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

public class meshGenerator : MonoBehaviour{

    Mesh mesh;
    Material m;
    MeshFilter mf;
    MeshRenderer mr;
    Voxel v;
    Vector3[] vertices;
    int[] triangles;

    void Start() {
        mf = GetComponent<MeshFilter>();
        mr = GetComponent<MeshRenderer>();
        mesh = new Mesh();
        v = new Voxel(new Vector3Int(0, 0, 0));
        int indexOffset = 0;
        vertices = v.vertices.ToArray();
        triangles = v.returnTriangles(indexOffset);
        mesh.vertices = vertices;
        mesh.triangles = triangles;
        mf.mesh = mesh;
    }

    public class Voxel {
        Vector3Int position;
        public static Vector3Int[] corners = new Vector3Int[8]{
            new Vector3Int(1, 1, 0), // 0
            new Vector3Int(1, 0, 0), // 1
            new Vector3Int(0, 0, 0), // 2
            new Vector3Int(0, 1, 0), // 3

            new Vector3Int(0, 1, 1), // 4
            new Vector3Int(1, 1, 1), // 5
            new Vector3Int(1, 0, 1), // 6
            new Vector3Int(0, 0, 1)  // 7
        };

        Dictionary<string, bool> visibleFaces = new Dictionary<string, bool>{
            { "top",    true },
            { "north",  true },
            { "east",   true },
            { "south",  true },
            { "west",   true },
            { "bottom", true }
        };

        public List<Vector3> vertices = new List<Vector3>();
        List<int> triangles = new List<int>();

        public Voxel(Vector3Int pos) {
            position = pos;
            //  checkNeighbours();
            pushFaces();
            pushTriangles();
        }

        /*  void checkNeighbours() {

            }*/

        void pushVertices(Vector3Int A, Vector3Int B, Vector3Int C, Vector3Int D) {
            vertices.Add(A + position);
            vertices.Add(B + position);
            vertices.Add(C + position);
            vertices.Add(D + position);
        }

        int[] faceTriangles(int o) {
            return new int[] {
                o,
                o + 1,
                o + 2,
                o,
                o + 2,
                o + 3,
            };
        }

        void pushFaces() {
            if (visibleFaces["south"]) {
                pushVertices(corners[0], corners[1], corners[2], corners[3]);
            }
            if (visibleFaces["top"]) {
                pushVertices(corners[0], corners[3], corners[4], corners[5]);
            }
            if (visibleFaces["east"]) {
                pushVertices(corners[0], corners[5], corners[6], corners[1]);
            }
            if (visibleFaces["north"]) {
                pushVertices(corners[7], corners[6], corners[5], corners[4]);
            }
            if (visibleFaces["west"]) {
                pushVertices(corners[7], corners[4], corners[3], corners[2]);
            }
            if (visibleFaces["bottom"]) {
                pushVertices(corners[7], corners[2], corners[1], corners[6]);
            }
        }

        void pushTriangles() {
            int end = 0;
            foreach (bool v in visibleFaces.Values) if(v) end+=4;
            for (int i = 0; i < end; i+=4) {
                triangles.AddRange(faceTriangles(i));
            }
        }

        public int[] returnTriangles(int offset = 0) {
            int[] ts = triangles.ToArray();
            for (int i = 0; i < ts.Length; i++) ts[i] += offset;
            return ts;
        }
    }
}