showcasecore.go

// Copyright (C) 2013 Andras Belicza. All rights reserved.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

// A Gowut "Showcase of Features" application.

package showcasecore

import (
	"fmt"
	"log"
	"time"

	"github.com/icza/gowut/gwu"
)

// plural returns an empty string if i is equal to 1,
// "s" otherwise.
func plural(i int) string {
	if i == 1 {
		return ""
	}
	return "s"
}

func buildHomeDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	content := []string{
		"This app is written in and showcases Gowut " + gwu.GowutVersion + ".",
		"Everything you see here is modeled and represented in Go (server side). Everything is created with Go code only (no HTML).",
		"When you make modifications to components (e.g. enter text into a TextBox), that is automatically trasmitted to the server side via AJAX calls.",
		"If you close the window and reopen the URL, you will see everything as you left it.",
		"What you see and do here is also bound to You (using a Session), others don't see it and they can't interfere with it.",
		"You may notice a small delay between your actions and the result (response). This is due to the network latency: your action needs to be transmitted to the Gowut server, and changed (dirty) components need to be refreshed (re-rendered). Gowut apps that run locally do not have such delays.",
		"Select components on the left side to see them in action.",
	}

	for _, s := range content {
		p.Add(gwu.NewLabel(s))
		p.AddVSpace(20)
	}

	return p
}

func buildExpanderDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	l := gwu.NewLabel("Click on the Expander's header.")
	l.Style().SetColor(gwu.ClrGreen)
	p.Add(l)
	p.AddVSpace(5)
	e := gwu.NewExpander()
	e.SetHeader(gwu.NewLabel("I'm an Expander."))
	e.SetContent(gwu.NewLabel("And I'm the content of the Expander."))
	p.Add(e)
	e.AddEHandlerFunc(func(ev gwu.Event) {
		if e.Expanded() {
			l.SetText("You expanded it.")
		} else {
			l.SetText("You collapsed it.")
		}
		ev.MarkDirty(l)
	}, gwu.ETypeStateChange)

	p.AddVSpace(20)
	var ee gwu.Expander
	for i := 5; i >= 0; i-- {
		e2 := gwu.NewExpander()
		e2.SetHeader(gwu.NewLabel(fmt.Sprintf("I hide embedded expanders. #%d", i)))
		if i == 5 {
			e2.SetContent(gwu.NewLabel("No more."))
		} else {
			e2.SetContent(ee)
		}
		ee = e2
	}
	p.Add(ee)

	return p
}

func buildLinkContainerDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	link := gwu.NewLink("An obvious link, to Google Home", "https://google.com/")
	inside := gwu.NewPanel()
	inside.Style().SetPadding("5px").SetMarginTopPx(2).SetBorder2(1, gwu.BrdStyleSolid, gwu.ClrGray)
	inside.Add(gwu.NewLabel("Everything inside this box also links to Google!"))
	inside.Add(gwu.NewButton("Me too!"))
	link.SetComp(inside)
	p.Add(link)

	return p
}

func buildPanelDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("Panel with horizontal layout:"))
	h := gwu.NewHorizontalPanel()
	for i := 1; i <= 5; i++ {
		h.Add(gwu.NewButton(fmt.Sprintf("Button %d", i)))
	}
	p.Add(h)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Panel with vertical layout:"))
	v := gwu.NewVerticalPanel()
	for i := 1; i <= 5; i++ {
		v.Add(gwu.NewButton(fmt.Sprintf("Button %d", i)))
	}
	p.Add(v)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Panel with natural layout:"))
	n := gwu.NewNaturalPanel()
	for i := 1; i <= 40; i++ {
		n.Add(gwu.NewButton(fmt.Sprintf("LONG BUTTON %d", i)))
	}
	p.Add(n)

