local PANEL = {}

AccessorFunc(PANEL, "m_pPropertySheet", "PropertySheet")
AccessorFunc(PANEL, "m_pPanel", "Panel")

Derma_Hook(PANEL, "Paint", "Paint", "Tab")

function PANEL:Init()
    self:SetMouseInputEnabled(true)
    self:SetContentAlignment(7)
    self:SetTextInset(0, 4)
end

function PANEL:Setup(label, pPropertySheet, pPanel, strMaterial)
    self:SetText(label)
    self:SetPropertySheet(pPropertySheet)
    self:SetPanel(pPanel)

    if (strMaterial) then
        self.Image = vgui.Create("DImage", self)
        self.Image:SetImage(strMaterial)
        self.Image:SizeToContents()
        self:InvalidateLayout()
    end
end

function PANEL:IsActive()
    return self:GetPropertySheet():GetActiveTab() == self
end

function PANEL:DoClick()
    self:GetPropertySheet():SetActiveTab(self)
end

function PANEL:PerformLayout()
    self:ApplySchemeSettings()

    if (! self.Image) then return end

    self.Image:SetPos(7, 3)

    if (! self:IsActive()) then
        self.Image:SetImageColor(Color(255, 255, 255, 155))
    else
        self.Image:SetImageColor(color_white)
    end
end

function PANEL:UpdateColours(skin)
    if (self:IsActive()) then
        if (self:GetDisabled()) then return self:SetTextStyleColor(skin.Colours.Tab.Active.Disabled) end
        if (self:IsDown()) then return self:SetTextStyleColor(skin.Colours.Tab.Active.Down) end
        if (self.Hovered) then return self:SetTextStyleColor(skin.Colours.Tab.Active.Hover) end

        return self:SetTextStyleColor(skin.Colours.Tab.Active.Normal)
    end

    if (self:GetDisabled()) then return self:SetTextStyleColor(skin.Colours.Tab.Inactive.Disabled) end
    if (self:IsDown()) then return self:SetTextStyleColor(skin.Colours.Tab.Inactive.Down) end
    if (self.Hovered) then return self:SetTextStyleColor(skin.Colours.Tab.Inactive.Hover) end

    return self:SetTextStyleColor(skin.Colours.Tab.Inactive.Normal)
end

function PANEL:GetTabHeight()
    if (self:IsActive()) then
        return 28
    else
        return 20
    end
end

function PANEL:ApplySchemeSettings()
    local ExtraInset = 10

    if (self.Image) then
        ExtraInset = ExtraInset + self.Image:GetWide()
    end

    self:SetTextInset(ExtraInset, 4)
    local w, h = self:GetContentSize()
    h = self:GetTabHeight()

    self:SetSize(w + 10, h)

    DLabel.ApplySchemeSettings(self)
end

--
-- DragHoverClick
--
function PANEL:DragHoverClick(HoverTime)
    self:DoClick()
end

function PANEL:GenerateExample()
    -- Do nothing!
end

function PANEL:DoRightClick()
    if (! IsValid(self:GetPropertySheet())) then return end

    local tabs = DermaMenu()
    for k, v in pairs(self:GetPropertySheet().Items) do
        if (! v || ! IsValid(v.Tab) || ! v.Tab:IsVisible()) then continue end
        local option = tabs:AddOption(v.Tab:GetText(), function()
            if (! v || ! IsValid(v.Tab) || ! IsValid(self:GetPropertySheet()) || ! IsValid(self:GetPropertySheet().tabScroller)) then return end
            v.Tab:DoClick()
            self:GetPropertySheet().tabScroller:ScrollToChild(v.Tab)
        end)
        if (IsValid(v.Tab.Image)) then option:SetIcon(v.Tab.Image:GetImage()) end
    end
    tabs:Open()
end

derma.DefineControl("DTab", "A Tab for use on the PropertySheet", PANEL, "DButton")

--[[---------------------------------------------------------
	DPropertySheet
-----------------------------------------------------------]]

local PANEL = {}

Derma_Hook(PANEL, "Paint", "Paint", "PropertySheet")

AccessorFunc(PANEL, "m_pActiveTab", "ActiveTab")
AccessorFunc(PANEL, "m_iPadding", "Padding")
AccessorFunc(PANEL, "m_fFadeTime", "FadeTime")

AccessorFunc(PANEL, "m_bShowIcons", "ShowIcons")

function PANEL:Init()
    self:SetShowIcons(true)

    self.tabScroller = vgui.Create("DHorizontalScroller", self)
    self.tabScroller:SetOverlap(5)
    self.tabScroller:Dock(TOP)
    self.tabScroller:DockMargin(3, 0, 3, 0)

    self:SetFadeTime(0.1)
    self:SetPadding(8)

    --self.animFade = Derma_Anim( "Fade", self, self.CrossFade )

    self.Items = {}
end

function PANEL:AddSheet(label, panel, material, NoStretchX, NoStretchY, Tooltip)
    if (! IsValid(panel)) then
        ErrorNoHalt("DPropertySheet:AddSheet tried to add invalid panel!")
        debug.Trace()
        return
    end

    local Sheet = {}

    Sheet.Name = label

    Sheet.Tab = vgui.Create("DTab", self)
    Sheet.Tab:SetTooltip(Tooltip)
    Sheet.Tab:Setup(label, self, panel, material)

