local M = {}

local awful = require("awful")
local naughty = require("naughty")

-- mapping from logical screen indices to indices corresponding to their
-- physical layout
function M.screen_physical(n)
    local function screen_cmp(s1, s2)
        return s1.geometry.x < s2.geometry.x
    end

    local screens = {}
    for s in screen do
        screens[s.index] = s
    end

    table.sort(screens, screen_cmp)

    if screens[n] ~= nil then
        return screens[n]
    end
    return nil
end

function M.screen_focus_physical(n)
    local s = M.screen_physical(n)
    if s then
        awful.screen.focus(s)
    end
end

-- audio control functions
function M.vol_control(n)
    local cmd = string.format("amixer -q set Master %d%%", math.abs(n)) .. (n < 0 and "-" or "+")
    awful.spawn(cmd)
end

function M.vol_mute_toggle()
    awful.spawn("amixer -q set Master toggle")
end

function M.auto_mute_toggle(wsp)
    local control = "'Auto-Mute Mode'"
    awful.spawn.easy_async("amixer sget " .. control,
        function(stdout, stderr, exitreason, exitcode)
            if exitcode ~= 0 then
                naughty.notify({ preset = naughty.config.presets.warn,
                                 title  = "Error getting the auto-mute mode",
                                 text   = stderr })
                return
            end

            -- parse valid auto-mute items
            local items_raw = string.match(stdout, "\n%s*Items:%s*([^\n]+)\n")
            local items = {}
            for item in string.gmatch(items_raw, "'[^']+'") do
                table.insert(items, item)
            end

            -- parse current item
            local cur_item = string.match(stdout, "\n%s*Item0:%s*('[^'\n]+')\n")

            -- find the next item
            local next_item = nil
            for i, v in ipairs(items) do
                if v == cur_item then
                    next_item = items[(i % #items) + 1]
                    break
                end
            end
            if next_item == nil then return end

            -- set the next item
            awful.spawn.easy_async('amixer -q sset ' .. control .. ' ' .. next_item,
                function(stdout, stderr, exitreason, exitcode)
                    if exitcode ~= 0 then
                        naughty.notify({ preset = naughty.config.presets.warn,
                                         title  = "Error setting the auto-mute mode",
                                         text   = stderr })
                        return
                    end

                    M.notify_singleton(wsp, 'auto_mute',
                                       { title  = "Auto-mute", text   = next_item })
                end
            )
        end)
end

function M.spawn_current(command)
    awful.spawn(command, {tag = mouse.screen.selected_tag})
end

function M.screen_lock()
    awful.spawn.easy_async("xscreensaver-command -lock",
        function(stdout, stderr, exitreason, exitcode)
            if exitcode ~= 0 then
                naughty.notify({ preset = naughty.config.presets.critical,
                                 title = "Error locking the screen",
                                 text  = table.concat({stdout, stderr}, "\n") })

            end
        end)

end

function M.notify_singleton(wsp, id, args)
    local prev_notify = wsp.notify_tbl[id]
    if prev_notify and prev_notify.box.visible then
        args.replaces_id = prev_notify.id
    end
    wsp.notify_tbl[id] = naughty.notify(args)
end

return M