	return p
}

func buildTableDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	l := gwu.NewLabel("Tip: Switch to the 'debug' theme (top right) to see cell borders.")
	l.Style().SetColor(gwu.ClrRed).SetFontStyle(gwu.FontStyleItalic)
	p.Add(l)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("A simple form aligned with a table:"))
	p.AddVSpace(10)
	t := gwu.NewTable()
	t.SetCellPadding(2)
	t.EnsureSize(2, 2)
	var c gwu.Comp
	t.Add(gwu.NewLabel("User name:"), 0, 0)
	c = gwu.NewTextBox("")
	c.Style().SetWidthPx(160)
	t.Add(c, 0, 1)
	t.Add(gwu.NewLabel("Password:"), 1, 0)
	c = gwu.NewPasswBox("")
	c.Style().SetWidthPx(160)
	t.Add(c, 1, 1)
	t.Add(gwu.NewLabel("Go to:"), 2, 0)
	c = gwu.NewListBox([]string{"Inbox", "User preferences", "Last visited page"})
	c.Style().SetWidthPx(160)
	t.Add(c, 2, 1)
	p.Add(t)

	p.AddVSpace(30)
	p.Add(gwu.NewLabel("Advanced table structure with modified alignment, row- and col spans:"))
	p.AddVSpace(10)
	t = gwu.NewTable()
	t.Style().SetBorder2(1, gwu.BrdStyleSolid, gwu.ClrGrey)
	t.SetAlign(gwu.HARight, gwu.VATop)
	t.EnsureSize(5, 5)
	for row := 0; row < 5; row++ {
		for col := 0; col < 5; col++ {
			t.Add(gwu.NewButton(fmt.Sprintf("Button %d%d", row, col)), row, col)
		}
	}
	t.SetColSpan(2, 1, 2)
	t.SetRowSpan(3, 1, 2)
	t.CellFmt(2, 2).Style().SetSizePx(150, 80)
	t.CellFmt(2, 2).SetAlign(gwu.HARight, gwu.VABottom)
	t.RowFmt(2).SetAlign(gwu.HADefault, gwu.VAMiddle)
	t.CompAt(2, 1).Style().SetFullSize()
	t.CompAt(4, 2).Style().SetFullWidth()
	t.RowFmt(0).Style().SetBackground(gwu.ClrRed)
	t.RowFmt(1).Style().SetBackground(gwu.ClrGreen)
	t.RowFmt(2).Style().SetBackground(gwu.ClrBlue)
	t.RowFmt(3).Style().SetBackground(gwu.ClrGrey)
	t.RowFmt(4).Style().SetBackground(gwu.ClrTeal)
	p.Add(t)

	return p
}

func buildTabPanelDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	t := gwu.NewTabPanel()
	t.Style().SetSizePx(500, 300)

	table := gwu.NewTable()
	table.SetCellPadding(2)
	table.EnsureSize(3, 2)
	table.Add(gwu.NewLabel("Change tab bar placement:"), 0, 0)
	table.Add(gwu.NewLabel("Tab bar horizontal align:"), 1, 0)
	table.Add(gwu.NewLabel("Tab bar vertical align:"), 2, 0)

	placemslb := gwu.NewListBox([]string{"Top", "Right", "Bottom", "Left"})
	placems := []gwu.TabBarPlacement{gwu.TbPlacementTop, gwu.TbPlacementRight, gwu.TbPlacementBottom, gwu.TbPlacementLeft}
	halignslb := gwu.NewListBox([]string{"Left", "Center", "Right"})
	haligns := []gwu.HAlign{gwu.HALeft, gwu.HACenter, gwu.HARight}
	valignslb := gwu.NewListBox([]string{"Top", "Middle", "Bottom"})
	valigns := []gwu.VAlign{gwu.VATop, gwu.VAMiddle, gwu.VABottom}
	placemslb.Style().SetFullWidth()
	halignslb.Style().SetFullWidth()
	valignslb.Style().SetFullWidth()
	table.Add(placemslb, 0, 1)
	table.Add(halignslb, 1, 1)
	table.Add(valignslb, 2, 1)

