// Copyright 2020 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef TYPECD_PORT_H_
#define TYPECD_PORT_H_

#include <map>
#include <memory>
#include <string>
#include <utility>

#include <gtest/gtest_prod.h>

#include "typecd/cable.h"
#include "typecd/ec_util.h"
#include "typecd/partner.h"

namespace typecd {

// Possible return values for the various CanEnter*() Mode entry checks.
enum class ModeEntryResult {
  kSuccess = 0,
  kCableError = 1,
  kPartnerError = 2,
};

// This class is used to represent a Type C Port. It can be used to access PD
// state associated with the port, and will also contain handles to the object
// representing a peripheral (i.e "Partner") if one is connected to the port.
class Port {
 public:
  static std::unique_ptr<Port> CreatePort(const base::FilePath& syspath);
  Port(const base::FilePath& syspath, int port_num);
  virtual ~Port() = default;

  void AddPartner(const base::FilePath& path);
  void RemovePartner();

  void AddCable(const base::FilePath& path);
  void RemoveCable();
  void AddCablePlug(const base::FilePath& path);

  // Add/remove an alternate mode for the partner.
  void AddRemovePartnerAltMode(const base::FilePath& path, bool added);

  void AddCableAltMode(const base::FilePath& path);

  void PartnerChanged();

  void PortChanged();

  void SetCurrentMode(TypeCMode mode) { current_mode_ = mode; }

  TypeCMode GetCurrentMode() { return current_mode_; }

  void SetActiveStateOnModeEntry(bool state) {
    user_active_on_mode_entry_ = state;
  }
  bool GetActiveStateOnModeEntry() { return user_active_on_mode_entry_; }

  // Returns the current data role for the port.
  // Returns either "host" or "device" on success, empty string on failure.
  virtual std::string GetDataRole();

  // Check whether we can enter DP Alt Mode. This should check for the presence
  // of required attributes on the Partner and (if applicable) Cable.
  virtual bool CanEnterDPAltMode();

  // Check whether we can enter Thunderbolt Compatibility Alt Mode. This should
  // check for the presence of required attributes on the Partner and
  // (if applicable) Cable.
  virtual ModeEntryResult CanEnterTBTCompatibilityMode();

  // Returns whether the partner can enter USB4. This should check the following
  // attributes for USB4 support:
  // - Partner(SOP) PD identity.
  // - Cable speed.
  // - Cable type.
  virtual ModeEntryResult CanEnterUSB4();

  // Returns true when all PD discovery information (PD Identity VDOs, all
  // Discover Mode data) for a partner has been processed.
  //
  // NOTE: Any mode entry decision logic should only run if this function
  // returns true.
  virtual bool IsPartnerDiscoveryComplete();

  // Return true when all PD discovery information (PD Identity VDOs, all
  // Discover Mode data) for a cable has been processed.
  //
  // NOTE: Any mode entry decision logic should only run if this function
  // returns true.
  virtual bool IsCableDiscoveryComplete();

  // Calls the |partner_|'s metrics reporting function, if a |partner_| is
  // registered.
  void ReportPartnerMetrics(Metrics* metrics);

  // Calls the |cable_|'s metrics reporting function, if a |cable_| is
  // registered.
  void ReportCableMetrics(Metrics* metrics);

  // Reports port level metrics.
  void ReportPortMetrics(Metrics* metrics);

 private:
  friend class PortTest;
  FRIEND_TEST(PortTest, TestBasicAdd);
  FRIEND_TEST(PortTest, TestDPAltModeEntryCheckTrue);
  FRIEND_TEST(PortTest, TestDPAltModeEntryCheckFalseWithDPSID);
  FRIEND_TEST(PortTest, TestDPAltModeEntryCheckFalse);
  FRIEND_TEST(PortTest, TestTBTCompatibilityModeEntryCheckTrueStartech);
  FRIEND_TEST(PortTest, TestTBTCompatibilityModeEntryCheckFalseStartech);
  FRIEND_TEST(PortTest, TestTBTCompatibilityModeEntryCheckTrueWD19TB);
  FRIEND_TEST(PortTest, TestUSB4EntryTrueGatkexPassiveTBT3Cable);
  FRIEND_TEST(PortTest, TestUSB4EntryTrueGatkexPassiveNonTBT3Cable);
  FRIEND_TEST(PortTest, TestUSB4EntryFalseGatkexPassiveNonTBT3Cable);
  FRIEND_TEST(PortTest, TestUSB4EntryFalseGatkexActiveTBT3Cable);
  FRIEND_TEST(PortTest, TestUSB4EntryTrueGatkexAppleTBT3ProCable);

  bool IsPartnerAltModePresent(uint16_t altmode_sid);

  bool IsCableAltModePresent(uint16_t altmode_sid);

  // Reads the current port data role from sysfs and stores it in |data_role_|.
  void ParseDataRole();

  // Sysfs path used to access partner PD information.
  base::FilePath syspath_;
  // Port number as described by the Type C connector class framework.
  int port_num_;
  std::unique_ptr<Cable> cable_;
  std::unique_ptr<Partner> partner_;
  // Tracks the user active state when a mode was last entered.
  bool user_active_on_mode_entry_;
  TypeCMode current_mode_;
  // Field which tracks whether port metrics have been reported. This
  // prevents duplicate reporting.
  bool metrics_reported_;
  std::string data_role_;
};

}  // namespace typecd

#endif  // TYPECD_PORT_H_