/*
 *
 *    Copyright (c) 2013-2017 Nest Labs, 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.
 */

/**
 *    @file
 *      This file implements a platform-specific Weave log interface.
 *
 */

#include <stdarg.h>
#include <stdio.h>

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <os/log.h>

#include <Weave/Support/logging/WeaveLogging.h>

#if WEAVE_ERROR_LOGGING || WEAVE_PROGRESS_LOGGING || WEAVE_DETAIL_LOGGING

#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)

namespace nl {

namespace Weave {

namespace Logging {

/*
 *  void Log()
 *
 *  Description:
 *    This routine writes to the Foundation log stream, the
 *    specified Weave-related variable argument message for the
 *    specified Weave module and category.
 *
 *  Input(s):
 *    aModule   - An enumeration indicating the Weave module or
 *                subsystem the message is associated with.
 *    aCategory - An enumeration indicating the Weave category
 *                the message is associated with.
 *    aMsg      - A NULL-terminated C string containing the message,
 *                with C Standard I/O-style format specifiers, to log.
 *    ...       - A variable argument list, corresponding to format
 *                specifiers in the message.
 *
 *  Output(s):
 *    N/A
 *
 *  Returns:
 *    N/A
 *
 */
void Log(uint8_t aModule, uint8_t aCategory, const char *aMsg, ...)
{
    va_list v;

    va_start(v, aMsg);

    if (IsCategoryEnabled(aCategory))
    {
        char formattedMsg[512];
        size_t prefixLen;

        char moduleName[nlWeaveLoggingModuleNameLen + 1];
        GetModuleName(moduleName, aModule);

        prefixLen = snprintf(formattedMsg, sizeof(formattedMsg), "WEAVE:%s: %s", moduleName,
                             (aCategory == kLogCategory_Error) ? "ERROR: " : "");
        if (prefixLen >= sizeof(formattedMsg))
            prefixLen = sizeof(formattedMsg) - 1;

        vsnprintf(formattedMsg + prefixLen, sizeof(formattedMsg) - prefixLen, aMsg, v);
		
		// For versions >= iOS 10, NSLog is not using Apple System logger anymore
		// So for the logs to always show up in device console, we need to use os_log
		// with OS_LOG_DEFAULT which always gets logged in accordance with system's 
		// standard behavior
		if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"10.0")) {
			os_log(OS_LOG_DEFAULT, formattedMsg);
		} else {
			NSLog(@"%s", formattedMsg);
		}

    }

    va_end(v);
}

} // namespace Logging

} // namespace Weave

} // namespace nl

#endif // WEAVE_ERROR_LOGGING || WEAVE_PROGRESS_LOGGING || WEAVE_DETAIL_LOGGING