#include "framelesswindow.h"
#include <QApplication>
#include <QPoint>
#include <QSize>
#ifdef Q_OS_WIN

#include <windows.h>
#include <WinUser.h>
#include <windowsx.h>
#include <dwmapi.h>
#include <objidl.h> // Fixes error C2504: 'IUnknown' : base class undefined
#include <gdiplus.h>
#include <GdiPlusColor.h>
#pragma comment (lib,"Dwmapi.lib") // Adds missing library, fixes error LNK2019: unresolved external symbol __imp__DwmExtendFrameIntoClientArea
#pragma comment (lib,"user32.lib")

CFramelessWindow::CFramelessWindow(QWidget *parent)
 : QMainWindow(parent),
 m_titlebar(Q_NULLPTR),
 m_borderWidth(5),
 m_bJustMaximized(false),
 m_bResizeable(true)
{
// setWindowFlag(Qt::Window,true);
// setWindowFlag(Qt::FramelessWindowHint, true);
// setWindowFlag(Qt::WindowSystemMenuHint, true);
// setWindowFlag() is not avaliable before Qt v5.9, so we should use setWindowFlags instead

 setWindowFlags(windowFlags() | Qt::Window | Qt::FramelessWindowHint | Qt::WindowSystemMenuHint);

 setResizeable(m_bResizeable);
}

void CFramelessWindow::setResizeable(bool resizeable)
{
 bool visible = isVisible();
 m_bResizeable = resizeable;
 if (m_bResizeable){
 setWindowFlags(windowFlags() | Qt::WindowMaximizeButtonHint);
// setWindowFlag(Qt::WindowMaximizeButtonHint);

 //此行代码可以带回Aero效果,同时也带回了标题栏和边框,在nativeEvent()会再次去掉标题栏
 //
 //this line will get titlebar/thick frame/Aero back, which is exactly what we want
 //we will get rid of titlebar and thick frame again in nativeEvent() later
 HWND hwnd = (HWND)this->winId();
 DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);
 ::SetWindowLong(hwnd, GWL_STYLE, style | WS_MAXIMIZEBOX | WS_THICKFRAME | WS_CAPTION);
 }else{
 setWindowFlags(windowFlags() & ~Qt::WindowMaximizeButtonHint);
// setWindowFlag(Qt::WindowMaximizeButtonHint,false);

 HWND hwnd = (HWND)this->winId();
 DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);
 ::SetWindowLong(hwnd, GWL_STYLE, style & ~WS_MAXIMIZEBOX & ~WS_CAPTION);
 }

 //保留一个像素的边框宽度,否则系统不会绘制边框阴影
 //
 //we better left 1 piexl width of border untouch, so OS can draw nice shadow around it
 const MARGINS shadow = { 1, 1, 1, 1 };
 DwmExtendFrameIntoClientArea(HWND(winId()), &shadow);

 setVisible(visible);
}

void CFramelessWindow::setResizeableAreaWidth(int width)
{
 if (1 > width) width = 1;
 m_borderWidth = width;
}

void CFramelessWindow::setTitleBar(QWidget* titlebar)
{
 m_titlebar = titlebar;
 if (!titlebar) return;
 connect(titlebar, SIGNAL(destroyed(QObject*)), this, SLOT(onTitleBarDestroyed()));
}

void CFramelessWindow::onTitleBarDestroyed()
{
 if (m_titlebar == QObject::sender())
 {
 m_titlebar = Q_NULLPTR;
 }
}

void CFramelessWindow::addIgnoreWidget(QWidget* widget)
{
 if (!widget) return;
 if (m_whiteList.contains(widget)) return;
 m_whiteList.append(widget);
}

bool CFramelessWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
 //Workaround for known bug -> check Qt forum : https://forum.qt.io/topic/93141/qtablewidget-itemselectionchanged/13
 #if (QT_VERSION == QT_VERSION_CHECK(5, 11, 1))
 MSG* msg = *reinterpret_cast<MSG**>(message);
 #else
 MSG* msg = reinterpret_cast<MSG*>(message);
 #endif
 
 switch (msg->message)
 {
 case WM_NCCALCSIZE:
 {
 NCCALCSIZE_PARAMS& params = *reinterpret_cast<NCCALCSIZE_PARAMS*>(msg->lParam);
 	if (params.rgrc[0].top != 0)
		params.rgrc[0].top -= 1;

