// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROMEOS_COMPONENTS_MAGIC_BOOST_PUBLIC_CPP_MAGIC_BOOST_STATE_H_
#define CHROMEOS_COMPONENTS_MAGIC_BOOST_PUBLIC_CPP_MAGIC_BOOST_STATE_H_

#include "base/component_export.h"
#include "base/functional/callback.h"
#include "base/observer_list.h"
#include "base/types/expected.h"

namespace chromeos {

// HMR consent is two phases. These are flows and state transitions.
//
// Flow A (Mini Card):
// 1. Mini card is shown (kUnset -> kPendingDisclaimer | kDeclined)
// 2. Disclaimer dialog is shown (kPendingDisclaimer -> kApproved | kDeclined)
//
// *: If a user has pressed [No Thanks] in the mini card, kDeclined is set.
//
// Flow B (Settings):
// 1. A user toggles HMR settings in Settings UI
//    (kUnset | kDeclined -> kPendingDisclaimer)
// 2. Disclaimer dialog is shown (kPendingDisclaimer -> kApproved | kDeclined)
enum class HMRConsentStatus : int {
  // User has agreed to consent by pressing the accept button on the disclaimer
  // UI.
  kApproved = 0,
  // User has disagreed to consent by pressing the decline button on the
  // disclaimer UI or the opt-in card.
  kDeclined = 1,
  // This state is being used when the feature is turned on through the Settings
  // app or a mini card and consent status is unset. In this case, we will show
  // the disclaimer UI when users try to access the Mahi feature through the
  // Mahi menu card.
  kPendingDisclaimer = 2,
  // Users hasn't accept nor decline the consent.
  kUnset = 3,
};

COMPONENT_EXPORT(MAGIC_BOOST)
std::ostream& operator<<(std::ostream& os, HMRConsentStatus status);

// A class that holds MagicBoost related prefs and states.
//
// ## Magic Boost prefs model
//
// The table below shows the behavior of the HMR feature based on its three
// main preference values. Other features should follow the same logic.
//
// Note that this model is different from Quick Answers prefs model. Refer
// `quick_answers_state.h` for its prefs model. QuickAnswersState is a class to
// abstract these differences for Quick Answers code base.
//
// | magic_boost_enabled | hmr_enabled    | consent_status     | HMR Behavior |
// |:--------------------|:---------------|:-------------------|:-------------|
// | false               | false          | kUnset             | Disabled     |
// | false               | false          | kPendingDisclaimer | Disabled     |
// | false               | false          | kApproved          | Disabled     |
// | false               | false          | kDeclined          | Disabled     |
// | false               | true           | kUnset             | Disabled     |
// | false               | true           | kPendingDisclaimer | Disabled     |
// | false               | true           | kApproved          | Disabled     |
// | false               | true           | kDeclined          | Disabled     |
// | true                | false          | kUnset             | Disabled     |
// | true                | false          | kPendingDisclaimer | Disabled     |
// | true                | false          | kApproved          | Disabled     |
// | true                | false          | kDeclined          | Disabled     |
// | true (default)      | true (default) | kUnset (default)   | Show consent |
// | true                | true           | kPendingDisclaimer | Show consent |
// | true                | true           | kApproved          | Show HMR     |
// | true                | true           | kDeclined          | Disabled     |
class COMPONENT_EXPORT(MAGIC_BOOST) MagicBoostState {
 public:
  // A checked observer which receives MagicBoost state changes.
  class Observer : public base::CheckedObserver {
   public:
    virtual void OnUserEligibleForGenAIFeaturesUpdated(bool eligible) {}
    virtual void OnMagicBoostEnabledUpdated(bool enabled) {}
    virtual void OnHMREnabledUpdated(bool enabled) {}
    virtual void OnHMRConsentStatusUpdated(HMRConsentStatus status) {}

    // `MagicBoostState` is being deleted. All `ScopedObservation`s MUST get
    // reset. `ScopedObservation::Reset` accesses source (i.e., magic boost
    // state pointer). This is intentionally defined as a pure virtual function
    // as all observers care this.
    virtual void OnIsDeleting() = 0;
  };

  enum class Error {
    kUninitialized,
  };

  // Checks preconditions of HMR and crashes if they are not met.
  static void AssertPreconditionsOfHelpMeReadOrCrash();

  static MagicBoostState* Get();

