#include <TROOT.h>
#include <TCanvas.h>
#include <TPad.h>
#include <TText.h>
#include <TLine.h>
#include <TExec.h>

bool flag = 1;
void MyExec();

void RootDrawingBug()
{
	//Make a TCanvas with 2 pads:
	//	A pad to show 3 static vertical lines and a TExec to get mouse position,
	//	A pad to with text that shows mouse position and can be updated with that TExec

	std::string name;

	TCanvas* cnvs = nullptr;
	TPad* pad1 = nullptr;
	TPad* pad2 = nullptr;

	name = "MyCanvas";
	cnvs = (TCanvas*)gROOT->FindObject(name.c_str());
	if(!cnvs)
	{
		cnvs = new TCanvas
		(
			name.c_str(),
			name.c_str(),
			0,
			0,
			600,
			800
		);
	}

	name = "MyPad1";
	pad1 = (TPad*)gROOT->FindObject(name.c_str());
	if(!pad1)
	{
		pad1 = new TPad
		(
			name.c_str(),
			name.c_str(),
			0.0,
			0.5,
			1.0,
			1.0
		);

		pad1->Range(0.0, 0.0, 1.0, 1.0);
		cnvs->cd();
		pad1->Draw();

		//Draw 3 vertical lines on MyPad1 on MyCanvas
		pad1->cd();
		double temp;
		TLine line;

		for(temp = 0.25; temp < 1.0; temp += 0.25)
		{
			line.SetX1(temp);
			line.SetY1(0.0);
			line.SetX2(temp);
			line.SetY2(1.0);

			line.DrawClone();
		}

		pad1->AddExec
		(
			"MyExec",
			"MyExec()"
		);
	}

	name = "MyPad2";
	pad2 = (TPad*)gROOT->FindObject(name.c_str());
	if(!pad2)
	{
		pad2 = new TPad
		(
			name.c_str(),
			name.c_str(),
			0.0,
			0.0,
			1.0,
			0.5
		);

		pad2->Range(0.0, 0.0, 1.0, 1.0);
		cnvs->cd();
		pad2->Draw();

		//Add some text on MyPad2 on MyCanvas
		pad2->cd();
		TText* disp_text = new TText
		(
			0.5,
			0.5,
			Form("X: %0.3f Y: %0.3f", 0.0, 0.0)
		);
		disp_text->SetTextAlign(22);
		disp_text->SetName("DispText");	//so we can find it later with gROOT->FindObject
		disp_text->Draw();
	}

	//cnvs->Update();
	cnvs->Show();
	//cnvs->SetEditable(0);
}

void MyExec()
{
	//"Update" MyPad2 to show mouse position
	float x = gPad->AbsPixeltoX(gPad->GetEventX());
	float y = gPad->AbsPixeltoY(gPad->GetEventY());

	TText* disp_text = (TText*)gROOT->FindObject("DispText");
	if(disp_text)disp_text->SetTitle(Form("X: %0.3f Y: %0.3f", x, y));

	TPad* disp_pad = (TPad*)gROOT->FindObject("MyPad2");
	if(disp_pad)disp_pad->Update();

	if(flag)
	{
		std::cout << std::endl;
		std::cout << "The mouse position is retrieved successfully and we've updated the text and pad correctly:" << std::endl;
		std::cout << disp_text->GetTitle() << std::endl;
		std::cout << disp_pad->GetName() << std::endl;
		std::cout << "However, \"MyPad2\" isn't updated even though we called Update()" << std::endl;
		std::cout << std::endl;
	}

	//Draw another pad when left-clicked
	if(gPad->GetEvent() != 11)return;

	std::string name;
	TCanvas* cnvs = nullptr;
	TPad* pad1 = nullptr;

	name = "MyExecCanvas";
	cnvs = (TCanvas*)gROOT->FindObject(name.c_str());
	if(!cnvs)
	{
		cnvs = new TCanvas
		(
			name.c_str(),
			name.c_str(),
			650,
			0,
			600,
			800
		);
	}

	name = "MyExecPad1";
	pad1 = (TPad*)gROOT->FindObject(name.c_str());
	if(!pad1)
	{
		pad1 = new TPad
		(
			name.c_str(),
			name.c_str(),
			0.0,
			0.0,
			1.0,
			1.0
		);

		pad1->Range(0.0, 0.0, 1.0, 1.0);
		cnvs->cd();
		pad1->Draw();

		pad1->cd();
		double temp;
		TLine line;

		std::cout << "I cd the newly created \"MyExecPad1\"" << std::endl;
		std::cout << "We can see that gPad is indeed this pad:" << std::endl;
		std::cout << "gPad->GetName(): " << gPad->GetName() << std::endl;
		std::cout << "However, these lines appear on \"MyPad1\"" << std::endl;
		flag = 0;

		for(temp = 0.25; temp < 1.0; temp += 0.25)
		{
			line.SetX1(0.0);
			line.SetY1(temp);
			line.SetX2(1.0);
			line.SetY2(temp);

			line.DrawClone();
		}
	}

	cnvs->Show();
}