CCGUI container

--[[

    ComputerCraft GUI
    Container element

--]]

ccgui = ccgui or {}

local Container = common.newClass({
    -- Children
    children = nil,
    -- Focused child index
    childFocus = nil
}, ccgui.Element)
ccgui.Container = Container

function Container:init()
    ccgui.Element.init(self)

    self.children = {}

    -- Paint
    self:on("paint", self.drawChildren, self)
    self:sinkEvent("beforepaint")
    self:sinkEvent("afterpaint")
    self:sinkEvent("beforeframe")
    self:sinkEvent("afterframe")

    -- Mouse
    self:sinkEvent("mouse_click")
    self:sinkEvent("mouse_drag")
    self:sinkEventToCurrent("mouse_scroll")

    -- Keyboard
    self:sinkEventToCurrent("key")
    self:sinkEventToCurrent("char")
end

function Container:find(elem, deep)
    if elem == nil then return nil end

    -- Deep search in child containers
    deep = not not deep

    for i,child in ipairs(self.children) do
        if child == elem then
            return i
        elseif (deep and type(child.find) == "function") then
            if child:find(elem) ~= nil then
                return i
            end
        end
    end
    return nil
end

function Container:each(func)
    local n = #self.children
    for i,child in ipairs(self.children) do
        func(child, i, i == n)
    end
end

function Container:eachVisible(func)
    -- Check if there is another visible child
    -- after the given child index
    local hasVisibleAfter = function(i)
        for j=i+1, #self.children do
            if self.children[j].isVisible then
                return true
            end
        end
        return false
    end

    -- Process only visible children
    self:each(function(child, i)
        if child.isVisible then
            func(child, i, not hasVisibleAfter(i))
        end
    end)
end

function Container:add(...)
    local children = {...}

    -- Add as child
    for i,child in ipairs(children) do
        child.parent = self
        table.insert(self.children, child)
    end

    return #self.children
end

function Container:remove(child)
    if child.parent ~= self then
        return false
    end

    -- Remove as parent
    child.parent = nil

    -- Remove from children
    local i = common.ifind(self.children, child)
    if i ~= nil then
        table.remove(self.children, i)
        -- Fix focused child
        if self.childFocus ~= nil then
            if self.childFocus == i then
                -- Currently focused child removed
                self.childFocus = nil
                self:updateFocus(nil)
            elseif self.childFocus > i then
                -- Adjust focused child index
                self.childFocus = self.childFocus - 1
            end
        end
    end

    return true
end

function Container:drawChildren()
    -- Repaint all children
    self:eachVisible(function(child)
        child:paint()
    end)
end

--[[

    Focus

]]

function Container:updateFocus(newFocus)
    local newIndex = self:find(newFocus)

    -- Blur previously focused child
    if self.childFocus ~= nil and self.childFocus ~= newIndex then
        self.children[self.childFocus]:blur()
    end

    -- Set focused child
    self.childFocus = newIndex

    -- Bubble up to parent
    if self.parent ~= nil then
        if newFocus == nil then
            self.parent:updateFocus(nil)
        else
            self.parent:updateFocus(self)
        end
    end
end

function Container:blur()
    -- Blur previously focused child
    if self.childFocus ~= nil then
        self.children[self.childFocus]:blur()
        self.childFocus = nil
    end

    -- Call super
    return ccgui.Element.blur(self)
end

--[[

    Event sinking

]]--

function Container:sinkEvent(event)
    self:on(event, function(self, ...)
        if self.isVisible then
            local args = { ... }
            self:each(function(child)
                child:trigger(event, unpack(args))
            end)
        end
    end, self, 1000)
end

function Container:sinkEventToCurrent(event)
    self:on(event, function(self, ...)
        if self.isVisible and self.childFocus ~= nil then
            self.children[self.childFocus]:trigger(event, ...)
        end
    end, self, 1000)
end