--[[
  PKTOK overlay setup for OBS Studio
  ---------------------------------
  Paste the overlay link from your PKTOK console, press one button, and the browser source is
  created with the settings that people otherwise get wrong by hand: the right canvas size, a
  transparent background, "shutdown when not visible" off, and browser audio routed through OBS.

  Load it in OBS: Tools -> Scripts -> "+" -> pick this file. Nothing is installed, nothing is
  sent anywhere: the script only talks to OBS on this machine.

  Docs: https://pktok.com/obs-plugin/
  Source of truth for this file: tools/obs/pktok-obs-setup.lua in the LiveTok/PKTOK repo.

  ⚠️ SECURITY RULE FOR ANYONE EDITING THIS FILE: the overlay link contains an access token, and
  OBS log files are routinely uploaded to the OBS forum's log analyzer when people ask for help.
  Never pass a raw link to script_log() — always run it through mask().
]]

obs = obslua

local VERSION = "1.0.0"

-- OBS's own default browser-source CSS. It MUST be set explicitly: a browser source created from
-- a script with an empty `css` renders on black instead of transparent.
local DEFAULT_CSS = "body { background-color: rgba(0, 0, 0, 0); margin: 0px auto; overflow: hidden; }"

-- Every source this script owns starts with this prefix, so "refresh" can find them all and a
-- streamer running two channels gets two clearly named sources instead of one fighting over both.
local SOURCE_PREFIX = "PKTOK "

-- Hosts we accept. The old app.livetok.hu is deliberately still alive for a couple of streamers
-- whose consoles hand out the legacy link, so rejecting it would break exactly those users.
local ALLOWED_HOSTS = {
  ["app.pktok.com"] = true,
  ["app.livetok.hu"] = true,
  ["localhost:3200"] = true,   -- local development
  ["127.0.0.1:3200"] = true,
}

local overlay_url = ""
local status_text = "Paste your overlay link above, then press the button."

--=============================================================================
-- helpers
--=============================================================================

-- Cut the token out of anything that may reach a log file or the UI.
local function mask(url)
  if not url or url == "" then return "(empty)" end
  return (string.gsub(url, "token=[^&]*", "token=***"))
end

local function log(msg)
  obs.script_log(obs.LOG_INFO, "[PKTOK] " .. tostring(msg))
end

local function trim(s)
  return (string.gsub(tostring(s or ""), "^%s*(.-)%s*$", "%1"))
end

-- Parse and validate the overlay link.
-- Returns a table on success, or nil plus a human-readable reason.
local function parse_overlay_url(raw)
  local url = trim(raw)
  if url == "" then
    return nil, "Paste the overlay link from your PKTOK console first."
  end

  local scheme, host, rest = string.match(url, "^(https?)://([^/]+)(/.*)$")
  if not scheme then
    return nil, "That does not look like a link. Copy the whole line from the console, starting with https://"
  end
  if not ALLOWED_HOSTS[host] then
    return nil, "This is not a PKTOK overlay link (host: " .. host .. "). Copy it from your PKTOK console."
  end

  local slug, page, query = string.match(rest, "^/overlay/([^/]+)/([^/?]+)%??(.*)$")
  if not slug then
    return nil, "This is a PKTOK link, but not an overlay link. In the console, copy the video layer link."
  end

  if page == "projector" then
    return nil, "That is the projector link (for watching), not the layer link. Copy the video layer link instead."
  end
  if page ~= "video" and page ~= "booster" then
    return nil, "Unknown overlay type: " .. page .. ". Copy the video layer link from the console."
  end

  if not string.find(query, "token=", 1, true) then
    return nil, "The link has no access token. Copy the whole link, the end of it matters too."
  end

  local landscape = string.find(query, "layout=landscape", 1, true) ~= nil
  local green = string.find(query, "bg=green", 1, true) ~= nil

  return {
    url = url,
    slug = slug,
    page = page,
    landscape = landscape,
    green = green,
    width = landscape and 1920 or 1080,
    height = landscape and 1080 or 1920,
    label = (page == "booster") and "2nd Layer" or "Overlay",
  }
end

local function source_name_for(info)
  return SOURCE_PREFIX .. info.label .. " (" .. info.slug .. ")"
end

