local lg = love.graphics

local t = {
  name = "",
  tooltip = "button",
  icon = false,
  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

local function debugLoop()
  local i = 0
  local j = 0
  local a = t
  repeat
    i = i + 1
    --print( "BUTTON", i, tostring( a ) )
    a = a.next
  until a == t or i > 100
  a = t
  repeat
    j = j + 1
    --print( "BUTTON", i, tostring( a ) )
    a = a.prev
  until a == t or j > 100
  print( i, j, "BUTTONS" )
end

local k = 1
function t.new( b )
  b = setmetatable( b or {}, t )
  b.next = t
  t.prev.next = b
  b.prev = t.prev
  t.prev = b
  --nonsense
  k = k + 1
  print( "ADD BUTTON", k, tostring( b ) )
  debugLoop()
  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.icon and b.h or 0),
      b.y + 0.5 * ( b.h - lg.getFont():getHeight() ),
      b.w - (b.icon and b.h or 0),
      "center" )
    if b.icon then 
      local h = b.icon:getHeight()
      lg.draw( b.icon,
        b.x, b.y,
        0,
        b.h / h )
    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 == t) or t.selected.visible
end

function t.selectPrev()
  repeat t.selected = t.selected.prev until (t.selected == t) or 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()
  --make sure our group is visible, otherwise the loop doesn't end
  local group = t.selected and t.selected.visible and t.selected.group
  if not group then return t.selectNext() end
  repeat t.selectNext() until group == t.selected.group
end

function t.selectPrevInGroup()
  --make sure our group is visible, otherwise the loop doesn't end
  local group = t.selected and t.selected.visible 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