-- panel 
local JGUI = {}

local contain = function(x, y, box)
    return x >= box.x and x <= box.x + box.width 
       and y >= box.y and y <= box.y + box.height 
end

local Widget = {
    -- common properties
    name,                -- name 
    x = 0, y = 0, width = 0, height = 0, -- boundary 
    swallow,             -- swallow event or not by default
    -- event callbacks
    onClick,             -- clicked callback 
    onHover,             -- hover callback 
    -- 
    onEvent,
}
Widget.__index = Widget
function Widget.onEvent(w, e)
    if e.type == "MouseButtonDown" then 
        if e.button == "Left" then 
            if contain(e.x, e.y, {x = w.x, y = w.y, width = w.width, height = w.height}) then 
                w.onClick()
            end
        end
    elseif e.type == "MouseButtonUp" then 
        if e.button == "Left" then 
            if contain(e.x, e.y, {x = w.x, y = w.y, width = w.width, height = w.height}) then 
                w.onRelease()
            end
        end
    end
end
function Widget.setSize(widget, w, h)
    widget.width = w 
    widget.height = h
end 
function Widget.setPosition(widget, x, y)
    widget.x = x 
    widget.y = y
end 

local Panel = {
    widgets = {}, 
    x = 0, 
    y = 0, 
    width = 0,
    height = 0,
    goon = true,
}
Panel.__index = Panel
function Panel.onEvent(p, e)
    for _, w in pairs(p.widgets) do 
        if goon then 
            w:onEvent(e)
        else 
            break
        end
    end
    goon = true
end
function Panel.onUpdate(p, dt)

end
function Panel.setSize(p, w, h)
    p.width = w
    p.height = h
end
function Panel.add(p, w)
    table.insert(p.widgets, w)
end 

local Button = {}
Button.__index = Button
setmetatable(Button, Widget)


------------------------------------
-- 
------------------------------------
JGUI.newButton = function(name, ...)
    local b = {} 
    b.name = name 
    setmetatable(b, Button)
    if b.init then 
        b.init(...)
    end 
    return b
end 

JGUI.newPanel = function(name, ...)
    local p = {} 
    p.name = name
    setmetatable(p, Panel)
    if p.init then 
        p.init(...)
    end 
    return p
end

return JGUI