// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/offline_pages/core/background_snapshot_controller.h"

#include "base/functional/bind.h"
#include "base/location.h"
#include "base/task/single_thread_task_runner.h"
#include "base/time/time.h"
#include "components/offline_pages/core/offline_page_feature.h"

namespace {
// Default delay, in milliseconds, between the main document OnLoad event and
// snapshot.
const int64_t kDelayAfterDocumentOnLoadCompletedMsBackground = 2000;

// Default delay, in milliseconds, between renovations finishing and
// taking a snapshot. Allows for page to update in response to the
// renovations.
const int64_t kDelayAfterRenovationsCompletedMs = 2000;

// Delay for testing to keep polling times reasonable.
const int64_t kDelayForTests = 0;

}  // namespace

namespace offline_pages {

BackgroundSnapshotController::BackgroundSnapshotController(
    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
    BackgroundSnapshotController::Client* client,
    bool renovations_enabled)
    : task_runner_(task_runner),
      client_(client),
      state_(State::READY),
      delay_after_document_on_load_completed_ms_(
          kDelayAfterDocumentOnLoadCompletedMsBackground),
      delay_after_renovations_completed_ms_(kDelayAfterRenovationsCompletedMs) {
  DCHECK(!renovations_enabled);
  if (offline_pages::ShouldUseTestingSnapshotDelay()) {
    delay_after_document_on_load_completed_ms_ = kDelayForTests;
    delay_after_renovations_completed_ms_ = kDelayForTests;
  }
}

BackgroundSnapshotController::~BackgroundSnapshotController() = default;

void BackgroundSnapshotController::Reset() {
  // Cancel potentially delayed tasks that relate to the previous 'session'.
  weak_ptr_factory_.InvalidateWeakPtrs();
  state_ = State::READY;
}

void BackgroundSnapshotController::Stop() {
  state_ = State::STOPPED;
}

void BackgroundSnapshotController::RenovationsCompleted() {
}

void BackgroundSnapshotController::DocumentOnLoadCompletedInPrimaryMainFrame() {
  // Post a delayed task to snapshot and then stop this controller.
  task_runner_->PostDelayedTask(
      FROM_HERE,
      base::BindOnce(&BackgroundSnapshotController::MaybeStartSnapshotThenStop,
                     weak_ptr_factory_.GetWeakPtr()),
      base::Milliseconds(delay_after_document_on_load_completed_ms_));
}

void BackgroundSnapshotController::MaybeStartSnapshot() {
  if (state_ != State::READY) {
    return;
  }
  state_ = State::SNAPSHOT_PENDING;
  client_->StartSnapshot();
}

void BackgroundSnapshotController::MaybeStartSnapshotThenStop() {
  MaybeStartSnapshot();
  Stop();
}

int64_t
BackgroundSnapshotController::GetDelayAfterDocumentOnLoadCompletedForTest() {
  return delay_after_document_on_load_completed_ms_;
}

int64_t
BackgroundSnapshotController::GetDelayAfterRenovationsCompletedForTest() {
  return delay_after_renovations_completed_ms_;
}

}  // namespace offline_pages