CCGUI page

--[[

    ComputerCraft GUI
    Page

--]]

ccgui = ccgui or {}

local Page = common.newClass({
    -- Paint layer
    layer = nil,
    -- Frames per second
    fps = 5,
    -- Identifier of frame timer
    frameTimer = nil
}, ccgui.FlowContainer)
ccgui.Page = Page

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

    -- Create paint layer
    self.layer = ccgui.PaintLayer.new({
        output = self.output or term
    })

    self:on("beforepaint", self.pageLayout, self)
    self:on("timer", self.pageTimer, self)

    -- Restart timer after drawing frame
    self:on("afterframe", self.restartFrameTimer, self)

    -- Start frame timer
    self:startFrameTimer()
end

function Page:getOutput()
    return self.layer.output
end

function Page:pageLayout()
    -- Fill whole screen
    self:updateLayout(self.layer:getBounds())
end

function Page:drawUnsafe(x, y, text, fgColor, bgColor)
    -- Draw on layer
    self.layer:write(x, y, text, fgColor, bgColor)
end

function Page:show()
    if ccgui.FlowContainer.show(self) then
        self:startFrameTimer()
    end
end

function Page:hide()
    self:stopFrameTimer()
    ccgui.FlowContainer.hide(self)
end

function Page:startFrameTimer()
    if self.frameTimer == nil then
        self:restartFrameTimer()
    end
end

function Page:restartFrameTimer()
    self.frameTimer = os.startTimer(1 / self.fps)
end

function Page:stopFrameTimer()
    self.frameTimer = nil
end

function Page:pageTimer(timerId)
    -- Handle frame timer
    if timerId == self.frameTimer then
        self:frame()
    end
end

function Page:frame()
    if not self.isVisible then return end

    -- Paint
    self:paint()

    -- Paint layer
    self:trigger("beforeframe")
    self.layer:paint()
    self:trigger("afterframe")
end

function Page:repaint()
    if not self.isVisible then return end

    -- Paint
    self:paint()

    -- Force repaint layer
    self:trigger("beforeframe")
    self.layer:repaint()
    self:trigger("afterframe")
end

function Page:reset()
    self.layer:clear()
end