  MagicBoostState();

  MagicBoostState(const MagicBoostState&) = delete;
  MagicBoostState& operator=(const MagicBoostState&) = delete;

  virtual ~MagicBoostState();

  void AddObserver(Observer* observer);
  void RemoveObserver(Observer* observer);

  // Check if HMR requires the notice banner to appear in the settings page.
  // It will be false in lacros and if the HMR consent status is anything other
  // than Declined.
  virtual bool CanShowNoticeBannerForHMR() = 0;

  // Increments HMRWindowDismissCount count and returns an incremented value.
  // Note that this method is not thread safe, i.e., this increment does NOT
  // operate as an atomic operation. Reading HMRWindowDismissCount immediately
  // after the write can read a stale value.
  virtual int32_t AsyncIncrementHMRConsentWindowDismissCount() = 0;

  // Writes consent status and a respective enabled state to the pref. Note that
  // this method returns BEFORE a write is completed. Reading consent status
  // and/or enabled state immediately after the write can read a stale value.
  virtual void AsyncWriteConsentStatus(HMRConsentStatus consent_status) = 0;

  // Writes HMR enabled value to the pref. Note that this method returns BEFORE
  // a write is completed. Reading consent status and/or enabled state
  // immediately after the write can read a stale value.
  virtual void AsyncWriteHMREnabled(bool enabled) = 0;

  // Indicates if the Orca feature should be included in the opt-in flow.
  virtual void ShouldIncludeOrcaInOptIn(
      base::OnceCallback<void(bool)> callback) {}

  virtual bool ShouldIncludeOrcaInOptInSync() = 0;

  // Marks Orca consent status as rejected and disable the feature.
  virtual void DisableOrcaFeature() = 0;

  // Marks Lobster settings toggle off.
  virtual void DisableLobsterSettings() = 0;

  // Returns true if Quick Answers or Mahi card should be shown (either consent
  // is approved or pending).
  bool ShouldShowHmrCard();

  // `IsUserEligibleForGenAIFeature` tries reading eligibility value again if
  // it's not set yet. See crbug.com/429501088 for details.
  bool IsUserEligibleForGenAIFeatures();

  base::expected<bool, Error> is_user_eligible_for_genai_features() const {
    return is_user_eligible_for_genai_features_;
  }

  base::expected<bool, Error> magic_boost_enabled() const {
    return magic_boost_enabled_;
  }

  base::expected<bool, Error> hmr_enabled() const { return hmr_enabled_; }

  base::expected<HMRConsentStatus, Error> hmr_consent_status() const {
    return hmr_consent_status_;
  }

  int hmr_consent_window_dismiss_count() const {
    return hmr_consent_window_dismiss_count_;
  }

 protected:
  void UpdateUserEligibleForGenAIFeatures(bool eligible);
  void UpdateMagicBoostEnabled(bool enabled);
  void UpdateHMREnabled(bool enabled);
  void UpdateHMRConsentStatus(HMRConsentStatus status);
  void UpdateHMRConsentWindowDismissCount(int32_t count);

  // Returns eligibility of gen-AI features. Returns `Error::kUninitialized` if
  // a dependent service is not initialized yet.
  virtual base::expected<bool, chromeos::MagicBoostState::Error>
  IsUserEligibleForGenAIFeaturesExpected() const = 0;

 private:
  void NotifyOnIsDeleting();

  // Use `base::expected` instead of `std::optional` to avoid implicit bool
  // conversion: https://abseil.io/tips/141.
  base::expected<bool, Error> is_user_eligible_for_genai_features_ =
      base::unexpected(Error::kUninitialized);
  base::expected<bool, Error> magic_boost_enabled_ =
      base::unexpected(Error::kUninitialized);
  base::expected<bool, Error> hmr_enabled_ =
      base::unexpected(Error::kUninitialized);
  base::expected<HMRConsentStatus, Error> hmr_consent_status_ =
      base::unexpected(Error::kUninitialized);
  int32_t hmr_consent_window_dismiss_count_ = 0;

  base::ObserverList<Observer> observers_;
};

}  // namespace chromeos

#endif  // CHROMEOS_COMPONENTS_MAGIC_BOOST_PUBLIC_CPP_MAGIC_BOOST_STATE_H_