#include "aos/logging/implementations.h"

#include <stdarg.h>
#include <inttypes.h>

#include <algorithm>
#include <chrono>

#include "aos/die.h"
#include "aos/logging/printf_formats.h"
#include "aos/queue_types.h"
#include "aos/time/time.h"
#include "aos/ipc_lib/queue.h"
#include "aos/once.h"

namespace aos {
namespace logging {
namespace {

namespace chrono = ::std::chrono;

// The root LogImplementation. It only logs to stderr/stdout.
// Some of the things specified in the LogImplementation documentation doesn't
// apply here (mostly the parts about being able to use LOG) because this is the
// root one.
class RootLogImplementation : public SimpleLogImplementation {
 public:
  void have_other_implementation() { only_implementation_ = false; }

 private:
  void set_next(LogImplementation *) override {
    LOG(FATAL, "can't have a next logger from here\n");
  }

  __attribute__((format(GOOD_PRINTF_FORMAT_TYPE, 3, 0)))
  void DoLog(log_level level, const char *format, va_list ap) override {
    LogMessage message;
    internal::FillInMessage(level, format, ap, &message);
    internal::PrintMessage(stderr, message);
    if (!only_implementation_) {
      fputs("root logger got used, see stderr for message\n", stdout);
    }
  }

  bool only_implementation_ = true;
};

RootLogImplementation *root_implementation = nullptr;

void SetGlobalImplementation(LogImplementation *implementation) {
  if (root_implementation == nullptr) {
    fputs("Somebody didn't call logging::Init()!\n", stderr);
    abort();
  }

  internal::Context *context = internal::Context::Get();

  context->implementation = implementation;
  internal::global_top_implementation.store(implementation);
}

void NewContext() {
  internal::Context::Delete();
}

void *DoInit() {
  SetGlobalImplementation(root_implementation = new RootLogImplementation());

  if (pthread_atfork(NULL /*prepare*/, NULL /*parent*/,
                     NewContext /*child*/) != 0) {
    LOG(FATAL, "pthread_atfork(NULL, NULL, %p) failed\n",
        NewContext);
  }

  return NULL;
}

}  // namespace
namespace internal {
namespace {

void FillInMessageBase(log_level level, LogMessage *message) {
  Context *context = Context::Get();

  message->level = level;
  message->source = context->source;
  memcpy(message->name, context->name, context->name_size);
  message->name_length = context->name_size;

  monotonic_clock::time_point monotonic_now = monotonic_clock::now();
  message->seconds =
      chrono::duration_cast<chrono::seconds>(monotonic_now.time_since_epoch())
          .count();
  message->nseconds =
      chrono::duration_cast<chrono::nanoseconds>(
          monotonic_now.time_since_epoch() - chrono::seconds(message->seconds))
          .count();

  message->sequence = context->sequence++;
}

}  // namespace

void FillInMessageStructure(log_level level,
                            const ::std::string &message_string, size_t size,
                            const MessageType *type,
                            const ::std::function<size_t(char *)> &serialize,
                            LogMessage *message) {
  type_cache::AddShm(type->id);
  message->structure.type_id = type->id;

  FillInMessageBase(level, message);

  if (message_string.size() + size > sizeof(message->structure.serialized)) {
    LOG(FATAL,
        "serialized struct %s (size %zd + %zd > %zd) and message %s too big\n",
        type->name.c_str(), message_string.size(), size,
        sizeof(message->structure.serialized), message_string.c_str());
  }
  message->structure.string_length = message_string.size();
  memcpy(message->structure.serialized, message_string.data(),
         message->structure.string_length);

  message->message_length = serialize(
      &message->structure.serialized[message->structure.string_length]);
  message->type = LogMessage::Type::kStruct;
}

void FillInMessageMatrix(log_level level,
                         const ::std::string &message_string, uint32_t type_id,
                         int rows, int cols, const void *data,
                         LogMessage *message) {
  CHECK(MessageType::IsPrimitive(type_id));
  message->matrix.type = type_id;

  const auto element_size = MessageType::Sizeof(type_id);