 //this kills the window frame and title bar we added with WS_THICKFRAME and WS_CAPTION
 *result = WVR_REDRAW;
 return true;
 }
 case WM_NCHITTEST:
 {
 *result = 0;

 const LONG border_width = m_borderWidth;
 RECT winrect;
 GetWindowRect(HWND(winId()), &winrect);

 long x = GET_X_LPARAM(msg->lParam);
 long y = GET_Y_LPARAM(msg->lParam);

 if(m_bResizeable)
 {

 bool resizeWidth = minimumWidth() != maximumWidth();
 bool resizeHeight = minimumHeight() != maximumHeight();

 if(resizeWidth)
 {
 //left border
 if (x >= winrect.left && x < winrect.left + border_width)
 {
 *result = HTLEFT;
 }
 //right border
 if (x < winrect.right && x >= winrect.right - border_width)
 {
 *result = HTRIGHT;
 }
 }
 if(resizeHeight)
 {
 //bottom border
 if (y < winrect.bottom && y >= winrect.bottom - border_width)
 {
 *result = HTBOTTOM;
 }
 //top border
 if (y >= winrect.top && y < winrect.top + border_width)
 {
 *result = HTTOP;
 }
 }
 if(resizeWidth && resizeHeight)
 {
 //bottom left corner
 if (x >= winrect.left && x < winrect.left + border_width &&
 y < winrect.bottom && y >= winrect.bottom - border_width)
 {
 *result = HTBOTTOMLEFT;
 }
 //bottom right corner
 if (x < winrect.right && x >= winrect.right - border_width &&
 y < winrect.bottom && y >= winrect.bottom - border_width)
 {
 *result = HTBOTTOMRIGHT;
 }
 //top left corner
 if (x >= winrect.left && x < winrect.left + border_width &&
 y >= winrect.top && y < winrect.top + border_width)
 {
 *result = HTTOPLEFT;
 }
 //top right corner
 if (x < winrect.right && x >= winrect.right - border_width &&
 y >= winrect.top && y < winrect.top + border_width)
 {
 *result = HTTOPRIGHT;
 }
 }
 }
 if (0!=*result) return true;

 //*result still equals 0, that means the cursor locate OUTSIDE the frame area
 //but it may locate in titlebar area
 if (!m_titlebar) return false;

 //support highdpi
 double dpr = this->devicePixelRatioF();
 QPoint pos = m_titlebar->mapFromGlobal(QPoint(x/dpr,y/dpr));

 if (!m_titlebar->rect().contains(pos)) return false;
 QWidget* child = m_titlebar->childAt(pos);
 if (!child)
 {
 *result = HTCAPTION;
 return true;
 }else{
 if (m_whiteList.contains(child))
 {
 *result = HTCAPTION;
 return true;
 }
 }
 return false;
 } //end case WM_NCHITTEST
 case WM_GETMINMAXINFO:
 {
 if (::IsZoomed(msg->hwnd)) {
 RECT frame = { 0, 0, 0, 0 };
 AdjustWindowRectEx(&frame, WS_OVERLAPPEDWINDOW, FALSE, 0);

 //record frame area data
 double dpr = this->devicePixelRatioF();

 m_frames.setLeft(abs(frame.left)/dpr+0.5);
 m_frames.setTop(abs(frame.bottom)/dpr+0.5);
 m_frames.setRight(abs(frame.right)/dpr+0.5);
 m_frames.setBottom(abs(frame.bottom)/dpr+0.5);

 QMainWindow::setContentsMargins(m_frames.left()+m_margins.left(), \
 m_frames.top()+m_margins.top(), \
 m_frames.right()+m_margins.right(), \
 m_frames.bottom()+m_margins.bottom());
 m_bJustMaximized = true;
 }else {
 if (m_bJustMaximized)
 {
 QMainWindow::setContentsMargins(m_margins);
 m_frames = QMargins();
 m_bJustMaximized = false;
 }
 }
 return false;
 }
 default:
 return QMainWindow::nativeEvent(eventType, message, result);
 }
}

void CFramelessWindow::setContentsMargins(const QMargins &margins)
{
 QMainWindow::setContentsMargins(margins+m_frames);
 m_margins = margins;
}
void CFramelessWindow::setContentsMargins(int left, int top, int right, int bottom)
{
 QMainWindow::setContentsMargins(left+m_frames.left(),\
 top+m_frames.top(), \
 right+m_frames.right(), \
 bottom+m_frames.bottom());
 m_margins.setLeft(left);
 m_margins.setTop(top);
 m_margins.setRight(right);
 m_margins.setBottom(bottom);
}
QMargins CFramelessWindow::contentsMargins() const
{
 QMargins margins = QMainWindow::contentsMargins();
 margins -= m_frames;
 return margins;
}
void CFramelessWindow::getContentsMargins(int *left, int *top, int *right, int *bottom) const
{
 QMainWindow::getContentsMargins(left,top,right,bottom);
 if (!(left&&top&&right&&bottom)) return;
 if (isMaximized())
 {
 *left -= m_frames.left();
 *top -= m_frames.top();
 *right -= m_frames.right();
 *bottom -= m_frames.bottom();
 }
}
QRect CFramelessWindow::contentsRect() const
{
 QRect rect = QMainWindow::contentsRect();
 int width = rect.width();
 int height = rect.height();
 rect.setLeft(rect.left() - m_frames.left());
 rect.setTop(rect.top() - m_frames.top());
 rect.setWidth(width);
 rect.setHeight(height);
 return rect;
}
void CFramelessWindow::showFullScreen()
{
 if (isMaximized())
 {
 QMainWindow::setContentsMargins(m_margins);
 m_frames = QMargins();
 }
 QMainWindow::showFullScreen();
}

#endif //Q_OS_WIN