// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/actor/actor_task.h"

#include <memory>
#include <optional>
#include <ostream>

#include "base/barrier_callback.h"
#include "base/cancelable_callback.h"
#include "base/containers/map_util.h"
#include "base/feature_list.h"
#include "base/no_destructor.h"
#include "base/state_transitions.h"
#include "base/strings/to_string.h"
#include "base/task/sequenced_task_runner.h"
#include "build/build_config.h"
#include "chrome/browser/actor/action_tracker_for_metrics.h"
#include "chrome/browser/actor/actor_keyed_service.h"
#include "chrome/browser/actor/actor_metrics.h"
#include "chrome/browser/actor/enterprise_policy_checker.h"
#include "chrome/browser/actor/execution_engine.h"
#include "chrome/browser/actor/tab_observation_strategy.h"
#include "chrome/browser/actor/ui/event_dispatcher.h"
#include "chrome/browser/glic/public/glic_perf_traits_tracker.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/actor.mojom-forward.h"
#include "chrome/common/actor/action_result.h"
#include "chrome/common/actor_webui.mojom.h"
#include "chrome/common/chrome_features.h"
#include "components/actor/core/actor_features.h"
#include "components/actor/core/actor_ui_mode.h"
#include "components/actor/core/journal_details_builder.h"
#include "components/actor/public/mojom/actor_types.mojom.h"
#include "components/performance_manager/public/decorators/page_live_state_decorator.h"
#include "components/tabs/public/tab_interface.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/page.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_widget_host.h"
#include "content/public/browser/render_widget_host_view.h"
#include "content/public/browser/visibility.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/buildflags.h"
#include "ui/gfx/geometry/size.h"

namespace actor {

namespace {

void MaybeRunLater(base::OnceClosure task) {
  // TODO(b/461256502): This killswitch-guarded change made it so the doesn't
  // re-post the reply from Act() but this means (to ensure consistent async
  // behavior) we need to PostTask the cases where we would otherwise run the
  // callback synchronously. Once this killswitch is removed this function can
  // be renamed to RunLater.
  if (base::FeatureList::IsEnabled(
          actor::kGlicPerformActionsReturnsBeforeStateChange)) {
    base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, std::move(task));
  } else {
    std::move(task).Run();
  }
}

bool IsStateActorControlledAndNotWaiting(ActorTask::State state) {
  return (state == ActorTask::State::kCreated ||
          state == ActorTask::State::kActing ||
          state == ActorTask::State::kReflecting);
}

bool IsStateActorControlled(ActorTask::State state) {
  return IsStateActorControlledAndNotWaiting(state) ||
         // Although waiting on the user, this state is used when the user can
         // only interact with the client. i.e. The user cannot interact with
         // the task's tabs in this state so it is still considered to be under
         // the client's control.
         state == ActorTask::State::kWaitingOnUser;
}

bool IsInterruptedState(ActorTask::State state) {
  return (state == ActorTask::State::kWaitingOnUser ||
          state == ActorTask::State::kPausedByActor ||
          state == ActorTask::State::kPausedByUser);
}

void SetFocusState(content::WebContents* contents,
                   std::optional<bool> focus_state) {
  if (content::RenderWidgetHostView* view =
          contents->GetRenderWidgetHostView()) {
    if (content::RenderWidgetHost* host = view->GetRenderWidgetHost()) {
      // If a new state was provided, use that. Otherwise us the state from
      // the view.
      bool new_state = focus_state.value_or(view->HasFocus());
      if (new_state) {
        host->Focus();
      } else {
        host->Blur();
      }
    }
  }
}

}  // namespace

ActorTask::ActorControlledTabState::ActorControlledTabState(
    ActorTask* task,
    bool stop_task_on_detach)
    : task(task), stop_task_on_detach(stop_task_on_detach) {}
ActorTask::ActorControlledTabState::~ActorControlledTabState() {
  // Stop observing the Webcontents immediately to prevent reentrant calls to
  // OnVisibilityChanged() when other members (e.g. `actuation_runner`) are
  // destroyed.
  Observe(nullptr);
}

void ActorTask::ActorControlledTabState::SetContents(
    content::WebContents* contents) {
  Observe(contents);
}

void ActorTask::ActorControlledTabState::PrimaryPageChanged(
    content::Page& page) {
  content::WebContents* contents =
      content::WebContents::FromRenderFrameHost(&page.GetMainDocument());
  if (task->IsUnderActorControl()) {
    task->DidContentsEnterActorControl(this, contents);
  } else {
    task->DidContentsExitActorControl(this, contents);
  }
}

void ActorTask::ActorControlledTabState::OnVisibilityChanged(
    content::Visibility visibility) {
  if (!task->IsUnderActorControl()) {
    return;
  }
  task->UpdateVisibilityTimes();
  task->RecomputeHasVisibleTab();
}

