using System;
using System.Collections.Generic;
using Luneraria.Core;
using UnityEngine;
using UnityEngine.UIElements;

namespace Luneraria.UI
{
    /// <summary>Where a HUD click sends the camera: a lane, a map point or a named target (base, enemy_base, grotto, hero).</summary>
    public sealed class LuneFocusTarget
    {
        public string Lane = "";
        public Vec2? Point;
        public string Camera = "";

        public bool IsEmpty { get { return Lane.Length == 0 && Point == null && Camera.Length == 0; } }
        public static LuneFocusTarget ForLane(string lane) { return new LuneFocusTarget { Lane = lane ?? "" }; }
        public static LuneFocusTarget ForPoint(Vec2 point) { return new LuneFocusTarget { Point = point }; }
        public static LuneFocusTarget ForCamera(string target) { return new LuneFocusTarget { Camera = target ?? "" }; }

        public override string ToString() { return Lane + "|" + (Point.HasValue ? Point.Value.ToString() : "") + "|" + Camera; }
    }

    /// <summary>
    /// Colours of the armour and damage types (G3 open point, Legion TD principle): a damage type
    /// has the colour of the armour it hits for 130 % (DamageMatrix: type i is strong against armour i).
    /// </summary>
    public static class LuneTypeColors
    {
        public static readonly Color[] Types = { LuneUiTheme.Hex("e2b46b"), LuneUiTheme.Hex("7fb2e5"), LuneUiTheme.Hex("c39bf0") };

        public static Color Armor(int armorType) { return Types[Mathf.Clamp(armorType, 0, 2)]; }

        public static Color Damage(int attackType)
        {
            int row = Mathf.Clamp(attackType, 0, 2);
            for (int armor = 0; armor < 3; armor++)
            {
                if (LuneUnit.DamageMatrix[row, armor] == 1.30)
                    return Types[armor];
            }
            return LuneUiTheme.Muted;
        }
    }

    /// <summary>
    /// The viewer's own gold with the coin symbol and the base income of the next settlement
    /// (Godot LuneResourceDisplay). It is only ever fed the own seat's gold.
    /// </summary>
    public sealed class LuneResourceDisplay : VisualElement
    {
        public readonly Label Amount;
        public readonly Label Detail;
        int _shown = -1;
        float _flash;

        public LuneResourceDisplay()
        {
            style.flexDirection = FlexDirection.Row;
            style.alignItems = Align.Center;
            pickingMode = PickingMode.Position;
            LuneUi.Glyph("coin", LuneUiTheme.Gold, 30f, this);
            VisualElement column = LuneUi.Box(true, -2f, this);
            column.style.marginLeft = 8f;
            Amount = LuneUi.Label("0", "HudGold", column);
            Detail = LuneUi.Label("", "HudMuted", column);
        }

        public void SetValues(int gold, int income, bool showIncome = true)
        {
            if (gold != _shown)
            {
                if (_shown >= 0 && !LunePreferences.ReducedMotion)
                    _flash = .45f;
                _shown = gold;
                Amount.text = LuneUiTheme.Number(gold);
            }
            string line = showIncome ? "+" + LuneUiTheme.Number(income) + " nächste Runde" : "";
            if (Detail.text != line)
                Detail.text = line;
            LuneUi.Show(Detail, showIncome);
        }

        public void Tick(float delta)
        {
            if (_flash <= 0f)
                return;
            _flash = Mathf.Max(0f, _flash - delta);
            // Godot modulate (1.35, 1.2, .8) fading back to white.
            float t = _flash / .45f;
            Color gold = LuneUiTheme.Gold;
            var flash = new Color(Mathf.Min(1f, gold.r * 1.35f), Mathf.Min(1f, gold.g * 1.2f), gold.b * .8f, 1f);
            LuneUi.SetColor(Amount, Color.Lerp(gold, flash, t));
        }
    }

