require 'mp.options'

function handle_file_load ()
    if mp.get_property("metadata/by-key/artist") == nil and mp.get_property("metadata/by-key/title") == nil then
        -- media-title is filename if no title is set
        if mp.get_property("media-title") ~= mp.get_property("filename") then
            info = mp.get_property("media-title")
        else
            info = mp.get_property("filename/no-ext")
        end
    else
        info = mp.get_property("metadata/by-key/artist") .. " – " .. mp.get_property("metadata/by-key/title")
    end

    -- check for youtube-dl
    if mp.get_property("stream-open-filename") ~= mp.get_property("path") then
        info = info .. "\n(" .. mp.get_property("path") .. ")"
    end

    file = io.open(options.write, "w")
    io.output(file)
    io.write(info .. "\n")
    io.close(file)
end

options = {
    write = "",
}
read_options(options)

if options.write ~= "" then
    mp.register_event("file-loaded", handle_file_load)
end