using FarseerPhysics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
using System.Collections.Generic;
using System.Xml.Linq;
using Voronoi2;

namespace Barotrauma.Items.Components
{
    class Radar : Powered
    {
        private float range;

        private float pingState;

        private readonly Sprite pingCircle, screenOverlay;

        private readonly Sprite radarBlip;

        private GUITickBox isActiveTickBox;

        private List<RadarBlip> radarBlips;
        private float prevPingRadius;

        float prevPassivePingRadius;

        private Vector2 center;
        private float displayRadius;
        private float displayScale;
                
        [HasDefaultValue(10000.0f, false)]
        public float Range
        {
            get { return range; }
            set { range = MathHelper.Clamp(value, 0.0f, 100000.0f); }
        }
        
        [HasDefaultValue(false, false)]
        public bool DetectSubmarineWalls
        {
            get;
            set;
        }

        public override bool IsActive
        {
            get
            {
                return base.IsActive;
            }

            set
            {
                base.IsActive = value;
                if (isActiveTickBox != null) isActiveTickBox.Selected = value;
            }
        }

        public Radar(Item item, XElement element)
            : base(item, element)
        {
            radarBlips = new List<RadarBlip>();

            foreach (XElement subElement in element.Elements())
            {
                switch (subElement.Name.ToString().ToLowerInvariant())
                {
                    case "pingcircle":
                        pingCircle = new Sprite(subElement);
                        break;
                    case "screenoverlay":
                        screenOverlay = new Sprite(subElement);
                        break;
                    case "blip":
                        radarBlip = new Sprite(subElement);
                        break;
                }
            }
            
            isActiveTickBox = new GUITickBox(new Rectangle(0, 0, 20, 20), "Active Sonar", Alignment.TopLeft, GuiFrame);
            isActiveTickBox.OnSelected = (GUITickBox box) =>
            {
                IsActive = box.Selected;
                item.NewComponentEvent(this, true, false);

                return true;
            };
            
            GuiFrame.CanBeFocused = false;

            IsActive = false;
        }

        public override void Update(float deltaTime, Camera cam)
        {
            currPowerConsumption = powerConsumption;

            base.Update(deltaTime, cam);
            
            if (voltage >= minVoltage || powerConsumption <= 0.0f)
            {
                pingState = pingState + deltaTime * 0.5f;
                if (pingState > 1.0f)
                {
                    if (item.CurrentHull != null) item.CurrentHull.AiTarget.SoundRange = Math.Max(Range * pingState, item.CurrentHull.AiTarget.SoundRange);
                    item.Use(deltaTime);
                    pingState = 0.0f;
                }
            }
            else
            {
                pingState = 0.0f;
            }

            Voltage -= deltaTime;
        }

        public override bool Use(float deltaTime, Character character = null)
        {
            return pingState > 1.0f;
        }

        public override void AddToGUIUpdateList()
        {
            GuiFrame.AddToGUIUpdateList();
        }

        public override void UpdateHUD(Character character)
        {
            GuiFrame.Update((float)Timing.Step);
            
            for (int i = radarBlips.Count - 1; i >= 0; i--)
            {
                radarBlips[i].FadeTimer -= (float)Timing.Step * 0.5f;
                if (radarBlips[i].FadeTimer <= 0.0f) radarBlips.RemoveAt(i);
            }

            float radius = (GuiFrame.Rect.Height / 2 - 30);

            if (IsActive)
            {
                float pingRadius = displayRadius * pingState;
                Ping(item.WorldPosition, pingRadius, prevPingRadius, displayScale, range, 2.0f);
                prevPingRadius = pingRadius;
            }

            float passivePingRadius = (float)Math.Sin(Timing.TotalTime * 10);
            if (passivePingRadius > 0.0f)
            {
                foreach (AITarget t in AITarget.List)
                {
                    if (t.SoundRange <= 0.0f) continue;
                    
                    if (Vector2.Distance(t.WorldPosition, item.WorldPosition) < t.SoundRange)
                    {
                        Ping(t.WorldPosition, t.SoundRange * passivePingRadius * 0.2f, t.SoundRange * prevPassivePingRadius * 0.2f, displayScale, t.SoundRange, 0.5f);
                        