    /// <summary>
    /// The own team (Godot LuneTeamPanel): per seat the name, lane, hero (committed hero of the
    /// others, own draft for the viewer), readiness during planning and whether a human, a bot or –
    /// after a disconnect – a bot on a human's seat plays it. Gold or plans of others never appear.
    /// </summary>
    public sealed class LuneTeamPanel : VisualElement
    {
        sealed class Row
        {
            public VisualElement Element;
            public LuneGlyphElement Status;
            public LunePortraitElement Portrait;
            public Label Name;
            public Label Lane;
            public LuneStatusBadge Badge;
            public LuneHudModel.MemberInfo Data;
        }

        readonly List<Row> _rows = new List<Row>();
        readonly Label _header;
        readonly LuneGlyphElement _emblem;
        string _signature = "";

        public LuneTeamPanel()
        {
            pickingMode = PickingMode.Ignore;
            var column = (LuneBox)LuneUi.Box(true, 3f, this);
            VisualElement head = LuneUi.Box(false, 6f, column);
            _emblem = LuneUi.Glyph("emblem_0", LuneUiTheme.Team[0], 15f, head);
            _header = LuneUi.Label("DEIN TEAM", "HudCaps", head);
            for (int index = 0; index < 3; index++)
            {
                VisualElement element = LuneUi.Box(false, 6f, column);
                element.pickingMode = PickingMode.Position;
                element.style.minHeight = 28f;
                var row = new Row { Element = element };
                row.Status = LuneUi.Glyph("human", LuneUiTheme.Muted, 15f, element);
                row.Portrait = new LunePortraitElement();
                row.Portrait.style.width = 26f;
                row.Portrait.style.height = 26f;
                element.Add(row.Portrait);
                row.Name = LuneUi.Clip(LuneUi.Label("", "HudText", element));
                row.Name.style.flexGrow = 1f;
                row.Lane = LuneUi.Label("", "HudMuted", element);
                row.Badge = new LuneStatusBadge();
                element.Add(row.Badge);
                _rows.Add(row);
                int captured = index;
                LuneTooltip.Attach(element, () => Tip(captured));
            }
        }

        public void Apply(List<LuneHudModel.MemberInfo> members, int team, bool planning, bool networked)
        {
            string signature = string.Join(",", members) + "|" + team + "|" + planning + "|" + networked;
            if (signature == _signature)
                return;
            _signature = signature;
            _emblem.Glyph = "emblem_" + team;
            _emblem.Color = LuneUiTheme.TeamColor(team);
            _header.text = "DEIN TEAM · " + LuneUi.Upper(LuneUiTheme.TeamName(team));
            for (int index = 0; index < Mathf.Min(3, members.Count); index++)
            {
                LuneHudModel.MemberInfo member = members[index];
                Row row = _rows[index];
                row.Data = member;
                string status = member.Status;
                row.Status.Glyph = status == "self" ? "star" : status == "bot" ? "bot" : status == "offline" ? "offline" : "human";
                row.Status.Color = status == "self" ? LuneUiTheme.BronzeLight : status == "offline" ? LuneUiTheme.Danger : LuneUiTheme.Muted;
                row.Name.text = member.Name;
                LuneUi.SetColor(row.Name, member.IsSelf ? LuneUiTheme.BronzeLight : LuneUiTheme.Text);
                row.Lane.text = LuneUi.Upper(LuneMap.LaneNames[member.Lane]);
                LuneUi.Show(row.Portrait, member.HeroId.Length > 0);
                if (member.HeroId.Length > 0)
                    row.Portrait.ShowModel(LuneContent.Heroes[member.HeroId].Model);
                if (status == "offline")
                    row.Badge.SetState("BOT ÜBERNIMMT", LuneUiTheme.Danger, "offline");
                else if (status == "bot")
                    row.Badge.SetState("BOT", LuneUiTheme.Muted, "bot");
                else if (planning && member.Ready)
                    row.Badge.SetState("BEREIT", LuneUiTheme.Good, "check");
                else if (planning)
                    row.Badge.SetState("PLANT", LuneUiTheme.Warn, "clock");
                else
                    row.Badge.SetState("IM KAMPF", LuneUiTheme.Info);
            }
        }

