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

namespace Luneraria.UI
{
    /// <summary>
    /// Minimap from the public match state (port of scripts/luneraria/ui/lune_minimap.gd). Lanes,
    /// river, grotto and both bases as the map; every building in its team's shape language (round
    /// = Blau, angular = Rot; Ancients as crescent and sun disc with an HP ring); heroes as small
    /// portraits (G3 open point, Dota principle), attack champions and the boss as their own
    /// markers; troops and monsters merged per map cell into one marker whose size grows with the
    /// count, so there is no cloud of pixels. Click or drag moves the camera; the minimap never
    /// buys, orders or changes anything. It redraws only when the HUD refreshes it (about ten times
    /// a second in combat); the camera frame lives on a separate overlay.
    /// </summary>
    public sealed class LuneMinimap : VisualElement
    {
        public const float Cell = 6f;
        /// <summary>Radius of the grotto arena (lune_terrain.gd ARENA_RADIUS).</summary>
        public const float ArenaRadius = 7.8f;
        const float Extent = (float)LuneMap.HalfExtent + 4f;
        const float HeroMarker = 18f;

        public event Action<Vec2> FocusRequested;
        public LuneMatch Match;
        public int ViewerTeam;
        public int HumanSlot;
        /// <summary>Counts for tests and the performance log.</summary>
        public int Clusters { get; private set; }
        public int Heroes { get; private set; }
        public int Champions { get; private set; }
        public int Bosses { get; private set; }
        public int Units { get; private set; }
        public int Redraws { get; private set; }

        readonly List<(int team, Vector2 at, int count)> _clusters = new List<(int, Vector2, int)>();
        readonly List<LuneUnit> _specials = new List<LuneUnit>();
        readonly List<Announcement> _dangers = new List<Announcement>();
        readonly VisualElement _heroLayer;
        readonly List<VisualElement> _heroMarkers = new List<VisualElement>();
        readonly VisualElement _overlay;
        Vec2[] _footprint = new Vec2[0];
        Vec2 _focus;
        float _span = 34f;
        bool _dragging;

        public LuneMinimap()
        {
            style.width = 224f;
            style.height = 224f;
            style.overflow = Overflow.Hidden;
            pickingMode = PickingMode.Position;
            generateVisualContent += Draw;
            _heroLayer = new VisualElement { pickingMode = PickingMode.Ignore };
            _heroLayer.style.position = Position.Absolute;
            _heroLayer.style.left = 0f;
            _heroLayer.style.top = 0f;
            _heroLayer.style.right = 0f;
            _heroLayer.style.bottom = 0f;
            Add(_heroLayer);
            _overlay = new VisualElement { pickingMode = PickingMode.Ignore };
            _overlay.style.position = Position.Absolute;
            _overlay.style.left = 0f;
            _overlay.style.top = 0f;
            _overlay.style.right = 0f;
            _overlay.style.bottom = 0f;
            _overlay.generateVisualContent += DrawFrame;
            Add(_overlay);
            RegisterCallback<PointerDownEvent>(OnDown);
            RegisterCallback<PointerMoveEvent>(OnMove);
            RegisterCallback<PointerUpEvent>(OnUp);
            RegisterCallback<GeometryChangedEvent>(_ => { MarkDirtyRepaint(); _overlay.MarkDirtyRepaint(); PlaceHeroes(); });
        }

        Vector2 Size { get { return new Vector2(layout.width, layout.height); } }

        public Vector2 ToMap(Vec2 v)
        {
            Vector2 size = Size;
            return new Vector2(((float)v.X + Extent) / (Extent * 2f) * size.x, ((float)v.Y + Extent) / (Extent * 2f) * size.y);
        }

        public Vec2 ToWorld(Vector2 p)
        {
            Vector2 size = Size;
            return new Vec2(p.x / Mathf.Max(1f, size.x) * Extent * 2f - Extent, p.y / Mathf.Max(1f, size.y) * Extent * 2f - Extent);
        }

        void OnDown(PointerDownEvent evt)
        {
            if (evt.button != 0)
                return;
            _dragging = true;
            this.CapturePointer(evt.pointerId);
            FocusRequested?.Invoke(ToWorld(evt.localPosition));
            evt.StopPropagation();
        }

        void OnMove(PointerMoveEvent evt)
        {
            if (!_dragging)
                return;
            FocusRequested?.Invoke(ToWorld(evt.localPosition));
            evt.StopPropagation();
        }

        void OnUp(PointerUpEvent evt)
        {
            if (!_dragging)
                return;
            _dragging = false;
            this.ReleasePointer(evt.pointerId);
            evt.StopPropagation();
        }

