local math = math
local rawget,rawset=rawget,rawset
local beautiful    = require( "beautiful"               )
local base = nil

local module = {
  colors_by_id = {}
}

-- Do some magic to cache the highest state
local function return_data(tab, key)
  return tab._real_table[key]
end

-- Common method to set foreground and background color dependeing on state
function module.update_colors(item, current_state_override)
  local state = item.state or {}
  local current_state = current_state_override or state._current_key or nil

  local state_name = base.colors_by_id[current_state]

  -- Awesome use "focus" and radical "selected", convert the name
  if current_state == base.item_flags.SELECTED or (item._tmp_menu) then
    item.widget:set_bg     ( item.bg_focus      )
    item.widget:set_bgimage( item.bgimage_focus )
    item.widget:set_fg     ( item.fg_focus      )
    item.widget:set_shape_border_color(item.border_color_focus
      or item["border_color"])
  elseif state_name then
    item.widget:set_bg     (item["bg_"..state_name]      )
    item.widget:set_bgimage(item["bgimage_"..state_name] )
    item.widget:set_fg     (item["fg_"..state_name]      )
    item.widget:set_shape_border_color(item["border_color_"..state_name]
      or item["border_color"])
  else
    item.widget:set_bg     ( nil        )
    item.widget:set_bgimage( nil        )
    item.widget:set_fg     ( item["fg"] )
    item.widget:set_shape_border_color(item["border_color"])
  end
end

local function change_data(tab, key,value)
  if not value and key == rawget(tab,"_current_key") then
    -- Loop the array to find a new current_key
    local win = math.huge
    for k,v in pairs(tab._real_table) do
      if k < win and k ~= key then
        win = k
      end
    end
    rawset(tab,"_current_key",win ~= math.huge and win or nil)
    if tab._item._internal.text_w and tab._item._internal.text_w.cache then
      tab._item._internal.text_w.cache = {}
    end
    tab._item:emit_signal("state::changed",win)
  elseif value and (rawget(tab,"_current_key") or math.huge) > key then
    rawset(tab,"_current_key",key)
    if tab._item._internal.text_w and tab._item._internal.text_w.cache then
      tab._item._internal.text_w.cache = {}
    end
    tab._item:emit_signal("state::changed",key)
  end
  tab._real_table[key] = value
end

function module.init_state(item)
  base = base or require("radical.base")
  local mt = {__newindex = change_data,__index=return_data}
  return setmetatable({_real_table={},_item=item},mt)
end

-- Util to help match colors to states
local theme_colors = {}

local function load_section(data,priv,section,args)
  args = args or {}
  local bg,fg = section.."_bg_", section.."_fg_"
  for k,v in pairs(theme_colors) do
    priv[bg..k] = args[bg..v.beautiful_name] or beautiful["menu_"..bg..v.beautiful_name] or beautiful[bg..v.beautiful_name]
    priv[fg..k] = args[fg..v.beautiful_name] or beautiful["menu_"..fg..v.beautiful_name] or beautiful[fg..v.beautiful_name]
  end
end

function module.register_color(state_id,name,beautiful_name,allow_fallback)
  theme_colors[name] = {id=state_id,beautiful_name=beautiful_name,fallback=allow_fallback}
  module.colors_by_id[state_id] = name
end

function module.setup_colors(data,args)
  local priv = data._internal.private_data
  for k,v in pairs(theme_colors) do
      priv["fg_"..k] = args["fg_"..k] or beautiful["menu_fg_"..v.beautiful_name] or beautiful["fg_"..v.beautiful_name] or (v.fallback and beautiful.fg_normal)
      priv["bg_"..k] = args["bg_"..k] or beautiful["menu_bg_"..v.beautiful_name] or beautiful["bg_"..v.beautiful_name] or (v.fallback and beautiful.bg_normal)
      priv["bgimage_"..k] = args["bgimage_"..k] or beautiful["menu_bgimage_"..v.beautiful_name] or beautiful["bgimage_"..v.beautiful_name]
      priv["border_color_"..k] = args["border_color_"..k]
        or args["item_border_color"] or args["border_color"]
        or beautiful["menu_border_color_"..v.beautiful_name]
        or beautiful["border_color_"..v.beautiful_name]
        or (v.fallback and beautiful.border_color)
  end

  -- Handle custom sections
  for _,section in ipairs(priv.section or {}) do
    load_section(data,priv,section,args)
  end
end

--TODO URGENT use metatable for this, it is damn slow
function module.setup_item_colors(data,item,args)
  local priv = item._private_data
  for k,v in pairs(theme_colors) do

    -- Foreground
    if args["fg_"..k] then
      priv["fg_"..k] = args["fg_"..k]
    else
      rawset(item,"get_fg_"..k,function()
        return priv["fg_"..k] or data["fg_"..k]
      end)
    end

    -- Background
    if args["bg_"..k] then
      priv["bg_"..k] = args["bg_"..k]
    else
      rawset(item,"get_bg_"..k, function()
        return priv["bg_"..k] or data["bg_"..k]
      end)
    end

    -- Background image
    if args["bgimage_"..k] then
      priv["bgimage_"..k] = args["bgimage_"..k]
    else
      rawset(item,"get_bgimage_"..k, function()
        return priv["bgimage_"..k] or data["bgimage_"..k]
      end)
    end

    -- Border color
    if args["border_color_"..k] then
      priv["border_color_"..k] = args["border_color_"..k]
    else
      rawset(item,"get_border_color_"..k, function()
        return priv["border_color_"..k] or data["border_color_"..k]
      end)
    end
  end
end

--- Apply a set of background and foreground colors from beautiful to `data`
-- @arg data The menu
-- @arg namespace The beautiful prefix used for that set of values
function module.add_colors_from_namespace(data,namespace)
  local priv = data._internal.private_data
  for k,v in pairs(theme_colors) do
    priv["fg_"..k] = beautiful[namespace.."_fg_"..v.beautiful_name] or priv["fg_"..k]
    priv["bg_"..k] = beautiful[namespace.."_bg_"..v.beautiful_name] or priv["bg_"..k]
    priv["bgimage_"..k] = beautiful[namespace.."_bgimage_"..v.beautiful_name] or priv["bgimage_"..k]
    priv["border_color_"..k] = beautiful[namespace.."_border_color_"..v.beautiful_name] or priv["border_color_"..k]
  end
  priv["fg"] = beautiful[namespace.."_fg"] or priv["fg"]
  priv["bg"] = beautiful[namespace.."_bg"] or priv["bg"]
  priv["bgimage"] = beautiful[namespace.."_bgimage"] or priv["bgimage"]
  priv["border_color"] = beautiful[namespace.."_border_color"] or priv["border_color"]
  priv["item_border_color"] = beautiful[namespace.."_item_border_color"] or priv["item_border_color"]
  priv.namespace = priv.namespace or {}
  priv.namespace[#priv.namespace+1] = namespace
end

-- Utils to add new color-able elements of an item
-- this can be used either for extentions, such as {pre,suf}fixes
-- or "special" [item_]styles

function module.add_section(data,section,args)
  local priv = data._internal.private_data

  load_section(data,priv,section,args)

  priv.section = priv.section or {}
  priv.section[#priv.section+1] = section
end

return module
-- kate: space-indent on; indent-width 2; replace-tabs on;