using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;
using UnityEngine.UIElements;

namespace Luneraria.UI
{
    /// <summary>
    /// Options and controls (port of scripts/luneraria/ui/lune_settings.gd): volume, mute, full
    /// screen, reduced motion and the HUD size; the key list is the one place where every shortcut
    /// is shown. A running combat pauses offline while this window is open (the game controller
    /// does that on Opened/Closed).
    /// </summary>
    public sealed class LuneSettingsPanel : VisualElement
    {
        public static readonly float[] Scales = { .9f, 1f, 1.15f, 1.3f };
        public static readonly (string group, (string key, string action)[] pairs)[] Keys =
        {
            ("Planung", new[] { ("1–5", "Truppe kaufen"), ("Leertaste", "Bereit"), ("Klick auf Einheit", "Details, Aufwerten, Einsatz"), ("Esc", "Auswahl oder Fenster schließen") }),
            ("Kampf", new[] { ("Leertaste / P", "Pause (offline)"), ("Tempo-Knopf", "1× · 2× · 4×") }),
            ("Kamera", new[] { ("F2 · F3 · F4", "Top · Mid · Bottom"), ("G", "Bossgrotte"), ("B", "eigener Ancient"), ("H", "eigener Held"), ("Tab", "nächste Lane"),
                ("O", "Übersicht"), ("R", "zurücksetzen"), ("Q / E", "drehen"), ("WASD · Pfeile · mittlere Maustaste", "verschieben"), ("Mausrad", "Zoom"), ("Minimap", "klicken oder ziehen") }),
            ("Allgemein", new[] { ("F1", "Optionen"), ("M", "Ton an/aus"), ("F11", "Vollbild") }),
        };

        public event Action Opened;
        public event Action Closed;
        readonly LuneSlider _volume;
        readonly Dictionary<string, LuneSwitch> _checks = new Dictionary<string, LuneSwitch>();
        public readonly List<LuneButton> ScaleButtons = new List<LuneButton>();

        public LuneSettingsPanel()
        {
            style.position = Position.Absolute;
            style.left = 0f;
            style.top = 0f;
            style.right = 0f;
            style.bottom = 0f;
            style.backgroundColor = new Color(.02f, .03f, .04f, .9f);
            style.justifyContent = Justify.Center;
            style.alignItems = Align.Center;
            RegisterCallback<WheelEvent>(evt => evt.StopPropagation());
            var panel = new LunePanel(LunePanels.Menu);
            panel.style.width = 900f;
            Add(panel);
            VisualElement column = LuneUi.Box(true, 10f, panel);
            Label heading = LuneUi.Label("Optionen & Steuerung", "HeadingLabel", column);
            heading.style.alignSelf = Align.Center;
            LuneUi.Label("Ein laufender Kampf pausiert offline, solange dieses Fenster geöffnet ist.", "MutedLabel", column).style.alignSelf = Align.Center;
            VisualElement top = LuneUi.Box(false, 30f, column);
            top.style.alignItems = Align.FlexStart;
            VisualElement left = LuneUi.Box(true, 8f, top);
            left.style.flexGrow = 1f;
            left.style.flexBasis = 0f;
            LuneUi.Label("LAUTSTÄRKE", "SectionLabel", left);
            _volume = new LuneSlider();
            left.Add(_volume);
            _volume.Changed += value =>
            {
                LunePreferences.Volume = value;
                LunePreferences.Commit();
                Apply();
            };
            foreach ((string key, string text) entry in new[] { ("muted", "Ton stumm [M]"), ("fullscreen", "Vollbild [F11]"), ("reduced_motion", "Bewegung reduzieren"), ("ambient_occlusion", "Umgebungsverdeckung (SSAO)") })
            {
                var check = new LuneSwitch(entry.text);
                left.Add(check);
                string key = entry.key;
                check.Changed += value =>
                {
                    if (key == "muted")
                        LunePreferences.Muted = value;
                    else if (key == "fullscreen")
                        LunePreferences.Fullscreen = value;
                    else if (key == "ambient_occlusion")
                        LunePreferences.AmbientOcclusion = value;
                    else
                        LunePreferences.ReducedMotion = value;
                    LunePreferences.Commit();
                    Apply();
                };
                _checks[key] = check;
            }
            VisualElement right = LuneUi.Box(true, 8f, top);
            right.style.flexGrow = 1f;
            right.style.flexBasis = 0f;
            LuneUi.Label("UI-GRÖSSE IM SPIEL", "SectionLabel", right);
            VisualElement scales = LuneUi.Box(false, 6f, right);
            foreach (float value in Scales)
            {
                var button = new LuneButton(Mathf.RoundToInt(value * 100f) + " %", LuneButtons.HudToggle, scales);
                button.style.flexGrow = 1f;
                float captured = value;
                button.Clicked += () =>
                {
                    LunePreferences.UiScale = captured;
                    LunePreferences.Commit();
                    Sync();
                };
                ScaleButtons.Add(button);
            }
            LuneUi.Wrap(LuneUi.Label("Größer für hochauflösende oder weit entfernte Bildschirme. Das HUD begrenzt die Größe selbst, sodass nichts aus dem Fenster ragt.", "MutedLabel", right));
            var line = new VisualElement { pickingMode = PickingMode.Ignore };
            line.style.height = 1f;
            line.style.marginTop = 7f;
            line.style.marginBottom = 7f;
            line.style.backgroundColor = LuneUiTheme.WithAlpha(LuneUiTheme.Bronze, .35f);
            column.Add(line);
            LuneUi.Label("STEUERUNG", "SectionLabel", column);
            VisualElement keys = LuneUi.Box(false, 26f, column);
            keys.style.alignItems = Align.FlexStart;
            for (int index = 0; index < 2; index++)
            {
                VisualElement list = LuneUi.Box(true, 2f, keys);
                list.style.flexGrow = 1f;
                list.style.flexBasis = 0f;
                var groups = index == 0 ? new[] { Keys[0], Keys[1], Keys[3] } : new[] { Keys[2] };
                foreach (var group in groups)
                {
                    LuneUi.Label(LuneUi.Upper(group.group), "EyebrowLabel", list, 14f).style.marginTop = 6f;
                    foreach (var pair in group.pairs)
                    {
                        VisualElement row = LuneUi.Box(false, 14f, list);
                        Label key = LuneUi.Label(pair.key, "CardFactLabel", row, 15f);
                        key.style.minWidth = 160f;
                        LuneUi.SetColor(key, LuneUiTheme.BronzeLight);
                        LuneUi.Wrap(LuneUi.Label(pair.action, "MutedLabel", row, 15f)).style.flexGrow = 1f;
                    }
                }
            }
            var back = new LuneButton("ZURÜCK  [Esc]", LuneButtons.Primary, column);
            back.style.alignSelf = Align.Center;
            back.Clicked += Close;
            LuneUi.Show(this, false);
        }

