local lg = love.graphics

local t = {
  name = "",
  tooltip = "button",
  icon = lg.newImage( "icons/eye.bmp" ),
  x = 8,
  y = 250,
  w = 176,
  h = 24,
  group = false,
  visible = true,
  callback = function( self ) return print( "clicked button: ", self.name, self.x, self.y, self.w, self.h, self.visible ) end
}
t.selected, t.next, t.prev = t, t, t

function t.contains( button, x, y )
  return x < button.x + button.w and x > button.x
  and    y < button.y + button.h and y > button.y
end

function t.new( b )
  b = setmetatable( b or {}, t )
  b.next = t
  t.prev.next = b
  b.prev = t.prev
  t.prev = b
  return b
end

local drawPassOngoing = false
function t.draw( b )
  if b == t then
    drawPassOngoing = not( drawPassOngoing )
    if not drawPassOngoing then return end
  elseif b.visible then
    lg.rectangle( "line", b.x, b.y, b.w, b.h, 6 )
    lg.printf( b.name,
      b.x,
      b.y + 0.5 * ( b.h- lg.getFont():getHeight() ),
      b.w - 5,
      "right" )
    if b.icon then lg.draw( b.icon,
        b.x, b.y + 0.5 * (b.h - b.icon:getHeight()),
        0,
        0.5, 0.5 )
    end
    if t.selected == b then
      lg.rectangle( "fill", b.x, b.y, b.w, b.h, 6 )
    end
  end
  return t.draw( b.next )
end

function t.select( b )
  t.selected = b
end

function t.selectNext()
  repeat t.selected = t.selected.next until t.selected.visible
end

function t.selectPrev()
  repeat t.selected = t.selected.prev until t.selected.visible
end

function t.selectIn( x, y )
  t.selected = t
  repeat t.selected = t.selected.next until (t.selected == t) or (t.selected.visible and t.selected:contains( x, y ))
end

function t.selectNextInGroup()
  local group = t.selected and t.selected.group
  if not group then return t.selectNext() end
  repeat t.selectNext() until group == t.selected.group
end

function t.selectPrevInGroup()
  local group = t.selected and t.selected.group
  if not group then return t.selectPrev() end
  repeat t.selectPrev() until group == t.selected.group
end

function t.displayGroup( group, show )
  local b = t
  repeat 
    b = b.next
    b.visible = ( b.group == group )
  until b == t
  t.visible = true
end

function t.deselect( b )
  t.selected = t
end

setmetatable( t, t )
t.__index = t
t.__call = t.new

return t