	placemslb.AddEHandlerFunc(func(e gwu.Event) {
		t.SetTabBarPlacement(placems[placemslb.SelectedIdx()])
		e.MarkDirty(t)
	}, gwu.ETypeChange)
	halignslb.AddEHandlerFunc(func(e gwu.Event) {
		t.TabBarFmt().SetHAlign(haligns[halignslb.SelectedIdx()])
		e.MarkDirty(t)
	}, gwu.ETypeChange)
	valignslb.AddEHandlerFunc(func(e gwu.Event) {
		t.TabBarFmt().SetVAlign(valigns[valignslb.SelectedIdx()])
		e.MarkDirty(t)
	}, gwu.ETypeChange)

	p.Add(table)

	fix := gwu.NewCheckBox("Fixed size")
	fix.SetState(true)
	fix.AddEHandlerFunc(func(e gwu.Event) {
		if fix.State() {
			t.Style().SetSizePx(500, 300)
		} else {
			t.Style().SetSize("", "")
		}
		e.MarkDirty(t)
	}, gwu.ETypeClick)
	p.Add(fix)

	p.AddVSpace(10)
	l := gwu.NewLabel("Click on tabs...")
	l.Style().SetColor(gwu.ClrGreen)
	p.Add(l)
	t.AddEHandlerFunc(func(e gwu.Event) {
		l.SetText(fmt.Sprintf("Clicked on tab: %d", t.Selected()))
		e.MarkDirty(l)
	}, gwu.ETypeStateChange)
	p.AddVSpace(10)
	c := gwu.NewPanel()
	c.Add(gwu.NewLabel("This is a TabPanel."))
	c.Add(gwu.NewLabel("Click on other tabs to see their content."))
	c.AddVSpace(15)
	c.Add(gwu.NewLabel("Or click here to see what's in the Hollow:"))
	b := gwu.NewButton("Take me to the Hollow!")
	b.AddEHandlerFunc(func(e gwu.Event) {
		t.SetSelected(3)
		e.MarkDirty(t)
	}, gwu.ETypeClick)
	c.Add(b)
	t.AddString("Home", c)
	c = gwu.NewPanel()
	c.Add(gwu.NewLabel("You have no new messages."))
	t.AddString("Inbox", c)
	c = gwu.NewPanel()
	c.Add(gwu.NewLabel("You have no sent messages."))
	t.AddString("Sent", c)
	c = gwu.NewPanel()
	c.Add(gwu.NewLabel("There is nothing in the hollow."))
	t.AddString("Hollow", c)
	c = gwu.NewPanel()
	tb := gwu.NewTextBox("Click to edit this comment.")
	tb.SetRows(10)
	tb.SetCols(40)
	c.Add(tb)
	t.AddString("Comment", c)
	p.Add(t)

	return p
}

func buildWindowDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("The Window represents the whole window, the page inside the browser."))
	p.AddVSpace(20)
	p.Add(gwu.NewLabel("The Window is the top of the component hierarchy. It is an extension of the Panel."))

	return p
}

func buildCheckBoxDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	suml := gwu.NewLabel("")

	p.Add(gwu.NewLabel("Check the days you want to work on:"))

	cbs := []gwu.CheckBox{gwu.NewCheckBox("Monday"), gwu.NewCheckBox("Tuesday"), gwu.NewCheckBox("Wednesday"),
		gwu.NewCheckBox("Thursday"), gwu.NewCheckBox("Friday"), gwu.NewCheckBox("Saturday"), gwu.NewCheckBox("Sunday")}
	cbs[5].SetEnabled(false)
	cbs[6].SetEnabled(false)

	for _, cb := range cbs {
		p.Add(cb)
		cb.AddEHandlerFunc(func(e gwu.Event) {
			sum := 0
			for _, cb2 := range cbs {
				if cb2.State() {
					sum++
				}
			}
			suml.SetText(fmt.Sprintf("%d day%s is a total of %d hours a week.", sum, plural(sum), sum*8))
			e.MarkDirty(suml)
		}, gwu.ETypeClick)
	}

	p.Add(suml)

	return p
}

func buildListBoxDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	row := gwu.NewHorizontalPanel()
	l := gwu.NewLabel("Select a background color:")
	row.Add(l)
	lb := gwu.NewListBox([]string{"", "Black", "Red", "Green", "Blue", "White"})
	lb.AddEHandlerFunc(func(e gwu.Event) {
		l.Style().SetBackground(lb.SelectedValue())
		e.MarkDirty(l)
	}, gwu.ETypeChange)
	row.Add(lb)
	p.Add(row)