                        radarBlips.Add(new RadarBlip(t.WorldPosition, 1.0f));
                    }
                }
            }
            prevPassivePingRadius = passivePingRadius;

        }

        public override void DrawHUD(SpriteBatch spriteBatch, Character character)
        {
            GuiFrame.Draw(spriteBatch);

            spriteBatch.End();
            spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.Additive);

            int radius = GuiFrame.Rect.Height / 2 - 30;
            DrawRadar(spriteBatch, new Rectangle((int)GuiFrame.Center.X - radius, (int)GuiFrame.Center.Y - radius, radius * 2, radius * 2));

            spriteBatch.End();
            spriteBatch.Begin(SpriteSortMode.Immediate, null, null, null, GameMain.ScissorTestEnable);
        }

        private void DrawRadar(SpriteBatch spriteBatch, Rectangle rect)
        {
            center = new Vector2(rect.X + rect.Width * 0.5f, rect.Center.Y);
            displayRadius = rect.Width / 2.0f;
            displayScale = displayRadius / range;

            if (IsActive)
            {
                pingCircle.Draw(spriteBatch, center, Color.White * (1.0f - pingState), 0.0f, (rect.Width / pingCircle.size.X) * pingState);
            }
                     
            if (item.Submarine != null && !DetectSubmarineWalls)
            {
                float simScale = displayScale * Physics.DisplayToSimRation;

                foreach (Submarine submarine in Submarine.Loaded)
                {
                    if (submarine != item.Submarine && !submarine.DockedTo.Contains(item.Submarine)) continue;

                    Vector2 offset = ConvertUnits.ToSimUnits(submarine.WorldPosition - item.WorldPosition);

                    for (int i = 0; i < submarine.HullVertices.Count; i++)
                    {
                        Vector2 start = (submarine.HullVertices[i] + offset) * simScale;
                        start.Y = -start.Y;
                        Vector2 end = (submarine.HullVertices[(i + 1) % submarine.HullVertices.Count] + offset) * simScale;
                        end.Y = -end.Y;

                        GUI.DrawLine(spriteBatch, center + start, center + end, Color.Green);
                    }
                }
            }

            foreach (RadarBlip radarBlip in radarBlips)
            {
                DrawBlip(spriteBatch, radarBlip, center, radarBlip.FadeTimer / 2.0f);                
            }

            if (GameMain.DebugDraw)
            {
                GUI.DrawString(spriteBatch, rect.Location.ToVector2(), radarBlips.Count.ToString(), Color.White);
            }

            if (screenOverlay != null)
            {
                screenOverlay.Draw(spriteBatch, center, 0.0f, rect.Width / screenOverlay.size.X);
            }
            
            if (GameMain.GameSession == null) return;

            DrawMarker(spriteBatch,
                GameMain.GameSession.StartLocation.Name,
                (Level.Loaded.StartPosition - item.WorldPosition), displayScale, center, (rect.Width * 0.5f));

            DrawMarker(spriteBatch,
                GameMain.GameSession.EndLocation.Name,
                (Level.Loaded.EndPosition - item.WorldPosition), displayScale, center, (rect.Width * 0.5f));

            if (GameMain.GameSession.Mission != null)
            {
                var mission = GameMain.GameSession.Mission;

                if (!string.IsNullOrWhiteSpace(mission.RadarLabel) && mission.RadarPosition != Vector2.Zero)
                {
                    DrawMarker(spriteBatch,
                        mission.RadarLabel,
                        mission.RadarPosition - item.WorldPosition, displayScale, center, (rect.Width * 0.55f));
                }
            }

            foreach (Submarine sub in Submarine.Loaded)
            {
                if (!sub.OnRadar) continue;
                if (item.Submarine == sub || sub.DockedTo.Contains(item.Submarine)) continue;
                if (sub.WorldPosition.Y > Level.Loaded.Size.Y) continue;
                
