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().SetBorder2(1, gwu.BRD_STYLE_SOLID, gwu.CLR_GRAY)
	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 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.ETYPE_CLICK)
	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.ETYPE_MOUSE_OVER:
			l.SetText("Mouse is over...")
		case gwu.ETYPE_MOUSE_OUT:
			l.SetText("Mouse is out.")
		case gwu.ETYPE_CLICK:
			x, y := e.Mouse()
			l.SetText(fmt.Sprintf("Clicked at x=%d, y=%d", x, y))
		}
		e.MarkDirty(l)
	}, gwu.ETYPE_CLICK, gwu.ETYPE_MOUSE_OVER, gwu.ETYPE_MOUSE_OUT)
	btnp.Add(b)

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

	p.Add(btnp)

	p.Add(l)

	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", "http://golang.org/doc/gopher/frontpage.png")
	img.Style().SetSizePx(250, 340)
	state := false
	img.AddEHandlerFunc(func(e gwu.Event) {

		switch e.Type() {
		case gwu.ETYPE_CLICK:
			switch state {
			case false:
				img.SetUrl("https://www.google.com/images/srpr/logo3w.png")
				img.Style().SetSizePx(275, 95)
				state = true
			case true:
				img.SetUrl("http://golang.org/doc/gopher/frontpage.png")
				img.Style().SetSizePx(250, 340)
				state = false
			}
		}
		e.MarkDirty(img)
	}, gwu.ETYPE_CLICK)
	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.ETYPE_CLICK)
	p.Add(b)

	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.ETYPE_CLICK)
	}

	p.Add(suml)

	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("Button " + strconv.Itoa(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("Button " + strconv.Itoa(i)))
	}
	p.Add(v)

	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Panel with natural layout:"))
	n := gwu.NewNaturalPanel()
	for i := 1; i <= 20; i++ {
		n.Add(gwu.NewButton("LONG BUTTON " + strconv.Itoa(i)))
	}
	p.Add(n)

	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 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(5)
	p.Add(gwu.NewLabel("The Window is the top of the component hierarchy. It is an extension of the Panel."))

	return p
}

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

	p.Add(gwu.NewLabel("This app is written in and showcases Gowut version " + gwu.GOWUT_VERSION + "."))
	p.AddVSpace(20)
	p.Add(gwu.NewLabel("Select components on the left side to see them in action."))

	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.CLR_RED).SetFontStyle(gwu.FONT_STYLE_ITALIC)
	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.BRD_STYLE_SOLID, gwu.CLR_GREY)
	t.SetAlign(gwu.HA_RIGHT, gwu.VA_TOP)
	t.EnsureSize(5, 5)
	for row := 0; row < 5; row++ {
		for col := 0; col < 5; col++ {
			t.Add(gwu.NewButton("Button "+strconv.Itoa(row)+strconv.Itoa(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.HA_RIGHT, gwu.VA_BOTTOM)
	t.RowFmt(2).SetAlign(gwu.HA_DEFAULT, gwu.VA_MIDDLE)
	t.CompAt(2, 1).Style().SetFullSize()
	t.CompAt(4, 2).Style().SetFullWidth()
	t.RowFmt(0).Style().SetBackground(gwu.CLR_RED)
	t.RowFmt(1).Style().SetBackground(gwu.CLR_GREEN)
	t.RowFmt(2).Style().SetBackground(gwu.CLR_BLUE)
	t.RowFmt(3).Style().SetBackground(gwu.CLR_GREY)
	t.RowFmt(4).Style().SetBackground(gwu.CLR_TEAL)
	p.Add(t)

	return p
}

func updateTables(tables gwu.Panel) {
	var sorted SortBySellPrice
	for card, _ := range PriceHistory {
		sorted = append(sorted, StockedItem{
			card,
			currentState.DeterminePrice(card, 1, true),
			currentState.DeterminePrice(card, 1, false),
		})
	}
	sort.Sort(sorted)

	tables.Clear()
	tables.Add(createFAQ())

	tables.AddHSpace(100)
	for rarity, rarityStr := range []string{"Commons", "Uncommons", "Rares"} {
		layout := gwu.NewPanel()
		tables.Add(layout)
		tables.AddHSpace(30)

		layout.SetHAlign(gwu.HA_CENTER)
		layout.Style().SetBackground("rgba(0,0,0,0.5)")
		layout.Style().SetWidthPx(320)

		header := gwu.NewLabel(rarityStr)
		header.Style().SetColor("rgb(255,255,255)")
		header.Style().SetFontWeight("bold")
		header.Style().SetFontSize("x-large")
		layout.Add(header)

		table := gwu.NewTable()
		layout.Add(table)

		table.SetCellPadding(5)

		row := 0
		for _, sortedItem := range sorted {
			if CardRarities[sortedItem.card] != rarity {
				continue
			}

			table.Add(gwu.NewImage("", fmt.Sprintf("images/%s.png", CardResources[sortedItem.card])), row, 0)
			table.Add(gwu.NewLabel(string(sortedItem.card)), row, 1)
			table.Add(gwu.NewLabel(fmt.Sprintf("%d", sortedItem.buy)), row, 2)
			table.Add(gwu.NewLabel(fmt.Sprintf("%d", sortedItem.sell)), row, 3)
			if row%2 == 0 {
				table.RowFmt(row).Style().SetBackground("rgba(255,255,255,0.75)")
			} else {
				table.RowFmt(row).Style().SetBackground("rgba(150,150,150,0.75)")
			}
			row++
		}
	}
}