	p.AddVSpace(10)
	p.Add(gwu.NewLabel("Select numbers that add up to 89: (hold down the CTRL while selecting)"))
	sumLabel := gwu.NewLabel("")
	lb2 := gwu.NewListBox([]string{"1", "2", "4", "8", "16", "32", "64", "128"})
	lb2.SetMulti(true)
	lb2.SetRows(10)
	lb2.AddEHandlerFunc(func(e gwu.Event) {
		sum := 0
		for _, idx := range lb2.SelectedIndices() {
			sum += 1 << uint(idx)
		}
		if sum == 89 {
			sumLabel.SetText("Hooray! You did it!")
		} else {
			sumLabel.SetText(fmt.Sprintf("Now quite there... (sum = %d)", sum))
		}
		e.MarkDirty(sumLabel)
	}, gwu.ETypeChange)
	p.Add(lb2)
	p.Add(sumLabel)

	return p
}

func buildTextBoxDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("Enter your name (max 15 characters):"))
	row := gwu.NewHorizontalPanel()
	tb := gwu.NewTextBox("")
	tb.SetMaxLength(15)
	tb.AddSyncOnETypes(gwu.ETypeKeyUp)
	length := gwu.NewLabel("")
	length.Style().SetFontSize("80%").SetFontStyle(gwu.FontStyleItalic)
	tb.AddEHandlerFunc(func(e gwu.Event) {
		rem := 15 - len(tb.Text())
		length.SetText(fmt.Sprintf("(%d character%s left...)", rem, plural(rem)))
		e.MarkDirty(length)
	}, gwu.ETypeChange, gwu.ETypeKeyUp)
	row.Add(tb)
	row.Add(length)
	p.Add(row)

	p.AddVSpace(10)
	p.Add(gwu.NewLabel("Short biography:"))
	bio := gwu.NewTextBox("")
	bio.SetRows(5)
	bio.SetCols(40)
	p.Add(bio)

	p.AddVSpace(10)
	rtb := gwu.NewTextBox("This is just a read-only text box...")
	rtb.SetReadOnly(true)
	p.Add(rtb)

	p.AddVSpace(10)
	dtb := gwu.NewTextBox("...and a disabled one.")
	dtb.SetEnabled(false)
	p.Add(dtb)

	return p
}

func buildPasswBoxDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("Enter your password:"))
	p.Add(gwu.NewPasswBox(""))

	return p
}

func buildRadioButtonDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("Select your favorite programming language:"))

	group := gwu.NewRadioGroup("lang")
	rbs := []gwu.RadioButton{gwu.NewRadioButton("Go", group), gwu.NewRadioButton("Java", group), gwu.NewRadioButton("C / C++", group),
		gwu.NewRadioButton("Python", group), gwu.NewRadioButton("QBasic (nah this can't be your favorite)", group)}
	rbs[4].SetEnabled(false)

	for _, rb := range rbs {
		p.Add(rb)
	}

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Select your favorite computer game:"))

	group = gwu.NewRadioGroup("game")
	rbs = []gwu.RadioButton{gwu.NewRadioButton("StarCraft II", group), gwu.NewRadioButton("Minecraft", group),
		gwu.NewRadioButton("Other", group)}

	for _, rb := range rbs {
		p.Add(rb)
	}

	return p
}

func buildSwitchButtonDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()
	p.SetCellPadding(1)

	row := gwu.NewHorizontalPanel()
	row.Add(gwu.NewLabel("Here's an ON/OFF switch which enables/disables the other one:"))
	sw := gwu.NewSwitchButton()
	sw.SetOnOff("ENB", "DISB")
	sw.SetState(true)
	row.Add(sw)
	p.Add(row)

