#include "Log.h"
#include <windows.h>

CLog::CLog()
:   m_stdout(0), m_stderr(0)
{


}

CLog::~CLog()
{
    if(0 != m_stderr)
    {
        fclose(m_stderr);
        m_stderr = 0;
    }

    if(0 != m_stdout)
    {
        fclose(m_stdout);
        m_stdout = 0;
    }
}


bool CLog::RedirectStdErr(const char* szFileName)
{
    char szLogFileName[MAX_PATH];

    if(MakeFileName(szFileName, szLogFileName))
    {
        m_stderr = freopen(szLogFileName, "at", stderr);
        return (0 != m_stderr);
    }

    return false;
}

bool CLog::RedirectStdOut(const char *szFileName)
{
    char szLogFileName[MAX_PATH];
    
    if(MakeFileName(szFileName, szLogFileName))
    {
        m_stdout = freopen(szLogFileName, "at", stdout);
        return (0 != m_stdout);
    }

    return false;
}



bool CLog::MakeFileName(const char* szFileName, char* szLogFileName)
{
    // create log file name in good order
	for(unsigned long dwSpinCount = 0; TRUE; ++dwSpinCount)
	{
		int nLength = _snprintf(szLogFileName, MAX_PATH, "%s%04d.log", 
            szFileName, dwSpinCount);

        if(nLength < 0)
        {
            return false;
        }
        
		if (INVALID_FILE_ATTRIBUTES == GetFileAttributes(szLogFileName))
        {
			break;
		}
        else
        {
            HANDLE hFile = CreateFile(szLogFileName, GENERIC_READ, FILE_SHARE_READ, 
                NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

            if(hFile != INVALID_HANDLE_VALUE)
            {
                DWORD dwFileHighSize = 0;
                DWORD dwFileSize = GetFileSize(hFile, &dwFileHighSize);

                CloseHandle(hFile);

                if(0 == dwFileHighSize && dwFileSize < 10 * 1024 * 1024)
                {
                    break;
                }
            }
        }
	}

    return true;
}