                DrawMarker(spriteBatch, sub.Name, sub.WorldPosition - item.WorldPosition, displayScale, center, (rect.Width * 0.45f));
            }

            if (!GameMain.DebugDraw) return;

            var steering = item.GetComponent<Steering>();
            if (steering == null || steering.SteeringPath == null) return;

            Vector2 prevPos = Vector2.Zero;

            foreach (WayPoint wp in steering.SteeringPath.Nodes)
            {
                Vector2 pos = (wp.Position - item.WorldPosition) * displayScale;
                if (pos.Length() > displayRadius) continue;

                pos.Y = -pos.Y;
                pos += center;

                GUI.DrawRectangle(spriteBatch, new Rectangle((int)pos.X - 3 / 2, (int)pos.Y - 3, 6, 6), (steering.SteeringPath.CurrentNode == wp) ? Color.LightGreen : Color.Green, false);

                if (prevPos != Vector2.Zero)
                {
                    GUI.DrawLine(spriteBatch, pos, prevPos, Color.Green);
                }

                prevPos = pos;
            }
        }

        private void Ping(Vector2 pingSource, float pingRadius, float prevPingRadius, float displayScale, float range, float pingStrength = 1.0f)
        {
            foreach (Submarine submarine in Submarine.Loaded)
            {
                if (item.Submarine == submarine && !DetectSubmarineWalls) continue;
                if (item.Submarine != null && item.Submarine.DockedTo.Contains(submarine)) continue;
                if (submarine.HullVertices == null) continue;

                for (int i = 0; i < submarine.HullVertices.Count; i++)
                {
                    Vector2 start = ConvertUnits.ToDisplayUnits(submarine.HullVertices[i]);
                    Vector2 end = ConvertUnits.ToDisplayUnits(submarine.HullVertices[(i + 1) % submarine.HullVertices.Count]);

                    if (item.Submarine == submarine)
                    {
                        start += Rand.Vector(500.0f);
                        end += Rand.Vector(500.0f);
                    }

                    CreateBlipsForLine(
                        start + submarine.WorldPosition,
                        end + submarine.WorldPosition,
                        pingRadius, prevPingRadius,
                        200.0f, 2.0f, range, 1.0f);
                }
            }

            if (Level.Loaded != null && (item.CurrentHull == null || !DetectSubmarineWalls))
            {
                if (Level.Loaded.Size.Y - pingSource.Y < range)
                {
                    CreateBlipsForLine(
                        new Vector2(pingSource.X - range, Level.Loaded.Size.Y),
                        new Vector2(pingSource.X + range, Level.Loaded.Size.Y),
                        pingRadius, prevPingRadius,
                        250.0f, 150.0f, range, pingStrength);
                }

                List<VoronoiCell> cells = Level.Loaded.GetCells(pingSource, 7);
                foreach (VoronoiCell cell in cells)
                {
                    foreach (GraphEdge edge in cell.edges)
                    {
                        if (!edge.isSolid) continue;
                        float cellDot = Vector2.Dot(cell.Center - pingSource, (edge.Center + cell.Translation) - cell.Center);
                        if (cellDot > 0) continue;

                        float facingDot = Vector2.Dot(
                            Vector2.Normalize(edge.point1 - edge.point2),
                            Vector2.Normalize(cell.Center - pingSource));

