/**
 * Platform compatibility layer for POSIX functions on Windows
 */

#ifndef PLATFORM_COMPAT_H
#define PLATFORM_COMPAT_H

#ifdef _WIN32
    #include <winsock2.h>
    #include <ws2tcpip.h>
    #include <windows.h>
    #include <io.h>
    #include <time.h>
    
    // POSIX functions missing on Windows
    #define strcasecmp _stricmp
    #define strncasecmp _strnicmp
    
    // poll() implementation for Windows
    #ifndef POLLIN
        #define POLLIN 0x0001
    #endif
    #ifndef POLLOUT
        #define POLLOUT 0x0004
    #endif
    #ifndef POLLERR
        #define POLLERR 0x0008
    #endif
    #ifndef POLLHUP
        #define POLLHUP 0x0010
    #endif
    #ifndef POLLNVAL
        #define POLLNVAL 0x0020
    #endif
    #ifndef POLLPRI
        #define POLLPRI 0x0002
    #endif
    
    struct pollfd {
        int fd;
        short events;
        short revents;
    };
    
    // gettimeofday for Windows
    struct timezone {
        int tz_minuteswest;
        int tz_dsttime;
    };
    
    static inline int gettimeofday(struct timeval *tv, struct timezone *tz) {
        (void)tz;
        if (tv) {
            FILETIME ft;
            ULARGE_INTEGER ull;
            GetSystemTimeAsFileTime(&ft);
            ull.LowPart = ft.dwLowDateTime;
            ull.HighPart = ft.dwHighDateTime;
            // Convert from 100-nanosecond intervals since 1601 to Unix epoch
            tv->tv_sec = (long)(ull.QuadPart / 10000000ULL - 11644473600ULL);
            tv->tv_usec = (long)((ull.QuadPart % 10000000ULL) / 10);
        }
        return 0;
    }
    
    // Pipe creation for Windows
    static inline int pipe(int pipefd[2]) {
        return _pipe(pipefd, 4096, _O_BINARY);
    }
    
    // poll() using select() for Windows
    static inline int poll(struct pollfd *fds, nfds_t nfds, int timeout) {
        fd_set readfds, writefds, exceptfds;
        FD_ZERO(&readfds);
        FD_ZERO(&writefds);
        FD_ZERO(&exceptfds);
        
        int max_fd = -1;
        for (nfds_t i = 0; i < nfds; i++) {
            if (fds[i].fd < 0) continue;
            if (fds[i].events & POLLIN) FD_SET(fds[i].fd, &readfds);
            if (fds[i].events & POLLOUT) FD_SET(fds[i].fd, &writefds);
            FD_SET(fds[i].fd, &exceptfds);
            if (fds[i].fd > max_fd) max_fd = fds[i].fd;
        }
        
        struct timeval tv, *ptv = NULL;
        if (timeout >= 0) {
            tv.tv_sec = timeout / 1000;
            tv.tv_usec = (timeout % 1000) * 1000;
            ptv = &tv;
        }
        
        int ret = select(max_fd + 1, &readfds, &writefds, &exceptfds, ptv);
        if (ret < 0) return ret;
        
        // Set revents
        for (nfds_t i = 0; i < nfds; i++) {
            fds[i].revents = 0;
            if (fds[i].fd < 0) continue;
            if (FD_ISSET(fds[i].fd, &readfds)) fds[i].revents |= POLLIN;
            if (FD_ISSET(fds[i].fd, &writefds)) fds[i].revents |= POLLOUT;
            if (FD_ISSET(fds[i].fd, &exceptfds)) fds[i].revents |= POLLERR;
        }
        
        return ret;
    }
    
    // fcntl replacement for Windows (simplified - only supports F_GETFL/F_SETFL with O_NONBLOCK)
    #define F_GETFL 3
    #define F_SETFL 4
    #define O_NONBLOCK 0x4000
    
    static inline int fcntl(int fd, int cmd, ... /* arg */ ) {
        va_list ap;
        va_start(ap, cmd);
        
        if (cmd == F_GETFL) {
            va_end(ap);
            // Return current flags (always 0 on Windows, can't query easily)
            return 0;
        } else if (cmd == F_SETFL) {
            int flags = va_arg(ap, int);
            va_end(ap);
            if (flags & O_NONBLOCK) {
                // Set non-blocking mode
                u_long mode = 1;
                return ioctlsocket(fd, FIONBIO, &mode);
            }
            return 0;
        }
        
        va_end(ap);
        errno = EINVAL;
        return -1;
    }
    
    // nanosleep replacement
    static inline int nanosleep(const struct timespec *req, struct timespec *rem) {
        (void)rem;
        Sleep((DWORD)(req->tv_sec * 1000 + req->tv_nsec / 1000000));
        return 0;
    }
    
#else
    // POSIX - include standard headers
    #include <sys/time.h>
    #include <strings.h>
    #include <arpa/inet.h>
    #include <netinet/in.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <poll.h>
#endif

#endif // PLATFORM_COMPAT_H