--[[

     Awesome-Freedesktop
     Freedesktop.org compliant desktop entries and menu

     Menu section

     Licensed under GNU General Public License v2
      * (c) 2016, Luke Bonham
      * (c) 2014, Harvey Mittens

--]]

local awful_menu = require("awful.menu")
local menu_gen   = require("menubar.menu_gen")
local menu_utils = require("menubar.utils")
local icon_theme = require("menubar.icon_theme")

local io, pairs, string, table, os = io, pairs, string, table, os

-- Add support for NixOS systems too
table.insert(menu_gen.all_menu_dirs, string.format("%s/.nix-profile/share/applications", os.getenv("HOME")))

-- Expecting a wm_name of awesome omits too many applications and tools
menu_utils.wm_name = ""

-- Menu
-- freedesktop.menu
local menu = {}

-- Determines if a path points to a directory, by checking if it can be read
-- (which is `nil` also for empty files) and if its size is not 0.
-- @author blueyed
-- @param path the path to check
function menu.is_dir(path)
    local f = io.open(path)
    return f and not f:read(0) and f:seek("end") ~= 0 and f:close()
end

-- Remove non existent paths in order to avoid issues
local existent_paths = {}
for k,v in pairs(menu_gen.all_menu_dirs) do
    if menu.is_dir(v) then
        table.insert(existent_paths, v)
    end
end
menu_gen.all_menu_dirs = existent_paths

-- Determines whether an table includes a certain element
-- @param tab a given table
-- @param val the element to search for
-- @return true if the given string is found within the search table; otherwise, false if not
function menu.has_value (tab, val)
    for index, value in pairs(tab) do
        if val:find(value) then
            return true
        end
    end
    return false
end

-- Use MenuBar parsing utils to build a menu for Awesome
-- @return awful.menu
function menu.build(args)
    local args       = args or {}
    local icon_size  = args.icon_size
    local before     = args.before or {}
    local after      = args.after or {}
    local skip_items = args.skip_items or {}
    local sub_menu   = args.sub_menu or false

    local result     = {}
    local _menu      = awful_menu({ items = before })

    menu_gen.generate(function(entries)
        -- Add category icons
        for k, v in pairs(menu_gen.all_categories) do
            table.insert(result, { k, {}, v.icon })
        end

        -- Get items table
        for k, v in pairs(entries) do
            for _, cat in pairs(result) do
                if cat[1] == v.category then
                    if not menu.has_value(skip_items, v.name) then
                        table.insert(cat[2], { v.name, v.cmdline, v.icon })
                    end
                    break
                end
            end
        end

        -- Cleanup things a bit
        for i = #result, 1, -1 do
            local v = result[i]
            if #v[2] == 0 then
                -- Remove unused categories
                table.remove(result, i)
            else
                --Sort entries alphabetically (by name)
                table.sort(v[2], function (a, b) return string.byte(a[1]) < string.byte(b[1]) end)
                -- Replace category name with nice name
                v[1] = menu_gen.all_categories[v[1]].name
            end
        end

        -- Sort categories alphabetically also
        table.sort(result, function(a, b) return string.byte(a[1]) < string.byte(b[1]) end)

        -- Add menu item to hold the generated menu
        if sub_menu then
            result = {{sub_menu, result}}
        end

        -- Add items to menu
        for _, v in pairs(result) do _menu:add(v) end
        for _, v in pairs(after)  do _menu:add(v) end
    end)

    -- Set icon size
    if icon_size then
        for _,v in pairs(menu_gen.all_categories) do
            v.icon = icon_theme():find_icon_path(v.icon_name, icon_size)
        end
    end

    -- Hold the menu in the module
    menu.menu = _menu

    return _menu
end

return menu
