/// Copyright 2015 Google Inc. All rights reserved.
///
/// 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.

#import "SNTLogging.h"

#import <asl.h>

#ifdef DEBUG
static LogLevel logLevel = LOG_LEVEL_DEBUG;
#else
static LogLevel logLevel = LOG_LEVEL_INFO;  // default to info
#endif

void logMessage(LogLevel level, FILE *destination, NSString *format, ...) {
  static BOOL useSyslog = NO;
  static const char *binaryName;
  static dispatch_once_t pred;

  dispatch_once(&pred, ^{
      binaryName = [[[NSProcessInfo processInfo] processName] UTF8String];

      // If debug logging is enabled, the process must be restarted.
      if ([[[NSProcessInfo processInfo] arguments] containsObject:@"--debug"]) {
        logLevel = LOG_LEVEL_DEBUG;
      }

      // If requested, redirect output to syslog.
      if ([[[NSProcessInfo processInfo] arguments] containsObject:@"--syslog"] ||
          strcmp(binaryName, "santad") == 0) {
        useSyslog = YES;
      }
  });

  if (logLevel < level) return;

  va_list args;
  va_start(args, format);
  NSString *s = [[NSString alloc] initWithFormat:format arguments:args];
  va_end(args);

  if (useSyslog) {
    aslclient client = asl_open(NULL, "com.google.santa", 0);
    asl_set_filter(client, ASL_FILTER_MASK_UPTO(ASL_LEVEL_DEBUG));

    char *levelName;
    int syslogLevel = ASL_LEVEL_DEBUG;
    switch (level) {
      case LOG_LEVEL_ERROR: levelName = "E"; syslogLevel = ASL_LEVEL_ERR; break;
      case LOG_LEVEL_WARN: levelName = "W"; syslogLevel = ASL_LEVEL_WARNING; break;
      case LOG_LEVEL_INFO: levelName = "I"; syslogLevel = ASL_LEVEL_INFO; break;
      case LOG_LEVEL_DEBUG: levelName = "D"; syslogLevel = ASL_LEVEL_DEBUG; break;
    }

    asl_log(client, NULL, syslogLevel, "%s %s: %s", levelName, binaryName, [s UTF8String]);
    asl_close(client);
  } else {
    fprintf(destination, "%s\n", [s UTF8String]);
  }
}