ActorTask::ActorTask(
    base::PassKey<ActorKeyedService, ActorTask>,
    ActorKeyedService& service,
    TaskId id,
    std::unique_ptr<ui::UiEventDispatcher> ui_event_dispatcher,
    webui::mojom::TaskOptionsPtr options,
    const TaskSourceInfo& source_info,
    const EnterprisePolicyChecker* policy_checker,
    base::WeakPtr<ActorTaskDelegate> delegate,
    std::optional<glic::mojom::InvocationSource> initial_invocation_source)
    : service_(service),
      id_(id),
      source_info_(source_info),
      create_time_(base::TimeTicks::Now()),
      action_tracker_for_metrics_(std::make_unique<ActionTrackerForMetrics>()),
      ui_event_dispatcher_(std::move(ui_event_dispatcher)),
      journal_(service_->GetJournal().GetSafeRef()),
      title_(options && options->title.has_value() ? options->title.value()
                                                   : ""),
      duration_(options && options->duration.has_value() &&
                        options->duration.value() ==
                            actor::webui::mojom::TaskDuration::kTransient
                    ? TaskDuration::kTransient
                    : TaskDuration::kDefault),
      feature_mode_(options && options->feature_mode.has_value()
                        ? options->feature_mode.value()
                        : glic::mojom::FeatureMode::kUnspecified),
      initial_invocation_source_(initial_invocation_source),
      policy_checker_(*policy_checker),
      delegate_(std::move(delegate)),
      ui_weak_ptr_factory_(ui_event_dispatcher_.get()) {
  CHECK(policy_checker);
  CHECK(!id_.is_null());
  execution_engine_ = ExecutionEngine::Create(*this);
}

ActorTask::~ActorTask() {
  // The owner of the ActorTasks (ActorKeyedService) should have stopped all
  // tasks already.
  CHECK(IsCompleted());
}

// static
std::unique_ptr<ActorTask> ActorTask::CreateForTesting(
    ActorKeyedService& service,
    TaskId id,
    std::unique_ptr<ui::UiEventDispatcher> ui_event_dispatcher,
    webui::mojom::TaskOptionsPtr options,
    const TaskSourceInfo& source_info,
    const EnterprisePolicyChecker* policy_checker,
    base::WeakPtr<ActorTaskDelegate> delegate,
    std::optional<glic::mojom::InvocationSource> initial_invocation_source) {
  return std::make_unique<ActorTask>(
      base::PassKey<ActorTask>(), service, id, std::move(ui_event_dispatcher),
      std::move(options), source_info, policy_checker, std::move(delegate),
      initial_invocation_source);
}

ExecutionEngine& ActorTask::GetExecutionEngine() const {
  CHECK(execution_engine_);
  return *execution_engine_;
}

ActorTask::State ActorTask::GetState() const {
  return state_;
}

base::WeakPtr<ActorTask> ActorTask::GetWeakPtr() {
  return weak_ptr_factory_.GetWeakPtr();
}

Profile* ActorTask::GetProfile() const {
  return service_->GetProfile();
}

#if BUILDFLAG(IS_ANDROID)
void ActorTask::SetIsInPip(bool is_in_pip) {
  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
  is_in_pip_ = is_in_pip;
}
#endif

ActorUiMode ActorTask::GetUiMode() const {
  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
  if (is_in_pip_) {
    return ActorUiMode::kPip;
  }
  return has_visible_tab_ ? ActorUiMode::kForeground : ActorUiMode::kBackground;
}

void ActorTask::SetState(State new_state) {
  using enum State;
  journal_->Log(GURL(), id(), "ActorTask::SetState",
                JournalDetailsBuilder()
                    .Add("current_state", ToString(state_))
                    .Add("new_state", ToString(new_state))
                    .Build());
#if DCHECK_IS_ON()
  static const base::NoDestructor<base::StateTransitions<State>>
      allowed_transitions(base::StateTransitions<State>(
          {{kCreated,
            {kActing, kReflecting, kPausedByActor, kPausedByUser, kCancelled,
             kFinished, kFailed}},
           {kActing,
            {kReflecting, kPausedByActor, kPausedByUser, kCancelled, kFinished,
             kWaitingOnUser, kFailed}},
           {kReflecting,
            {kActing, kPausedByActor, kPausedByUser, kCancelled, kFinished,
             kWaitingOnUser, kFailed}},
           {kPausedByActor, {kReflecting, kCancelled, kFinished, kFailed}},
           {kPausedByUser, {kReflecting, kCancelled, kFinished, kFailed}},
           {kWaitingOnUser,
            {kActing, kReflecting, kPausedByActor, kPausedByUser, kCancelled,
             kFinished, kFailed}},
           {kCancelled, {}},
           {kFailed, {}},
           {kFinished, {}}}));
  if (new_state != state_) {
    DCHECK_STATE_TRANSITION(allowed_transitions,
                            /*old_state=*/state_,
                            /*new_state=*/new_state);
  }
#endif  // DCHECK_IS_ON()