  FillInMessageBase(level, message);

  message->message_length = rows * cols * element_size;
  if (message_string.size() + message->message_length >
      sizeof(message->matrix.data)) {
    LOG(FATAL, "%dx%d matrix of type %" PRIu32
               " (size %u) and message %s is too big\n",
        rows, cols, type_id, element_size, message_string.c_str());
  }
  message->matrix.string_length = message_string.size();
  memcpy(message->matrix.data, message_string.data(),
         message->matrix.string_length);

  message->matrix.rows = rows;
  message->matrix.cols = cols;
  SerializeMatrix(type_id, &message->matrix.data[message->matrix.string_length],
                  data, rows, cols);
  message->type = LogMessage::Type::kMatrix;
}

void FillInMessage(log_level level, const char *format, va_list ap,
                   LogMessage *message) {
  FillInMessageBase(level, message);

  message->message_length =
      ExecuteFormat(message->message, sizeof(message->message), format, ap);
  message->type = LogMessage::Type::kString;
}

void PrintMessage(FILE *output, const LogMessage &message) {
#define BASE_ARGS                                                              \
  AOS_LOGGING_BASE_ARGS(                                                       \
      message.name_length, message.name, static_cast<int32_t>(message.source), \
      message.sequence, message.level, message.seconds, message.nseconds)
  switch (message.type) {
    case LogMessage::Type::kString:
      fprintf(output, AOS_LOGGING_BASE_FORMAT "%.*s", BASE_ARGS,
              static_cast<int>(message.message_length), message.message);
      break;
    case LogMessage::Type::kStruct: {
      char buffer[4096];
      size_t output_length = sizeof(buffer);
      size_t input_length = message.message_length;
      if (!PrintMessage(
              buffer, &output_length,
              message.structure.serialized + message.structure.string_length,
              &input_length, type_cache::Get(message.structure.type_id))) {
        LOG(FATAL,
            "printing message (%.*s) of type %s into %zu-byte buffer failed\n",
            static_cast<int>(message.message_length), message.message,
            type_cache::Get(message.structure.type_id).name.c_str(),
            sizeof(buffer));
      }
      if (input_length > 0) {
        LOG(WARNING, "%zu extra bytes on message of type %s\n", input_length,
            type_cache::Get(message.structure.type_id).name.c_str());
      }
      fprintf(output, AOS_LOGGING_BASE_FORMAT "%.*s: %.*s\n", BASE_ARGS,
              static_cast<int>(message.structure.string_length),
              message.structure.serialized,
              static_cast<int>(sizeof(buffer) - output_length), buffer);
    } break;
    case LogMessage::Type::kMatrix: {
      char buffer[1024];
      size_t output_length = sizeof(buffer);
      if (message.message_length !=
          static_cast<size_t>(message.matrix.rows * message.matrix.cols *
                              MessageType::Sizeof(message.matrix.type))) {
        LOG(FATAL, "expected %d bytes of matrix data but have %zu\n",
            message.matrix.rows * message.matrix.cols *
                MessageType::Sizeof(message.matrix.type),
            message.message_length);
      }
      if (!PrintMatrix(buffer, &output_length,
                       message.matrix.data + message.matrix.string_length,
                       message.matrix.type, message.matrix.rows,
                       message.matrix.cols)) {
        LOG(FATAL, "printing %dx%d matrix of type %" PRIu32 " failed\n",
            message.matrix.rows, message.matrix.cols, message.matrix.type);
      }
      fprintf(output, AOS_LOGGING_BASE_FORMAT "%.*s: %.*s\n", BASE_ARGS,
              static_cast<int>(message.matrix.string_length),
              message.matrix.data,
              static_cast<int>(sizeof(buffer) - output_length), buffer);
    } break;
  }
#undef BASE_ARGS
}