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

        public void Show()
        {
            Sync();
            LuneUi.Show(this, true);
            BringToFront();
            Opened?.Invoke();
        }

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

        /// <summary>Reads the preferences into the controls (Godot sync()).</summary>
        public void Sync()
        {
            _volume.SetValueWithoutNotify(LunePreferences.Volume);
            _checks["muted"].SetValueWithoutNotify(LunePreferences.Muted);
            _checks["fullscreen"].SetValueWithoutNotify(LunePreferences.Fullscreen);
            _checks["reduced_motion"].SetValueWithoutNotify(LunePreferences.ReducedMotion);
            _checks["ambient_occlusion"].SetValueWithoutNotify(LunePreferences.AmbientOcclusion);
            int best = 1;
            for (int index = 0; index < Scales.Length; index++)
            {
                if (Mathf.Abs(Scales[index] - LunePreferences.UiScale) < Mathf.Abs(Scales[best] - LunePreferences.UiScale))
                    best = index;
            }
            for (int index = 0; index < ScaleButtons.Count; index++)
                ScaleButtons[index].On = index == best;
        }

        /// <summary>Volume, mute, full screen and ambient occlusion take effect at once.</summary>
        public static void Apply()
        {
            AudioListener.volume = LunePreferences.Muted ? 0f : LunePreferences.Volume;
            ApplyAmbientOcclusion(LunePreferences.AmbientOcclusion);
            if (Application.isBatchMode)
                return;
            if (Screen.fullScreen != LunePreferences.Fullscreen)
                Screen.fullScreen = LunePreferences.Fullscreen;
        }

        /// <summary>
        /// Switches the SSAO feature of the URP renderer (U5.4). Only in the player: in the editor
        /// the renderer is a project asset, and switching it there would change the file.
        /// </summary>
        static void ApplyAmbientOcclusion(bool on)
        {
            if (Application.isEditor)
                return;
            ScriptableRendererFeature feature = AmbientOcclusionFeature();
            if (feature != null && feature.isActive != on)
                feature.SetActive(on);
        }

        /// <summary>The SSAO feature of the active URP renderer, or null (player self-test).</summary>
        public static ScriptableRendererFeature AmbientOcclusionFeature()
        {
            if (!(GraphicsSettings.currentRenderPipeline is UniversalRenderPipelineAsset pipeline))
                return null;
            foreach (ScriptableRendererData data in pipeline.rendererDataList)
            {
                if (data == null)
                    continue;
                foreach (ScriptableRendererFeature feature in data.rendererFeatures)
                {
                    if (feature is ScreenSpaceAmbientOcclusion)
                        return feature;
                }
            }
            return null;
        }
    }

