/*
 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#if defined(WEBRTC_WIN)
#if !defined(WIN32_LEAN_AND_MEAN)
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#if _MSC_VER < 1900
#define snprintf _snprintf
#endif
#undef ERROR  // wingdi.h
#endif

#if defined(WEBRTC_MAC) && !defined(WEBRTC_IOS)
#include <CoreServices/CoreServices.h>
#elif defined(WEBRTC_ANDROID)
#include <android/log.h>
// Android has a 1024 limit on log inputs. We use 60 chars as an
// approx for the header/tag portion.
// See android/system/core/liblog/logd_write.c
static const int kMaxLogLineSize = 1024 - 60;
#endif  // WEBRTC_MAC && !defined(WEBRTC_IOS) || WEBRTC_ANDROID

#include <time.h>
#include <limits.h>

#include <algorithm>
#include <iomanip>
#include <ostream>
#include <vector>

#include "rtc_base/criticalsection.h"
#include "rtc_base/logging.h"
#include "rtc_base/platform_thread_types.h"
#include "rtc_base/stringencode.h"
#include "rtc_base/strings/string_builder.h"
#include "rtc_base/stringutils.h"
#include "rtc_base/timeutils.h"

namespace rtc {
namespace {
// By default, release builds don't log, debug builds at info level
#if !defined(NDEBUG)
static LoggingSeverity g_min_sev = LS_INFO;
static LoggingSeverity g_dbg_sev = LS_INFO;
#else
static LoggingSeverity g_min_sev = LS_NONE;
static LoggingSeverity g_dbg_sev = LS_NONE;
#endif

// Return the filename portion of the string (that following the last slash).
const char* FilenameFromPath(const char* file) {
  const char* end1 = ::strrchr(file, '/');
  const char* end2 = ::strrchr(file, '\\');
  if (!end1 && !end2)
    return file;
  else
    return (end1 > end2) ? end1 + 1 : end2 + 1;
}

std::ostream& GetNoopStream() {
  class NoopStreamBuf : public std::streambuf {
   public:
    int overflow(int c) override { return c; }
  };
  static NoopStreamBuf noop_buffer;
  static std::ostream noop_stream(&noop_buffer);
  return noop_stream;
}

// Global lock for log subsystem, only needed to serialize access to streams_.
CriticalSection g_log_crit;
}  // namespace


/////////////////////////////////////////////////////////////////////////////
// LogMessage
/////////////////////////////////////////////////////////////////////////////

bool LogMessage::log_to_stderr_ = true;

// The list of logging streams currently configured.
// Note: we explicitly do not clean this up, because of the uncertain ordering
// of destructors at program exit.  Let the person who sets the stream trigger
// cleanup by setting to null, or let it leak (safe at program exit).
LogMessage::StreamList LogMessage::streams_ RTC_GUARDED_BY(g_log_crit);

// Boolean options default to false (0)
bool LogMessage::thread_, LogMessage::timestamp_;

LogMessage::LogMessage(const char* file,
                       int line,
                       LoggingSeverity sev,
                       LogErrorContext err_ctx,
                       int err)
    : severity_(sev), is_noop_(IsNoop(sev)) {
  // If there's no need to do any work, let's not :)
  if (is_noop_)
    return;

  if (timestamp_) {
    // Use SystemTimeMillis so that even if tests use fake clocks, the timestamp
    // in log messages represents the real system time.
    int64_t time = TimeDiff(SystemTimeMillis(), LogStartTime());
    // Also ensure WallClockStartTime is initialized, so that it matches
    // LogStartTime.
    WallClockStartTime();
    print_stream_ << "[" << std::setfill('0') << std::setw(3) << (time / 1000)
                  << ":" << std::setw(3) << (time % 1000) << std::setfill(' ')
                  << "] ";
  }

  if (thread_) {
    PlatformThreadId id = CurrentThreadId();
    print_stream_ << "[" << std::dec << id << "] ";
  }

  if (file != nullptr)
    print_stream_ << "(" << FilenameFromPath(file)  << ":" << line << "): ";

  if (err_ctx != ERRCTX_NONE) {
    char tmp_buf[1024];
    SimpleStringBuilder tmp(tmp_buf);
    tmp.AppendFormat("[0x%08X]", err);
    switch (err_ctx) {
      case ERRCTX_ERRNO:
        tmp << " " << strerror(err);
        break;
#ifdef WEBRTC_WIN
      case ERRCTX_HRESULT: {
        char msgbuf[256];
        DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM |
                      FORMAT_MESSAGE_IGNORE_INSERTS;
        if (DWORD len = FormatMessageA(
                flags, nullptr, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                msgbuf, sizeof(msgbuf) / sizeof(msgbuf[0]), nullptr)) {
          while ((len > 0) &&
              isspace(static_cast<unsigned char>(msgbuf[len-1]))) {
            msgbuf[--len] = 0;
          }
          tmp << " " << msgbuf;
        }
        break;
      }
#endif  // WEBRTC_WIN
#if defined(WEBRTC_MAC) && !defined(WEBRTC_IOS)
      case ERRCTX_OSSTATUS: {
        std::string desc(DescriptionFromOSStatus(err));
        tmp << " " << (desc.empty() ? "Unknown error" : desc.c_str());
        break;
      }
#endif  // WEBRTC_MAC && !defined(WEBRTC_IOS)
      default:
        break;
    }
    extra_ = tmp.str();
  }
}

