-- cache for alredy resolved titles and titles that could not be resolved (filenames)
-- filename => title
local title_cache = {}

mp.register_script_message("osc_update_title", function(filename, title)
        title_cache[filename] = title
    end)

function get_playlist()
    local pos = mp.get_property_number('playlist-pos', 0) + 1
    local count, limlist = limited_list('playlist', pos)
    if count == 0 then
        return 'Empty playlist.'
    end

    local message = string.format('Playlist [%d/%d]:\n', pos, count)
    for i, v in ipairs(limlist) do
        local title = v.title
        if not title then
            -- try getting title from cache
            if title_cache[v.filename] then
                title = title_cache[v.filename]

            -- title not in cache
            else
                local _
                _, title = utils.split_path(v.filename)
                -- set title to filename
                title_cache[v.filename] = title

                -- try to resolving title in background
                mp.commandv('script-message', 'ytdl_resolve_title', v.filename)
            end
        end
        message = string.format('%s %s %s\n', message,
            (v.current and '●' or '○'), title)
    end
    return message
end