using CaeMesh;
using System;
using System.Collections.Generic;
using System.Linq;

namespace CaeKnowledge
{
    public class MeshTools
    {
        public static double Distance(double x1, double y1, double z1, double x2, double y2, double z2)
        {
            return Math.Sqrt(Math.Pow(x1 - x2, 2) + Math.Pow(y1 - y2, 2) + Math.Pow(z1 - z2, 2));
        }

        private static double Distance(FeNode n1, FeNode n2)
        {
            return Math.Sqrt(Math.Pow(n1.X - n2.X, 2) + Math.Pow(n1.Y - n2.Y, 2) + Math.Pow(n1.Z - n2.Z, 2));
        }

        public static List<FeNode> GetClosestNodes(FeMesh mesh, FeNode _base, double minimum)
        {
            var list = new List<FeNode>();

            foreach (var node in mesh.Nodes.Values)
            {
                var dist = Distance(node, _base);
                if (dist < minimum) list.Add(node);
            }

            return list;
        }

        public static List<FeElement> GetClosestElements(FeMesh mesh, FeNode _base, double minimum)
        {
            var list = new List<FeElement>();

            foreach (var element in mesh.Elements.Values)
            {
                var nodes = (from id in element.NodeIds select mesh.Nodes[id]).ToList();

                if (nodes.All(node => Distance(node, _base) < minimum))
                {
                    list.Add(element);
                }
            }

            return list;
        }

        public static List<FeNode> GetClosestNodesInNodeSet(FeMesh mesh, string nodeSetName, FeNode _base, double minimum)
        {
            if (!mesh.NodeSets.TryGetValue(nodeSetName, out var nodeSet))
                return null;

            var nodes = (from id in nodeSet.Labels select mesh.Nodes[id]).ToList();

            var list = new List<FeNode>();
            nodes.ForEach(node =>
            {
                if (Distance(node, _base) < minimum)
                    list.Add(node);
            });

            return list;
        }

        public static List<Tuple<FeElement, FeFaceName>> FindAllElements(FeMesh mesh, string nodeSetName)
        {
            if (!mesh.NodeSets.TryGetValue(nodeSetName, out var nodeSet))
                return null;

            var list = new List<Tuple<FeElement, FeFaceName>>();

            foreach (var element in from element
                         in mesh.Elements.Values.OfType<FeElement3D>()
                                    select element)
            {
                // 四面体单元
                foreach (var faceName in new[] { FeFaceName.S1, FeFaceName.S2, FeFaceName.S3, FeFaceName.S4 })
                {
                    var ids = element.GetNodeIdsFromFaceName(faceName);

                    if (ids.All(x => nodeSet.Labels.Contains(x)))
                        list.Add(new Tuple<FeElement, FeFaceName>(element, faceName));
                }
            }

            return list;
        }

        public static List<int> GetClosestFaces(FeMesh mesh, string nodeSetName, FeNode _base, double minimum)
        {
            var nodes = (from x in GetClosestNodesInNodeSet(mesh, nodeSetName, _base, minimum) select x.Id).ToList();

            if (nodes.Count == 0) return null;

            var allElements = FindAllElements(mesh, nodeSetName);

            if (allElements == null || allElements.Count == 0) return null;

            var list = new List<int>();

            foreach (var (element, faceName) in allElements)
            {
                var ids = element.GetNodeIdsFromFaceName(faceName);

                if (!ids.Any(x => nodes.Contains(x)))
                    continue;

                var label = element.Id * 10 + (int)faceName - 1;
                list.Add(label);
            }

            list.Sort();

            return list;
        }

        public static List<FeFace> FindSurfaceAllFaces(string srfName, FeMesh mesh)
        {
            if (!mesh.Surfaces.TryGetValue(srfName, out var surface))
                return null;

            var faceIds = surface.FaceIds;

            return (from faceId in faceIds
                    let elemId = faceId / 10
                    let faceTag = faceId % 10 + 1
                    let element = mesh.Elements[elemId]
                    let faceName = (FeFaceName)faceTag
                    select new FeFace(element, faceName)).ToList();
        }
    }
}