        /// <summary>Camera focus, view span and the ground outline of the view (empty = rectangle around the focus).</summary>
        public void SetCamera(Vec2 focus, float span, Vec2[] footprint)
        {
            bool moved = footprint == null || footprint.Length != _footprint.Length;
            if (!moved)
            {
                for (int index = 0; index < footprint.Length; index++)
                {
                    if (footprint[index].DistanceSquaredTo(_footprint[index]) > .04)
                        moved = true;
                }
            }
            moved |= focus.DistanceSquaredTo(_focus) > .04 || Mathf.Abs(span - _span) > .1f;
            if (!moved)
                return;
            _footprint = footprint ?? new Vec2[0];
            _focus = focus;
            _span = span;
            _overlay.MarkDirtyRepaint();
        }

        /// <summary>Recomputes markers from the match (called by the HUD at its update rate).</summary>
        public void Refresh(List<Announcement> announcements)
        {
            _clusters.Clear();
            _specials.Clear();
            _dangers.Clear();
            if (announcements != null)
                _dangers.AddRange(announcements);
            Clusters = Heroes = Champions = Bosses = Units = 0;
            if (Match != null && Match.Phase == Phase.Combat && Match.Combat != null)
            {
                var cells = new Dictionary<(int, int, int), (Vector2 sum, int count)>();
                var order = new List<(int, int, int)>();
                foreach (LuneUnit unit in Match.Combat.Units)
                {
                    if (!unit.Alive || !unit.IsMobile())
                        continue;
                    Units++;
                    if (unit.Kind == "hero" || unit.Kind == "champion" || unit.Kind == "boss")
                    {
                        _specials.Add(unit);
                        if (unit.Kind == "hero")
                            Heroes++;
                        else if (unit.Kind == "champion")
                            Champions++;
                        else
                            Bosses++;
                        continue;
                    }
                    var key = (unit.Team, (int)Math.Floor(unit.Position.X / Cell), (int)Math.Floor(unit.Position.Y / Cell));
                    if (!cells.TryGetValue(key, out var entry))
                    {
                        entry = (Vector2.zero, 0);
                        order.Add(key);
                    }
                    cells[key] = (entry.sum + new Vector2((float)unit.Position.X, (float)unit.Position.Y), entry.count + 1);
                }
                foreach (var key in order)
                {
                    var entry = cells[key];
                    _clusters.Add((key.Item1, entry.sum / entry.count, entry.count));
                }
                Clusters = _clusters.Count;
            }
            Redraws++;
            MarkDirtyRepaint();
            PlaceHeroes();
        }