        LuneTip Tip(int index)
        {
            LuneHudModel.MemberInfo member = _rows[index].Data;
            if (member == null)
                return null;
            string kind = member.Status == "self" ? "Du" : member.Status == "human" ? "Mensch" : member.Status == "bot" ? "Bot" : "Verbindung getrennt – ein Bot spielt den Platz weiter";
            string hero = "kein Held";
            if (member.HeroId.Length > 0)
                hero = LuneContent.Heroes[member.HeroId].Name + " · Stufe " + member.HeroLevel;
            var tip = new LuneTip
            {
                Title = member.Name,
                Subtitle = LuneMap.LaneNames[member.Lane] + "-Lane · " + ContentData.FactionNames.GetValueOrDefault(member.Bund, ""),
                Note = member.IsSelf ? "" : "Gold und laufende Planung anderer Spieler bleiben privat.",
            };
            tip.Stat("human", "Spieler", kind).Stat("crown", "Held", hero).Stat("check", "Planung", member.Ready ? "bereit" : "plant noch");
            return tip;
        }
    }

    /// <summary>
    /// Purchase card (Godot LuneUnitCard): real-model portrait, name, role, gold price, hotkey and
    /// availability; the armour and damage type as coloured symbols (G3 open point). The champion
    /// variant uses the copper card style, a hatched portrait and the "1 WELLE" band at the bottom
    /// of the portrait, so temporary attack champions never read like permanent troops.
    /// </summary>
    public sealed class LuneUnitCard : LuneButton
    {
        static readonly Dictionary<string, string> RoleGlyphs = new Dictionary<string, string>
            { { "front", "tank" }, { "melee", "melee" }, { "ranged", "ranged" }, { "splash", "splash" }, { "support", "support" }, { "schutz", "tank" }, { "druck", "tempo" }, { "siege", "siege" } };
        static readonly Dictionary<string, string> RoleText = new Dictionary<string, string>
            { { "front", "Tank" }, { "melee", "Nahkampf" }, { "ranged", "Fernkampf" }, { "splash", "Fläche" }, { "support", "Support" }, { "schutz", "Schutz" }, { "druck", "Druck" }, { "siege", "Belagerung" } };

        public string TypeId = "";
        public bool Champion;
        public int Cost;
        public string Reason = "";
        public readonly LunePortraitElement Portrait;
        readonly Label _name;
        readonly LuneGlyphElement _roleGlyph;
        readonly Label _role;
        readonly Label _cost;
        readonly Label _key;
        readonly VisualElement _band;
        readonly LuneGlyphElement _lock;
        readonly LuneGlyphElement _armor;
        readonly LuneGlyphElement _attack;

        public LuneUnitCard() : base(null, LuneButtons.HudCard)
        {
            style.width = 116f;
            style.height = 132f;
            style.flexDirection = FlexDirection.Column;
            style.alignItems = Align.Stretch;
            style.justifyContent = Justify.FlexStart;
            style.paddingLeft = 6f;
            style.paddingRight = 6f;
            style.paddingTop = 6f;
            style.paddingBottom = 5f;
            Portrait = new LunePortraitElement();
            Portrait.style.minHeight = 62f;
            Portrait.style.flexGrow = 1f;
            Add(Portrait);
            _key = LuneUi.Label("", "HudCaps", Portrait);
            _key.style.position = Position.Absolute;
            _key.style.left = 4f;
            _key.style.top = 1f;
            // Armour and damage type, top right (Legion TD: what it is good against).
            VisualElement types = LuneUi.Box(false, 2f, Portrait);
            types.style.position = Position.Absolute;
            types.style.right = 3f;
            types.style.top = 3f;
            _attack = LuneUi.Glyph("sword", LuneUiTheme.Muted, 13f, types);
            _armor = LuneUi.Glyph("armor", LuneUiTheme.Muted, 13f, types);
            _band = LuneUi.Box(false, 2f, Portrait);
            _band.style.position = Position.Absolute;
            _band.style.left = 0f;
            _band.style.right = 0f;
            _band.style.bottom = 0f;
            _band.style.height = 16f;
            _band.style.justifyContent = Justify.Center;
            _band.style.backgroundColor = new Color(0f, 0f, 0f, .62f);
            LuneUi.Glyph("hourglass", LuneUiTheme.Champion, 12f, _band);
            LuneUi.SetColor(LuneUi.Label("1 WELLE", "HudCaps", _band, 14f), LuneUiTheme.Champion);
            LuneUi.Show(_band, false);
            _lock = LuneUi.Glyph("lock", LuneUiTheme.Muted, 18f, Portrait);
            _lock.style.position = Position.Absolute;
            _lock.style.left = new Length(50f, LengthUnit.Percent);
            _lock.style.top = new Length(50f, LengthUnit.Percent);
            _lock.style.translate = new Translate(new Length(-50f, LengthUnit.Percent), new Length(-50f, LengthUnit.Percent));
            LuneUi.Show(_lock, false);
            _name = LuneUi.Clip(LuneUi.Label("", "HudText", this));
            _name.style.unityTextAlign = TextAnchor.MiddleCenter;
            _name.style.marginTop = 1f;
            VisualElement roleRow = LuneUi.Box(false, 4f, this);
            roleRow.style.justifyContent = Justify.Center;
            roleRow.style.marginTop = 1f;
            _roleGlyph = LuneUi.Glyph("", LuneUiTheme.Muted, 14f, roleRow);
            _role = LuneUi.Label("", "HudMuted", roleRow);
            VisualElement costRow = LuneUi.Box(false, 4f, this);
            costRow.style.justifyContent = Justify.Center;
            costRow.style.marginTop = 1f;
            LuneUi.Glyph("coin", LuneUiTheme.Gold, 15f, costRow);
            _cost = LuneUi.Label("", "HudValue", costRow);
        }

