using System;
using Luneraria.Core;
using Luneraria.Net;
using Luneraria.View;
using UnityEngine;
using UnityEngine.UIElements;

namespace Luneraria.UI
{
    /// <summary>
    /// Owns the session and the TCP link (port of lune_main.gd): title menu, match, return,
    /// rematch. Offline is a local host with bot-filled seats. Host/Join uses LuneSession over
    /// LuneTcp. Every setup from the host (first join, rejoin, rematch) relaunches the match.
    /// The scene builder puts it next to the game controller, so the start screen comes first.
    /// Tests and the benchmark keep the scene's own match (LuneMatchDriver.DirectStart,
    /// LuneBenchmark.Running); then the shell stays out and LuneGame starts as before U4.
    /// </summary>
    [DefaultExecutionOrder(-50)]
    public sealed class LuneNetPlay : MonoBehaviour
    {
        /// <summary>The start screen draws above the HUD (sorting order 10).</summary>
        public const int MenuSortingOrder = 20;

        public LuneGame Game;
        public LuneMatchDriver Driver;
        public LuneMatchView View;
        public LuneCameraRig Rig;
        public LuneUiAssets UiAssets;

        public LuneSession Session { get; private set; }
        public LuneMainMenu Menu { get; private set; }
        /// <summary>
        /// The start screen's own document. The HUD takes over the UIDocument of the match object
        /// and clears it on every launch, so the menu cannot live there.
        /// </summary>
        public UIDocument MenuDocument { get; private set; }

        LuneTcp _tcp;
        MatchOptions _lastOptions;
        bool _relaunch;
        PanelSettings _panel;

        void Awake()
        {
            if (Game == null)
                Game = GetComponent<LuneGame>();
            if (Driver == null)
                Driver = GetComponent<LuneMatchDriver>();
            if (View == null)
                View = GetComponent<LuneMatchView>();
            if (Rig == null)
                Rig = GetComponent<LuneCameraRig>();
            if (UiAssets == null && Game != null)
                UiAssets = Game.UiAssets;
        }

        void Start()
        {
            if (LuneMatchDriver.DirectStart || LuneBenchmark.Running)
            {
                enabled = false;
                return;
            }
            BuildMenu();
            if (Game != null)
            {
                Game.Net = this;
                Game.enabled = false;
            }
            if (Driver != null)
                Driver.enabled = false;
            ShowMenu();
            LuneSmoke.StartIfRequested(this);
        }

        void BuildMenu()
        {
            LuneUi.Assets = UiAssets;
            _panel = ScriptableObject.CreateInstance<PanelSettings>();
            _panel.name = "LuneMenuPanel";
            _panel.themeStyleSheet = UiAssets != null ? UiAssets.Theme : null;
            _panel.scaleMode = PanelScaleMode.ScaleWithScreenSize;
            _panel.referenceResolution = LuneHud.Reference;
            _panel.screenMatchMode = PanelScreenMatchMode.Expand;
            _panel.sortingOrder = MenuSortingOrder;
            var holder = new GameObject("Menu");
            holder.transform.SetParent(transform, false);
            MenuDocument = holder.AddComponent<UIDocument>();
            MenuDocument.panelSettings = _panel;
            // While a match runs the menu is hidden; its root must not take the HUD's clicks.
            MenuDocument.rootVisualElement.pickingMode = PickingMode.Ignore;
            Menu = new LuneMainMenu();
            MenuDocument.rootVisualElement.Add(Menu);
            Menu.StartOffline += StartOffline;
            Menu.HostRequested += HostMatch;
            Menu.JoinRequested += JoinMatch;
            Menu.QuitRequested += Quit;
        }

        /// <summary>The start screen over the empty map; the camera rests, the fields take W, A, S, D, Q and E.</summary>
        void ShowMenu()
        {
            Menu.Enter();
            if (Rig != null)
            {
                Rig.Interactive = false;
                Rig.SetYaw(0f);
                Rig.Overview(true);
            }
        }

        void Update()
        {
            if (_tcp != null)
                _tcp.Pump();
            if (_relaunch)
            {
                _relaunch = false;
                Launch();
            }
        }

        void StartOffline(MatchOptions options)
        {
            ResetSession();
            Session = new LuneSession();
            Session.HostOffline(options.HumanSlot, options);
            _lastOptions = options;
            Menu.Leave();
            Launch();
        }