	p.AddVSpace(10)
	row = gwu.NewHorizontalPanel()
	row.Add(gwu.NewLabel("And the other one:"))
	sw2 := gwu.NewSwitchButton()
	sw2.SetEnabled(true)
	sw2.Style().SetWidthPx(100)
	row.Add(sw2)
	sw.AddEHandlerFunc(func(e gwu.Event) {
		sw2.SetEnabled(sw.State())
		e.MarkDirty(sw2)
	}, gwu.ETypeClick)
	p.Add(row)

	return p
}

func buildButtonDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	l := gwu.NewLabel("")

	btnp := gwu.NewHorizontalPanel()
	b := gwu.NewButton("Normal Button")
	b.AddEHandlerFunc(func(e gwu.Event) {
		switch e.Type() {
		case gwu.ETypeMouseOver:
			l.SetText("Mouse is over...")
		case gwu.ETypeMouseOut:
			l.SetText("Mouse is out.")
		case gwu.ETypeClick:
			x, y := e.Mouse()
			l.SetText(fmt.Sprintf("Clicked at x=%d, y=%d", x, y))
		}
		e.MarkDirty(l)
	}, gwu.ETypeClick, gwu.ETypeMouseOver, gwu.ETypeMouseOut)
	btnp.Add(b)

	b = gwu.NewButton("Disabled Button")
	b.SetEnabled(false)
	btnp.Add(b)

	p.Add(btnp)

	p.Add(l)

	return p
}

func buildHTMLDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	html := `<span onclick="alert('Hi from HTML!');">Hi! I'm inserted as HTML. Click on me!</span>`

	p.Add(gwu.NewLabel("The following HTML code is inserted after the text box as an HTML component:"))
	ta := gwu.NewTextBox(html)
	ta.SetReadOnly(true)
	ta.Style().SetWidthPx(500)
	ta.SetRows(4)
	p.Add(ta)

	p.AddVSpace(20)
	h := gwu.NewHTML(html)
	p.Add(h)

	return p
}

func buildImageDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("Google's logo:"))
	img := gwu.NewImage("Google's logo", "https://www.google.com/images/srpr/logo3w.png")
	img.Style().SetSizePx(275, 95)
	p.Add(img)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Go's Gopher:"))
	img = gwu.NewImage("Go's Gopher", "https://golang.org/doc/gopher/frontpage.png")
	img.Style().SetSizePx(250, 340)
	p.Add(img)

	return p
}

func buildLabelDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("This is a Label."))
	p.Add(gwu.NewLabel("世界 And another one. ㅈㅈ"))
	p.Add(gwu.NewLabel("Nothing special about them, but they may be the mostly used components."))

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("You can change their text:"))
	b := gwu.NewButton("Change!")
	b.AddEHandlerFunc(func(e gwu.Event) {
		for i := 0; i < p.CompsCount(); i++ {
			if l, ok := p.CompAt(i).(gwu.Label); ok && l != b {
				reversed := []rune(l.Text())
				for i, j := 0, len(reversed)-1; i < j; i, j = i+1, j-1 {
					reversed[i], reversed[j] = reversed[j], reversed[i]
				}
				l.SetText(string(reversed))
			}
		}
		e.MarkDirty(p)
	}, gwu.ETypeClick)
	p.Add(b)

	return p
}

func buildLinkDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()
	p.SetCellPadding(3)

	p.Add(gwu.NewLink("Visit the Gowut Wiki", "https://github.com/icza/gowut/wiki"))
	p.Add(gwu.NewLink("Visit the Gowut Project page", "https://github.com/icza/gowut"))

	row := gwu.NewHorizontalPanel()
	row.SetCellPadding(3)
	row.Add(gwu.NewLabel("Discussion forum:"))
	row.Add(gwu.NewLink("https://groups.google.com/d/forum/gowebuitoolkit", "https://groups.google.com/d/forum/gowebuitoolkit"))
	p.Add(row)

	row = gwu.NewHorizontalPanel()
	row.SetCellPadding(3)
	row.Add(gwu.NewLabel("Send e-mail to the Gowut author:"))
	emailBytes := []byte("jd{bbbAhnbjm/dpn")
	for i, v := range emailBytes {
		emailBytes[i] = v - 1
	}
	email := string(emailBytes)
	row.Add(gwu.NewLink("András Belicza <"+email+">", "mailto:"+email))
	p.Add(row)

	return p
}

func buildSessMonitorDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()

	p.Add(gwu.NewLabel("The SessMonitor component monitors and displays the session timeout and network connectivity without interacting with the session."))
	p.AddVSpace(20)
	p.Add(gwu.NewLabel("An example SessMonitor can be viewed on the right side of the header."))