        public void Setup(string id, string modelId, string title, string roleKey, int price, string hotkey = "", bool champion = false, UnitDef definition = null)
        {
            TypeId = id;
            Champion = champion;
            Cost = price;
            Look = champion ? LuneButtons.HudChampionCard : LuneButtons.HudCard;
            Portrait.ShowModel(modelId);
            _name.text = title;
            _roleGlyph.Glyph = RoleGlyphs.TryGetValue(roleKey ?? "", out string glyph) ? glyph : "melee";
            _role.text = RoleText.TryGetValue(roleKey ?? "", out string text) ? text : roleKey;
            _cost.text = price.ToString();
            _key.text = hotkey;
            LuneUi.Show(_key, hotkey.Length > 0);
            LuneUi.Show(_band, champion);
            Portrait.Hatch = champion ? LuneUiTheme.WithAlpha(LuneUiTheme.Champion, .13f) : Color.clear;
            if (definition != null)
            {
                _attack.Color = LuneTypeColors.Damage(definition.AttackType);
                _armor.Color = LuneTypeColors.Armor(definition.ArmorType);
            }
        }

        /// <summary>ok = purchasable now; otherwise `why` explains it (tooltip) and the card greys out.</summary>
        public void SetAvailable(bool ok, string why = "", bool locked = false, bool unaffordable = false)
        {
            Reason = why ?? "";
            Disabled = !ok;
            Portrait.Dimmed = !ok;
            LuneUi.Show(_lock, locked);
            LuneUi.SetColor(_cost, unaffordable ? LuneUiTheme.Danger : LuneUiTheme.Bright);
            LuneUi.SetColor(_name, ok ? LuneUiTheme.Text : LuneUiTheme.Muted);
        }
    }

    /// <summary>
    /// One own troop in the army strip (Godot LuneArmyChip): real-model portrait, a band with its
    /// lane (T, M, B or G) and stage (II for upgraded troops). Selected = pressed style. In combat a
    /// fallen troop is dimmed and crossed out.
    /// </summary>
    public sealed class LuneArmyChip : LuneButton
    {
        public const float Band = 15f;
        public string Uid = "";
        public string TypeId = "";
        public string Lane = "mid";
        public readonly LunePortraitElement Portrait;
        readonly Label _lane;
        readonly Label _stage;
        bool _fallen;

        public LuneArmyChip() : base(null, LuneButtons.HudChip)
        {
            style.flexDirection = FlexDirection.Column;
            style.alignItems = Align.Stretch;
            style.justifyContent = Justify.FlexStart;
            style.paddingLeft = 2f;
            style.paddingRight = 2f;
            style.paddingTop = 2f;
            style.paddingBottom = 1f;
            Portrait = new LunePortraitElement();
            Portrait.style.flexGrow = 1f;
            Add(Portrait);
            VisualElement band = LuneUi.Box(false, 0f, this);
            band.style.height = Band;
            band.style.backgroundColor = new Color(0f, 0f, 0f, .55f);
            band.style.justifyContent = Justify.SpaceBetween;
            band.style.paddingLeft = 3f;
            band.style.paddingRight = 3f;
            _lane = LuneUi.Label("", "HudCaps", band, 14f);
            _stage = LuneUi.Label("II", "HudCaps", band, 14f);
            LuneUi.SetColor(_stage, LuneUiTheme.Gold);
        }

