--[[

     Licensed under GNU General Public License v2
      * (c) 2014,      projektile
      * (c) 2013,      Luke Bonham
      * (c) 2012,      Josh Komoroske
      * (c) 2010-2012, Peter Hofmann

--]]

local beautiful = require("beautiful")
local ipairs    = ipairs
local math      = { ceil = math.ceil, sqrt = math.sqrt }
local tonumber  = tonumber

local uselessfair = {}

local function fair(p, orientation)
    -- A useless gap (like the dwm patch) can be defined with
    -- beautiful.useless_gap_width.
    local useless_gap = tonumber(beautiful.useless_gap_width) or 0
    if useless_gap < 0 then useless_gap = 0 end

    -- A global border can be defined with
    -- beautiful.global_border_width.
    local global_border = tonumber(beautiful.global_border_width) or 0
    if global_border < 0 then global_border = 0 end

    -- Themes border width requires an offset.
    local bw = tonumber(beautiful.border_width) or 0

    -- Total window size extend
    local ext = 2 * bw + useless_gap

    -- get our orientation right.
    local wa = p.workarea
    local cls = p.clients

    wa.height = wa.height - 2 * global_border - useless_gap
    wa.width  = wa.width -  2 * global_border - useless_gap
    wa.x = wa.x + useless_gap + global_border
    wa.y = wa.y + useless_gap + global_border

    if #cls > 0 then
        local cells = math.ceil(math.sqrt(#cls))
        local strips = math.ceil(#cls / cells)

        local cell = 0
        local strip = 0
        for k, c in ipairs(cls) do
            local g = {}

            if ( orientation == "east" and #cls > 2 )
            or ( orientation == "south" and #cls <= 2 ) then
                if #cls < (strips * cells) and strip == strips - 1 then
                    g.width = wa.width / (cells - ((strips * cells) - #cls))
                else
                    g.width = wa.width / cells
                end
                g.height = wa.height / strips

                g.x = wa.x + cell * g.width
                g.y = wa.y + strip * g.height

            else
                if #cls < (strips * cells) and strip == strips - 1 then
                    g.height = wa.height / (cells - ((strips * cells) - #cls))
                else
                    g.height = wa.height / cells
                end
                g.width = wa.width / strips

                g.x = wa.x + strip * g.width
                g.y = wa.y + cell * g.height

            end

            g.width = g.width - ext
            g.height = g.height - ext

            c:geometry(g)

            cell = cell + 1
            if cell == cells then
                cell = 0
                strip = strip + 1
            end
        end
    end
end

--- Horizontal fair layout.
-- @param screen The screen to arrange.
uselessfair.horizontal = {}
uselessfair.horizontal.name = "uselessfairh"
function uselessfair.horizontal.arrange(p)
    return fair(p, "east")
end

-- Vertical fair layout.
-- @param screen The screen to arrange.
uselessfair.name = "uselessfair"
function uselessfair.arrange(p)
    return fair(p, "south")
end

return uselessfair