}  // namespace internal

void SimpleLogImplementation::LogStruct(
    log_level level, const ::std::string &message, size_t size,
    const MessageType *type, const ::std::function<size_t(char *)> &serialize) {
  char serialized[1024];
  if (size > sizeof(serialized)) {
    LOG(FATAL, "structure of type %s too big to serialize\n",
        type->name.c_str());
  }
  size_t used = serialize(serialized);
  char printed[1024];
  size_t printed_bytes = sizeof(printed);
  if (!PrintMessage(printed, &printed_bytes, serialized, &used, *type)) {
    LOG(FATAL, "PrintMessage(%p, %p(=%zd), %p, %p(=%zd), %p(name=%s)) failed\n",
        printed, &printed_bytes, printed_bytes, serialized, &used, used, type,
        type->name.c_str());
  }
  DoLogVariadic(level, "%.*s: %.*s\n", static_cast<int>(message.size()),
                message.data(),
                static_cast<int>(sizeof(printed) - printed_bytes), printed);
}

void SimpleLogImplementation::LogMatrix(
    log_level level, const ::std::string &message, uint32_t type_id,
    int rows, int cols, const void *data) {
  char serialized[1024];
  if (static_cast<size_t>(rows * cols * MessageType::Sizeof(type_id)) >
      sizeof(serialized)) {
    LOG(FATAL, "matrix of size %u too big to serialize\n",
        rows * cols * MessageType::Sizeof(type_id));
  }
  SerializeMatrix(type_id, serialized, data, rows, cols);
  char printed[1024];
  size_t printed_bytes = sizeof(printed);
  if (!PrintMatrix(printed, &printed_bytes, serialized, type_id, rows, cols)) {
    LOG(FATAL, "PrintMatrix(%p, %p(=%zd), %p, %" PRIu32 ", %d, %d) failed\n",
        printed, &printed_bytes, printed_bytes, serialized, type_id, rows,
        cols);
  }
  DoLogVariadic(level, "%.*s: %.*s\n", static_cast<int>(message.size()),
                message.data(),
                static_cast<int>(sizeof(printed) - printed_bytes), printed);
}

void HandleMessageLogImplementation::DoLog(log_level level, const char *format,
                                           va_list ap) {
  LogMessage message;
  internal::FillInMessage(level, format, ap, &message);
  HandleMessage(message);
}

void HandleMessageLogImplementation::LogStruct(
    log_level level, const ::std::string &message_string, size_t size,
    const MessageType *type, const ::std::function<size_t(char *)> &serialize) {
  LogMessage message;
  internal::FillInMessageStructure(level, message_string, size, type, serialize,
                                   &message);
  HandleMessage(message);
}

void HandleMessageLogImplementation::LogMatrix(
    log_level level, const ::std::string &message_string, uint32_t type_id,
    int rows, int cols, const void *data) {
  LogMessage message;
  internal::FillInMessageMatrix(level, message_string, type_id, rows, cols,
                                data, &message);
  HandleMessage(message);
}

StreamLogImplementation::StreamLogImplementation(FILE *stream)
    : stream_(stream) {}

void StreamLogImplementation::HandleMessage(const LogMessage &message) {
  internal::PrintMessage(stream_, message);
}

void AddImplementation(LogImplementation *implementation) {
  internal::Context *context = internal::Context::Get();

  if (implementation->next() != NULL) {
    LOG(FATAL, "%p already has a next implementation, but it's not"
        " being used yet\n", implementation);
  }