        public void Setup(RosterEntry entry, float edge)
        {
            Uid = entry.Uid;
            TypeId = entry.TypeId;
            Lane = entry.Lane;
            style.width = edge;
            style.height = edge + Band;
            Portrait.ShowModel(TypeId);
            bool grotto = Lane == LuneMatch.Grotto;
            _lane.text = grotto ? "G" : LuneMap.LaneNames.TryGetValue(Lane, out string name) ? name.Substring(0, 1) : "?";
            LuneUi.SetColor(_lane, grotto ? LuneUiTheme.Team[2] : LuneUiTheme.BronzeLight);
            LuneUi.Show(_stage, LuneStats.StageOf(TypeId) == 2);
        }

        public bool Fallen
        {
            get { return _fallen; }
            set
            {
                if (value == _fallen)
                    return;
                _fallen = value;
                Portrait.Dimmed = value;
                Portrait.Crossed = value;
            }
        }
    }

    /// <summary>
    /// A hero item (Godot LuneItemSlot): one of the three slots (compact: symbol only) or a card in
    /// the item shop (symbol, name, cost, main effect, state). States say why something cannot be
    /// done: equipped, available, unaffordable, incompatible (hero level), unique (already carried),
    /// slots full, locked (plan committed) or an empty slot.
    /// </summary>
    public sealed class LuneItemSlot : LuneButton
    {
        public enum State { Empty, Equipped, Available, Unaffordable, Incompatible, Unique, Full, Locked }

        static readonly Dictionary<State, string> StateText = new Dictionary<State, string>
        {
            { State.Equipped, "AUSGERÜSTET" }, { State.Available, "KAUFBAR" }, { State.Unaffordable, "ZU TEUER" }, { State.Incompatible, "STUFE FEHLT" },
            { State.Unique, "GETRAGEN" }, { State.Full, "PLÄTZE VOLL" }, { State.Locked, "GESPERRT" }, { State.Empty, "LEER" },
        };
        static readonly Dictionary<string, Color> ItemColors = new Dictionary<string, Color>
        {
            { "basaltschild", LuneUiTheme.Hex("9fb2c8") }, { "glutklinge", LuneUiTheme.Hex("ff9a5a") }, { "rankenmantel", LuneUiTheme.Hex("8fd08a") },
            { "funkenfokus", LuneUiTheme.Hex("f5d76a") }, { "quellamulett", LuneUiTheme.Hex("7ad6e6") }, { "kristallsplitter", LuneUiTheme.Hex("c7a2ff") },
        };

        public string ItemId = "";
        public State Current = State.Empty;
        public readonly bool Compact;
        readonly LuneGlyphElement _glyph;
        readonly Label _name;
        readonly Label _effect;
        readonly Label _cost;
        readonly LuneStatusBadge _badge;

        public static Color ColorOf(string id)
        {
            return ItemColors.TryGetValue(id ?? "", out Color color) ? color : LuneUiTheme.Muted;
        }

        public LuneItemSlot(bool compact = true) : base(null, compact ? LuneButtons.HudChip : LuneButtons.HudCard)
        {
            Compact = compact;
            if (compact)
            {
                style.width = 30f;
                style.height = 30f;
                style.paddingLeft = 5f;
                style.paddingRight = 5f;
                style.paddingTop = 5f;
                style.paddingBottom = 5f;
                _glyph = LuneUi.Glyph("", Color.white, 20f, this);
                _glyph.style.flexGrow = 1f;
                return;
            }
            style.minHeight = 74f;
            style.justifyContent = Justify.FlexStart;
            style.paddingLeft = 10f;
            style.paddingRight = 8f;
            style.paddingTop = 6f;
            style.paddingBottom = 6f;
            _glyph = LuneUi.Glyph("", Color.white, 34f, this);
            VisualElement column = LuneUi.Box(true, 0f, this);
            column.style.marginLeft = 10f;
            column.style.flexGrow = 1f;
            column.style.flexShrink = 1f;
            column.style.minWidth = 0f;
            column.style.justifyContent = Justify.Center;
            VisualElement head = LuneUi.Box(false, 6f, column);
            _name = LuneUi.Clip(LuneUi.Label("", "HudValue", head));
            _name.style.flexGrow = 1f;
            LuneUi.Glyph("coin", LuneUiTheme.Gold, 14f, head);
            _cost = LuneUi.Label("", "HudValue", head);
            _effect = LuneUi.Clip(LuneUi.Label("", "HudMuted", column));
            _badge = new LuneStatusBadge();
            _badge.style.alignSelf = Align.FlexStart;
            column.Add(_badge);
        }