-- Canvas size of the current OBS project.
local function canvas_size()
  local ovi = obs.obs_video_info()
  if obs.obs_get_video_info(ovi) then
    return ovi.base_width, ovi.base_height
  end
  return nil, nil
end

-- Make the item cover the whole canvas without distorting it.
local function fit_to_canvas(item)
  local cw, ch = canvas_size()
  if not cw or cw == 0 or ch == 0 then return end

  local pos = obs.vec2()
  pos.x = 0
  pos.y = 0
  obs.obs_sceneitem_set_pos(item, pos)

  local bounds = obs.vec2()
  bounds.x = cw
  bounds.y = ch
  obs.obs_sceneitem_set_alignment(item, 5)        -- OBS_ALIGN_LEFT | OBS_ALIGN_TOP
  obs.obs_sceneitem_set_bounds_type(item, obs.OBS_BOUNDS_SCALE_INNER)
  obs.obs_sceneitem_set_bounds_alignment(item, 0) -- OBS_ALIGN_CENTER
  obs.obs_sceneitem_set_bounds(item, bounds)
end

-- Ask a browser source to reload the page. The browser source exposes this as a button property;
-- clicking it programmatically is the only reliable way to force a reload from a script.
-- Older/newer OBS builds do not all expose the same id getter; calling a missing one is a hard
-- Lua error, so resolve it once and fall back.
local function source_type_id(source)
  local getter = obs.obs_source_get_unversioned_id or obs.obs_source_get_id
  if not getter then return "" end
  return getter(source) or ""
end

local function reload_browser_source(source)
  local props = obs.obs_source_properties(source)
  if not props then return false end
  local ok = false
  for _, key in ipairs({ "refreshnocache", "refresh" }) do
    local p = obs.obs_properties_get(props, key)
    if p then
      obs.obs_property_button_clicked(p, source)
      ok = true
      break
    end
  end
  obs.obs_properties_destroy(props)
  return ok
end

--=============================================================================
-- the one action: create or update the layer
--=============================================================================

local function set_up_layer()
  local info, why = parse_overlay_url(overlay_url)
  if not info then
    status_text = "⚠️ " .. why
    log("setup refused: " .. why)
    return
  end

  local scene_source = obs.obs_frontend_get_current_scene()
  if not scene_source then
    status_text = "⚠️ No scene is open in OBS. Create or select a scene first, then press the button again."
    return
  end
  local scene = obs.obs_scene_from_source(scene_source)
  if not scene then
    obs.obs_source_release(scene_source)
    status_text = "⚠️ OBS did not give back a usable scene. Select a normal scene and try again."
    return
  end

  local name = source_name_for(info)
  local notes = {}

  -- Settings that make a PKTOK layer behave: transparent, always running, audio through OBS.
  local settings = obs.obs_data_create()
  obs.obs_data_set_string(settings, "url", info.url)
  obs.obs_data_set_int(settings, "width", info.width)
  obs.obs_data_set_int(settings, "height", info.height)
  obs.obs_data_set_string(settings, "css", DEFAULT_CSS)
  obs.obs_data_set_bool(settings, "shutdown", false)
  obs.obs_data_set_bool(settings, "restart_when_active", false)
  obs.obs_data_set_bool(settings, "reroute_audio", true)

  -- Idempotent by design: running this twice must never leave two layers behind.
  local existing = obs.obs_get_source_by_name(name)
  local created = false
  local source

  if existing and source_type_id(existing) ~= "browser_source" then
    obs.obs_source_release(existing)
    obs.obs_data_release(settings)
    obs.obs_source_release(scene_source)
    status_text = "⚠️ A source called \"" .. name .. "\" already exists but is not a browser source. "
      .. "Rename or delete it, then press the button again."
    return
  end

  if existing then
    obs.obs_source_update(existing, settings)
    source = existing
    table.insert(notes, "existing layer updated")
  else
    source = obs.obs_source_create("browser_source", name, settings, nil)
    created = true
    if not source then
      obs.obs_data_release(settings)
      obs.obs_source_release(scene_source)
      status_text = "⚠️ OBS could not create a browser source. Is this a full OBS Studio install?"
      log("obs_source_create returned nil")
      return
    end
  end
  obs.obs_data_release(settings)

