using System.Collections.Generic;
using System.Linq;
using Assets.Cities;
using Assets.Common;
using Assets.Voronoi;

namespace Assets.AnnotationPass
{
    public class CityFieldsPass : IAnnotationPass
    {
        private System.Random _random;
        private Graph<Point> _voronoiGraph;
        private Graph<Location> _locationGraph;
        private Graph<MapSite> _basicGraph;
        private List<int> verticesForRoads;
        private List<int> verticesForCitites;
        
        List<City> cities = new List<City>();
        Graph<MapSite> roads = new Graph<MapSite>();
        Graph<Point> mainRoads = new Graph<Point>();
        double minimumAngle;

        List<int> CountProbablitityOfCity(List<int> vertices)
        {
            List<int> probabilities = new List<int>();
            vertices.ForEach(v => probabilities.Add((v % 2 == 0 ? _random.Next(0, 50) : _random.Next(50, 100))));
            return probabilities;
        }

        List<int> LocateCities()
        {
            //  var verticesForCitites = CountProbablitityOfCity(ChoosePoints(20));
            // verticesForCitites.Sort();
            // return verticesForCitites.GetRange(0, 10);
            return ChoosePoints(20);
        }

        public bool IsPointInsideCity(City city, Point point)
        {
            return city.sites.Any(s => PointUtils.IsPointInside(point, s.Boundary.Select(i => _voronoiGraph[i]).ToArray()));
        }

        City CreateCity(int vertex, int size)
        {
            City newCity = new City(_basicGraph);
            
            var site = _basicGraph.Vertices[vertex];
            var sites = new List<MapSite> { site };
            var location = site.Metadata.GetProperty<Location>(LandmassPass.SiteLocationProperty);

            for (int i = 0; i < size - 1; i++)
            {
                var neighbours = _basicGraph.Neighbours(site.Index).Select(j => _basicGraph.Vertices[j]).Where(s => s.Metadata.GetProperty<Location>(LandmassPass.SiteLocationProperty) == location).ToList();
                site = neighbours[_random.Next(neighbours.Count)];
                sites.Add(site);
            }

            foreach (var s in sites.Distinct())
            {
                newCity.AddSite(s);
            }

            newCity.CreateRoadGraph(_voronoiGraph.Vertices);

            var edges = newCity.roads.Edges.ToList();
            foreach (var (a, b) in edges)
            {
                var (va, vb) = (newCity.roads[a], newCity.roads[b]);
                var center = (va + vb) / 2;

                if (!IsPointInsideCity(newCity, center))
                    newCity.roads.DeleteEdge(a, b);
            }

            ConnectPointsIntoRoads(newCity);
            FixRoadsDensity(newCity, minimumAngle);
            CreateFieldBoundaries(newCity);

            return newCity;
        }

        List<int> ChoosePoints(int number)
        {
            var vertices = new List<int>();
            for (int i = 0; i < number; i++)
            {
                var randomLocation = _locationGraph.Vertices[_random.Next(1, _locationGraph.Vertices.Count())];
                var count = randomLocation.Sites.Count();
                var randomPoint = randomLocation.Sites[_random.Next(0, count)];
                vertices.Add(randomPoint.Index);
            }
            return vertices;
        }

        void ConnectPointsIntoRoads(City city)
        {
            var original = city.roads.Morph(s => s, e => Point.Dist(city.roads[e.Item1], city.roads[e.Item2]));

            //1.Sort all the edges in non - decreasing order of their weight.
            //2.Pick the smallest edge.Check if it forms a cycle with the spanning tree formed so far. If cycle is not formed, include this edge.Else, discard it.
            //3.Repeat step#2 until there are (V-1) edges in the spanning tree.

            var edges = original.Edges.OrderByDescending(e => original.GetEdgeData(e));

            Graph<Point> roads = new Graph<Point>() { Vertices = city.roads.Vertices };

            foreach (var edge in original.Edges)
            {
                roads.AddEdge(edge.Item1, edge.Item2);

                if (Graph<Point>.HasCycle(roads))
                    roads.DeleteEdge(edge.Item1, edge.Item2);
                if (roads.Edges.Count() == roads.Vertices.Count() - 1)
                    break;
            }

            city.roads = roads;
        }

        private void CreateFieldBoundaries(City city)
        {
            foreach (var (a, b) in city.roads.Edges)
                city.fieldBoundaries.AddEdge(a, b);

            var deadEnds = city.fieldBoundaries.Vertices.Select((_, i) => i).Where(i => city.fieldBoundaries.Neighbours(i).Count() == 1);

            foreach (var deadEnd in deadEnds)
            {
                var neighbour = city.fieldBoundaries.Neighbours(deadEnd).First();
                var closest = city.fieldBoundaries.Vertices
                    .Select((_, i) => i)
                    .OrderBy(i => Point.Dist(city.fieldBoundaries[i], city.fieldBoundaries[deadEnd]))
                    .Skip(1)
                    .First(c => c != neighbour);

                city.fieldBoundaries.AddEdge(deadEnd, closest);
                city.roads.AddEdge(deadEnd, closest);
            }
        }


        private void FixRoadsDensity(City city, double angle = 0.25f)
        {
            // dla każdego punktu w grafie dróg
            // chyba że ma 2 to pomiń?
            // wyznacz punkt 0
            // oblicz odległości kątowe do wszystkich punktów
            // posortuj je
            // między wszystkimiu parami oblicz kąt
            // potem według jakiegoś parametru usuń te, które są za bliskie


            for (int i = 0; i < city.roads.Vertices.Count(); i++)
            {
                var p = city.roads[i];
                if (city.roads.Neighbours(i).Count() <= 2)
                    continue;

                var reference = new Point(p.x, p.y + 30);

                var orderedNeighours = city.roads.Neighbours(i)
                    .Select(n => (Vertex: n, Point: city.roads[n]))
                    .Select(x => (Vertex: x.Vertex, Angle: PointUtils.AngleBetween(p, reference, x.Point)))
                    .OrderBy(x => x.Angle)
                    .Select(x => x.Vertex);

                foreach (var (a, b) in orderedNeighours.RotateRight(1).Zip(orderedNeighours, (a, b) => (a, b)))
                {
                    if( PointUtils.AngleBetween(p, city.roads[a], city.roads[b]) < angle)
                    {
                        city.roads.DeleteEdge(i, a);
                    }
                }
            }
        }

        void CreateWorldRoadGraph()
        {
            roads.Vertices = verticesForCitites.Select(i => _basicGraph.Vertices[i]).ToList();

            VoronoiGenerator generator = new VoronoiGenerator(roads.Vertices.Select(s => s.Center).ToList());
            generator.Generate();

            roads.Edges = generator.Delaunay.Edges;
        }

        void AddLanesToRoads()
        {
            // ergo dodaj randomowe połączenia xd
        }

        public void Annotate(Map map)
        {
            _basicGraph    = map.Sites.Clone() as Graph<MapSite>;
            _voronoiGraph  = map.Boundaries;
            _locationGraph = map.Metadata.GetProperty<Graph<Location>>(LandmassPass.MapLocationsProperty);

            verticesForCitites = LocateCities();
            foreach (var index in verticesForCitites)
            {
                cities.Add(CreateCity(index, _random.Next(0, 10)));
            }

            CreateWorldRoadGraph();
            mainRoads = roads.Morph(s => s.Center);
        }
    }
}