main.lua

-- TODO why is mpv sometimes but not always slow to quit? (takes few seconds
--      before btfs_cleanup is called)
--   - this happens even when running btfs outside mpv
--   - TODO don't need extra bash scripts (they don't help with this issue I
--      don't think)
-- TODO possible before fusermount -u was not slow and was actually above issue;
--      double check and get rid of shell scripts if this is the case
-- TODO btfs mount will fail for previously mounted torrents if unmount is false
--      (but this doesn't actually cause any problems, just a fuse message)

local settings = {
   unmount = true,
   base_mount_directory = "/tmp/mpv-btfs",
   only_handle_prefixed_files = false,
   btfs_data_directory = "",
   btfs_flags = [[]],
}

(require "mp.options").read_options(settings, "btfs-stream")

local utils = require "mp.utils";

local btfs_mountpoints = {}

-- * Helpers
-- http://lua-users.org/wiki/StringRecipes
local function ends_with(str, ending)
   return ending == "" or str:sub(-#ending) == ending
end

local function is_handled_url(url)
   if settings.only_handle_prefixed_files then
      return url:find("btfs://") == 1
   else
      return (url:find("magnet:") == 1 or url:find("peerflix://") == 1
                 or url:find("btfs://") == 1
                 or ends_with(url, "torrent"))
   end
end

-- * Main
local function btfs_play_torrent()
   local url = mp.get_property("stream-open-filename")
   if is_handled_url(url) then
      if url:find("btfs://") == 1 then
         url = url:sub(8)
      end
      if url:find("peerflix://") == 1 then
         url = url:sub(12)
      end

      local new_dir = mp.get_time()
      local torrent_info = mp.command_native({
            name = "subprocess",
            playback_only = false,
            capture_stdout = true,
            args = {"webtorrent", "info", url},
      })
      if torrent_info.status == 0  then
         local infoHash = utils.parse_json(torrent_info.stdout)["infoHash"]
         if infoHash ~= nil then
            new_dir = infoHash
         end
      end
      local mount_dir = utils.join_path(settings.base_mount_directory, new_dir)
      mp.commandv("run", "mkdir", "-p", mount_dir)

      local btfs_command = {"run", "btfs"}
      local btfs_flags = utils.parse_json(settings.btfs_flags)
      if btfs_flags ~= nil then
         for _, flag in pairs(btfs_flags) do
            table.insert(btfs_command, flag)
         end
      end
      if settings.btfs_data_directory ~= "" then
         local data_dir = mp.command_native({"expand-path",
                                             settings.btfs_data_directory})
         table.insert(btfs_command, "--data-directory=" .. data_dir)
      end
      table.insert(btfs_command, url)
      table.insert(btfs_command, mount_dir)
      mp.command_native(btfs_command)

      mp.msg.info("Waiting for video to load")
      -- os.execute('until find "' .. mount_dir ..  '" -mindepth 1 -maxdepth 1 | read; do sleep 1; done')
      while utils.readdir(mount_dir)[1] == nil do
         os.execute("sleep 1")
      end

      table.insert(btfs_mountpoints, mount_dir)
      mp.set_property("stream-open-filename", mount_dir)
   end
end

local function btfs_cleanup()
   if settings.unmount then
      local script_dir = mp.get_script_directory()
      local cleanup_script_path =
         utils.join_path(script_dir, "background-btfs-cleanup.sh")
      for _, mount_dir in pairs(btfs_mountpoints) do
         -- os.execute, commandv, and command_native all block even with nohup
         -- from docs: "Only the run command can start processes in a truly
         -- detached way." (not supbrocess)
         mp.msg.verbose("Unmounting and deleting " .. mount_dir)
         mp.command_native_async({
               "run", cleanup_script_path, script_dir, mount_dir
         })
      end
   end
end

mp.add_hook("on_load", 50, btfs_play_torrent)

mp.register_event("shutdown", btfs_cleanup)