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

namespace Metamesh
{
    public class GoldbergBuilder
    {
        public class GoldbergVertexDataOption
        {
            public float size = 1;
            public float sizeX = 1;
            public float sizeY = 1;
            public float sizeZ = 1;
        };

        public class GoldbergCreationOption : GoldbergVertexDataOption
        {
            public int m;
            public int n;
        }

        public class VertexData
        {
            public List<Vector3> vertices;
            public List<int> indices;
            public List<Vector3> normals;
            public List<Vector2> uvs;
        }

        public VertexData CreateGoldbergVertexData(GoldbergVertexDataOption options, PolyhedronData goldbergData)
        {
            var size = options.size;
            var sizeX = options.sizeX;// || size || 1;
            var sizeY = options.sizeY;// || size || 1;
            var sizeZ = options.sizeZ;// || size || 1;

            var positions = new List<Vector3>();
            var indices = new List<int>();
            var normals = new List<Vector3>();
            var uvs = new List<Vector2>();

            var minX = float.MaxValue;
            var maxX = float.MinValue;
            var minY = float.MaxValue;
            var maxY = float.MinValue;

            for (var v = 0; v < goldbergData.vertex.Count; v++)
            {
                minX = Mathf.Min(minX, goldbergData.vertex[v].x * sizeX);
                maxX = Mathf.Max(maxX, goldbergData.vertex[v].x * sizeX);
                minY = Mathf.Min(minY, goldbergData.vertex[v].y * sizeY);
                maxY = Mathf.Max(maxY, goldbergData.vertex[v].y * sizeY);
            }

            var index = 0;
            for (var f = 0; f < goldbergData.face.Count; f++)
            {
                var verts = goldbergData.face[f];
                var a = goldbergData.vertex[verts[0]];
                var b = goldbergData.vertex[verts[2]];
                var c = goldbergData.vertex[verts[1]];
                var ba = b - a;
                var ca = c - a;
                var norm = Vector3.Cross(ca, ba).normalized;
                for (var v = 0; v < verts.Count; v++)
                {
                    normals.Add(norm);
                    var pdata = goldbergData.vertex[verts[v]];
                    positions.Add(new Vector3(pdata[0] * sizeX, pdata[1] * sizeY, pdata[2] * sizeZ));
                    var vCoord = (pdata[1] * sizeY - minY) / (maxY - minY);
                    uvs.Add(new Vector2((pdata[0] * sizeX - minX) / (maxX - minX), vCoord));
                }
                for (var v = 0; v < verts.Count - 2; v++)
                {
                    indices.AddRange(new int[] { index, index + v + 2, index + v + 1 });
                }
                index += verts.Count;
            }
            /*
            VertexData._ComputeSides(sideOrientation, positions, indices, normals, uvs);

            const vertexData = new VertexData();
            vertexData.positions = positions;
            vertexData.indices = indices;
            vertexData.normals = normals;
            vertexData.uvs = uvs;
            return vertexData;
            */
            return new VertexData()
            {
                vertices = positions,
                indices = indices,
                normals = normals,
                uvs = uvs,
            };
        }

        /**
         * Creates the Mesh for a Goldberg Polyhedron which is made from 12 pentagonal and the rest hexagonal faces
         * @see https://en.wikipedia.org/wiki/Goldberg_polyhedron
         * @see https://doc.babylonjs.com/features/featuresDeepDive/mesh/creation/polyhedra/goldberg_poly
         * @param name defines the name of the mesh
         * @param options an object used to set the following optional parameters for the polyhedron, required but can be empty
         * @param scene defines the hosting scene
         * @returns Goldberg mesh
         */
        public VertexData CreateGoldberg(GoldbergCreationOption options)
        {
            var size = options.size;
            var sizeX = options.sizeX;// || size || 1;
            var sizeY = options.sizeY;// || size || 1;
            var sizeZ = options.sizeZ;// || size || 1;
            var m = options.m;// || 1;
            var n = options.n;// || 0;
            if (n > m)
            {
                var temp = n;
                n = m;
                m = temp;
                Debug.LogWarning("n > m therefore m and n swapped");
            }
            var primTri = new PrimaryIsoTriangle();
            primTri.Build(m, n);
            var geodesicData = GeodesicData.BuildGeodesicData(primTri);
            var goldbergData = geodesicData.ToGoldbergPolyhedronData();

            //var goldberg = new Mesh();
            //goldberg.name = name;

            var vertexData = CreateGoldbergVertexData(options, goldbergData);
            return vertexData;

            /*
            vertexData.applyToMesh(goldberg, options.updatable);

            goldberg.goldbergData.nbSharedFaces = geodesicData.sharedNodes;
            goldberg.goldbergData.nbUnsharedFaces = geodesicData.poleNodes;
            goldberg.goldbergData.adjacentFaces = geodesicData.adjacentFaces;
            goldberg.goldbergData.nbFaces = goldberg.goldbergData.nbSharedFaces + goldberg.goldbergData.nbUnsharedFaces;
            goldberg.goldbergData.nbFacesAtPole = (goldberg.goldbergData.nbUnsharedFaces - 12) / 12;
            
            for (var f = 0; f < geodesicData.vertex.Count; f++)
            {
                
                goldberg.goldbergData.faceCenters.push(Vector3.FromArray(geodesicData.vertex[f]));
                goldberg.goldbergData.faceCenters[f].x *= sizeX;
                goldberg.goldbergData.faceCenters[f].y *= sizeY;
                goldberg.goldbergData.faceCenters[f].z *= sizeZ;
                goldberg.goldbergData.faceColors.push(new Color4(1, 1, 1, 1));
                
            }

            for (var f = 0; f < goldbergData.face.Count; f++)
            {
                var verts = goldbergData.face[f];
                var a = goldbergData.vertex[verts[0]];
                var b = goldbergData.vertex[verts[2]];
                var c = goldbergData.vertex[verts[1]];
                var ba = b - a;
                var ca = c - a;
                var norm = Vector3.Cross(ca, ba).normalized;
                var z = Vector3.Cross(ca, norm).normalized;
                //goldberg.goldbergData.faceXaxis.push(ca.normalize());
                //goldberg.goldbergData.faceYaxis.push(norm);
                //goldberg.goldbergData.faceZaxis.push(z);
            }
            
            return goldberg;
            */
        }
    }

}