using System.Collections.Generic;
using UnityEngine;

namespace HexFiled
{
	[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
	public class HexMesh : MonoBehaviour {

		Mesh hexMesh;
		List<Vector3> vertices;
		List<Color> colors;
		List<int> triangles;

		MeshCollider meshCollider;

		void Awake () {
			GetComponent<MeshFilter>().mesh = hexMesh = new Mesh();
			meshCollider = gameObject.AddComponent<MeshCollider>();
			hexMesh.name = "Hex Mesh";
			vertices = new List<Vector3>();
			colors = new List<Color>();
			triangles = new List<int>();
		}

		public void Triangulate (HexCell[] cells) {
			hexMesh.Clear();
			vertices.Clear();
			colors.Clear();
			triangles.Clear();
			for (int i = 0; i < cells.Length; i++) {
				Triangulate(cells[i]);
			}
			hexMesh.vertices = vertices.ToArray();
			hexMesh.colors = colors.ToArray();
			hexMesh.triangles = triangles.ToArray();
			hexMesh.RecalculateNormals();
			meshCollider.sharedMesh = hexMesh;
		}

		void Triangulate (HexCell cell) {
			Vector3 center = cell.transform.localPosition;
			for (int i = 0; i < 6; i++) {
				AddTriangle(
					center,
					center + HexMetrics.corners[i],
					center + HexMetrics.corners[i + 1]
				);
				AddTriangleColor(cell.color);
			}
		}

		void AddTriangle (Vector3 v1, Vector3 v2, Vector3 v3) {
			int vertexIndex = vertices.Count;
			vertices.Add(v1);
			vertices.Add(v2);
			vertices.Add(v3);
			triangles.Add(vertexIndex);
			triangles.Add(vertexIndex + 1);
			triangles.Add(vertexIndex + 2);
		}

		void AddTriangleColor (Color color) {
			colors.Add(color);
			colors.Add(color);
			colors.Add(color);
		}
	}
}