        /// <summary>Hero markers are portraits in rings: child elements placed over the map.</summary>
        void PlaceHeroes()
        {
            int used = 0;
            float scale = Size.x / 224f;
            if (float.IsNaN(scale) || scale <= 0f)
                return;
            foreach (LuneUnit unit in _specials)
            {
                if (unit.Kind != "hero")
                    continue;
                if (used >= _heroMarkers.Count)
                {
                    var marker = new VisualElement { pickingMode = PickingMode.Ignore };
                    marker.style.position = Position.Absolute;
                    marker.style.overflow = Overflow.Hidden;
                    var portrait = new LunePortraitElement();
                    portrait.style.flexGrow = 1f;
                    marker.Add(portrait);
                    _heroLayer.Add(marker);
                    _heroMarkers.Add(marker);
                }
                VisualElement element = _heroMarkers[used++];
                float edge = HeroMarker * scale;
                Vector2 at = ToMap(unit.Position);
                element.style.left = at.x - edge * .5f;
                element.style.top = at.y - edge * .5f;
                element.style.width = edge;
                element.style.height = edge;
                float radius = edge * .5f;
                element.style.borderTopLeftRadius = radius;
                element.style.borderTopRightRadius = radius;
                element.style.borderBottomLeftRadius = radius;
                element.style.borderBottomRightRadius = radius;
                Color ring = unit.OwnerSlot == HumanSlot ? Color.white : LuneUiTheme.Hero;
                float width = 1.6f * scale;
                element.style.borderLeftWidth = width;
                element.style.borderRightWidth = width;
                element.style.borderTopWidth = width;
                element.style.borderBottomWidth = width;
                element.style.borderLeftColor = ring;
                element.style.borderRightColor = ring;
                element.style.borderTopColor = ring;
                element.style.borderBottomColor = ring;
                element.style.backgroundColor = LuneUiTheme.TeamColor(unit.Team);
                ((LunePortraitElement)element[0]).ShowModel(unit.Def.Id);
                LuneUi.Show(element, true);
            }
            for (int index = used; index < _heroMarkers.Count; index++)
                LuneUi.Show(_heroMarkers[index], false);
        }

        void Draw(MeshGenerationContext context)
        {
            Painter2D p = context.painter2D;
            Vector2 size = Size;
            if (size.x <= 0f)
                return;
            LunePlates.Polygon(p, LuneHpBar.Corners(new Rect(0f, 0f, size.x, size.y)), new Color(.035f, .05f, .06f, .95f));
            if (Match == null)
                return;
            float s = size.x / 224f;
            // Ground: the Kluft from the grotto spring into the south-eastern delta, lanes, plazas.
            Vec2 spring = LuneMap.Grotto + LuneMap.Axis * ArenaRadius;
            Polyline(p, new[] { ToMap(spring), ToMap(new Vec2(40, 40)) }, new Color(.1f, .3f, .34f, .9f), 6f * s);
            Disc(p, ToMap(new Vec2(33, 33)), 10f * s, new Color(.1f, .3f, .34f, .9f));
            for (int team = 0; team < 2; team++)
                Disc(p, ToMap(Match.Map.CorePosition(team)), 17f * s, LuneUiTheme.WithAlpha(LuneUiTheme.TeamDark[team], .55f));
            foreach (string lane in LuneMap.Lanes)
            {
                Vec2[] points = Match.Map.LanePaths[lane].Points;
                var mapped = new Vector2[points.Length];
                for (int index = 0; index < points.Length; index++)
                    mapped[index] = ToMap(points[index]);
                Polyline(p, mapped, new Color(.2f, .19f, .16f), 7f * s);
                Polyline(p, mapped, new Color(.55f, .5f, .4f), 3.2f * s);
            }
            DrawGrotto(p, s);
            foreach (BuildingDef definition in Match.Map.Buildings)
                DrawBuilding(p, definition, s);
            // Announced dangers: a warning mark in the middle of the lane.
            foreach (Announcement entry in _dangers)
            {
                if (entry.Team == ViewerTeam)
                    continue;
                Vector2 at = ToMap(Match.Map.LanePoint(ViewerTeam, entry.Lane, Match.Map.LanePaths[entry.Lane].Length * .5));
                float edge = 13f * s;
                Disc(p, at, edge * .62f, new Color(0f, 0f, 0f, .6f));
                LuneGlyphs.Draw(p, entry.Kind == "boss" ? "crown" : "warning", new Rect(at - new Vector2(edge, edge) * .5f, new Vector2(edge, edge)), LuneUiTheme.Danger);
            }
            // Armies merged per cell.
            foreach (var cluster in _clusters)
            {
                Vector2 at = ToMap(new Vec2(cluster.at.x, cluster.at.y));
                float radius = (2f + 1.15f * Mathf.Sqrt(cluster.count)) * s;
                Color tint = cluster.team <= 1 ? LuneUiTheme.TeamColor(cluster.team) : LuneUiTheme.Team[2];
                Shape(p, cluster.team, at, radius + 1.2f * s, new Color(0f, 0f, 0f, .7f));
                Shape(p, cluster.team, at, radius, LuneUiTheme.WithAlpha(tint, .9f));
            }
            // Champions and the boss on top (heroes are portrait elements over the map).
            foreach (LuneUnit unit in _specials)
            {
                Vector2 at = ToMap(unit.Position);
                Color tint = LuneUiTheme.TeamColor(unit.Team);
                if (unit.Kind == "hero")
                {
                    Disc(p, at, (HeroMarker * .5f + 1.5f) * s, new Color(0f, 0f, 0f, .75f));
                }
                else if (unit.Kind == "champion")
                {
                    float edge = 12f * s;
                    Disc(p, at, edge * .55f, new Color(0f, 0f, 0f, .75f));
                    LuneGlyphs.Draw(p, "champion", new Rect(at - new Vector2(edge, edge) * .5f, new Vector2(edge, edge)), Color.Lerp(tint, LuneUiTheme.Champion, .35f));
                }
                else
                {
                    float edge = 17f * s;
                    Disc(p, at, edge * .6f, new Color(0f, 0f, 0f, .8f));
                    Ring(p, at, edge * .6f, 0f, Mathf.PI * 2f, tint, 1.6f * s);
                    LuneGlyphs.Draw(p, "crown", new Rect(at - new Vector2(edge, edge) * .45f, new Vector2(edge, edge) * .9f), LuneUiTheme.Lightened(tint, .2f));
                }
            }
            LunePlates.Outline(p, LuneHpBar.Corners(new Rect(.5f, .5f, size.x - 1f, size.y - 1f)), LuneUiTheme.Hex("3a4656"), 1f);
        }