                        CreateBlipsForLine(
                            edge.point1 + cell.Translation,
                            edge.point2 + cell.Translation,
                            pingRadius, prevPingRadius,
                            350.0f, 3.0f * (Math.Abs(facingDot) + 1.0f), range, pingStrength);
                    }
                }

                foreach (RuinGeneration.Ruin ruin in Level.Loaded.Ruins)
                {
                    if (!MathUtils.CircleIntersectsRectangle(pingSource, range, ruin.Area)) continue;

                    foreach (var ruinShape in ruin.RuinShapes)
                    {
                        foreach (RuinGeneration.Line wall in ruinShape.Walls)
                        {
                            float cellDot = Vector2.Dot(
                                Vector2.Normalize(ruinShape.Center - pingSource),
                                Vector2.Normalize((wall.A + wall.B) / 2.0f - ruinShape.Center));
                            if (cellDot > 0) continue;

                            CreateBlipsForLine(
                                wall.A, wall.B,
                                pingRadius, prevPingRadius,
                                100.0f, 1000.0f, range, pingStrength);
                        }
                    }
                }
            }

            foreach (Character c in Character.CharacterList)
            {
                if (c.AnimController.CurrentHull != null || !c.Enabled) continue;
                if (DetectSubmarineWalls && c.AnimController.CurrentHull == null && item.CurrentHull != null) continue;

                foreach (Limb limb in c.AnimController.Limbs)
                {
                    float pointDist = (limb.WorldPosition - pingSource).Length() * displayScale;

                    if (limb.SimPosition == Vector2.Zero || pointDist > displayRadius) continue;

                    if (pointDist > prevPingRadius && pointDist < pingRadius)
                    {
                        for (int i = 0; i <= limb.Mass / 100.0f; i++)
                        {
                            var blip = new RadarBlip(limb.WorldPosition + Rand.Vector(limb.Mass / 10.0f), MathHelper.Clamp(limb.Mass, 0.1f, pingStrength));
                            radarBlips.Add(blip);
                        }
                    }
                }
            }
        }

        private void CreateBlipsForLine(Vector2 point1, Vector2 point2, float pingRadius, float prevPingRadius,
            float lineStep, float zStep, float range, float pingStrength)
        {
            float length = (point1 - point2).Length();

            Vector2 lineDir = (point2 - point1) / length;

            range *= displayScale;
            
            for (float x = 0; x < length; x += lineStep*Rand.Range(0.8f,1.2f))
            {
                Vector2 point = point1 + lineDir * x;
                //point += cell.Translation;

                float pointDist = Vector2.Distance(item.WorldPosition, point) * displayScale;

                if (pointDist > displayRadius) continue;
                if (pointDist < prevPingRadius || pointDist > pingRadius) continue;
                
                float alpha = pingStrength * Rand.Range(1.5f, 2.0f);
                for (float z = 0; z < displayRadius - pointDist * displayScale; z += zStep)
                {
                    Vector2 pos = point + Rand.Vector(150.0f) + Vector2.Normalize(point - item.WorldPosition) * z / displayScale;
                    float fadeTimer = alpha * (1.0f - pointDist / range);

                    int minDist = 200;
                    radarBlips.RemoveAll(b => b.FadeTimer < fadeTimer && Math.Abs(pos.X - b.Position.X) < minDist && Math.Abs(pos.Y - b.Position.Y) < minDist);

                    var blip = new RadarBlip(pos, fadeTimer);

                    radarBlips.Add(blip);
                    zStep += 0.5f;

                    if (z == 0)
                    {
                        alpha = Math.Min(alpha - 0.5f, 1.5f);
                    }
                    else
                    {
                        alpha -= 0.1f;
                    }
                    
                    if (alpha < 0) break;
                }

            }
        }

        private void DrawBlip(SpriteBatch spriteBatch, RadarBlip blip, Vector2 center, float strength)
        {
            strength = MathHelper.Clamp(strength, 0.0f, 1.0f);

