local type = type
local ipairs = ipairs
local color = require("gears.color")
local gsurface = require("gears.surface")
local cairo = require("lgi").cairo
local pango = require("lgi").Pango
local pangocairo = require("lgi").PangoCairo
local beautiful = require("beautiful")
local shape = require("gears.shape")

local module = {}

local pango_l,pango_crx = {},{}

--TODO using the current cairo path extents, it would be possible to merge the 2 function
-- and have an abstract underlay that work with most shapes

local function draw_item(cr,x,y,width,height,padding,args)
  cr:save()
  cr:rectangle(x,y,width+padding,height+padding)
  cr:clip()

  local s = shape.transform(shape.rounded_bar) : translate(x + padding, y + padding/4)
  s(cr, width - 2*padding, height - padding/2)

  cr:set_source(color(args.bg or beautiful.bg_underlay or beautiful.bg_alternate))
  cr:fill()

  cr:set_source(color(args.fg or beautiful.bg_normal))
  cr:set_operator(cairo.Operator.CLEAR)
  cr:move_to(x+height/2 + 2,y+padding/4 + (args.margins or 0)-(args.padding or 0)/2)
  cr:show_layout(pango_l[height])
  cr:restore()
end

function module.draw_arrow(cr,x,y,width,height,padding,args)
  cr:save()
  cr:rectangle(x,y,width+padding,height+padding)
  cr:clip()
  padding=padding/2
  local mid = (height-2*padding)/2

  local s = shape.transform(shape.hexagon) : translate(x, padding)
  s(cr, width, height - 2*padding)

  cr:set_source(color(args.bg or beautiful.bg_underlay or beautiful.bg_alternate))
  cr:fill()
  cr:set_source(color(args.fg or beautiful.bg_normal))
  cr:set_operator(cairo.Operator.CLEAR)
  cr:move_to(x+height/2+2,y+padding/2)
  cr:show_layout(pango_l[height])
  cr:restore()
end

function module.fit(text, args, context)
  local context = context or {}
  local args = args or {}
  local height = args.height or (beautiful.menu_height)
  local padding = height/4--beautiful.default_height/3

  local dpi = context.dpi or beautiful.xresources.get_dpi(1)

  -- Get text height
  if not pango_l[height] then
    local pango_crx = pangocairo.font_map_get_default():create_context()
    pango_l[height] = pango.Layout.new(pango_crx)
    local desc = pango.FontDescription()
    desc:set_family("Verdana")
    desc:set_weight(pango.Weight.BOLD)
    desc:set_size((height-padding*2) * pango.SCALE)
--     desc:set_variant(pango.Variant.SMALL_CAPS)
    pango_l[height]:set_font_description(desc)
  end

  local pango_layout = pango_l[height]

  pango_layout:get_context():set_resolution(dpi)
  pango_layout:context_changed()

  -- Compute full width
  local ret,full_width = {},0
  for k,v in ipairs(type(text) == "table" and text or {text}) do
    pango_layout.text = v
    ret[k] = pango_layout:get_pixel_extents().width + height + padding
    full_width = full_width + ret[k]
  end
  return full_width,ret
end

function module.draw(text, args, context)
  local args = args or {}
  local height = args.height or (beautiful.menu_height)
  local padding = height/4--beautiful.default_height/3
  local full_width,ret = module.fit(text, args, context)

  local img = cairo.ImageSurface.create(cairo.Format.ARGB32, full_width+(args.padding_right or 0), height+padding)
  cr = cairo.Context(img)

  -- Draw every item
  local x = 0
  for k,v in ipairs(type(text) == "table" and text or {text}) do
    pango_l[height].text = v
    local draw_f = args.style or draw_item
    draw_f(cr,x,0,ret[k],height,padding,args)
    x =  x + ret[k]
  end
  return img
end

return setmetatable(module, { __call = function(_, ...) return new(...) end })
-- kate: space-indent on; indent-width 2; replace-tabs on;