/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef SRC_TRACE_PROCESSOR_IMPORTERS_PROTO_PACKET_SEQUENCE_STATE_H_
#define SRC_TRACE_PROCESSOR_IMPORTERS_PROTO_PACKET_SEQUENCE_STATE_H_

#include <stdint.h>

#include <unordered_map>
#include <vector>

#include "perfetto/base/compiler.h"
#include "perfetto/protozero/proto_decoder.h"
#include "perfetto/trace_processor/trace_blob_view.h"
#include "src/trace_processor/importers/proto/stack_profile_tracker.h"
#include "src/trace_processor/storage/trace_storage.h"
#include "src/trace_processor/types/trace_processor_context.h"
#include "src/trace_processor/util/interned_message_view.h"

#include "protos/perfetto/trace/trace_packet_defaults.pbzero.h"
#include "protos/perfetto/trace/track_event/track_event.pbzero.h"

namespace perfetto {
namespace trace_processor {

using InternedMessageMap =
    std::unordered_map<uint64_t /*iid*/, InternedMessageView>;
using InternedFieldMap =
    std::unordered_map<uint32_t /*field_id*/, InternedMessageMap>;

class PacketSequenceState;

class PacketSequenceStateGeneration {
 public:
  // Returns |nullptr| if the message with the given |iid| was not found (also
  // records a stat in this case).
  template <uint32_t FieldId, typename MessageType>
  typename MessageType::Decoder* LookupInternedMessage(uint64_t iid);

  InternedMessageView* GetInternedMessageView(uint32_t field_id, uint64_t iid);
  // Returns |nullptr| if no defaults were set.
  InternedMessageView* GetTracePacketDefaultsView() {
    if (!trace_packet_defaults_)
      return nullptr;
    return &trace_packet_defaults_.value();
  }

  // Returns |nullptr| if no defaults were set.
  protos::pbzero::TracePacketDefaults::Decoder* GetTracePacketDefaults() {
    InternedMessageView* view = GetTracePacketDefaultsView();
    if (!view)
      return nullptr;
    return view->GetOrCreateDecoder<protos::pbzero::TracePacketDefaults>();
  }

  // Returns |nullptr| if no TrackEventDefaults were set.
  protos::pbzero::TrackEventDefaults::Decoder* GetTrackEventDefaults() {
    auto* packet_defaults_view = GetTracePacketDefaultsView();
    if (packet_defaults_view) {
      auto* track_event_defaults_view =
          packet_defaults_view
              ->GetOrCreateSubmessageView<protos::pbzero::TracePacketDefaults,
                                          protos::pbzero::TracePacketDefaults::
                                              kTrackEventDefaultsFieldNumber>();
      if (track_event_defaults_view) {
        return track_event_defaults_view
            ->GetOrCreateDecoder<protos::pbzero::TrackEventDefaults>();
      }
    }
    return nullptr;
  }

  PacketSequenceState* state() const { return state_; }
  size_t generation_index() const { return generation_index_; }

 private:
  friend class PacketSequenceState;

  PacketSequenceStateGeneration(PacketSequenceState* state,
                                size_t generation_index)
      : state_(state), generation_index_(generation_index) {}

  PacketSequenceStateGeneration(PacketSequenceState* state,
                                size_t generation_index,
                                InternedFieldMap interned_data,
                                TraceBlobView defaults)
      : state_(state),
        generation_index_(generation_index),
        interned_data_(interned_data),
        trace_packet_defaults_(InternedMessageView(std::move(defaults))) {}

  void InternMessage(uint32_t field_id, TraceBlobView message);

  void SetTracePacketDefaults(TraceBlobView defaults) {
    // Defaults should only be set once per generation.
    PERFETTO_DCHECK(!trace_packet_defaults_);
    trace_packet_defaults_ = InternedMessageView(std::move(defaults));
  }

  PacketSequenceState* state_;
  size_t generation_index_;
  InternedFieldMap interned_data_;
  base::Optional<InternedMessageView> trace_packet_defaults_;
};

class PacketSequenceState {
 public:
  PacketSequenceState(TraceProcessorContext* context)
      : context_(context), sequence_stack_profile_tracker_(context) {
    current_generation_.reset(
        new PacketSequenceStateGeneration(this, generation_index_++));
  }

  int64_t IncrementAndGetTrackEventTimeNs(int64_t delta_ns) {
    PERFETTO_DCHECK(track_event_timestamps_valid());
    track_event_timestamp_ns_ += delta_ns;
    return track_event_timestamp_ns_;
  }

  int64_t IncrementAndGetTrackEventThreadTimeNs(int64_t delta_ns) {
    PERFETTO_DCHECK(track_event_timestamps_valid());
    track_event_thread_timestamp_ns_ += delta_ns;
    return track_event_thread_timestamp_ns_;
  }

  int64_t IncrementAndGetTrackEventThreadInstructionCount(int64_t delta) {
    PERFETTO_DCHECK(track_event_timestamps_valid());
    track_event_thread_instruction_count_ += delta;
    return track_event_thread_instruction_count_;
  }