        public void SetItem(string id, State state)
        {
            ItemId = id ?? "";
            Current = state;
            Color tint = ColorOf(ItemId);
            bool usable = state == State.Available || state == State.Equipped;
            _glyph.Glyph = ItemId;
            _glyph.Color = usable || Compact ? tint : LuneUiTheme.WithAlpha(tint, .45f);
            if (Compact)
            {
                Disabled = ItemId.Length == 0;
                return;
            }
            LuneContent.Items.TryGetValue(ItemId, out ItemSpec item);
            _name.text = item != null ? item.Name : "";
            _cost.text = item != null ? item.Cost.ToString() : "";
            LuneUi.SetColor(_cost, state == State.Unaffordable ? LuneUiTheme.Danger : LuneUiTheme.Bright);
            _effect.text = item != null ? item.Text : "";
            Color badge = state == State.Equipped ? LuneUiTheme.Good : state == State.Available ? LuneUiTheme.BronzeLight : LuneUiTheme.Muted;
            if (state == State.Unaffordable)
                badge = LuneUiTheme.Danger;
            string glyph = state == State.Equipped || state == State.Unique ? "check" : state == State.Incompatible || state == State.Locked ? "lock" : "";
            _badge.SetState(StateText[state], badge, glyph, state == State.Equipped);
            Disabled = !usable;
        }
    }

    /// <summary>
    /// Short event list (Godot LuneEventFeed): tower falls, champions, boss, critical Ancients,
    /// round results. At most five entries, newest on top; each fades after a while. A click on an
    /// entry with a place moves the camera there. It never lists every kill.
    /// </summary>
    public sealed class LuneEventFeed : VisualElement
    {
        public const int Limit = 5;
        public const float Lifetime = 14f;
        public event Action<LuneFocusTarget> FocusRequested;

        sealed class Entry
        {
            public string Text;
            public string Level;
            public float Born;
            public LuneButton Node;
        }

        readonly List<Entry> _entries = new List<Entry>();
        float _clock;

        public LuneEventFeed()
        {
            pickingMode = PickingMode.Ignore;
            LuneUi.Show(this, false);
        }

        public IReadOnlyList<string> Texts
        {
            get { return _entries.ConvertAll(e => e.Text); }
        }

        static Color LevelColor(string level)
        {
            return level == "good" ? LuneUiTheme.Good : level == "warn" ? LuneUiTheme.Warn : level == "danger" ? LuneUiTheme.Danger : LuneUiTheme.Info;
        }

        /// <summary>level: info, good, warn, danger. target: null or a lane, point or camera target.</summary>
        public void Push(string text, string level = "info", string glyph = "", LuneFocusTarget target = null)
        {
            foreach (Entry entry in _entries)
            {
                if (entry.Text == text && _clock - entry.Born < 4f)
                    return;
            }
            var button = new LuneButton(null, LuneButtons.HudRow);
            button.style.minHeight = 30f;
            button.style.justifyContent = Justify.FlexStart;
            button.style.paddingLeft = 8f;
            button.style.paddingRight = 8f;
            button.style.marginBottom = 3f;
            Color tint = LevelColor(level);
            LuneUi.Glyph(glyph.Length > 0 ? glyph : "star", tint, 15f, button).style.marginRight = 7f;
            Label label = LuneUi.Clip(LuneUi.Label(text, "HudText", button));
            label.style.flexGrow = 1f;
            LuneUi.SetColor(label, Color.Lerp(tint, LuneUiTheme.Text, .45f));
            bool hasTarget = target != null && !target.IsEmpty;
            button.Clicked += () =>
            {
                if (hasTarget)
                    FocusRequested?.Invoke(target);
            };
            LuneTooltip.Attach(button, () => new LuneTip { Title = text, Note = hasTarget ? "Klick: Kamera dorthin" : "" });
            Insert(0, button);
            _entries.Insert(0, new Entry { Text = text, Level = level, Born = _clock, Node = button });
            while (_entries.Count > Limit)
            {
                Entry old = _entries[_entries.Count - 1];
                _entries.RemoveAt(_entries.Count - 1);
                old.Node.RemoveFromHierarchy();
            }
            LuneUi.Show(this, true);
        }