#if defined(WEBRTC_ANDROID)
LogMessage::LogMessage(const char* file,
                       int line,
                       LoggingSeverity sev,
                       const char* tag)
    : LogMessage(file,
                 line,
                 sev,
                 ERRCTX_NONE,
                 0 /* err */) {
  if (!is_noop_) {
    tag_ = tag;
    print_stream_ << tag << ": ";
  }
}
#endif

// DEPRECATED. Currently only used by downstream projects that use
// implementation details of logging.h. Work is ongoing to remove those
// dependencies.
LogMessage::LogMessage(const char* file, int line, LoggingSeverity sev,
                       const std::string& tag)
    : LogMessage(file, line, sev) {
  if (!is_noop_)
    print_stream_ << tag << ": ";
}

LogMessage::~LogMessage() {
  if (is_noop_)
    return;

  FinishPrintStream();

  // TODO(tommi): Unfortunately |ostringstream::str()| always returns a copy
  // of the constructed string. This means that we always end up creating
  // two copies here (one owned by the stream, one by the return value of
  // |str()|). It would be nice to switch to something else.
  const std::string str = print_stream_.str();

  if (severity_ >= g_dbg_sev) {
#if defined(WEBRTC_ANDROID)
    OutputToDebug(str, severity_, tag_);
#else
    OutputToDebug(str, severity_);
#endif
  }

  CritScope cs(&g_log_crit);
  for (auto& kv : streams_) {
    if (severity_ >= kv.second) {
      kv.first->OnLogMessage(str);
    }
  }
}

std::ostream& LogMessage::stream() {
  return is_noop_ ? GetNoopStream() : print_stream_;
}

bool LogMessage::Loggable(LoggingSeverity sev) {
  return sev >= g_min_sev;
}

int LogMessage::GetMinLogSeverity() {
  return g_min_sev;
}

LoggingSeverity LogMessage::GetLogToDebug() {
  return g_dbg_sev;
}
int64_t LogMessage::LogStartTime() {
  static const int64_t g_start = SystemTimeMillis();
  return g_start;
}

uint32_t LogMessage::WallClockStartTime() {
  static const uint32_t g_start_wallclock = time(nullptr);
  return g_start_wallclock;
}

void LogMessage::LogThreads(bool on) {
  thread_ = on;
}

void LogMessage::LogTimestamps(bool on) {
  timestamp_ = on;
}

void LogMessage::LogToDebug(LoggingSeverity min_sev) {
  g_dbg_sev = min_sev;
  CritScope cs(&g_log_crit);
  UpdateMinLogSeverity();
}

void LogMessage::SetLogToStderr(bool log_to_stderr) {
  log_to_stderr_ = log_to_stderr;
}

int LogMessage::GetLogToStream(LogSink* stream) {
  CritScope cs(&g_log_crit);
  LoggingSeverity sev = LS_NONE;
  for (auto& kv : streams_) {
    if (!stream || stream == kv.first) {
      sev = std::min(sev, kv.second);
    }
  }
  return sev;
}

void LogMessage::AddLogToStream(LogSink* stream, LoggingSeverity min_sev) {
  CritScope cs(&g_log_crit);
  streams_.push_back(std::make_pair(stream, min_sev));
  UpdateMinLogSeverity();
}

void LogMessage::RemoveLogToStream(LogSink* stream) {
  CritScope cs(&g_log_crit);
  for (StreamList::iterator it = streams_.begin(); it != streams_.end(); ++it) {
    if (stream == it->first) {
      streams_.erase(it);
      break;
    }
  }
  UpdateMinLogSeverity();
}

void LogMessage::ConfigureLogging(const char* params) {
  LoggingSeverity current_level = LS_VERBOSE;
  LoggingSeverity debug_level = GetLogToDebug();

  std::vector<std::string> tokens;
  tokenize(params, ' ', &tokens);

  for (const std::string& token : tokens) {
    if (token.empty())
      continue;

    // Logging features
    if (token == "tstamp") {
      LogTimestamps();
    } else if (token == "thread") {
      LogThreads();

    // Logging levels
    } else if (token == "sensitive") {
      current_level = LS_SENSITIVE;
    } else if (token == "verbose") {
      current_level = LS_VERBOSE;
    } else if (token == "info") {
      current_level = LS_INFO;
    } else if (token == "warning") {
      current_level = LS_WARNING;
    } else if (token == "error") {
      current_level = LS_ERROR;
    } else if (token == "none") {
      current_level = LS_NONE;

    // Logging targets
    } else if (token == "debug") {
      debug_level = current_level;
    }
  }