    /// <summary>Horizontal slider in the HUD look (track, bronze fill, handle); value 0–1.</summary>
    public sealed class LuneSlider : VisualElement
    {
        public event Action<float> Changed;
        public float Value { get; private set; }
        bool _drag;

        public LuneSlider()
        {
            style.height = 28f;
            pickingMode = PickingMode.Position;
            generateVisualContent += Draw;
            RegisterCallback<PointerDownEvent>(evt =>
            {
                if (evt.button != 0)
                    return;
                _drag = true;
                this.CapturePointer(evt.pointerId);
                Set(evt.localPosition.x);
            });
            RegisterCallback<PointerMoveEvent>(evt =>
            {
                if (_drag)
                    Set(evt.localPosition.x);
            });
            RegisterCallback<PointerUpEvent>(evt =>
            {
                _drag = false;
                this.ReleasePointer(evt.pointerId);
            });
        }

        void Set(float x)
        {
            float value = Mathf.Clamp01((x - 9f) / Mathf.Max(1f, layout.width - 18f));
            if (Mathf.Approximately(value, Value))
                return;
            Value = value;
            MarkDirtyRepaint();
            Changed?.Invoke(value);
        }

        public void SetValueWithoutNotify(float value)
        {
            Value = Mathf.Clamp01(value);
            MarkDirtyRepaint();
        }

        void Draw(MeshGenerationContext context)
        {
            Painter2D p = context.painter2D;
            float width = layout.width;
            float y = layout.height * .5f;
            LunePlates.Line(p, new Vector2(9f, y), new Vector2(width - 9f, y), new Color(0f, 0f, 0f, .55f), 6f);
            float x = 9f + (width - 18f) * Value;
            LunePlates.Line(p, new Vector2(9f, y), new Vector2(x, y), LuneUiTheme.Bronze, 6f);
            p.fillColor = LuneUiTheme.BronzeLight;
            p.BeginPath();
            p.Arc(new Vector2(x, y), 8f, Angle.Degrees(0f), Angle.Degrees(360f));
            p.ClosePath();
            p.Fill();
        }
    }

    /// <summary>On/off switch with a label (Godot CheckButton with the toggle icons of the menu theme).</summary>
    public sealed class LuneSwitch : VisualElement
    {
        public event Action<bool> Changed;
        public bool Value { get; private set; }
        readonly VisualElement _knob;

        public LuneSwitch(string text)
        {
            style.flexDirection = FlexDirection.Row;
            style.alignItems = Align.Center;
            style.height = 34f;
            pickingMode = PickingMode.Position;
            Label label = LuneUi.Label(text, "CardFactLabel", this);
            label.style.flexGrow = 1f;
            _knob = new VisualElement { pickingMode = PickingMode.Ignore };
            _knob.style.width = 44f;
            _knob.style.height = 22f;
            _knob.generateVisualContent += Draw;
            Add(_knob);
            RegisterCallback<PointerDownEvent>(evt =>
            {
                if (evt.button == 0)
                    Click();
            });
        }

        /// <summary>Text of the switch (self-test lookup).</summary>
        public string Text { get { return this.Q<Label>()?.text ?? ""; } }

        /// <summary>Flips the switch as a click does.</summary>
        public void Click()
        {
            Value = !Value;
            _knob.MarkDirtyRepaint();
            Changed?.Invoke(Value);
        }

        public void SetValueWithoutNotify(bool value)
        {
            Value = value;
            _knob.MarkDirtyRepaint();
        }

        void Draw(MeshGenerationContext context)
        {
            Painter2D p = context.painter2D;
            float w = _knob.layout.width;
            float h = _knob.layout.height;
            float r = h * .5f;
            p.fillColor = Value ? LuneUiTheme.WithAlpha(LuneUiTheme.Bronze, .85f) : new Color(0f, 0f, 0f, .5f);
            p.BeginPath();
            p.Arc(new Vector2(r, r), r, Angle.Degrees(90f), Angle.Degrees(270f));
            p.LineTo(new Vector2(w - r, 0f));
            p.Arc(new Vector2(w - r, r), r, Angle.Degrees(270f), Angle.Degrees(450f));
            p.ClosePath();
            p.Fill();
            p.fillColor = Value ? LuneUiTheme.Parchment : LuneUiTheme.Muted;
            p.BeginPath();
            p.Arc(new Vector2(Value ? w - r : r, r), r - 3f, Angle.Degrees(0f), Angle.Degrees(360f));
            p.ClosePath();
            p.Fill();
        }
    }
}