	return p
}

func buildTimerDemo(event gwu.Event) gwu.Comp {
	p := gwu.NewPanel()
	p.SetCellPadding(3)

	// Add timers to a panel which is always attached instead of our panel
	// because the user can switch to another component demo causing this panel to be removed
	// and that way timer events would address components that are not part of the window (returning error).
	hiddenPan := event.Session().Attr("hiddenPan").(gwu.Panel)

	p.Add(gwu.NewLabel("A Timer is used to detonate a bomb after 3 seconds."))
	p.AddVSpace(10)
	defText := "You can defuse the bomb with the button below. Tick... Tack..."
	l := gwu.NewLabel(defText)
	p.Add(l)
	t := gwu.NewTimer(3 * time.Second)
	b := gwu.NewButton("Defuse!")
	t.AddEHandlerFunc(func(e gwu.Event) {
		l.SetText("BOOOOM! You were too slow!")
		l.Style().SetColor(gwu.ClrRed)
		b.SetEnabled(false)
		e.MarkDirty(l, b)
	}, gwu.ETypeStateChange)
	hiddenPan.Add(t)
	row := gwu.NewHorizontalPanel()
	b.AddEHandlerFunc(func(e gwu.Event) {
		t.SetActive(false)
		l.SetText("Bomb defused! Phew! Good Job!")
		l.Style().SetColor(gwu.ClrGreen)
		b.SetEnabled(false)
		e.MarkDirty(t, l, b)
	}, gwu.ETypeClick)
	row.Add(b)
	b2 := gwu.NewButton("Plant a new Bomb!")
	b2.AddEHandlerFunc(func(e gwu.Event) {
		t.SetActive(true)
		t.Reset()
		l.SetText(defText)
		l.Style().SetColor("")
		b.SetEnabled(true)
		e.MarkDirty(t, l, b)
	}, gwu.ETypeClick)
	row.Add(b2)
	p.Add(row)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("A Timer is used to refresh the time below repeatedly in every second for half a minute."))
	tl := gwu.NewLabel("")
	p.Add(tl)
	t2 := gwu.NewTimer(time.Second)
	t2.SetRepeat(true)
	counter := 30
	t2.AddEHandlerFunc(func(e gwu.Event) {
		counter--
		tl.SetText(fmt.Sprintf("%s (%d remaining)", time.Now().Format("2006-01-02 15:04:05"), counter))
		e.MarkDirty(tl)
		if counter <= 0 {
			t2.SetActive(false)
			e.MarkDirty(t2)
		}
	}, gwu.ETypeStateChange)
	hiddenPan.Add(t2)
	b3 := gwu.NewButton("Restart")
	b3.AddEHandlerFunc(func(e gwu.Event) {
		counter = 30
		t2.SetActive(true)
		e.MarkDirty(t2)
	}, gwu.ETypeClick)
	p.Add(b3)

	event.MarkDirty(hiddenPan)

	return p
}

type demo struct {
	link      gwu.Label
	buildFunc func(gwu.Event) gwu.Comp
	comp      gwu.Comp // Lazily initialized demo comp
}
type pdemo *demo

var extraHeadHTMLs []string

func buildShowcaseWin(sess gwu.Session) {
	win := gwu.NewWindow("show", "Showcase of Features - Gowut")
	for _, headHTML := range extraHeadHTMLs {
		win.AddHeadHTML(headHTML)
	}

	win.Style().SetFullSize()
	win.AddEHandlerFunc(func(e gwu.Event) {
		switch e.Type() {
		case gwu.ETypeWinLoad:
			log.Println("LOADING window:", e.Src().ID())
		case gwu.ETypeWinUnload:
			log.Println("UNLOADING window:", e.Src().ID())
		}
	}, gwu.ETypeWinLoad, gwu.ETypeWinUnload)