  // Actor and user control states must be mutually exclusive.
  CHECK(IsCompleted() || IsUnderActorControl() != IsUnderUserControl());

  action_tracker_for_metrics_->WillMoveToState(new_state);

  State old_state = state_;
  const base::TimeDelta old_state_duration = current_state_timer_.Elapsed();

  // If the old state was active, add its duration to the total active time for
  // the task.
  if (IsStateActorControlledAndNotWaiting(old_state)) {
    total_actor_controlled_active_time_ += old_state_duration;
  }

  // Record granular state transition histograms.
  RecordActorTaskStateTransitionDuration(old_state_duration, old_state);
  RecordActorTaskStateTransitionActionCount(actions_in_current_state_,
                                            old_state, new_state);

  state_ = new_state;
  current_state_timer_ = base::ElapsedTimer();
  actions_in_current_state_ = 0;
  // When transitioning into an actor-controlled state, start the timer for
  // visibility metrics and prepare each tab for actuation.
  if (IsStateActorControlled(new_state) && !IsStateActorControlled(old_state)) {
    visibility_timer_ = base::ElapsedTimer();
    for (const auto& [tab, _] : controlled_tabs_) {
      DidTabEnterActorControl(tab);
    }
    // When transitioning out of an actor-controlled state, record the final
    // visibility duration and clean up each tab.
  } else if (!IsStateActorControlled(new_state) &&
             IsStateActorControlled(old_state)) {
    UpdateVisibilityTimes();
    for (const auto& [tab, _] : controlled_tabs_) {
      DidTabExitActorControl(tab);
    }
    ResetToObserveTabsSet();
    ResetAdditionalTabObservations();
  }
  if (IsInterruptedState(new_state)) {
    ++total_number_of_interruptions_;
  }

  // Stopped tasks are tracked separately as they need to store additional
  // stopped_reason_ before they're cleared.
  if (!stopped_reason_) {
    ActorTask::State ui_task_state = new_state;
    // TODO(crbug.com/484367299): Implement a proper actor task state for
    // interrupt-with-user-control.
    if (base::FeatureList::IsEnabled(kActorFormScriptToolInterrupt) &&
        new_state == kWaitingOnUser && interrupted_task_needs_user_control_) {
      ui_task_state = kPausedByActor;
    }
    ui_event_dispatcher_->OnActorTaskSyncChange(
        ui::UiEventDispatcher::ChangeTaskState{.task_id = id_,
                                               .old_state = old_state,
                                               .new_state = ui_task_state});
  }
  service_->NotifyTaskStateChanged(*this);

  // If the state is to be finished/cancelled record a histogram.
  if (state_ == kFinished || state_ == kCancelled || state_ == kFailed) {
    CHECK(stopped_reason_.has_value());
    RecordActorTaskVisibilityDurationHistograms(
        total_time_visible_, total_time_not_visible_, stopped_reason_.value());
    RecordActorTaskCompletion(
        stopped_reason_.value(), base::TimeTicks::Now() - create_time_,
        total_actor_controlled_active_time_, total_number_of_interruptions_,
        total_number_of_actions_, initial_invocation_source_);
  }
}

void ActorTask::Act(std::vector<std::unique_ptr<ToolRequest>>&& actions,
                    ActCallback callback) {
  if (IsUnderUserControl()) {
    journal_->Log(GURL(), id(), "ActorTask::Act",
                  JournalDetailsBuilder().AddError("Task is paused").Build());
    MaybeRunLater(
        base::BindOnce(std::move(callback),
                       MakeResultVector(mojom::ActionResultCode::kTaskPaused),
                       TabObservationStrategy()));
    return;
  }
  if (IsCompleted()) {
    journal_->Log(GURL(), id(), "ActorTask::Act",
                  JournalDetailsBuilder().AddError("Task is Stopped").Build());
    MaybeRunLater(
        base::BindOnce(std::move(callback),
                       MakeResultVector(mojom::ActionResultCode::kTaskWentAway),
                       TabObservationStrategy()));
    return;
  }

  if (state_ == State::kWaitingOnUser) {
    journal_->Log(
        GURL(), id(), "ActorTask::Act",
        JournalDetailsBuilder().AddError("Task is Waiting for User").Build());
    MaybeRunLater(base::BindOnce(
        std::move(callback),
        MakeResultVector(mojom::ActionResultCode::kInvalidTaskStateForAct),
        TabObservationStrategy()));
    return;
  }

  ResetToObserveTabsSet();
  ResetAdditionalTabObservations();

  callback_for_act_ = std::move(callback);

