local setmetatable = setmetatable
local unpack       = unpack or table.unpack
local beautiful    = require( "beautiful"    )
local color        = require( "gears.color"  )
local cairo        = require( "lgi"          ).cairo
local base         = require( "radical.base" )
local shape        = require( "gears.shape"  )

local module = {
    margins = {
        BOTTOM = 10,
        TOP    = 10,
        LEFT   = 0 ,
        RIGHT  = 0 ,
    }
}

-- Matrix rotation per direction
local angles = {
    top    = math.pi     , -- 180
    bottom = 0           , -- 0
    left   = math.pi/2   , -- 90
    right  = 3*math.pi/2 , -- 270
}

-- If width and height need to be swapped
local swaps = {
    top   =  false,
    bottom=  false,
    right =  true ,
    left  =  true ,
}

local invert = {
    top    = "bottom",
    bottom = "top"   ,
    right  = "left"  , --FIXME this is wrong
    left   = "right" , --FIXME this is wrong
}

-- Constants
local radius       = 10
local arrow_height = 13

-- Generate the arrow position
local function gen_arrow_x(data,direction, width, height)
    local at = data.arrow_type
    local par_center_x = data.wibox.width/2

    if at == base.arrow_type.PRETTY or not at then
        if direction == "left" then
            data._arrow_x = data._internal.w.height -20 - (data.arrow_x_orig or 20)
        elseif direction == "right" then
            --TODO
        elseif direction == "bottom" then
            data._arrow_x = width -20 - (data.arrow_x_orig or 20)
            if par_center_x >= 0 then
                data._arrow_x = width - (par_center_x - 0) - arrow_height
            end
        elseif direction == "top" then
            --TODO
        end
    elseif at == base.arrow_type.CENTERED then
        if direction == "left" or direction == "right" then
            data._arrow_x = height/2 - arrow_height
        else
            data._arrow_x = width/2 - arrow_height
        end
    end
end

local function update_margins(data, pos)
    -- Set the margins correctly
    if data._internal.margin then
        data.margins.left   = module.margins.LEFT
        data.margins.right  = module.margins.RIGHT
        data.margins.top    = module.margins.TOP
        data.margins.bottom = module.margins.BOTTOM

        -- Add enough room for the arrow
        if pos and data.arrow_type ~= base.arrow_type.NONE then
            data.margins[invert[pos]] = data.margins[invert[pos]] + arrow_height
        end
    end
end

-- Generate a rounded cairo path with the arrow
local function draw_roundedrect_path(cr, width, height, radius, data, position)
    if data.arrow_type == base.arrow_type.NONE then
        return shape.rounded_rect(cr, width, height, radius)
    end

    local angle, swap = angles[position], swaps[position]

    -- Invert width and height to avoid distortion
    if swap then
        width, height = height, width
    end

    -- Use rounded rext for sub-menu and
    local s = shape.transform(shape.infobubble)

    -- Apply transformations
    s = s : rotate_at(width / 2, height / 2, angle)

    -- Decide where the arrow will be
    gen_arrow_x(data, data.direction, width, height)

    -- Forward to the real shape
    local ax = swap and width - (data._arrow_x or 20) or (data._arrow_x or 20)
    s(cr, width, height, radius, arrow_height, ax)
end

local function draw(data,args)
    local args = args or {}

    if not data._internal.arrow_setup then
        data._internal.w:set_shape_border_width(data.border_width or 1)
        data._internal.w:set_shape_border_color(color(beautiful.menu_outline_color or beautiful.menu_border_color or beautiful.fg_normal))
        data._internal.w:set_shape(data.shape or shape.infobubble, unpack(data.shape_args or {}))

        data._internal.w:connect_signal("property::position", function(_, pos)
            data._internal.w:set_shape(function(cr, w, h) draw_roundedrect_path(cr, w, h, radius, data, pos) end)
            update_margins(data, pos)
        end)

        local pos = data._internal.w.position
        if pos then
            data._internal.w:set_shape(function(cr, w, h) draw_roundedrect_path(cr, w, h, radius, data, data._internal.w.position) end)
        end
        update_margins(data, pos)

        data._internal.arrow_setup = true
    end

  return w,w2
end

return setmetatable(module, { __call = function(_, ...) return draw(...) end })
-- kate: space-indent on; indent-width 4; replace-tabs on;