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

public class Customized : MonoBehaviour
{
    Mesh mesh;

    Calculator2D calculator2D;

    public string formula;

    public int minX;
    public int maxX;
    // Start is called before the first frame update
    void Start()
    {
        mesh = new Mesh
        {
            name = "Customized"
        };
        calculator2D = new Calculator2D();
    }

    // Update is called once per frame
    void Update()
    {
        
    }

    public void DrawCustomized()
    {
        mesh.Clear();

        bool isContinue = false;

        Vector3[] vectors = new Vector3[100 * (maxX - minX) + 1];
        int[] triangle = new int[100 * (maxX - minX) * 2];
        int k = 0;
        float step = 0.01f;
        for (float i = minX; i <= maxX; i += step)
        {
            float y = 0;
            if(calculator2D.calculate2D(formula, i ,out y))
            {
                vectors[k] = new Vector3(i, y, 0);
                if (k != 0)
                {
                    if (isContinue)
                    {
                        triangle[2 * (k - 1)] = k - 1;
                        triangle[2 * (k - 1) + 1] = k;
                    }
                    else
                    {
                        triangle[2 * (k - 1)] = k;
                        triangle[2 * (k - 1) + 1] = k;
                    }
                } 
                isContinue = true;
            }
            else
            {
                if (k != 0)
                    vectors[k] = vectors[k - 1];
                else
                    vectors[k] = new Vector3(0, 0, -1000);
                isContinue = false;
            }
            k++;
        }
        mesh.vertices = vectors;
        mesh.SetIndices(triangle, MeshTopology.Lines, 0);

        GetComponent<MeshFilter>().mesh = mesh;
    }

    public void DrawCustomized3D()
    {
        mesh.Clear();

        bool isContinue = false;

        Vector3[] vectors = new Vector3[200 * (maxX - minX) + 2];
        int[] triangle = new int[100 * (maxX - minX) * 6];
        int k = 0;
        float step = 0.01f;
        for (float i = minX; i <= maxX; i += step)
        {
            float y = 0;
            if (calculator2D.calculate2D(formula, i, out y))
            {
                vectors[k] = new Vector3(i, y, -5);
                vectors[k + 1] = new Vector3(i, y, 5);
                if (k != 0)
                {
                    if (isContinue)
                    {
                        triangle[3 * (k - 2)] = k - 2;
                        triangle[3 * (k - 2) + 1] = k - 1;
                        triangle[3 * (k - 2) + 2] = k;
                        triangle[3 * (k - 2) + 3] = k - 1;
                        triangle[3 * (k - 2) + 4] = k + 1;
                        triangle[3 * (k - 2) + 5] = k;
                    }
                    else
                    {
                        triangle[3 * (k - 2)] = k - 2;
                        triangle[3 * (k - 2) + 1] = k - 1;
                        triangle[3 * (k - 2) + 2] = k - 1;
                        triangle[3 * (k - 2) + 3] = k;
                        triangle[3 * (k - 2) + 4] = k + 1;
                        triangle[3 * (k - 2) + 5] = k;
                    }
                }
                isContinue = true;
            }
            else
            {
                if (k != 0)
                {
                    vectors[k] = vectors[k - 2];
                    vectors[k + 1] = vectors[k - 1];
                }
                else
                {
                    vectors[k] = new Vector3(0, 0, -1000);
                    vectors[k + 1] = new Vector3(0, 0, -1000);
                }
                isContinue = false;
            }
            k += 2;
        }
        mesh.vertices = vectors;

        Vector2[] uvs = new Vector2[vectors.Length];
        for (int i = 0; i < uvs.Length; i++)
        {
            uvs[i] = new Vector2(0, vectors[i].y / 100);
        }
        mesh.uv = uvs;

        mesh.SetIndices(triangle, MeshTopology.Triangles, 0);

        GetComponent<MeshFilter>().mesh = mesh;
    }

    public void MeshClear()
    {
        mesh.Clear();
        GetComponent<MeshFilter>().mesh = mesh;
    }
}