--!nonstrict
-- Headless [[service]]: the single poller behind the OSTT recorder widget.
--
-- ostt writes $XDG_RUNTIME_DIR/ostt/recording.pid while the microphone is
-- capturing (and keeps the process alive through transcription). This service
-- polls that pidfile (liveness-checked — ostt leaves a stale file behind when
-- it is killed) plus a wrapper-written exit-code file, derives a phase, and
-- publishes it to the plugin state channel:
--
--   status = { phase = "idle"|"starting"|"recording"|"transcribing",
--              pid = number?, elapsed = seconds }
--
-- The recorder widget writes an `intent` record for every action it takes so
-- the service can distinguish widget-started sessions (notify on completion,
-- report failures) from external ones (`ostt launch` hotkeys — stay silent,
-- ostt's own popup already reports those):
--
--   intent = { action = "start"|"stop"|"cancel", pid = number?,
--              mode = "paste"|"clipboard", notify = boolean } | false
--
-- Time comes from the poll shell (`date +%s`), not the Luau VM, so elapsed
-- math never depends on os.* availability in the sandbox.

local function shq(s)
  return "'" .. (s:gsub("'", "'\\''")) .. "'"
end

local runtime = noctalia.getenv("XDG_RUNTIME_DIR")
local user = noctalia.getenv("USER") or "unknown"
local osttRuntimeDir = runtime and (runtime .. "/ostt") or ("/tmp/ostt-" .. user)
local pidFile = osttRuntimeDir .. "/recording.pid"
local exitFile = (runtime or "/tmp") .. "/noctalia-ostt-exit"

-- Emits one line: "<epoch> <live-pid|-> <exit-code|->"
local pollCmd = table.concat({
  "t=$(date +%s)",
  "p=$(cat " .. shq(pidFile) .. " 2>/dev/null)",
  'if [ -n "$p" ] && kill -0 "$p" 2>/dev/null; then :; else p=-; fi',
  "e=$(cat " .. shq(exitFile) .. " 2>/dev/null)",
  '[ -n "$e" ] || e=-',
  'echo "$t $p $e"',
}, "; ")

local STARTING_GRACE = 6 -- seconds to wait for the pidfile after a start intent

local phase = "idle"
local since = nil -- epoch when the live recorder was first observed
local startingSince = nil -- epoch when the start intent was first observed
local polling = false

local function getIntent()
  local v = noctalia.state.get("intent")
  return type(v) == "table" and v or nil
end

local function clearIntent()
  noctalia.state.set("intent", false)
end

local function publish(newPhase, pid, elapsed)
  phase = newPhase
  noctalia.state.set("status", { phase = newPhase, pid = pid, elapsed = elapsed or 0 })
  -- Poll faster while a session is in flight so stop/cancel feel immediate.
  noctalia.setUpdateInterval(newPhase == "idle" and 1000 or 500)
end

-- Session ended (pid gone). Notify only for widget-started sessions where the
-- wrapper reported an exit code; external sessions have neither intent nor
-- exit file and stay silent.
local function finishSession(exitCode)
  local intent = getIntent()
  clearIntent()
  noctalia.runAsync("rm -f " .. shq(exitFile))
  if not intent or intent.action == "cancel" then
    return
  end
  if exitCode == "0" then
    if intent.notify then
      local key = intent.mode == "paste" and "notify.done_paste" or "notify.done_clipboard"
      noctalia.notify(noctalia.tr("title"), noctalia.tr(key))
    end
  elseif exitCode ~= nil then
    noctalia.notifyError(noctalia.tr("title"), noctalia.tr("notify.failed", { code = exitCode }))
  end
end

local function handlePoll(t, pid, exitCode)
  local intent = getIntent()

  if pid then
    startingSince = nil
    -- Cancel raced the startup: the recorder appeared after the widget gave
    -- up on it. Kill it instead of adopting it.
    if intent and intent.action == "cancel" then
      noctalia.runAsync("kill -TERM " .. pid .. " 2>/dev/null; rm -f " .. shq(pidFile))
      clearIntent()
      publish("idle")
      return
    end
    since = since or t
    local stopping = intent and intent.action == "stop" and intent.pid == pid
    publish(stopping and "transcribing" or "recording", pid, t - since)
    return
  end

  -- No live recorder.
  local wasActive = phase == "recording" or phase == "transcribing"
  since = nil
  if wasActive then
    startingSince = nil
    finishSession(exitCode)
    publish("idle")
    return
  end

  if intent and intent.action == "start" then
    if exitCode then
      -- The wrapped command exited before the pidfile ever appeared
      -- (e.g. no audio device, ostt misconfigured).
      startingSince = nil
      finishSession(exitCode)
      publish("idle")
    else
      startingSince = startingSince or t
      if t - startingSince > STARTING_GRACE then
        startingSince = nil
        clearIntent()
        noctalia.notifyError(noctalia.tr("title"), noctalia.tr("notify.start_timeout"))
        publish("idle")
      else
        publish("starting")
      end
    end
    return
  end

  -- A cancel that raced startup: keep it briefly so a late-appearing recorder
  -- still gets killed, then expire it so it can never hit a future session.
  if intent and intent.action == "cancel" then
    startingSince = startingSince or t
    if t - startingSince > STARTING_GRACE then
      startingSince = nil
      clearIntent()
    end
    publish("idle")
    return
  end

  startingSince = nil
  if phase ~= "idle" then
    publish("idle")
  end
end

local function doPoll()
  if polling then
    return
  end
  polling = true
  local started = noctalia.runAsync(pollCmd, function(res)
    polling = false
    if res.exitCode ~= 0 then
      return
    end
    local t, pid, exitCode = string.match(res.stdout, "(%d+)%s+(%S+)%s+(%S+)")
    if not t then
      return
    end
    handlePoll(tonumber(t), pid ~= "-" and tonumber(pid) or nil, exitCode ~= "-" and exitCode or nil)
  end)
  if not started then
    polling = false
  end
end

-- React to widget actions immediately instead of waiting for the next tick.
noctalia.state.watch("intent", function()
  doPoll()
end)

noctalia.setUpdateInterval(1000)

function update()
  doPoll()
end