#include "../git-compat-util.h"

unsigned int _CRT_fmode = _O_BINARY;

#undef open
int mingw_open (const char *filename, int oflags, ...)
{
        va_list args;
        unsigned mode;
        va_start(args, oflags);
        mode = va_arg(args, int);
        va_end(args);

        if (!strcmp(filename, "/dev/null"))
                filename = "nul";
        int fd = open(filename, oflags, mode);
        if (fd < 0 && (oflags & O_CREAT) && errno == EACCES) {
                DWORD attrs = GetFileAttributes(filename);
                if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY))
                        errno = EISDIR;
        }
        return fd;
}

unsigned int sleep (unsigned int seconds)
{
        Sleep(seconds*1000);
        return 0;
}

int mkstemp(char *template)
{
        char *filename = mktemp(template);
        if (filename == NULL)
                return -1;
        return open(filename, O_RDWR | O_CREAT, 0600);
}

int gettimeofday(struct timeval *tv, void *tz)
{
        SYSTEMTIME st;
        struct tm tm;
        GetSystemTime(&st);
        tm.tm_year = st.wYear-1900;
        tm.tm_mon = st.wMonth-1;
        tm.tm_mday = st.wDay;
        tm.tm_hour = st.wHour;
        tm.tm_min = st.wMinute;
        tm.tm_sec = st.wSecond;
        tv->tv_sec = tm_to_time_t(&tm);
        if (tv->tv_sec < 0)
                return -1;
        tv->tv_usec = st.wMilliseconds*1000;
        return 0;
}

int poll(struct pollfd *ufds, unsigned int nfds, int timeout)
{
        return -1;
}

struct tm *gmtime_r(const time_t *timep, struct tm *result)
{
        /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
        memcpy(result, gmtime(timep), sizeof(struct tm));
        return result;
}

struct tm *localtime_r(const time_t *timep, struct tm *result)
{
        /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
        memcpy(result, localtime(timep), sizeof(struct tm));
        return result;
}

#undef getcwd
char *mingw_getcwd(char *pointer, int len)
{
        int i;
        char *ret = getcwd(pointer, len);
        if (!ret)
                return ret;
        for (i = 0; pointer[i]; i++)
                if (pointer[i] == '\\')
                        pointer[i] = '/';
        return ret;
}

#undef rename
int mingw_rename(const char *pold, const char *pnew)
{
        /*
         * Try native rename() first to get errno right.
         * It is based on MoveFile(), which cannot overwrite existing files.
         */
        if (!rename(pold, pnew))
                return 0;
        if (errno != EEXIST)
                return -1;
        if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
                return 0;
        /* TODO: translate more errors */
        if (GetLastError() == ERROR_ACCESS_DENIED) {
                DWORD attrs = GetFileAttributes(pnew);
                if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
                        errno = EISDIR;
                        return -1;
                }
        }
        errno = EACCES;
        return -1;
}

struct passwd *getpwuid(int uid)
{
        static char user_name[100];
        static struct passwd p;

        DWORD len = sizeof(user_name);
        if (!GetUserName(user_name, &len))
                return NULL;
        p.pw_name = user_name;
        p.pw_gecos = "unknown";
        p.pw_dir = NULL;
        return &p;
}

static HANDLE timer_event;
static HANDLE timer_thread;
static int timer_interval;
static int one_shot;
static sig_handler_t timer_fn = SIG_DFL;

/* The timer works like this:
 * The thread, ticktack(), is a trivial routine that most of the time
 * only waits to receive the signal to terminate. The main thread tells
 * the thread to terminate by setting the timer_event to the signalled
 * state.
 * But ticktack() interrupts the wait state after the timer's interval
 * length to call the signal handler.
 */

static __stdcall unsigned ticktack(void *dummy)
{
        while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
                if (timer_fn == SIG_DFL)
                        die("Alarm");
                if (timer_fn != SIG_IGN)
                        timer_fn(SIGALRM);
                if (one_shot)
                        break;
        }
        return 0;
}

static int start_timer_thread(void)
{
        timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
        if (timer_event) {
                timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
                if (!timer_thread )
                        return errno = ENOMEM,
                                error("cannot start timer thread");
        } else
                return errno = ENOMEM,
                        error("cannot allocate resources for timer");
        return 0;
}

static void stop_timer_thread(void)
{
        if (timer_event)
                SetEvent(timer_event);  /* tell thread to terminate */
        if (timer_thread) {
                int rc = WaitForSingleObject(timer_thread, 1000);
                if (rc == WAIT_TIMEOUT)
                        error("timer thread did not terminate timely");
                else if (rc != WAIT_OBJECT_0)
                        error("waiting for timer thread failed: %lu",
                              GetLastError());
                CloseHandle(timer_thread);
        }
        if (timer_event)
                CloseHandle(timer_event);
        timer_event = NULL;
        timer_thread = NULL;
}

static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
{
        return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
}

int setitimer(int type, struct itimerval *in, struct itimerval *out)
{
        static const struct timeval zero;
        static int atexit_done;

        if (out != NULL)
                return errno = EINVAL,
                        error("setitimer param 3 != NULL not implemented");
        if (!is_timeval_eq(&in->it_interval, &zero) &&
            !is_timeval_eq(&in->it_interval, &in->it_value))
                return errno = EINVAL,
                        error("setitimer: it_interval must be zero or eq it_value");

        if (timer_thread)
                stop_timer_thread();

        if (is_timeval_eq(&in->it_value, &zero) &&
            is_timeval_eq(&in->it_interval, &zero))
                return 0;

        timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
        one_shot = is_timeval_eq(&in->it_interval, &zero);
        if (!atexit_done) {
                atexit(stop_timer_thread);
                atexit_done = 1;
        }
        return start_timer_thread();
}

int sigaction(int sig, struct sigaction *in, struct sigaction *out)
{
        if (sig != SIGALRM)
                return errno = EINVAL,
                        error("sigaction only implemented for SIGALRM");
        if (out != NULL)
                return errno = EINVAL,
                        error("sigaction: param 3 != NULL not implemented");

        timer_fn = in->sa_handler;
        return 0;
}

#undef signal
sig_handler_t mingw_signal(int sig, sig_handler_t handler)
{
        if (sig != SIGALRM)
                return signal(sig, handler);
        sig_handler_t old = timer_fn;
        timer_fn = handler;
        return old;
}