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", "http://golang.org/doc/gopher/frontpage.png")
	img.Style().SetSizePx(250, 340)
	p.Add(img)

	return p
}

func createFAQ() gwu.Panel {
	panel := gwu.NewPanel()
	panel.Style().SetBackground("rgba(255,255,255,0.75)")

	addHeader := func(text string) {
		label := gwu.NewLabel(text)
		label.Style().SetColor("rgb(0,0,0)")
		label.Style().SetFontWeight("bold")
		label.Style().SetFontSize("large")
		panel.Add(label)
	}

	addText := func(text string) {
		label := gwu.NewLabel(text)
		label.Style().SetColor("rgb(0,0,0)")
		panel.Add(label)
	}

	addHeader("What is this?")
	addText("This site displays the prices for which the ClockworkAgent, a trading bot for the game Scrolls, will buy and sell cards for.")

	addHeader("How do I engage in trading with the bot?")
	addText("Just join the ingame channel 'clockwork' and say '!trade'. You will then be queued up for interaction with the bot in a trade.")

	addHeader("Why are these prices so different from Scrollsguide prices?")
	addText("Scrollsguide prices are determined from WTB and WTS messages in the Trading-channel. Thus they reflect what people expect to " +
		"pay/get for a card, not necessarily what the card is actually traded for. Since most people adjust their expectations to what " +
		"the current Scrollsguide price is, this can lead to a self-fulfilling prophecy. Also, it is pretty easy to manipulate the prices " +
		"for cards that are traded less often, enabling a way to scam the bot if it would use these prices.")

	addHeader("How then are these prices calculated?")
	addText("The price starts at 1500 for rares, 750 for uncommons and 187 for commons. Each time a card is sold to the bot, it will assume " +
		"that the card is less valuable, reducing the price by 100 / 50 / 12.5 depending on rarity. Each time a card is bought from the bot, " +
		"the price will	go up again.")

	addHeader("Why does the buy price fluctuate, when the sell price remains constant?")
	addText("If the bot has less than 2000 gold, the buy prices will be lowered down to a minimum of 50%. This way the bot can aquire more cards, " +
		"balancing out the fact that it had to overpay for most cards in order to determine the price, as well as new additions and general price deflation.")

	addHeader("Who created the bot, and where can I find the source code?")
	addText("Ingame: redefiance")
	addText("Reddit: lando-garner")
	panel.Add(gwu.NewLink("Source", "https://github.com/redefiance/ScrollsTradeBot"))

	return panel
}

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

	p.Add(gwu.NewLink("Visit Gowut Home page", "https://sites.google.com/site/gowebuitoolkit/"))
	p.Add(gwu.NewLink("Visit Gowut Project page", "http://code.google.com/p/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:"))
	email := "iczaaa" + "@" + "gmail.com"
	row.Add(gwu.NewLink("András Belicza <"+email+">", "mailto:"+email))
	p.Add(row)

	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.ETYPE_KEY_UP)
	length := gwu.NewLabel("")
	length.Style().SetFontSize("80%").SetFontStyle(gwu.FONT_STYLE_ITALIC)
	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.ETYPE_CHANGE, gwu.ETYPE_KEY_UP)
	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 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.ETYPE_CHANGE)
	row.Add(lb)
	p.Add(row)

	p.AddVSpace(10)
	p.Add(gwu.NewLabel("Select numbers that add up to 89:"))
	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.ETYPE_CHANGE)
	p.Add(lb2)
	p.Add(sumLabel)

	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.CLR_GREEN)
	p.Add(l)
	p.AddVSpace(5)
	e := gwu.NewExpander()
	e.SetHeader(gwu.NewLabel("I'm an Expander."))
	e.SetContent(gwu.NewLabel("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.ETYPE_STATE_CHANGE)

	p.AddVSpace(20)
	var ee gwu.Expander
	for i := 4; i >= 0; i-- {
		e2 := gwu.NewExpander()
		e2.SetHeader(gwu.NewLabel("I hide embedded expanders. #" + strconv.Itoa(i)))
		if i == 4 {
			e2.SetContent(gwu.NewLabel("No more."))
		} else {
			e2.SetContent(ee)
		}
		ee = e2
	}
	p.Add(ee)

	return p
}