        void HostMatch(int port, string displayName)
        {
            ResetSession();
            _tcp = new LuneTcp();
            Session = new LuneSession { Link = _tcp };
            _tcp.Session = Session;
            Session.SessionMessage += OnMessage;
            if (!_tcp.Host(port))
            {
                Menu.Notify(_tcp.LastError, true);
                ResetSession();
                return;
            }
            var options = new MatchOptions { Seed = Environment.TickCount & 0xffff, HumanSlot = 0 };
            for (int slot = 0; slot < 6; slot++)
                options.Bunds.Add(slot == 0 ? Menu.Bund : DataCatalog.Factions[(slot + options.Seed) % DataCatalog.Factions.Length]);
            if (!Session.HostNetwork(options, displayName))
            {
                Menu.Notify(Session.LastError, true);
                ResetSession();
                return;
            }
            _lastOptions = options;
            Menu.Notify("Warte auf Gäste auf Port " + port + " …");
            Menu.Leave();
            Launch();
        }

        void JoinMatch(string address, int port, string displayName)
        {
            ResetSession();
            _tcp = new LuneTcp();
            Session = new LuneSession { Link = _tcp };
            _tcp.Session = Session;
            Session.SessionMessage += OnMessage;
            Session.HostLost += () =>
            {
                string reason = Session != null ? Session.LastError : "";
                ReturnToMenu();
                if (Menu != null)
                    Menu.Notify(reason, true);
            };
            Session.MatchResetup += () =>
            {
                if (Session != null && Session.MatchState != null)
                    _relaunch = true;
            };
            if (!Session.JoinNetwork(displayName) || !_tcp.Join(address, port))
            {
                Menu.Notify(_tcp.LastError.Length > 0 ? _tcp.LastError : Session.LastError, true);
                ResetSession();
                return;
            }
            Menu.Notify("Verbinde mit " + address + ":" + port + " …");
        }

        void OnMessage(string text, bool isError)
        {
            if (Menu != null && LuneUi.Visible(Menu))
                Menu.Notify(text, isError);
            if (Game != null && Game.Hud != null && !isError)
                Game.Hud.Notify(text, isError);
        }

        void Launch()
        {
            if (Game == null || Session == null || Session.MatchState == null)
                return;
            bool networked = Session.IsNetworked();
            Game.Net = this;
            Game.Session = networked ? Session : null;
            Game.HumanSlot = Session.LocalSlot >= 0 ? Session.LocalSlot : 0;
            if (Driver != null)
            {
                Driver.enabled = true;
                if (networked)
                    Driver.Adopt(Session.MatchState, Session.LocalSlot, !Session.IsAuthority(), Session);
                else
                {
                    // Offline keeps the plain runner; the session already validated the setup path.
                    Driver.HumanSlot = Game.HumanSlot;
                    Driver.Bunds = _lastOptions != null && _lastOptions.Bunds != null ? _lastOptions.Bunds.ToArray() : null;
                    Driver.Seed = _lastOptions != null ? _lastOptions.Seed : Driver.Seed;
                    Driver.Restart();
                }
            }
            if (Rig != null)
            {
                // Every match starts with an unturned camera, like Godot's new game node.
                Rig.SetYaw(0f, true);
                Rig.Interactive = true;
            }
            Game.enabled = true;
            Game.Launch();
        }

        /// <summary>Host rematch: a new match with the same seats; clients relaunch on setup.</summary>
        public void Rematch()
        {
            if (Session == null || !Session.IsAuthority())
            {
                if (Game != null && Game.Hud != null)
                    Game.Hud.Notify("Eine Revanche startet der Host.", true);
                return;
            }
            if (_lastOptions != null)
                _lastOptions.Seed += 1;
            MatchOptions options = _lastOptions ?? new MatchOptions();
            Session.HostRematch(options);
            _relaunch = true;
        }

        /// <summary>
        /// Back to the start screen. Godot frees the game node; here the HUD closes and the driver
        /// holds a fresh match that never runs, so the map behind the menu is empty again.
        /// </summary>
        public void ReturnToMenu()
        {
            if (Game != null)
                Game.Close();
            if (Driver != null)
            {
                Driver.HumanSlot = -1;
                Driver.Restart();
                Driver.enabled = false;
            }
            ResetSession();
            if (Menu != null)
                ShowMenu();
        }

        void ResetSession()
        {
            if (_tcp != null)
            {
                _tcp.Close();
                _tcp = null;
            }
            if (Session != null)
            {
                Session.Close();
                Session = null;
            }
        }

        void OnDestroy()
        {
            ResetSession();
            if (_panel != null)
                Destroy(_panel);
        }

        static void Quit()
        {
#if UNITY_EDITOR
            UnityEditor.EditorApplication.isPlaying = false;
#else
            Application.Quit();
#endif
        }
    }
}