  // TODO(b/474410401): ActorTask tabs should be explicitly added by the client.
  if (base::FeatureList::IsEnabled(kGlicEarlyAddTaskTabs)) {
    absl::flat_hash_set<tabs::TabHandle> tabs_to_add;
    for (const std::unique_ptr<ToolRequest>& request : actions) {
      CHECK(request);
      tabs::TabHandle tab = request->GetTabHandle();
      if (tab != tabs::TabHandle::Null()) {
        tabs_to_add.insert(tab);
      }
    }

    did_add_tabs_callback_.Reset(base::BindOnce(
        &ActorTask::DidEarlyAddTabs, GetWeakPtr(), std::move(actions)));
    auto add_tabs_barrier = base::BarrierCallback<mojom::ActionResultPtr>(
        tabs_to_add.size(), did_add_tabs_callback_.callback());
    for (const tabs::TabHandle& tab : tabs_to_add) {
      AddTab(tab, /*stop_task_on_detach=*/true, add_tabs_barrier);
    }
  } else {
    SetState(State::kActing);

    actions_in_current_state_ += actions.size();
    total_number_of_actions_ += actions.size();

    action_tracker_for_metrics_->WillAct(actions);

    execution_engine_->Act(std::move(actions),
                           base::BindOnce(&ActorTask::OnFinishedAct,
                                          weak_ptr_factory_.GetWeakPtr()));
  }
}

void ActorTask::OnFinishedAct(
    std::vector<ActionResultWithLatencyInfo> action_results,
    TabObservationStrategy observation_strategy) {
  mojom::ActionResultPtr result = MakeOkResult();
  for (const auto& action_result : action_results) {
    if (!IsOk(action_result.result->code)) {
      result = action_result.result->Clone();
      break;
    }
  }

  if (state_ != State::kActing) {
    // Note: this likely isn't a problem when it happens - e.g. the task was
    // paused while the act was in progress but we note it here for debugging
    // purposes.
    journal_->Log(GURL(), id(), "ActorTask::OnFinishedAct",
                  JournalDetailsBuilder()
                      .Add("result", result ? ToDebugString(*result) : "null")
                      .Add("Not in kActing state", base::ToString(state_))
                      .Build());
  }

  // TODO(b/472322151): There's a subtle bug here - when we pause a task
  // callback_for_act_ is invoked immediately and
  // ExecutionEngine::CancelOngoingActions is used to terminate ExecutionEngine.
  // This relies on ActorTask's state not changing until the callback from
  // ExecutionEngine (this function) is invoked. However, if that takes longer
  // than expected and the task is resumed and a new action is sent to Act we
  // could end up here from the canceled call and acting on a new
  // `callback_for_act_`. Consider using a cancelable callback or specially
  // handling a pause result code.

  // The callback may already have been called, if the task was stopped or
  // paused.
  const bool is_paused_result =
      result && result->code == mojom::ActionResultCode::kTaskPaused;
  if (callback_for_act_) {
    // Interruption (WaitingOnUser) can happen while acting, but in that case
    // the tool is the source and must not finish before uninterrupting.
    DCHECK(state_ == State::kCreated || state_ == State::kActing ||
           IsUnderUserControl());
    if (result) {
      action_tracker_for_metrics_->OnFinishedAct(*result);
    }
    std::move(callback_for_act_)
        .Run(std::move(action_results), std::move(observation_strategy));
  }

  if (state_ == State::kActing ||
      (state_ == State::kPausedByActor && !is_paused_result)) {
    SetState(State::kReflecting);
  }
}

void ActorTask::Stop(StoppedReason stop_reason) {
  // Invoke the callback before changing states so that the client sees the Act
  // result before seeing the state transition.
  mojom::ActionResultCode result_code = mojom::ActionResultCode::kTaskWentAway;
  if (stop_reason == StoppedReason::kUserNavigatedAway) {
    result_code = mojom::ActionResultCode::kUserNavigatedAway;
  }

  if (callback_for_act_) {
    DCHECK(state_ == State::kActing || state_ == State::kWaitingOnUser);
    mojom::ActionResultPtr result = MakeResult(result_code);
    action_tracker_for_metrics_->OnFinishedAct(*result);
    std::move(callback_for_act_)
        .Run(MakeResultVector(std::move(result)), TabObservationStrategy());
  }

  CancelOngoingActions(result_code);

  end_time_ = base::Time::Now();
  State final_state = GetTaskStateFromStoppedReason(stop_reason);
  stopped_reason_ = stop_reason;
  // Remove all the tabs from the task.
  tabs::TabHandle last_tab_handle;
  while (!controlled_tabs_.empty()) {
    last_tab_handle = controlled_tabs_.begin()->first;
    RemoveTab(controlled_tabs_.begin()->first);
  }