    Sheet.Panel = panel
    Sheet.Panel.NoStretchX = NoStretchX
    Sheet.Panel.NoStretchY = NoStretchY
    Sheet.Panel:SetPos(self:GetPadding(), 20 + self:GetPadding())
    Sheet.Panel:SetVisible(false)

    panel:SetParent(self)

    table.insert(self.Items, Sheet)

    if (! self:GetActiveTab()) then
        self:SetActiveTab(Sheet.Tab)
        Sheet.Panel:SetVisible(true)
    end

    self.tabScroller:AddPanel(Sheet.Tab)

    return Sheet
end

function PANEL:SetActiveTab(active)
    if (! IsValid(active) || self.m_pActiveTab == active) then return end

    if (IsValid(self.m_pActiveTab)) then
        -- Only run this callback when we actually switch a tab, not when a tab is initially set active
        self:OnActiveTabChanged(self.m_pActiveTab, active)

        if (self:GetFadeTime() > 0) then
            -- self.animFade:Start(self:GetFadeTime(), { OldTab = self.m_pActiveTab, NewTab = active })
        else
            self.m_pActiveTab:GetPanel():SetVisible(false)
        end
    end

    self.m_pActiveTab = active
    self:InvalidateLayout()
end

function PANEL:OnActiveTabChanged(old, new)
    -- For override
end

function PANEL:Think()
    --	self.animFade:Run()
end

function PANEL:GetItems()
    return self.Items
end

function PANEL:CrossFade(anim, delta, data)
    if (! data || ! IsValid(data.OldTab) || ! IsValid(data.NewTab)) then return end

    local old = data.OldTab:GetPanel()
    local new = data.NewTab:GetPanel()

    if (! IsValid(old) && ! IsValid(new)) then return end

    if (anim.Finished) then
        if (IsValid(old)) then
            old:SetAlpha(255)
            old:SetZPos(0)
            old:SetVisible(false)
        end

        if (IsValid(new)) then
            new:SetAlpha(255)
            new:SetZPos(0)
            new:SetVisible(true) -- In case new == old
        end

        return
    end

    if (anim.Started) then
        if (IsValid(old)) then
            old:SetAlpha(255)
            old:SetZPos(0)
        end

        if (IsValid(new)) then
            new:SetAlpha(0)
            new:SetZPos(1)
        end
    end

    if (IsValid(old)) then
        old:SetVisible(true)
        if (! IsValid(new)) then old:SetAlpha(255 * (1 - delta)) end
    end

    if (IsValid(new)) then
        new:SetVisible(true)
        new:SetAlpha(255 * delta)
    end
end

function PANEL:PerformLayout()
    local ActiveTab = self:GetActiveTab()
    local Padding = self:GetPadding()

    if (! IsValid(ActiveTab)) then return end

    -- Update size now, so the height is definitiely right.
    ActiveTab:InvalidateLayout(true)

    --self.tabScroller:StretchToParent( Padding, 0, Padding, nil )
    self.tabScroller:SetTall(ActiveTab:GetTall())

    local ActivePanel = ActiveTab:GetPanel()

    for k, v in pairs(self.Items) do
        if (v.Tab:GetPanel() == ActivePanel) then
            if (IsValid(v.Tab:GetPanel())) then v.Tab:GetPanel():SetVisible(true) end
            v.Tab:SetZPos(100)
        else
            if (IsValid(v.Tab:GetPanel())) then v.Tab:GetPanel():SetVisible(false) end
            v.Tab:SetZPos(1)
        end

        v.Tab:ApplySchemeSettings()
    end

    if (IsValid(ActivePanel)) then
        if (! ActivePanel.NoStretchX) then
            ActivePanel:SetWide(self:GetWide() - Padding * 2)
        else
            ActivePanel:CenterHorizontal()
        end

        if (! ActivePanel.NoStretchY) then
            local _, y = ActivePanel:GetPos()
            ActivePanel:SetTall(self:GetTall() - y - Padding)
        else
            ActivePanel:CenterVertical()
        end

        ActivePanel:InvalidateLayout()
    end

    -- Give the animation a chance
    --	self.animFade:Run()
end

function PANEL:SizeToContentWidth()
    local wide = 0

    for k, v in pairs(self.Items) do
        if (IsValid(v.Panel)) then
            v.Panel:InvalidateLayout(true)
            wide = math.max(wide, v.Panel:GetWide() + self:GetPadding() * 2)
        end
    end

    self:SetWide(wide)
end

function PANEL:SwitchToName(name)
    for k, v in pairs(self.Items) do
        if (v.Name == name) then
            v.Tab:DoClick()
            return true
        end
    end

    return false
end

function PANEL:SetupCloseButton(func)
    self.CloseButton = self.tabScroller:Add("DImageButton")
    self.CloseButton:SetImage("icon16/circlecross.png")
    self.CloseButton:SetColor(Color(10, 10, 10, 200))
    self.CloseButton:DockMargin(1, 1, 1, 9)
    self.CloseButton:SetWide(18)
    self.CloseButton:Dock(RIGHT)
    self.CloseButton.DoClick = function()
        if (func) then func() end
    end
end

function PANEL:CloseTab(tab, bRemovePanelToo)
    for k, v in pairs(self.Items) do
        if (v.Tab != tab) then continue end

        table.remove(self.Items, k)
    end

    for k, v in pairs(self.tabScroller.Panels) do
        if (v != tab) then continue end

        table.remove(self.tabScroller.Panels, k)
    end

    self.tabScroller:InvalidateLayout(true)

    if (tab == self:GetActiveTab()) then
        self.m_pActiveTab = self.Items[#self.Items].Tab
    end

    local pnl = tab:GetPanel()

    if (bRemovePanelToo) then
        pnl:Remove()
    end

    tab:Remove()

    self:InvalidateLayout(true)

    return pnl
end

derma.DefineControl("DPropertySheet", "", PANEL, "Panel")