CCGUI tab

--[[

    ComputerCraft GUI
    Tab container

--]]

ccgui = ccgui or {}

local TabContainer = common.newClass({
    -- Current tab
    currentTab = nil,
    -- Spacing between tab buttons
    tabSpacing = 0,
    -- Stretch tab panes
    tabStretch = true,
    -- Style for tab buttons
    tabStyle = ccgui.Button
}, ccgui.FlowContainer)
ccgui.TabContainer = TabContainer

function TabContainer:init()
    ccgui.FlowContainer.init(self)

    self.tabBar = ccgui.FlowContainer:new{
        horizontal = not self.horizontal,
        spacing = self.tabSpacing
    }
    self.tabPane = ccgui.FlowContainer:new{
        horizontal = not self.horizontal,
        stretch = tabStretch
    }
    self:add(self.tabBar, self.tabPane)

    self:on("beforepaint", self.updateVisibleTab, self)
end

function TabContainer:tabCount()
    return #self.tabPane.children
end

function TabContainer:addTab(label, tab)
    if self.tabPane:find(tab, true) ~= nil then
        -- Tab already contained
        return tab
    end

    -- Add tab pane
    self.tabPane:add(tab)

    -- Add tab button
    local tabButton = self:addButton(label)

    -- Link button and pane
    tab.tabButton = tabButton
    tabButton.tab = tab

    -- Bind button to pane
    local container = self
    tabButton:on("buttonpress", function(self)
        container:setCurrentTab(self.tab)
    end, tabButton)

    self:updateVisibleTab()

    return tab
end

function TabContainer:addButton(label)
    local tabButton = self.tabStyle:new{
        text = label
    }
    self.tabBar:add(tabButton)
    return tabButton
end

function TabContainer:setCurrentTab(tab)
    if type(tab) ~= "table" then return false end

    -- Set as current tab
    self.currentTab = tab

    self:updateVisibleTab()
    --self.tabPane:markRepaint()
    return true
end

function TabContainer:removeTab(tab)
    if self.currentTab == tab then
        -- Current tab removed
        local i, n = self.tabPane:find(tab), self:tabCount()
        if n > 1 then
            -- Move to neighbour tab
            if i == n then
                i = i-1
            else
                i = i+1
            end
            self:setCurrentTab(self.tabPane.children[i])
        else
            -- No new current tab
            self.currentTab = nil
        end
    end

    -- Remove tab
    self.tabPane:remove(tab)

    -- Remove tab button
    self.tabBar:remove(tab.tabButton)

    self:updateVisibleTab()
end

function TabContainer:updateVisibleTab()
    if self.currentTab == nil and self:tabCount() > 0 then
        self.currentTab = self.tabPane.children[1]
    end

    -- Show current tab and hide others
    self.tabPane:each(function(child)
        if child == self.currentTab then
            child:show()
        else
            child:hide()
        end
    end)
end

function TabContainer:sinkEventToCurrent(event)
    self:on(event, function(...)
        if self.isVisible and self.currentTab ~= nil then
            self.currentTab:trigger(event, ...)
        end
    end, self)
end