  SetState(final_state);

  ui_event_dispatcher_->OnActorTaskSyncChange(ui::UiEventDispatcher::StopTask{
      .task_id = id_,
      .final_state = final_state,
      .title = title_,
      .last_acted_on_tab_handle = last_tab_handle,
      .duration = duration_,
      .feature_mode = feature_mode_});
}

void ActorTask::Pause(bool from_actor, bool cancel_existing_action) {
  if (IsCompleted()) {
    return;
  }

  // Invoke the callback before changing states so that the client sees the Act
  // result before seeing the state transition.
  if (callback_for_act_ && cancel_existing_action) {
    DCHECK(state_ == State::kActing || state_ == State::kWaitingOnUser ||
           state_ == State::kCreated);
    mojom::ActionResultPtr result =
        MakeResult(mojom::ActionResultCode::kTaskPaused);
    action_tracker_for_metrics_->OnFinishedAct(*result);
    std::move(callback_for_act_)
        .Run(MakeResultVector(std::move(result)), TabObservationStrategy());
  }

  if (cancel_existing_action) {
    CancelOngoingActions(mojom::ActionResultCode::kTaskPaused);
  } else {
    execution_engine_->PauseOngoingActions();
  }
  if (from_actor) {
    SetState(State::kPausedByActor);
  } else {
    SetState(State::kPausedByUser);
  }
}

void ActorTask::Resume() {
  // Only resume from a paused state.
  if (!IsUnderUserControl()) {
    return;
  }

  SetState(State::kReflecting);
}

void ActorTask::Interrupt(bool retain_user_control,
                          InterruptReason interrupt_reason) {
  if (GetState() != State::kReflecting && GetState() != State::kActing) {
    return;
  }
  interrupted_task_needs_user_control_ = retain_user_control;
  execution_engine_->PauseOngoingActions();
  interrupt_reason_ = interrupt_reason;
  SetState(State::kWaitingOnUser);
}

void ActorTask::Uninterrupt(State resumed_state) {
  if (GetState() != State::kWaitingOnUser) {
    return;
  }
  interrupt_reason_ = std::nullopt;
  interrupted_task_needs_user_control_ = false;
  SetState(resumed_state);
  execution_engine_->DidUninterruptTask();
}

bool ActorTask::CancelOngoingActions(mojom::ActionResultCode reason) {
  if (IsCompleted()) {
    return false;
  }
  did_add_tabs_callback_.Cancel();
  execution_engine_->CancelOngoingActions(reason);

  switch (reason) {
    case mojom::ActionResultCode::kTaskWentAway:
    case mojom::ActionResultCode::kActionsCancelled:
    case mojom::ActionResultCode::kUserNavigatedAway:
      execution_engine_->RunUserTakeoverCallbackIfExists(
          /*should_cancel=*/true);
      break;
    case mojom::ActionResultCode::kTaskPaused:
      execution_engine_->RunUserTakeoverCallbackIfExists(
          /*should_cancel=*/false);
      break;
    default:
      NOTREACHED();
  }

  return true;
}

bool ActorTask::IsUnderUserControl() const {
  return GetState() == State::kPausedByActor ||
         GetState() == State::kPausedByUser ||
         interrupted_task_needs_user_control_;
}

bool ActorTask::IsUnderActorControl() const {
  return IsStateActorControlled(state_) &&
         !interrupted_task_needs_user_control_;
}

bool ActorTask::IsCompleted() const {
  return IsCompletedState(GetState());
}

// static
bool ActorTask::IsCompletedState(State state) {
  return (state == State::kFinished) || (state == State::kCancelled) ||
         (state == State::kFailed);
}

base::Time ActorTask::GetEndTime() const {
  return end_time_;
}

void ActorTask::AddTab(tabs::TabHandle tab_handle,
                       bool stop_task_on_detach,
                       AddTabCallback callback) {
  if (!IsUnderActorControl()) {
    journal_->Log(
        GURL(), id(), "ActorTask::AddTab",
        JournalDetailsBuilder().AddError("Not Under Actor Control").Build());
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE,
        base::BindOnce(
            std::move(callback),
            MakeResult(IsUnderUserControl()
                           ? mojom::ActionResultCode::kTaskPaused
                           : mojom::ActionResultCode::kTaskWentAway)));
    return;
  }
  if (controlled_tabs_.contains(tab_handle)) {
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, base::BindOnce(std::move(callback), MakeOkResult()));
    return;
  }

  journal_->Log(
      GURL(), id(), "ActorTask::AddTab",
      JournalDetailsBuilder().Add("tab_id", tab_handle.raw_value()).Build());

  if (CheckCrossProfileAndLog(tab_handle.Get(), tab_handle,
                              "ActorTask::AddTab")) {
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE,
        base::BindOnce(std::move(callback),
                       MakeResult(mojom::ActionResultCode::kTaskWentAway)));
    return;
  }

  controlled_tabs_.emplace(
      tab_handle,
      std::make_unique<ActorControlledTabState>(this, stop_task_on_detach));

