-- Script will pause at the beginning of each new subtitle for the amount of time that
-- the subtitle would normally appear on the screen, multiplied by FACTOR.
-- So if a sub was going to appear for 4 seconds and you have a FACTOR of 0.5 then
-- then there will be a 2 second pause when that subtitle appears.
local FACTOR = 0.9
-- Set to true if you only want the subs displayed during the automatic pause
local HIDE_SUB_AFTER_PAUSE = true
-- Set to true if you want to anime to stay paused when you press spacebar or whatever
-- during one of the auto-pauses. Normal behavior is that pressing space would unpause
-- rather than switch into a permanently paused state that you must manually unpause.
local ENABLE_PERMA_PAUSE = true

local pause_disease = false
local auto_paused = true
local function unpause()
  if auto_paused then
    mp.set_property_native("pause", false)
    auto_paused = false
    if HIDE_SUB_AFTER_PAUSE then
      mp.set_property_bool("sub-visibility", false)
    end
  end
end

local function pause(_, subtxt)
  if not pause_disease or mp.get_property_number('sub-end') == nil or mp.get_property_bool("pause") then
    return
  end

  mp.set_property_bool("sub-visibility", true)
  if subtxt ~= "" then
    mp.set_property_native("pause", true)
    local pause_length = FACTOR * (mp.get_property_number('sub-end') - mp.get_property_number('sub-start'))
    auto_paused = true
    mp.add_timeout(pause_length, unpause)
  end
end


local function toggle_pause_disease()
  pause_disease = not pause_disease
  mp.osd_message("Pause disease " .. (pause_disease and "activated" or "deactived"), 3)
end

local function handle_pause_req(_, val)
  -- user is trying to "resume" during an auto-pause, switch modes to a regular pause
  if ENABLE_PERMA_PAUSE and val == false then
    if HIDE_SUB_AFTER_PAUSE and auto_paused == false then
      mp.set_property_bool("sub-visibility", false)
    end
    if auto_paused then
      auto_paused = false
      mp.set_property_native("pause", true)
    end
  end
end

mp.add_key_binding("ctrl+p", toggle_pause_disease)
mp.observe_property("sub-text", 'string', pause)
mp.observe_property("pause", "bool", handle_pause_req)