#if defined(WEBRTC_WIN)
  if ((LS_NONE != debug_level) && !::IsDebuggerPresent()) {
    // First, attempt to attach to our parent's console... so if you invoke
    // from the command line, we'll see the output there.  Otherwise, create
    // our own console window.
    // Note: These methods fail if a console already exists, which is fine.
    if (!AttachConsole(ATTACH_PARENT_PROCESS))
      ::AllocConsole();
  }
#endif  // WEBRTC_WIN

  LogToDebug(debug_level);
}

void LogMessage::UpdateMinLogSeverity()
    RTC_EXCLUSIVE_LOCKS_REQUIRED(g_log_crit) {
  LoggingSeverity min_sev = g_dbg_sev;
  for (auto& kv : streams_) {
    min_sev = std::min(g_dbg_sev, kv.second);
  }
  g_min_sev = min_sev;
}

#if defined(WEBRTC_ANDROID)
void LogMessage::OutputToDebug(const std::string& str,
                               LoggingSeverity severity,
                               const char* tag) {
#else
void LogMessage::OutputToDebug(const std::string& str,
                               LoggingSeverity severity) {
#endif
  bool log_to_stderr = log_to_stderr_;
#if defined(WEBRTC_MAC) && !defined(WEBRTC_IOS) && defined(NDEBUG)
  // On the Mac, all stderr output goes to the Console log and causes clutter.
  // So in opt builds, don't log to stderr unless the user specifically sets
  // a preference to do so.
  CFStringRef key = CFStringCreateWithCString(kCFAllocatorDefault,
                                              "logToStdErr",
                                              kCFStringEncodingUTF8);
  CFStringRef domain = CFBundleGetIdentifier(CFBundleGetMainBundle());
  if (key != nullptr && domain != nullptr) {
    Boolean exists_and_is_valid;
    Boolean should_log =
        CFPreferencesGetAppBooleanValue(key, domain, &exists_and_is_valid);
    // If the key doesn't exist or is invalid or is false, we will not log to
    // stderr.
    log_to_stderr = exists_and_is_valid && should_log;
  }
  if (key != nullptr) {
    CFRelease(key);
  }
#endif  // defined(WEBRTC_MAC) && !defined(WEBRTC_IOS) && defined(NDEBUG)

#if defined(WEBRTC_WIN)
  // Always log to the debugger.
  // Perhaps stderr should be controlled by a preference, as on Mac?
  OutputDebugStringA(str.c_str());
  if (log_to_stderr) {
    // This handles dynamically allocated consoles, too.
    if (HANDLE error_handle = ::GetStdHandle(STD_ERROR_HANDLE)) {
      log_to_stderr = false;
      DWORD written = 0;
      ::WriteFile(error_handle, str.data(), static_cast<DWORD>(str.size()),
                  &written, 0);
    }
  }
#endif  // WEBRTC_WIN

#if defined(WEBRTC_ANDROID)
  // Android's logging facility uses severity to log messages but we
  // need to map libjingle's severity levels to Android ones first.
  // Also write to stderr which maybe available to executable started
  // from the shell.
  int prio;
  switch (severity) {
    case LS_SENSITIVE:
      __android_log_write(ANDROID_LOG_INFO, tag, "SENSITIVE");
      if (log_to_stderr) {
        fprintf(stderr, "SENSITIVE");
        fflush(stderr);
      }
      return;
    case LS_VERBOSE:
      prio = ANDROID_LOG_VERBOSE;
      break;
    case LS_INFO:
      prio = ANDROID_LOG_INFO;
      break;
    case LS_WARNING:
      prio = ANDROID_LOG_WARN;
      break;
    case LS_ERROR:
      prio = ANDROID_LOG_ERROR;
      break;
    default:
      prio = ANDROID_LOG_UNKNOWN;
  }

  int size = str.size();
  int line = 0;
  int idx = 0;
  const int max_lines = size / kMaxLogLineSize + 1;
  if (max_lines == 1) {
    __android_log_print(prio, tag, "%.*s", size, str.c_str());
  } else {
    while (size > 0) {
      const int len = std::min(size, kMaxLogLineSize);
      // Use the size of the string in the format (str may have \0 in the
      // middle).
      __android_log_print(prio, tag, "[%d/%d] %.*s", line + 1, max_lines, len,
                          str.c_str() + idx);
      idx += len;
      size -= len;
      ++line;
    }
  }
#endif  // WEBRTC_ANDROID
  if (log_to_stderr) {
    fprintf(stderr, "%s", str.c_str());
    fflush(stderr);
  }
}

// static
bool LogMessage::IsNoop(LoggingSeverity severity) {
  if (severity >= g_dbg_sev)
    return false;

  // TODO(tommi): We're grabbing this lock for every LogMessage instance that
  // is going to be logged. This introduces unnecessary synchronization for
  // a feature that's mostly used for testing.
  CritScope cs(&g_log_crit);
  return streams_.size() == 0;
}

void LogMessage::FinishPrintStream() {
  if (is_noop_)
    return;
  if (!extra_.empty())
    print_stream_ << " : " << extra_;
  print_stream_ << std::endl;
}

//////////////////////////////////////////////////////////////////////

}  // namespace rtc