  DidTabEnterActorControl(tab_handle);

  // Notify the UI of the new tab.
  base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
      FROM_HERE, base::BindOnce(&ui::UiEventDispatcher::OnActorTaskAsyncChange,
                                ui_weak_ptr_factory_.GetWeakPtr(),
                                ui::UiEventDispatcher::AddTab{
                                    .task_id = id_, .handle = tab_handle},
                                std::move(callback)));

  // Post-task this delegate call to avoid any performance issues.
  if (delegate_) {
    base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
        FROM_HERE, base::BindOnce(&ActorTaskDelegate::OnTabAddedToTask,
                                  delegate_, id_, tab_handle));
  }
}

// TODO(crbug.com/450524344): Add a test for this. Note that at this point the
// tab is not yet associated with the new_contents.
void ActorTask::HandleDiscardContents(tabs::TabInterface* tab,
                                      content::WebContents* old_contents,
                                      content::WebContents* new_contents) {
  CHECK(controlled_tabs_.contains(tab->GetHandle()));
  if (!IsUnderActorControl()) {
    // The observer should only be attached when we're under actor control.
    NOTREACHED(base::NotFatalUntil::M145);
    return;
  }
  ActorControlledTabState* state = controlled_tabs_[tab->GetHandle()].get();
  DidContentsEnterActorControl(state, new_contents);
}

void ActorTask::RemoveTab(tabs::TabHandle tab_handle) {
  if (IsActingOnTab(tab_handle)) {
    // Record the tab visibility duration.
    UpdateVisibilityTimes();
    DidTabExitActorControl(tab_handle);
  }
  auto num_removed = controlled_tabs_.erase(tab_handle);
  RecomputeHasVisibleTab();

  if (num_removed > 0) {
    journal_->Log(
        GURL(), id(), "ActorTask::RemoveTab",
        JournalDetailsBuilder().Add("tab_id", tab_handle.raw_value()).Build());

    // Notify the UI of the tab removal.
    // We call this synchronously since a Stop will destroy the ActorTask
    // in the same event pump and the UIEventDispatcher will be destroyed
    // before dispatching the event.
    ui_event_dispatcher_->OnActorTaskSyncChange(
        ui::UiEventDispatcher::RemoveTab{.task_id = id_, .handle = tab_handle});
  }
}

void ActorTask::ObserveTabOnce(tabs::TabHandle tab_handle) {
  CHECK(IsUnderActorControl());

  if (to_observe_tabs_.contains(tab_handle) ||
      controlled_tabs_.contains(tab_handle)) {
    return;
  }

  tabs::TabInterface* tab = tab_handle.Get();
  if (!tab) {
    journal_->Log(GURL(), id(), "ObserveTabOnce",
                  JournalDetailsBuilder()
                      .Add("tab_id", tab_handle.raw_value())
                      .AddError("Tab is gone")
                      .Build());
    return;
  }

  if (CheckCrossProfileAndLog(tab, tab_handle, "ObserveTabOnce")) {
    return;
  }

  journal_->Log(
      GURL(), id(), "ObserveTabOnce",
      JournalDetailsBuilder().Add("tab_id", tab_handle.raw_value()).Build());

  auto itr = to_observe_tabs_
                 .emplace(tab_handle, std::make_unique<ActorControlledTabState>(
                                          this, /*stop_task_on_detach=*/true))
                 .first;
  ActorControlledTabState* state = itr->second.get();

  DidContentsEnterActorControl(state, tab->GetContents());
}

void ActorTask::OnTabWillDetach(tabs::TabHandle handle) {
  to_observe_tabs_.erase(handle);

  // If the removed tab is only being observed, we can just remove it without
  // disrupting the task. If the task hasn't gotten the observation it wanted
  // for this tab, then won't be able to get it and will need to do something
  // else.
  if (!HasTab(handle)) {
    return;
  }

  const auto* controlled_tab_state =
      base::FindPtrOrNull(controlled_tabs_, handle);
  if (!controlled_tab_state || !controlled_tab_state->stop_task_on_detach) {
    return;
  }

  // TODO(mcnee): This will also stop a task that's paused. Should we leave
  // paused tasks as is?

  journal_->Log(
      GURL(), id(), "Acting Tab Deleted",
      JournalDetailsBuilder().Add("tab_id", handle.raw_value()).Build());

  service_->StopTask(id(), StoppedReason::kTabDetached);
}

void ActorTask::DidEarlyAddTabs(
    std::vector<std::unique_ptr<ToolRequest>>&& actions,
    std::vector<mojom::ActionResultPtr> add_tab_results) {
  CHECK(base::FeatureList::IsEnabled(kGlicEarlyAddTaskTabs));