	hiddenPan := gwu.NewNaturalPanel()
	sess.SetAttr("hiddenPan", hiddenPan)

	header := gwu.NewHorizontalPanel()
	header.Style().SetFullWidth().SetBorderBottom2(2, gwu.BrdStyleSolid, "#cccccc")
	title := gwu.NewLink("Gowut - Showcase of Features", win.Name())
	title.SetTarget("")
	title.Style().SetColor(gwu.ClrBlue).SetFontWeight(gwu.FontWeightBold).SetFontSize("120%").Set("text-decoration", "none")
	header.Add(title)
	header.AddHConsumer()
	header.Add(gwu.NewLabel("Session timeout:"))
	header.Add(gwu.NewSessMonitor())
	header.AddHSpace(10)
	header.Add(gwu.NewLabel("Theme:"))
	themes := gwu.NewListBox([]string{"default", "debug"})
	themes.AddEHandlerFunc(func(e gwu.Event) {
		win.SetTheme(themes.SelectedValue())
		e.ReloadWin("show")
	}, gwu.ETypeChange)
	header.Add(themes)
	header.AddHSpace(10)
	reset := gwu.NewLink("Reset", "#")
	reset.Style().SetColor(gwu.ClrBlue)
	reset.SetTarget("")
	reset.AddEHandlerFunc(func(e gwu.Event) {
		e.RemoveSess()
		e.ReloadWin("show")
	}, gwu.ETypeClick)
	header.Add(reset)
	setNoWrap(header)
	win.Add(header)

	content := gwu.NewHorizontalPanel()
	content.SetCellPadding(1)
	content.SetVAlign(gwu.VATop)
	content.Style().SetFullSize()

	demoWrapper := gwu.NewPanel()
	demoWrapper.Style().SetPaddingLeftPx(5)
	demoWrapper.AddVSpace(10)
	demoTitle := gwu.NewLabel("")
	demoTitle.Style().SetFontWeight(gwu.FontWeightBold).SetFontSize("110%")
	demoWrapper.Add(demoTitle)
	demoWrapper.AddVSpace(10)

	links := gwu.NewPanel()
	links.SetCellPadding(1)
	links.Style().SetPaddingRightPx(5)

	demos := make(map[string]pdemo)
	var selDemo pdemo

	selectDemo := func(d pdemo, e gwu.Event) {
		if selDemo != nil {
			selDemo.link.Style().SetBackground("")
			if e != nil {
				e.MarkDirty(selDemo.link)
			}
			demoWrapper.Remove(selDemo.comp)
		}
		selDemo = d
		d.link.Style().SetBackground("#88ff88")
		demoTitle.SetText(d.link.Text())
		if d.comp == nil {
			d.comp = d.buildFunc(e)
		}
		demoWrapper.Add(d.comp)
		if e != nil {
			e.MarkDirty(d.link, demoWrapper)
		}
	}

	createDemo := func(name string, buildFunc func(gwu.Event) gwu.Comp) pdemo {
		link := gwu.NewLabel(name)
		link.Style().SetFullWidth().SetCursor(gwu.CursorPointer).SetDisplay(gwu.DisplayBlock).SetColor(gwu.ClrBlue)
		demo := &demo{link: link, buildFunc: buildFunc}
		link.AddEHandlerFunc(func(e gwu.Event) {
			selectDemo(demo, e)
		}, gwu.ETypeClick)
		links.Add(link)
		demos[name] = demo
		return demo
	}