        void DrawFrame(MeshGenerationContext context)
        {
            Painter2D p = context.painter2D;
            Vector2 size = Size;
            if (size.x <= 0f)
                return;
            if (_footprint.Length == 4)
            {
                var outline = new Vector2[4];
                for (int index = 0; index < 4; index++)
                {
                    Vector2 corner = ToMap(_footprint[index]);
                    outline[index] = new Vector2(Mathf.Clamp(corner.x, 0f, size.x), Mathf.Clamp(corner.y, 0f, size.y));
                }
                LunePlates.Polygon(p, outline, new Color(1f, 1f, 1f, .05f));
                LunePlates.Outline(p, outline, new Color(1f, 1f, 1f, .75f), 1.3f);
            }
            else
            {
                Vector2 center = ToMap(_focus);
                float span = _span / (Extent * 2f) * size.x;
                LunePlates.Outline(p, LuneHpBar.Corners(new Rect(center.x - span * .9f, center.y - span * .55f, span * 1.8f, span * 1.1f)), new Color(1f, 1f, 1f, .6f), 1.2f);
            }
        }

        static void Shape(Painter2D p, int team, Vector2 at, float radius, Color color)
        {
            if (team == 1)
                LunePlates.Polygon(p, new[] { at + new Vector2(0f, -radius * 1.2f), at + new Vector2(radius * 1.2f, 0f), at + new Vector2(0f, radius * 1.2f), at + new Vector2(-radius * 1.2f, 0f) }, color);
            else
                Disc(p, at, radius, color);
        }

