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

#include <cstdlib>
#include <fbl/string_buffer.h>
#include <lib/log-writer-textfile/log-writer-textfile.h>
#include <lib/log/log.h>
#include <lib/log/log_writer.h>

namespace {

class TextFileWriter final : public log_writer {
 public:
  explicit TextFileWriter(FILE* file) : log_writer{&kOps}, file_(file) {}

  void Write(const log_message_t* msg);

 private:
  static const log_writer_ops_t kOps;

  FILE* file_;
};

void textfile_writer_write(log_writer_t* writer, const log_message_t* message) {
  auto self = static_cast<TextFileWriter*>(writer);
  self->Write(message);
}

const log_writer_ops_t TextFileWriter::kOps = {
    .version = LOG_WRITER_OPS_V1,
    .reserved = 0,
    .v1 =
        {
            .write = textfile_writer_write,
        },
};

void TextFileWriter::Write(const log_message* message) {
  constexpr size_t kMaxMessageSize = 2043;

  fbl::StringBuffer<kMaxMessageSize> buf;
  buf.Append("[");
  if (message->level >= LOG_LEVEL_INFO) {
    switch (message->level) {
      case LOG_LEVEL_INFO:
        buf.Append("INFO ");
        break;
      case LOG_LEVEL_WARNING:
        buf.Append("WARNING ");
        break;
      case LOG_LEVEL_ERROR:
        buf.Append("ERROR ");
        break;
      case LOG_LEVEL_FATAL:
        buf.Append("FATAL ");
        break;
      default:
        buf.Append("UNKNOWN_LEVEL ");
        break;
    }
  } else {
    buf.AppendPrintf("VERBOSITY:%d ", -(message->level));
  }
  int tag_counter = 0;
  buf.Append("TAGS:[");
  for (size_t i = 0; i < message->num_static_tags; i++) {
    if (++tag_counter > LOG_MAX_TAGS) {
      break;
    }
    if (tag_counter > 1) {
      buf.Append(", ");
    }
    buf.Append(message->static_tags[i]);
  }
  for (size_t i = 0; i < message->num_dynamic_tags; i++) {
    if (++tag_counter > LOG_MAX_TAGS) {
      break;
    }
    if (tag_counter > 1) {
      buf.Append(", ");
    }
    buf.Append(message->dynamic_tags[i]);
  }
  buf.Append("]] ");
  buf.Append(message->text, message->text_len);
  buf.Append("\n");
  fwrite(buf.data(), 1, buf.size(), file_);
}

}  // namespace

__EXPORT
log_writer_t* log_create_textfile_writer(FILE* log_destination) {
  ZX_DEBUG_ASSERT(log_destination != nullptr);
  return new TextFileWriter(log_destination);
}

__EXPORT
void log_destroy_textfile_writer(log_writer_t* writer) {
  delete static_cast<TextFileWriter*>(writer);
}