#include "LayeredWindow.h"

namespace ezui {

	std::vector<LayeredWindow*> g_layeredWnds;
	Timer g_layeredWndTimer;

	//WS_EX_LAYERED | WS_EX_NOACTIVATE | WS_EX_TRANSPARENT
	LayeredWindow::LayeredWindow(int width, int height, HWND owner, DWORD dwStyle, DWORD dwExStyle) :BorderlessWindow(width, height, owner, dwStyle, dwExStyle | WS_EX_LAYERED)
	{
		//初始化全局绘制计时器
		if (g_layeredWndTimer.Tick == NULL) {
			g_layeredWndTimer.Interval = 5;
			g_layeredWndTimer.Tick = [](Timer* t) {
				t->Stop();
				Invoke([]() {
					for (auto& it : g_layeredWnds) {
						it->Paint();
					}
					});
				};
		}
		//添加到全局绘制队列
		g_layeredWnds.push_back(this);
		//获取公共数据
		auto* publicData = this->GetPublicData();
		publicData->InvalidateRect = [this](const Rect& rect) ->void {
			//标记窗口无效区域
			this->InvalidateRect(rect);
			};
		publicData->Refresh = [this]()->void {
			//立即更新窗口中的无效区域
			this->Paint();
			};
		//获取客户区大小 创建一个位图给窗口绘制
		Size sz = GetClientRect().GetSize();
		m_winBitmap = new Bitmap(sz.Width, sz.Height);
	}
	LayeredWindow::~LayeredWindow() {
		if (m_winBitmap) {
			delete m_winBitmap;
		}
		//从全局中移除
		auto itor = std::find(g_layeredWnds.begin(), g_layeredWnds.end(), this);
		if (itor != g_layeredWnds.end()) {
			g_layeredWnds.erase(itor);
		}
	}

	void LayeredWindow::InvalidateRect(const Rect& _rect) {
		//将此区域添加到无效区域
		m_invalidateRect.push_back(_rect);
		//timer延迟绘制
		g_layeredWndTimer.Start();
	}

	void LayeredWindow::BeginPaint(Rect* out_rect)
	{
		const Rect& clientRect = GetClientRect();
		int Width = clientRect.Width;
		int Height = clientRect.Height;
		//将所有无效区域并集
		for (auto& it : m_invalidateRect) {
			Rect rect = it;
			//这段代码是保证重绘区域一定是在窗口内
			if (rect.X < 0) {
				rect.Width += rect.X;
				rect.X = 0;
				if (rect.Width < 0) rect.Width = 0;
			}
			if (rect.Y < 0) {
				rect.Height += rect.Y;
				rect.Y = 0;
				if (rect.Height < 0) rect.Height = 0;
			}
			if (rect.GetRight() > Width) {
				rect.Width = Width - rect.X;
				if (rect.Width < 0) rect.Width = 0;
			}
			if (rect.GetBottom() > Height) {
				rect.Height = Height - rect.Y;
				if (rect.Height < 0) rect.Height = 0;
			}
			//并集
			Rect::Union(*out_rect, *out_rect, rect);
		}
	}
	void LayeredWindow::EndPaint()
	{
		m_invalidateRect.clear();
	}
	void LayeredWindow::Paint()
	{
		if (IsVisible()) {
			Rect invalidateRect;
			BeginPaint(&invalidateRect);
			if ((m_winBitmap && !invalidateRect.IsEmptyArea())) {
				m_winBitmap->Earse(invalidateRect);//清除背景
				HDC winHDC = m_winBitmap->GetDC();
#if 1
				//不使用双缓冲
				DoPaint(winHDC, invalidateRect);
#else
				//使用双缓冲
				Bitmap doubleBuff(m_winBitmap->Width(), m_winBitmap->Height());
				DoPaint(doubleBuff.GetHDC(), invalidateRect);
				//使用BitBlt函数进行复制到winHDC  //如果窗体不规则 不适用于BitBlt进行复制
				::BitBlt(winHDC, invalidateRect.X, invalidateRect.Y,
					invalidateRect.Width, invalidateRect.Height,
					doubleBuff.GetHDC(), invalidateRect.X, invalidateRect.Y,
					SRCCOPY);
#endif
				UpdateLayeredWindow(winHDC);//updatelaredwindow 更新窗口
				EndPaint();
			}
		}
	}
	LRESULT LayeredWindow::WndProc(UINT uMsg, WPARAM wParam, LPARAM lParam)
	{
		switch (uMsg)
		{
		default:
			break;
		}
		return __super::WndProc(uMsg, wParam, lParam);
	}
	void LayeredWindow::OnSize(const Size& sz) {
		__super::OnSize(sz);
		if (m_winBitmap) {
			delete m_winBitmap;
		}
		m_winBitmap = new Bitmap(sz.Width, sz.Height);
		Invalidate();
	}

	void LayeredWindow::UpdateLayeredWindow(HDC hdc) {
		const Rect& _rectClient = GetClientRect();
		POINT point{ _rectClient.X,_rectClient.Y };
		SIZE size{ _rectClient.Width,  _rectClient.Height };
		BLENDFUNCTION blendFunc{ 0 };
		blendFunc.SourceConstantAlpha = 255 * this->Opacity;
		blendFunc.BlendOp = AC_SRC_OVER;
		blendFunc.AlphaFormat = AC_SRC_ALPHA;
		blendFunc.BlendFlags = 0;
		::UpdateLayeredWindow(Hwnd(), NULL, NULL, &size, hdc, &point, 0, &blendFunc, ULW_ALPHA);//透明
	}
}