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

public class DrawingController : MonoBehaviour
{
    public GameObject linePrefab;
    private LineRenderer currentLineRenderer;
    private List<Vector2> points = new List<Vector2>();

    void Update()
    {
#if UNITY_EDITOR || UNITY_STANDALONE
        HandleMouseInput();
#elif UNITY_ANDROID || UNITY_IOS
        HandleTouchInput();
#endif
    }

    void HandleMouseInput()
    {
        if (Input.GetMouseButtonDown(0))
            StartLine(Camera.main.ScreenToWorldPoint(Input.mousePosition));

        if (Input.GetMouseButton(0))
            ContinueLine(Camera.main.ScreenToWorldPoint(Input.mousePosition));
    }

    void HandleTouchInput()
    {
        if (Input.touchCount > 0)
        {
            Touch touch = Input.GetTouch(0);
            Vector2 pos = Camera.main.ScreenToWorldPoint(touch.position);

            if (touch.phase == TouchPhase.Began)
                StartLine(pos);
            else if (touch.phase == TouchPhase.Moved)
                ContinueLine(pos);
        }
    }

    void StartLine(Vector2 startPos)
    {
        GameObject newLine = Instantiate(linePrefab);
        newLine.tag = "Line";
        currentLineRenderer = newLine.GetComponent<LineRenderer>();

        currentLineRenderer.startWidth = 20.0f;
        currentLineRenderer.endWidth = 20.0f;

        points.Clear();
        points.Add(startPos);
        points.Add(startPos);
        currentLineRenderer.positionCount = 2;
        currentLineRenderer.SetPosition(0, startPos);
        currentLineRenderer.SetPosition(1, startPos);
    }

    void ContinueLine(Vector2 pos)
    {
        if (Vector2.Distance(pos, points[points.Count - 1]) > 0.05f)
        {
            points.Add(pos);
            currentLineRenderer.positionCount++;
            currentLineRenderer.SetPosition(currentLineRenderer.positionCount - 1, pos);
        }
    }

    public void ClearDrawing()
    {
        foreach (var line in GameObject.FindGameObjectsWithTag("Line"))
            Destroy(line);
    }
}