OnBookmarkControlEnd

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

namespace Oxide.Plugins
{
    [Info("Bookmark Control End Logger", "RustPluginGenerator", "1.0.0")]
    [Description("Tracks and announces when a player stops controlling a ComputerStation camera")]
    public class BookmarkControlEndLogger : RustPlugin
    {
        private class PluginConfig
        {
            [JsonProperty("Announce session end to player")]
            public bool AnnounceToPlayer = true;

            [JsonProperty("Broadcast session end to server")]
            public bool BroadcastToServer = false;
        }

        private class Session
        {
            public float StartedAt;
            public string EntityName;
        }

        private PluginConfig config;
        private readonly Dictionary<ulong, Session> sessions = new Dictionary<ulong, Session>();

        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>
            {
                ["SessionEnded"] = "You stopped viewing {0} after {1}s.",
                ["BroadcastEnded"] = "{0} stopped viewing a camera after {1}s."
            }, this);
        }

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

        private object OnBookmarkControlEnd(ComputerStation computerStation, BasePlayer ply, BaseEntity entity)
        {
            if (ply == null) return null;

            Session session;
            if (!sessions.TryGetValue(ply.userID.Get(), out session)) return null;
            sessions.Remove(ply.userID.Get());

            if (session == null) return null;

            var seconds = (int)Math.Max(0, UnityEngine.Time.realtimeSinceStartup - session.StartedAt);
            var name = session.EntityName ?? "camera";

            if (config.AnnounceToPlayer && ply.IsConnected)
                ply.ChatMessage(Msg("SessionEnded", ply.UserIDString, name, seconds));

            if (config.BroadcastToServer)
                Server.Broadcast(Msg("BroadcastEnded", null, ply.displayName, seconds));

            return null;
        }

        private object OnBookmarkControlStarted(ComputerStation computerStation, BasePlayer ply, BaseEntity entity)
        {
            if (ply == null) return null;

            var session = new Session
            {
                StartedAt = UnityEngine.Time.realtimeSinceStartup,
                EntityName = entity != null ? entity.ShortPrefabName : null
            };
            sessions[ply.userID.Get()] = session;
            return null;
        }

        private void OnPlayerDisconnected(BasePlayer player)
        {
            if (player == null) return;
            sessions.Remove(player.userID.Get());
        }

        private void Unload()
        {
            sessions.Clear();
        }
    }
}