update-paths.lua

obs = obslua
os = require("os")
io = require("io")

relative_path_from_home = "Dropbox/Twitch Assets"
settings_path = ""

function refresh_button_clicked(props, p)
  update()
end

function splitpath(path)
  return string.match(path,"^(.-)[\\/]?([^\\/]*)$")
end

function pathjoin(root, path)
  if string.sub(root, string.len(root) - 1) ~= "/" and string.sub(path, 0, 0) ~= "/" then
    return root .. "/" .. path
  else
    return root .. path
  end
end

function relative_path_iterator(path)
  local i = string.len(path)
  return function()
    if i == 0 then
      return nil
    end

    repeat
      i = i - 1
    until i <= 0 or string.sub(path, i, i) == "/"

    if i == 0 then
      return path
    else
      return string.sub(path, i + 1)
    end    
  end
end

function location_for_file(file)
  -- Nothing to do
  if obs.os_file_exists(file) then
    return true, file
  end

  for relative_path in relative_path_iterator(file) do
    obs.script_log(obs.LOG_INFO, "Trying " .. relative_path)
    local proposed_file = pathjoin(settings_path, relative_path)  
    if obs.os_file_exists(proposed_file) then
      return true, proposed_file
    end
  end

  return false, ''
end

function update()
	local sources = obs.obs_enum_sources()
	if sources ~= nil then
		for _, source in ipairs(sources) do
      local source_id = obs.obs_source_get_id(source)
      local source_name = obs.obs_source_get_name(source)

      local settings = obs.obs_source_get_settings(source)
      if settings then
        local process = false
        local settings_key = nil

        if source_id == "ffmpeg_source" and obs.obs_data_get_bool(settings, "is_local_file") ~= false then
          process = true
          settings_key = "local_file"
        elseif source_id == "image_source" then
          process = true
          settings_key = "file"
        end
  
        if process then
          file_from_settings = obs.obs_data_get_string(settings, settings_key)

          local found, local_file = location_for_file(file_from_settings)
          if found then
            if file_from_settings ~= local_file then
              obs.script_log(obs.LOG_INFO, source_id .. ": " .. source_name .. ": Updated file " .. file_from_settings .. " -> " .. local_file)
              obs.obs_data_set_string(settings, settings_key, local_file)
              obs.obs_source_update(source, settings)
            else
              obs.script_log(obs.LOG_INFO, source_id .. ": " .. source_name .. ": Already up-to-date " .. file_from_settings)
            end
          else
            obs.script_log(obs.LOG_INFO, source_id .. ": " .. source_name .. ": Not found " .. file_from_settings)
          end
        end
        obs.obs_data_release(settings)
      end
		end
	end
  obs.source_list_release(sources)
end

function handle_event(event)
	if event == obs.OBS_FRONTEND_EVENT_SCENE_CHANGED then
		-- handle_scene_change()	
  end
  if event == obs.OBS_FRONTEND_EVENT_SCENE_COLLECTION_CHANGED then
    update()
  end
end

function default_path()
  local default_path = ""

  local home_directory = os.getenv("HOME")
  if home_directory then
    default_path = home_directory .. "/" .. relative_path_from_home
  end

  return default_path
end

-- A function named script_properties defines the properties that the user
-- can change for the entire script module itself
function script_properties()
	local props = obs.obs_properties_create()
	obs.obs_properties_add_path(props, "path", "Path to images", obs.OBS_PATH_DIRECTORY, nil, default_path())

	obs.obs_properties_add_button(props, "refresh", "Refresh", refresh_button_clicked)

	return props
end

-- A function named script_description returns the description shown to
-- the user
function script_description()
	return "Updates source locations for this system"
end

-- A function named script_update will be called when settings are changed
function script_update(settings)
	settings_path = obs.obs_data_get_string(settings, "path")

  update()
end

-- A function named script_defaults will be called to set the default settings
function script_defaults(settings)
	obs.obs_data_set_default_string(settings, "path", default_path())
end

-- a function named script_load will be called on startup
function script_load(settings)
  obs.obs_frontend_add_event_callback(handle_event)
end