  // If any tabs failed to be added, return the first failing result and respond
  // with failure.
  for (mojom::ActionResultPtr& result : add_tab_results) {
    if (!IsOk(*result)) {
      OnFinishedAct(MakeResultVector(std::move(result)),
                    TabObservationStrategy());
      return;
    }
  }

  SetState(State::kActing);

  actions_in_current_state_ += actions.size();
  total_number_of_actions_ += actions.size();

  action_tracker_for_metrics_->WillAct(actions);

  execution_engine_->Act(std::move(actions),
                         base::BindOnce(&ActorTask::OnFinishedAct,
                                        weak_ptr_factory_.GetWeakPtr()));
}

void ActorTask::UpdateVisibilityTimes() {
  if (has_visible_tab_) {
    total_time_visible_ += visibility_timer_.Elapsed();
  } else {
    total_time_not_visible_ += visibility_timer_.Elapsed();
  }
  visibility_timer_ = base::ElapsedTimer();
}

void ActorTask::RecomputeHasVisibleTab() {
  // TODO(crbug.com/540512932): Track full window minimization and complete
  // window occlusion in addition to WebContents visibility.
  bool has_any_visible_tab = false;
  for (const auto& [handle, controlled_state] : controlled_tabs_) {
    if (controlled_state->web_contents() &&
        controlled_state->web_contents()->GetVisibility() ==
            content::Visibility::VISIBLE) {
      has_any_visible_tab = true;
      break;
    }
  }

  if (has_visible_tab_ == has_any_visible_tab) {
    return;
  }
  has_visible_tab_ = has_any_visible_tab;
  if (delegate_) {
    delegate_->OnTaskTabsVisibilityChanged(id_, has_visible_tab_);
  }
  service_->NotifyTaskVisibilityChanged(*this);
}

void ActorTask::ResetToObserveTabsSet() {
  for (const auto& [tab_handle, state] : to_observe_tabs_) {
    tabs::TabInterface* tab = tab_handle.Get();
    if (!tab) {
      continue;
    }

    DidContentsExitActorControl(state.get(), tab->GetContents());
  }
  to_observe_tabs_.clear();
}

void ActorTask::ResetAdditionalTabObservations() {
  additional_tab_observations_.clear();
}

bool ActorTask::HasTab(tabs::TabHandle tab) const {
  return controlled_tabs_.contains(tab);
}

bool ActorTask::IsActingOnTab(tabs::TabHandle tab) const {
  if (!IsUnderActorControl()) {
    return false;
  }

  return HasTab(tab);
}

absl::flat_hash_set<tabs::TabHandle> ActorTask::GetLastActedTabs() const {
  // TODO(crbug.com/420669167): Currently the client only acts on a single tab
  // so we can return the full set but with multi-tab this will need to be
  // smarter about which tabs are relevant to the last/current action.
  absl::flat_hash_set<tabs::TabHandle> last_acted_tabs = GetTabs();

  for (const auto& [handle, _] : to_observe_tabs_) {
    last_acted_tabs.insert(handle);
  }

  return last_acted_tabs;
}

absl::flat_hash_set<tabs::TabHandle> ActorTask::GetTabs() const {
  absl::flat_hash_set<tabs::TabHandle> handles;
  for (const auto& [handle, _] : controlled_tabs_) {
    handles.insert(handle);
  }
  return handles;
}

void ActorTask::DidTabEnterActorControl(tabs::TabHandle handle) {
  DCHECK(IsActingOnTab(handle));
  tabs::TabInterface* tab = handle.Get();
  if (!tab) {
    // This happens in unittests.
    return;
  }
  ActorControlledTabState* state = controlled_tabs_[handle].get();

  // TODO(b/454107412): This is assuming the tab isn't discarded but nothing
  // guarantees that.
  content::WebContents* contents = tab->GetContents();
  if (!contents) {
    return;
  }

  // TODO(crbug.com/450524344)): Add a test for discarded content.
  state->content_discarded_subscription =
      tab->RegisterWillDiscardContents(base::BindRepeating(
          &ActorTask::HandleDiscardContents, weak_ptr_factory_.GetWeakPtr()));
  DidContentsEnterActorControl(state, contents);