        public void ClearAll()
        {
            foreach (Entry entry in _entries)
                entry.Node.RemoveFromHierarchy();
            _entries.Clear();
            LuneUi.Show(this, false);
        }

        public void Tick(float delta)
        {
            _clock += delta;
            for (int index = _entries.Count - 1; index >= 0; index--)
            {
                Entry entry = _entries[index];
                float age = _clock - entry.Born;
                if (age > Lifetime)
                {
                    entry.Node.RemoveFromHierarchy();
                    _entries.RemoveAt(index);
                }
                else if (age > Lifetime - 2f)
                {
                    entry.Node.style.opacity = Mathf.Clamp01((Lifetime - age) / 2f);
                }
            }
            LuneUi.Show(this, _entries.Count > 0);
        }
    }

    /// <summary>
    /// A window over the field for detail work (hero, recruiting; Godot LuneModalPanel). A light
    /// backdrop keeps clicks away from the world and closes the window; Esc and the × close it too.
    /// The window never covers the whole screen and only opens on request.
    /// </summary>
    public sealed class LuneModalPanel : VisualElement
    {
        public event Action Closed;
        public readonly LunePanel Panel;
        public readonly VisualElement Body;
        public readonly Label Title;
        readonly Vector2 _box;

        public LuneModalPanel(Vector2 size)
        {
            _box = size;
            style.position = Position.Absolute;
            style.left = 0f;
            style.top = 0f;
            style.right = 0f;
            style.bottom = 0f;
            pickingMode = PickingMode.Position;
            var backdrop = new VisualElement();
            backdrop.style.position = Position.Absolute;
            backdrop.style.left = 0f;
            backdrop.style.top = 0f;
            backdrop.style.right = 0f;
            backdrop.style.bottom = 0f;
            backdrop.style.backgroundColor = new Color(.01f, .015f, .025f, .38f);
            backdrop.RegisterCallback<PointerDownEvent>(evt =>
            {
                if (evt.button == 0)
                    Close();
            });
            Add(backdrop);
            Panel = new LunePanel(LunePanels.Modal);
            Panel.style.position = Position.Absolute;
            Add(Panel);
            VisualElement column = LuneUi.Box(true, 12f, Panel);
            column.style.flexGrow = 1f;
            VisualElement head = LuneUi.Box(false, 0f, column);
            Title = LuneUi.Label("", "HudTitle", head);
            Title.style.flexGrow = 1f;
            var close = new LuneButton(null, LuneButtons.HudIconButton, head);
            close.style.width = 36f;
            close.style.height = 34f;
            LuneUi.Glyph("close", LuneUiTheme.Muted, 14f, close);
            close.Clicked += Close;
            LuneTooltip.Attach(close, () => new LuneTip { Title = "Schließen", Text = "Esc oder Klick neben das Fenster." });
            Body = LuneUi.Box(true, 10f, column);
            Body.style.flexGrow = 1f;
            RegisterCallback<GeometryChangedEvent>(_ => Layout());
            RegisterCallback<WheelEvent>(evt => evt.StopPropagation());
            LuneUi.Show(this, false);
        }

        public bool Open { get { return style.display != DisplayStyle.None; } }

        public void OpenWith(string heading)
        {
            Title.text = heading;
            LuneUi.Show(this, true);
            BringToFront();
            Layout();
        }

        public void Close()
        {
            if (!Open)
                return;
            LuneUi.Show(this, false);
            Closed?.Invoke();
        }

        void Layout()
        {
            float width = layout.width;
            float height = layout.height;
            if (float.IsNaN(width) || width <= 0f)
                return;
            var edge = new Vector2(Mathf.Min(_box.x, width - 40f), Mathf.Min(_box.y, height - 40f));
            Panel.style.width = edge.x;
            Panel.style.height = edge.y;
            Panel.style.left = Mathf.Floor((width - edge.x) * .5f);
            Panel.style.top = Mathf.Floor((height - edge.y) * .5f);
        }
    }
}