            Color[] colors = new Color[] {
                Color.TransparentBlack,
                new Color(0, 50, 160),
                new Color(0, 133, 166),
                new Color(2, 159, 30),
                new Color(255, 255, 255) };

            float scaledT = strength * (colors.Length - 1);
            Color color = Color.Lerp(colors[(int)scaledT], colors[(int)Math.Min(scaledT+1, colors.Length-1)], (scaledT - (int)scaledT));
            
            Vector2 pos = (blip.Position - item.WorldPosition) * displayScale;
            pos.Y = -pos.Y;

            if (pos.Length() > displayRadius)
            {
                blip.FadeTimer = 0.0f;
                return;
            }
            
            float posDist = pos.Length();
            Vector2 dir = pos / posDist;
            float distFactor = (posDist / displayRadius);

            Vector2 normal = new Vector2(dir.Y, -dir.X);

            float scale = (strength + 3.0f) * Math.Max(distFactor * 3.0f, 1.0f);

            if (radarBlip == null)
            {
                GUI.DrawRectangle(spriteBatch, center + pos, Vector2.One * 4, Color.Magenta, true);
                return;
            }

            radarBlip.Draw(spriteBatch, center + pos, color, radarBlip.Origin, MathUtils.VectorToAngle(pos), 
                new Vector2(scale * 0.3f, scale) * 0.04f, SpriteEffects.None, 0);
            
            pos += Rand.Range(0.0f, 1.0f) * dir + Rand.Range(-scale, scale) * normal;

            radarBlip.Draw(spriteBatch, center + pos, color * 0.5f, radarBlip.Origin, MathUtils.VectorToAngle(pos),
                new Vector2(scale * 0.3f, scale) * 0.08f, SpriteEffects.None, 0);
        }

        private void DrawMarker(SpriteBatch spriteBatch, string label, Vector2 position, float scale, Vector2 center, float radius)
        {
            //position += Level.Loaded.Position;

            float dist = position.Length();

            position *= scale;
            position.Y = -position.Y;

            float textAlpha = MathHelper.Clamp(1.5f - dist / 50000.0f, 0.5f, 1.0f);

            Vector2 dir = Vector2.Normalize(position);

            Vector2 markerPos = (dist*scale>radius) ? dir * radius : position;
            markerPos += center;

            markerPos.X = (int)markerPos.X;
            markerPos.Y = (int)markerPos.Y;

            GUI.DrawRectangle(spriteBatch, new Rectangle((int)markerPos.X, (int)markerPos.Y, 5, 5), Color.LightGreen * textAlpha);

            if (dir.X < 0.0f) markerPos.X -= GUI.SmallFont.MeasureString(label).X+10;

            string wrappedLabel = ToolBox.WrapText(label, 150, GUI.SmallFont);

            wrappedLabel += "\n"+((int)(dist * Physics.DisplayToRealWorldRatio) + " m");

            GUI.DrawString(spriteBatch, 
                new Vector2(markerPos.X + 10, markerPos.Y), 
                wrappedLabel, 
                Color.LightGreen * textAlpha, Color.Black * textAlpha * 0.5f, 
                2, GUI.SmallFont);              
        }

        protected override void RemoveComponentSpecific()
        {
            if (pingCircle!=null) pingCircle.Remove();
            if (screenOverlay != null) screenOverlay.Remove();
            if (radarBlip != null) radarBlip.Remove();
        }

        public override bool FillNetworkData(Networking.NetworkEventType type, Lidgren.Network.NetBuffer message)
        {
            message.Write(IsActive);

            return true;
        }

        public override void ReadNetworkData(Networking.NetworkEventType type, Lidgren.Network.NetIncomingMessage message, float sendingTime)
        {
            try
            {
                IsActive = message.ReadBoolean();
            }
            catch
            {
                return;
            }
        }
    }

    class RadarBlip
    {
        public float FadeTimer;
        public Vector2 Position;

        public RadarBlip(Vector2 pos, float fadeTimer)
        {
            Position = pos;
            FadeTimer = Math.Max(fadeTimer, 0.0f);
        }
    }
}