ({data.KillerId}).");
            else
                Puts("First blood is open for the next PvP kill.");
        }

        private void OnNewSave(string filename)
        {
            data = new FirstBloodData();
            Interface.Oxide.DataFileSystem.WriteObject(DataFile, data);
        }

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

            BasePlayer victim = entity as BasePlayer;
            if (victim == null || victim.IsNpc || !victim.IsConnected) return;

            BasePlayer killer = info.InitiatorPlayer;
            if (killer == null || killer.IsNpc || !killer.IsConnected) return;
            if (killer.userID == victim.userID) return;

            data.Claimed = true;
            data.KillerId = killer.UserIDString;
            data.KillerName = killer.displayName;
            data.Timestamp = Facepunch.Math.Epoch.Current;

            config.Claimed = true;
            config.KillerId = killer.UserIDString;
            config.KillerName = killer.displayName;
            config.Timestamp = data.Timestamp;
            SaveConfig();

            Interface.Oxide.DataFileSystem.WriteObject(DataFile, data);

            string weapon = info.WeaponPrefab != null ? info.WeaponPrefab.ShortPrefabName : "unknown";
            int distance = Mathf.RoundToInt(info.ProjectileDistance);

            if (config.Announce)
                Server.Broadcast(Msg("FirstBlood.Broadcast", null, killer.displayName, victim.displayName, weapon, distance));

            if (!config.RewardEnabled) return;

            List<string> given = new List<string>();
            foreach (RewardItem entry in config.RewardItems)
            {
                Item item = ItemManager.CreateByName(entry.Shortname, entry.Amount, entry.Skin);
                if (item == null) continue;
                if (!killer.inventory.GiveItem(item))
                    item.Drop(killer.transform.position, Vector3.zero);
                given.Add($"{entry.Amount}x {item.info.displayName.english}");
            }

            if (given.Count > 0)
                killer.ChatMessage(Msg("FirstBlood.Reward", killer.UserIDString, string.Join(", ", given)));
        }

        [ChatCommand("firstblood")]
        private void CmdFirstBlood(BasePlayer player, string command, string[] args)
        {
            if (player == null || args == null || args.Length == 0) return;

            switch (args[0].ToLower())
            {
                case "status":
                    if (!permission.UserHasPermission(player.UserIDString, PermAdmin))
                    {
                        player.ChatMessage(Msg("FirstBlood.NoPermission", player.UserIDString));
                        return;
                    }
                    if (data == null || !data.Claimed)
                    {
                        player.ChatMessage(Msg("FirstBlood.Status.Open", player.UserIDString));
                        return;
                    }
                    DateTime when = DateTimeOffset.FromUnixTimeSeconds(data.Timestamp).LocalDateTime;
                    player.ChatMessage(Msg("FirstBlood.Status.Claimed", player.UserIDString, data.KillerName, when.ToString("yyyy-MM-dd HH:mm")));
                    break;

                case "reset":
                    if (!permission.UserHasPermission(player.UserIDString, PermReset))
                    {
                        player.ChatMessage(Msg("FirstBlood.NoPermission", player.UserIDString));
                        return;
                    }
                    data = new FirstBloodData();
                    Interface.Oxide.DataFileSystem.WriteObject(DataFile, data);

                    config.Claimed = false;
                    config.KillerId = string.Empty;
                    config.KillerName = string.Empty;
                    config.Timestamp = 0;
                    SaveConfig();

                    player.ChatMessage(Msg("FirstBlood.Reset", player.UserIDString));
                    break;
            }
        }
    }
}