#include "win32/Font.h"
#include "win32/ClientDeviceContext.h"
#include "win32/DpiUtils.h"
#include "RegViewPage.h"

#define CLSNAME _T("CRegViewPage")

CRegViewPage::CRegViewPage(HWND hParent, const RECT& rect)
    : m_font(Framework::Win32::CreateFont(_T("Courier New"), 8))
{
	//Fill in render metrics
	{
		auto fontSize = GetFixedFontSize(m_font);
		m_renderMetrics.xmargin = Framework::Win32::PointsToPixels(6);
		m_renderMetrics.yspace = Framework::Win32::PointsToPixels(4);
		m_renderMetrics.ymargin = Framework::Win32::PointsToPixels(5);
		m_renderMetrics.fontSizeX = fontSize.cx;
		m_renderMetrics.fontSizeY = fontSize.cy;
	}

	if(!DoesWindowClassExist(CLSNAME))
	{
		WNDCLASSEX w;
		memset(&w, 0, sizeof(WNDCLASSEX));
		w.cbSize = sizeof(WNDCLASSEX);
		w.lpfnWndProc = CWindow::WndProc;
		w.lpszClassName = CLSNAME;
		w.hbrBackground = NULL;
		w.hInstance = GetModuleHandle(NULL);
		w.hCursor = LoadCursor(NULL, IDC_ARROW);
		RegisterClassEx(&w);
	}

	Create(0, CLSNAME, _T(""), WS_CHILD | WS_VSCROLL, rect, hParent, NULL);
	SetClassPtr();
}

void CRegViewPage::SetDisplayText(const char* text)
{
	m_text = text;
	UpdateScroll();
}

void CRegViewPage::Update()
{
	UpdateScroll();
	Redraw();
}

long CRegViewPage::OnVScroll(unsigned int nType, unsigned int nThumbPos)
{
	unsigned int nPosition = GetScrollPosition();
	switch(nType)
	{
	case SB_LINEDOWN:
		nPosition++;
		break;
	case SB_LINEUP:
		nPosition--;
		break;
	case SB_PAGEDOWN:
		nPosition += 10;
		break;
	case SB_PAGEUP:
		nPosition -= 10;
		break;
	case SB_THUMBPOSITION:
	case SB_THUMBTRACK:
		nPosition = GetScrollThumbPosition();
		break;
	default:
		return FALSE;
		break;
	}

	SCROLLINFO si;
	memset(&si, 0, sizeof(SCROLLINFO));
	si.cbSize = sizeof(SCROLLINFO);
	si.nPos = nPosition;
	si.fMask = SIF_POS;
	SetScrollInfo(m_hWnd, SB_VERT, &si, TRUE);

	Redraw();
	return TRUE;
}

long CRegViewPage::OnSize(unsigned int nX, unsigned int nY, unsigned int nType)
{
	Framework::Win32::CCustomDrawn::OnSize(nX, nY, nType);
	Update();
	return TRUE;
}

long CRegViewPage::OnMouseWheel(int x, int y, short z)
{
	if(z < 0)
	{
		OnVScroll(SB_LINEDOWN, 0);
	}
	else
	{
		OnVScroll(SB_LINEUP, 0);
	}
	return TRUE;
}

long CRegViewPage::OnLeftButtonDown(int nX, int nY)
{
	SetFocus();
	return TRUE;
}

unsigned int CRegViewPage::GetLineCount(const char* sText)
{
	unsigned int nLines = 0;

	const char* sNext = strchr(sText, '\n');
	while(sNext != NULL)
	{
		nLines++;
		sNext = strchr(sNext + 1, '\n');
	}

	return nLines;
}

unsigned int CRegViewPage::GetVisibleLineCount()
{
	auto clientRect = GetClientRect();
	unsigned int lineStep = (m_renderMetrics.fontSizeY + m_renderMetrics.yspace);
	unsigned int lines = (clientRect.Bottom() - (m_renderMetrics.ymargin * 2)) / lineStep;
	return lines;
}

void CRegViewPage::Paint(HDC hDC)
{
	RECT rwin = GetClientRect();

	BitBlt(hDC, 0, 0, rwin.right, rwin.bottom, NULL, 0, 0, WHITENESS);

	unsigned int nFontCY = m_renderMetrics.fontSizeY;
	unsigned int nTotal = GetVisibleLineCount();
	unsigned int nScrollPos = GetScrollPosition();

	SelectObject(hDC, m_font);

	unsigned int nCurrent = 0;
	unsigned int nCount = 0;
	unsigned int nX = m_renderMetrics.xmargin;
	unsigned int nY = m_renderMetrics.ymargin;

	const char* sLine = m_text.c_str();
	while(sLine != NULL)
	{
		const char* sNext = strchr(sLine, '\n');
		if(sNext != NULL)
		{
			sNext++;
		}

		if(nCurrent < nScrollPos)
		{
			nCurrent++;
			sLine = sNext;
			continue;
		}

		int textLength = (sNext == NULL) ? strlen(sLine) : static_cast<int>(sNext - sLine - 2);
		DrawTextA(hDC, sLine, textLength, Framework::Win32::CRect(nX, nY, nX, nY), DT_NOCLIP | DT_EXPANDTABS);
		nY += (nFontCY + m_renderMetrics.yspace);

		nCurrent++;
		sLine = sNext;

		nCount++;
		if(nCount >= nTotal)
		{
			break;
		}
	}
}

void CRegViewPage::UpdateScroll()
{
	int nTotal = GetLineCount(m_text.c_str()) - GetVisibleLineCount();

	if(nTotal < 0)
	{
		nTotal = 0;
	}

	SCROLLINFO si;
	memset(&si, 0, sizeof(SCROLLINFO));
	si.cbSize = sizeof(SCROLLINFO);
	si.fMask = SIF_RANGE;
	si.nMin = 0;
	si.nMax = nTotal;
	SetScrollInfo(m_hWnd, SB_VERT, &si, TRUE);
}

unsigned int CRegViewPage::GetScrollPosition()
{
	SCROLLINFO si;
	memset(&si, 0, sizeof(SCROLLINFO));
	si.cbSize = sizeof(SCROLLINFO);
	si.fMask = SIF_POS;
	GetScrollInfo(m_hWnd, SB_VERT, &si);
	return si.nPos;
}

unsigned int CRegViewPage::GetScrollThumbPosition()
{
	SCROLLINFO si;
	memset(&si, 0, sizeof(SCROLLINFO));
	si.cbSize = sizeof(SCROLLINFO);
	si.fMask = SIF_TRACKPOS;
	GetScrollInfo(m_hWnd, SB_VERT, &si);
	return si.nTrackPos;
}