  // Intern a message into the current generation.
  void InternMessage(uint32_t field_id, TraceBlobView message) {
    current_generation_->InternMessage(field_id, std::move(message));
  }

  // Set the trace packet defaults for the current generation. If the current
  // generation already has defaults set, starts a new generation without
  // invalidating other incremental state (such as interned data).
  void UpdateTracePacketDefaults(TraceBlobView defaults) {
    if (!current_generation_->GetTracePacketDefaultsView()) {
      current_generation_->SetTracePacketDefaults(std::move(defaults));
      return;
    }

    // The new defaults should only apply to subsequent messages on the
    // sequence. Add a new generation with the updated defaults but the
    // current generation's interned data state.
    current_generation_.reset(new PacketSequenceStateGeneration(
        this, generation_index_++, current_generation_->interned_data_,
        std::move(defaults)));
  }

  void SetThreadDescriptor(int32_t pid,
                           int32_t tid,
                           int64_t timestamp_ns,
                           int64_t thread_timestamp_ns,
                           int64_t thread_instruction_count) {
    track_event_timestamps_valid_ = true;
    pid_and_tid_valid_ = true;
    pid_ = pid;
    tid_ = tid;
    track_event_timestamp_ns_ = timestamp_ns;
    track_event_thread_timestamp_ns_ = thread_timestamp_ns;
    track_event_thread_instruction_count_ = thread_instruction_count;
  }

  void OnPacketLoss() {
    packet_loss_ = true;
    track_event_timestamps_valid_ = false;
  }

  // Starts a new generation with clean-slate incremental state and defaults.
  void OnIncrementalStateCleared() {
    packet_loss_ = false;
    current_generation_.reset(
        new PacketSequenceStateGeneration(this, generation_index_++));
  }

  bool IsIncrementalStateValid() const { return !packet_loss_; }

  SequenceStackProfileTracker& sequence_stack_profile_tracker() {
    return sequence_stack_profile_tracker_;
  }

  // Returns a ref-counted ptr to the current generation.
  std::shared_ptr<PacketSequenceStateGeneration> current_generation() const {
    return current_generation_;
  }

  bool track_event_timestamps_valid() const {
    return track_event_timestamps_valid_;
  }

  bool pid_and_tid_valid() const { return pid_and_tid_valid_; }

  int32_t pid() const { return pid_; }
  int32_t tid() const { return tid_; }

  TraceProcessorContext* context() const { return context_; }

 private:
  TraceProcessorContext* context_;

  size_t generation_index_ = 0;

  // If true, incremental state on the sequence is considered invalid until we
  // see the next packet with incremental_state_cleared. We assume that we
  // missed some packets at the beginning of the trace.
  bool packet_loss_ = true;

  // We can only consider TrackEvent delta timestamps to be correct after we
  // have observed a thread descriptor (since the last packet loss).
  bool track_event_timestamps_valid_ = false;

  // |pid_| and |tid_| are only valid after we parsed at least one
  // ThreadDescriptor packet on the sequence.
  bool pid_and_tid_valid_ = false;

  // Process/thread ID of the packet sequence set by a ThreadDescriptor
  // packet. Used as default values for TrackEvents that don't specify a
  // pid/tid override. Only valid after |pid_and_tid_valid_| is set to true.
  int32_t pid_ = 0;
  int32_t tid_ = 0;

  // Current wall/thread timestamps/counters used as reference for the next
  // TrackEvent delta timestamp.
  int64_t track_event_timestamp_ns_ = 0;
  int64_t track_event_thread_timestamp_ns_ = 0;
  int64_t track_event_thread_instruction_count_ = 0;

  std::shared_ptr<PacketSequenceStateGeneration> current_generation_;
  SequenceStackProfileTracker sequence_stack_profile_tracker_;
};

template <uint32_t FieldId, typename MessageType>
typename MessageType::Decoder*
PacketSequenceStateGeneration::LookupInternedMessage(uint64_t iid) {
  auto* interned_message_view = GetInternedMessageView(FieldId, iid);
  if (!interned_message_view)
    return nullptr;

  return interned_message_view->template GetOrCreateDecoder<MessageType>();
}

}  // namespace trace_processor
}  // namespace perfetto

#endif  // SRC_TRACE_PROCESSOR_IMPORTERS_PROTO_PACKET_SEQUENCE_STATE_H_