        void DrawBuilding(Painter2D p, BuildingDef definition, float s)
        {
            string id = definition.Id;
            int team = definition.Team;
            bool alive = Match.BuildingAlive(id);
            double hp = Match.BuildingHp.GetValueOrDefault(id, 0.0);
            if (Match.Phase == Phase.Combat && Match.Combat != null && Match.Combat.Buildings.TryGetValue(id, out LuneUnit unit))
            {
                alive = unit.Alive;
                hp = unit.Hp;
            }
            float fraction = alive ? Mathf.Clamp01((float)(hp / Math.Max(1.0, definition.MaxHp))) : 0f;
            Vector2 at = ToMap(definition.Position);
            Color tint = LuneUiTheme.TeamColor(team);
            if (definition.Tier == "core")
            {
                float edge = 18f * s;
                float radius = 10.5f * s;
                Disc(p, at, radius, new Color(0f, 0f, 0f, .7f));
                Ring(p, at, radius, 0f, Mathf.PI * 2f, LuneUiTheme.WithAlpha(tint, .25f), 2.4f * s);
                if (fraction > 0f)
                    Ring(p, at, radius, -Mathf.PI * .5f, -Mathf.PI * .5f + Mathf.PI * 2f * fraction, LuneHpBar.HealthColor(fraction, tint), 2.4f * s);
                LuneGlyphs.Draw(p, "emblem_" + team, new Rect(at - new Vector2(edge, edge) * .38f, new Vector2(edge, edge) * .76f), alive ? tint : new Color(.4f, .4f, .4f));
                return;
            }
            float r = (definition.Tier == "base" ? 4.4f : 3.8f) * s;
            if (alive)
            {
                Shape(p, team, at, r + 1.3f * s, new Color(0f, 0f, 0f, .75f));
                Shape(p, team, at, r, tint);
                if (fraction < .99f)
                {
                    var bar = new Rect(at.x - r - 1f, at.y + r + 2.5f * s, r * 2f + 2f, 2f * s);
                    LunePlates.Polygon(p, LuneHpBar.Corners(bar), new Color(0f, 0f, 0f, .8f));
                    LunePlates.Polygon(p, LuneHpBar.Corners(new Rect(bar.x, bar.y, bar.width * fraction, bar.height)), LuneHpBar.HealthColor(fraction, tint));
                }
            }
            else
            {
                Shape(p, team, at, r, new Color(0f, 0f, 0f, .55f));
                float cross = r * .8f;
                var gray = new Color(.55f, .55f, .58f);
                LunePlates.Line(p, at - new Vector2(cross, cross), at + new Vector2(cross, cross), gray, 1.4f * s);
                LunePlates.Line(p, at + new Vector2(-cross, cross), at + new Vector2(cross, -cross), gray, 1.4f * s);
            }
        }

        void DrawGrotto(Painter2D p, float s)
        {
            Vector2 at = ToMap(LuneMap.Grotto);
            BossClaim claim = Match.Boss.Claim;
            Color tint = LuneUiTheme.Team[2];
            if (claim != null)
                tint = LuneUiTheme.TeamColor(claim.Team);
            else if (!Match.GrottoAvailable())
                tint = new Color(.42f, .4f, .46f);
            float edge = 16f * s;
            Disc(p, at, edge * .72f, new Color(0f, 0f, 0f, .65f));
            Ring(p, at, edge * .72f, 0f, Mathf.PI * 2f, LuneUiTheme.WithAlpha(tint, .9f), 1.4f * s);
            LuneGlyphs.Draw(p, "grotto", new Rect(at - new Vector2(edge, edge) * .42f, new Vector2(edge, edge) * .84f), tint);
        }

        static void Disc(Painter2D p, Vector2 center, float radius, Color color)
        {
            p.fillColor = color;
            p.BeginPath();
            p.Arc(center, radius, Angle.Degrees(0f), Angle.Degrees(360f));
            p.ClosePath();
            p.Fill();
        }

        static void Ring(Painter2D p, Vector2 center, float radius, float start, float end, Color color, float width)
        {
            p.strokeColor = color;
            p.lineWidth = width;
            p.lineCap = LineCap.Butt;
            p.BeginPath();
            p.Arc(center, radius, Angle.Radians(start), Angle.Radians(end));
            p.Stroke();
        }

        static void Polyline(Painter2D p, Vector2[] points, Color color, float width)
        {
            p.strokeColor = color;
            p.lineWidth = width;
            p.lineJoin = LineJoin.Round;
            p.lineCap = LineCap.Round;
            p.BeginPath();
            p.MoveTo(points[0]);
            for (int index = 1; index < points.Length; index++)
                p.LineTo(points[index]);
            p.Stroke();
        }
    }
}