  RecomputeHasVisibleTab();
}

void ActorTask::DidContentsEnterActorControl(
    ActorTask::ActorControlledTabState* state,
    content::WebContents* contents) {
  SetFocusState(contents, true);
  state->SetContents(contents);
  state->actuation_runner =
      contents->IncrementCapturerCount(gfx::Size(),
                                       /*stay_hidden=*/false,
                                       /*stay_awake=*/true,
                                       /*is_activity=*/true);
  // Notify the tracker that the tab is getting actuated on to influence the
  // prioritization of the renderer process. This will prevent the priority of
  // the tab from dropping to BestEffort when it's not visible. When it is
  // visible, the tab's priority is already boosted.
  glic::GlicPerfTraitsTracker::GetInstance()->NotifyActuationStateChanged(
      contents, glic::GlicActuationState::kActuatingOnBackgroundTab);
#if BUILDFLAG(IS_MAC) && BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
  if (base::FeatureList::IsEnabled(features::kGlicActorInternalPopups)) {
    state->reenable_external_popups = contents->ForbidExternalPopupMenus();
  }
#endif  // BUILDFLAG(IS_MAC) && BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
}

void ActorTask::DidTabExitActorControl(tabs::TabHandle handle) {
  // Note that the state_ may still be in an actor controlled state if we are
  // just removing this tab (e.g. close the tab).
  DCHECK(controlled_tabs_.contains(handle));
  tabs::TabInterface* tab = handle.Get();
  if (!tab) {
    // This happens in unittests.
    return;
  }
  ActorControlledTabState* state = controlled_tabs_[handle].get();
  content::WebContents* contents = tab->GetContents();
  if (!contents) {
    return;
  }

  // Reset focus and remove observers.
  SetFocusState(contents, std::nullopt);
  state->SetContents(nullptr);
  state->content_discarded_subscription = {};
  DidContentsExitActorControl(state, contents);
}

void ActorTask::DidContentsExitActorControl(
    ActorTask::ActorControlledTabState* state,
    content::WebContents* contents) {
  glic::GlicPerfTraitsTracker::GetInstance()->NotifyActuationStateChanged(
      contents, glic::GlicActuationState::kNone);
  SetFocusState(contents, std::nullopt);
  state->SetContents(nullptr);
  // Triggers the ScopedClosureRunner's destructor (via std::optional's
  // destructor), which automatically calls DecrementCapturerCount on the
  // WebContents.
  state->actuation_runner = {};
#if BUILDFLAG(IS_MAC) && BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
  state->reenable_external_popups = {};
#endif  // BUILDFLAG(IS_MAC) && BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
}

bool ActorTask::CheckCrossProfileAndLog(tabs::TabInterface* tab,
                                        tabs::TabHandle tab_handle,
                                        std::string_view method_name) {
  if (tab && tab->GetContents() &&
      tab->GetContents()->GetBrowserContext() != GetProfile()) {
    journal_->Log(GURL(), id(), method_name,
                  JournalDetailsBuilder()
                      .Add("tab_id", tab_handle.raw_value())
                      .AddError("Cross-profile access denied")
                      .Build());
    return true;
  }
  return false;
}

void ActorTask::AddAdditionalTabObservations(
    std::vector<optimization_guide::proto::TabObservation> tab_observations) {
  // This is currently only used by the load and extract content tool.
  CHECK(base::FeatureList::IsEnabled(kGlicActorLoadAndExtractContentTool));
  CHECK(additional_tab_observations_.empty());

  additional_tab_observations_ = std::move(tab_observations);
}

std::string ToString(const ActorTask::State& state) {
  using enum ActorTask::State;
  switch (state) {
    case kCreated:
      return "Created";
    case kActing:
      return "Acting";
    case kReflecting:
      return "Reflecting";
    case kPausedByActor:
      return "PausedByActor";
    case kPausedByUser:
      return "PausedByUser";
    case kCancelled:
      return "Cancelled";
    case kFinished:
      return "Finished";
    case kWaitingOnUser:
      return "WaitingOnUser";
    case kFailed:
      return "Failed";
  }
}

std::ostream& operator<<(std::ostream& os, const ActorTask::State& state) {
  return os << ToString(state);
}

void ActorTask::SetStepProgress(std::string step_progress) {
  if (step_progress_ == step_progress) {
    return;
  }
  step_progress_ = std::move(step_progress);
  service_->NotifyTaskStepProgressChanged(*this, step_progress_);
}

// static
ActorTask::State ActorTask::GetTaskStateFromStoppedReason(
    StoppedReason stopped_reason) {
  State final_state;
  switch (stopped_reason) {
    case StoppedReason::kUserStartedNewChat:
    case StoppedReason::kUserLoadedPreviousChat:
    case StoppedReason::kStoppedByUser:
    case StoppedReason::kUserNavigatedAway:
    case StoppedReason::kTabDetached:
    case StoppedReason::kShutdown:
    case StoppedReason::kTimeout:
      final_state = State::kCancelled;
      break;
    case StoppedReason::kTaskComplete:
      final_state = State::kFinished;
      break;
    case StoppedReason::kModelError:
    case StoppedReason::kChromeFailure:
      final_state = State::kFailed;
      break;
  }
  return final_state;
}

}  // namespace actor