  LogImplementation *old = context->implementation;
  if (old != NULL) {
    implementation->set_next(old);
  }
  SetGlobalImplementation(implementation);
  root_implementation->have_other_implementation();
}

void Init() {
  static Once<void> once(DoInit);
  once.Get();
}

void Load() {
  internal::Context::Get();
}

void Cleanup() {
  internal::Context::Delete();
}

namespace {

RawQueue *queue = NULL;

int dropped_messages = 0;
monotonic_clock::time_point dropped_start, backoff_start;
// Wait this long after dropping a message before even trying to write any more.
constexpr chrono::milliseconds kDropBackoff = chrono::milliseconds(100);

LogMessage *GetMessageOrDie() {
  LogMessage *message = static_cast<LogMessage *>(queue->GetMessage());
  if (message == NULL) {
    LOG(FATAL, "%p->GetMessage() failed\n", queue);
  } else {
    return message;
  }
}

void Write(LogMessage *msg) {
  if (__builtin_expect(dropped_messages > 0, false)) {
    monotonic_clock::time_point message_time(
        chrono::seconds(msg->seconds) + chrono::nanoseconds(msg->nseconds));
    if (message_time - backoff_start < kDropBackoff) {
      ++dropped_messages;
      queue->FreeMessage(msg);
      return;
    }

    LogMessage *dropped_message = GetMessageOrDie();
    chrono::seconds dropped_start_sec = chrono::duration_cast<chrono::seconds>(
        dropped_start.time_since_epoch());
    chrono::nanoseconds dropped_start_nsec =
        chrono::duration_cast<chrono::nanoseconds>(
            dropped_start.time_since_epoch() - dropped_start_sec);
    internal::FillInMessageVarargs(
        ERROR, dropped_message,
        "%d logs starting at %" PRId32 ".%" PRId32 " dropped\n",
        dropped_messages, static_cast<int32_t>(dropped_start_sec.count()),
        static_cast<int32_t>(dropped_start_nsec.count()));
    if (queue->WriteMessage(dropped_message, RawQueue::kNonBlock)) {
      dropped_messages = 0;
    } else {
      // Don't even bother trying to write this message because it's not likely
      // to work and it would be confusing to have one log in the middle of a
      // string of failures get through.
      ++dropped_messages;
      backoff_start = message_time;
      queue->FreeMessage(msg);
      return;
    }
  }
  if (!queue->WriteMessage(msg, RawQueue::kNonBlock)) {
    if (dropped_messages == 0) {
      monotonic_clock::time_point message_time(
          chrono::seconds(msg->seconds) + chrono::nanoseconds(msg->nseconds));
      dropped_start = backoff_start = message_time;
    }
    ++dropped_messages;
  }
}

class LinuxQueueLogImplementation : public LogImplementation {
  __attribute__((format(GOOD_PRINTF_FORMAT_TYPE, 3, 0)))
  void DoLog(log_level level, const char *format, va_list ap) override {
    LogMessage *message = GetMessageOrDie();
    internal::FillInMessage(level, format, ap, message);
    Write(message);
  }

  void LogStruct(log_level level, const ::std::string &message_string,
                 size_t size, const MessageType *type,
                 const ::std::function<size_t(char *)> &serialize) override {
    LogMessage *message = GetMessageOrDie();
    internal::FillInMessageStructure(level, message_string, size, type,
                                     serialize, message);
    Write(message);
  }

  void LogMatrix(log_level level, const ::std::string &message_string,
                 uint32_t type_id, int rows, int cols,
                 const void *data) override {
    LogMessage *message = GetMessageOrDie();
    internal::FillInMessageMatrix(level, message_string, type_id, rows, cols,
                                  data, message);
    Write(message);
  }
};

}  // namespace

RawQueue *GetLoggingQueue() {
  return RawQueue::Fetch("LoggingQueue", sizeof(LogMessage), 1323, 40000);
}

void RegisterQueueImplementation() {
  Init();

  queue = GetLoggingQueue();
  if (queue == NULL) {
    Die("logging: couldn't fetch queue\n");
  }

  AddImplementation(new LinuxQueueLogImplementation());
}

}  // namespace logging
}  // namespace aos