	links.Style().SetFullHeight().SetBorderRight2(2, gwu.BrdStyleSolid, "#cccccc")
	links.AddVSpace(5)
	homeDemo := createDemo("Home", buildHomeDemo)
	selectDemo(homeDemo, nil)
	links.AddVSpace(5)
	l := gwu.NewLabel("Component Palette")
	l.Style().SetFontWeight(gwu.FontWeightBold).SetFontSize("110%")
	links.Add(l)
	links.AddVSpace(5)
	l = gwu.NewLabel("Containers")
	l.Style().SetFontWeight(gwu.FontWeightBold)
	links.Add(l)
	createDemo("Expander", buildExpanderDemo)
	createDemo("Link (as Container)", buildLinkContainerDemo)
	createDemo("Panel", buildPanelDemo)
	createDemo("Table", buildTableDemo)
	createDemo("TabPanel", buildTabPanelDemo)
	createDemo("Window", buildWindowDemo)
	links.AddVSpace(5)
	l = gwu.NewLabel("Input components")
	l.Style().SetFontWeight(gwu.FontWeightBold).SetDisplay(gwu.DisplayBlock)
	links.Add(l)
	createDemo("CheckBox", buildCheckBoxDemo)
	createDemo("ListBox", buildListBoxDemo)
	createDemo("TextBox", buildTextBoxDemo)
	createDemo("PasswBox", buildPasswBoxDemo)
	createDemo("RadioButton", buildRadioButtonDemo)
	createDemo("SwitchButton", buildSwitchButtonDemo)
	links.AddVSpace(5)
	l = gwu.NewLabel("Other components")
	l.Style().SetFontWeight(gwu.FontWeightBold)
	links.Add(l)
	createDemo("Button", buildButtonDemo)
	createDemo("HTML", buildHTMLDemo)
	createDemo("Image", buildImageDemo)
	createDemo("Label", buildLabelDemo)
	createDemo("Link", buildLinkDemo)
	createDemo("SessMonitor", buildSessMonitorDemo)
	createDemo("Timer", buildTimerDemo)
	links.AddVConsumer()
	setNoWrap(links)
	content.Add(links)
	content.Add(demoWrapper)
	content.CellFmt(demoWrapper).Style().SetFullWidth()

	win.Add(content)
	win.CellFmt(content).Style().SetFullSize()

	footer := gwu.NewHorizontalPanel()
	footer.Style().SetFullWidth().SetBorderTop2(2, gwu.BrdStyleSolid, "#cccccc")
	footer.Add(hiddenPan)
	footer.AddHConsumer()
	l = gwu.NewLabel("Copyright © 2013-2018 András Belicza. All rights reserved.")
	l.Style().SetFontStyle(gwu.FontStyleItalic).SetFontSize("95%")
	footer.Add(l)
	footer.AddHSpace(10)
	link := gwu.NewLink("Visit the Gowut Wiki", "https://github.com/icza/gowut/wiki")
	link.Style().SetFontStyle(gwu.FontStyleItalic).SetFontSize("95%")
	footer.Add(link)
	setNoWrap(footer)
	win.Add(footer)

	sess.AddWin(win)
}

// setNoWrap sets WhiteSpaceNowrap to all children of the specified panel.
func setNoWrap(panel gwu.Panel) {
	count := panel.CompsCount()
	for i := count - 1; i >= 0; i-- {
		panel.CompAt(i).Style().SetWhiteSpace(gwu.WhiteSpaceNowrap)
	}
}

// SessHandler is our session handler to build the showcases window.
type sessHandler struct{}

func (h sessHandler) Created(s gwu.Session) {
	buildShowcaseWin(s)
}

func (h sessHandler) Removed(s gwu.Session) {}

// StartServer creates and starts the Gowut GUI server.
func StartServer(appName, addr string, autoOpen bool) {
	// Create GUI server
	server := gwu.NewServer(appName, addr)
	for _, headHTML := range extraHeadHTMLs {
		server.AddRootHeadHTML(headHTML)
	}
	server.AddStaticDir("/asdf", "w:/")
	server.SetText("Gowut - Showcase of Features")

	server.AddSessCreatorName("show", "Showcase of Features - Gowut")
	server.AddSHandler(sessHandler{})
	// Just for the demo: Add an extra "Gowut-Server" header to all responses holding the Gowut version
	server.SetHeaders(map[string][]string{
		"Gowut-Server": {gwu.GowutVersion},
	})

	// Start GUI server
	var openWins []string
	if autoOpen {
		openWins = []string{"show"}
	}
	if err := server.Start(openWins...); err != nil {
		log.Println("Error: Cound not start GUI server:", err)
		return
	}
}