local lf = love.filesystem
local lg = love.graphics
local path = ...

local pop = {}
pop.elementClasses = {}
--pop.elements = {}
pop.window = {child = {}} --top level element, defined in pop.load()
--TODO we need a "focused" element for textinput or whatever

function pop.load()
    -- load element classes
    local elementList = lf.getDirectoryItems(path .. "/elements")

    for i=1, #elementList do
        local name = elementList[i]:sub(1, -5)
        pop.elementClasses[name] = require(path .. "/elements/" .. name)
        print("loaded \"" .. name .. "\" element")

        -- wrapper to be able to call pop.element() to create elements
        if not pop[name] then
            pop[name] = function(...) return pop.create(name, ...) end
            print("wrapper: pop." .. name .. "() created")
        end
    end

    -- set top element
    pop.window = pop.create("element"):setSize(lg.getWidth(), lg.getHeight())
    print("created pop.window")
end

function pop.create(elementType, parent, ...)
    if not parent then
        parent = pop.window
    end

    local newElement = pop.elementClasses[elementType](pop, parent, ...)
    table.insert(parent.child, newElement) --NOTE pop.window is its own parent?

    return newElement
end

function pop.update(dt, element)
    if not element then
        element = pop.window
    end

    if element.update then
        element:update(dt)
    end

    --NOTE add excludeUpdating for performance if needed
    for i=1,#element.child do
        pop.update(dt, element.child[i])
    end
end

function pop.draw(element)
    if not element then
        element = pop.window
    end

    if not element.excludeRendering then
        if element.draw then
            element:draw()
        end

        for i=1,#element.child do
            pop.draw(element.child[i])
        end
    end
end

function pop.mousepressed(button, x, y)
    --TODO find element, if it has a callback, call with button and LOCAL x/y
end

function pop.mousereleased(button, x, y)
    --TODO find element, if it has a callback, call with button and LOCAL x/y
end

function pop.keypressed(key)
    --TODO no idea what to do with this
end

function pop.keyreleased(key)
    --TODO no idea what to do with this
end

pop.load()

return pop