  local item = obs.obs_scene_find_source(scene, name)
  if item then
    -- Already in this scene: leave the streamer's own positioning alone.
    table.insert(notes, "kept its place in the scene")
  else
    item = obs.obs_scene_add(scene, source)
    if item then
      -- A freshly added item does not land on top on its own, and a PKTOK layer underneath the
      -- camera is invisible — which looks exactly like "the script did nothing". Only done when
      -- WE add it: if the layer was already in the scene, the streamer's own order is theirs.
      obs.obs_sceneitem_set_order(item, obs.OBS_ORDER_MOVE_TOP)
      fit_to_canvas(item)
      table.insert(notes, created and "added on top of the current scene" or "added to this scene too")
    end
  end

  obs.obs_source_release(source)
  obs.obs_source_release(scene_source)

  -- Warnings that are worth a sentence, not a silent fix.
  local cw, ch = canvas_size()
  if cw and ch then
    local canvas_landscape = cw > ch
    if canvas_landscape ~= info.landscape then
      table.insert(notes, string.format(
        "⚠️ your canvas is %dx%d but this link is %s — the layer will not fill the screen. "
        .. "Fix it in Settings → Video, or switch the mode in the PKTOK console.",
        cw, ch, info.landscape and "landscape (gamer mode)" or "vertical"))
    end
  end
  if info.green then
    table.insert(notes, "⚠️ this is the GREEN link, so it needs a chroma key filter. "
      .. "The transparent link from the console needs no filter — prefer that one.")
  end

  local joined = table.concat(notes, "; ")
  if string.sub(joined, -1) ~= "." then joined = joined .. "." end
  status_text = "✅ \"" .. name .. "\" is ready (" .. info.width .. "x" .. info.height .. "): " .. joined
  log("set up " .. name .. " -> " .. mask(info.url))
end

local function refresh_layers()
  local sources = obs.obs_enum_sources()
  local n = 0
  if sources then
    for _, src in ipairs(sources) do
      local nm = obs.obs_source_get_name(src)
      if nm and string.sub(nm, 1, #SOURCE_PREFIX) == SOURCE_PREFIX
         and source_type_id(src) == "browser_source" then
        if reload_browser_source(src) then n = n + 1 end
      end
    end
    obs.source_list_release(sources)
  end
  status_text = (n > 0)
    and ("🔄 Reloaded " .. n .. " PKTOK layer" .. (n == 1 and "" or "s") .. ".")
    or "Nothing to reload — no PKTOK layer exists yet."
  log(status_text)
end

--=============================================================================
-- OBS script interface
--=============================================================================

function script_description()
  return "<b>PKTOK overlay setup</b> (v" .. VERSION .. ")<br><br>"
    .. "Paste the overlay link from your PKTOK console and press the button. "
    .. "The layer is created at the right size, transparent, fitted to your canvas, "
    .. "with its sound routed through OBS.<br><br>"
    .. "Nothing is installed and nothing leaves this computer.<br>"
    .. "Help: <a href=\"https://pktok.com/obs-plugin/\">pktok.com/obs-plugin</a>"
end

function script_defaults(settings)
  obs.obs_data_set_default_string(settings, "overlay_url", "")
end

function script_update(settings)
  overlay_url = obs.obs_data_get_string(settings, "overlay_url")
end

function script_properties()
  local props = obs.obs_properties_create()

  obs.obs_properties_add_text(props, "overlay_url", "PKTOK overlay link", obs.OBS_TEXT_DEFAULT)

  obs.obs_properties_add_button(props, "setup_btn", "Set up the PKTOK layer", function(p, _)
    set_up_layer()
    local info = obs.obs_properties_get(p, "status")
    if info then obs.obs_property_set_description(info, status_text) end
    return true   -- redraw the panel so the status line below is up to date
  end)

  obs.obs_properties_add_button(props, "refresh_btn", "Reload the PKTOK layer", function(p, _)
    refresh_layers()
    local info = obs.obs_properties_get(p, "status")
    if info then obs.obs_property_set_description(info, status_text) end
    return true
  end)

  obs.obs_properties_add_text(props, "status", status_text, obs.OBS_TEXT_INFO)

  return props
end

function script_load(settings)
  overlay_url = obs.obs_data_get_string(settings, "overlay_url")
  obs.obs_frontend_add_tools_menu_item("Reload PKTOK overlay", refresh_layers)
  log("loaded, version " .. VERSION)
end