#include "log_helper.h"
#include <share.h>
#include <stdarg.h>
#include <stdio.h>

#include <mutex>

#define AMLOCK(A) std::lock_guard<std::mutex> lock(A)

#define LOG_ROLL_SIZE (1024 * 1024)

AMLog* AMLog::_log = NULL;
std::mutex _lock;

AMLog::AMLog(FILE* handle)
    : _handle(handle)
{
    _log = this;
}

AMLog::~AMLog()
{
    AMLOCK(_lock);
    if (_log && _handle) {
        fclose(_handle);
        _log = NULL;
    }
}

AMLog* AMLog::get(const char* path)
{
    if (_log || !path) {
        return _log;
    }
    DWORD size = 0;
    HANDLE file = CreateFileA(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (file != INVALID_HANDLE_VALUE) {
        size = GetFileSize(file, NULL);
        CloseHandle(file);
    }
    if (size != INVALID_FILE_SIZE && size > LOG_ROLL_SIZE) {
        if (DeleteFileA(path) == FALSE) {
            char roll_path[MAX_PATH];
            sprintf_s(roll_path, MAX_PATH, "%s.1", path);
            if (!MoveFileExA(path, roll_path, MOVEFILE_REPLACE_EXISTING)) {
                return NULL;
            }
        }
    }
    FILE* handle = _fsopen(path, "a+", _SH_DENYNO);
    if (!handle) {
        return NULL;
    }
    _log = new AMLog(handle);
    return _log;
}

void AMLog::printf(const char* format, ...)
{
    AMLOCK(_lock);
    va_list args;

    va_start(args, format);
    vfprintf(_handle, format, args);
    va_end(args);
    fflush(_handle);
}