// runtime/platform.h — Cross-Platform Compatibility Layer
// Copyright (C) 2024-2026 Salka Elmadani. All rights reserved.
// INPI eSoleau: 7phf-Ueye-2nWr-Vsgu — BSL-1.1
//
// One header. Linux, macOS, Windows. No #ifdef jungle in application code.
//
#pragma once

// ═══════════════════════════════════════════════════════════════════════════
// Platform Detection
// ═══════════════════════════════════════════════════════════════════════════

#if defined(_WIN32) || defined(_WIN64)
    #define IX_WINDOWS 1
    #define IX_POSIX   0
#elif defined(__APPLE__)
    #define IX_MACOS   1
    #define IX_POSIX   1
#else
    #define IX_LINUX   1
    #define IX_POSIX   1
#endif

// ═══════════════════════════════════════════════════════════════════════════
// Socket Abstraction
// ═══════════════════════════════════════════════════════════════════════════

#if IX_WINDOWS
    #ifndef WIN32_LEAN_AND_MEAN
    #define WIN32_LEAN_AND_MEAN
    #endif
    #include <winsock2.h>
    #include <ws2tcpip.h>
    #pragma comment(lib, "ws2_32.lib")
    
    using socket_t = SOCKET;
    #define IX_INVALID_SOCKET INVALID_SOCKET
    #define IX_SOCKET_ERROR   SOCKET_ERROR
    
    // MSG_NOSIGNAL doesn't exist on Windows (no SIGPIPE)
    #ifndef MSG_NOSIGNAL
    #define MSG_NOSIGNAL 0
    #endif
    
    inline int ix_close_socket(socket_t s) { return closesocket(s); }
    
    inline bool ix_socket_init() {
        WSADATA wsa;
        return WSAStartup(MAKEWORD(2, 2), &wsa) == 0;
    }
    
    inline void ix_socket_cleanup() { WSACleanup(); }
    
    inline int ix_send(socket_t s, const char* buf, int len, int flags) {
        return send(s, buf, len, flags);
    }
    
    inline int ix_recv(socket_t s, char* buf, int len, int flags) {
        return recv(s, buf, len, flags);
    }

#else  // POSIX (Linux + macOS)
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <unistd.h>
    #include <arpa/inet.h>
    #include <signal.h>
    
    using socket_t = int;
    #define IX_INVALID_SOCKET (-1)
    #define IX_SOCKET_ERROR   (-1)
    
    #ifndef MSG_NOSIGNAL
    #ifdef __APPLE__
        #define MSG_NOSIGNAL 0  // macOS uses SO_NOSIGPIPE instead
    #endif
    #endif
    
    inline int ix_close_socket(socket_t s) { return close(s); }
    
    inline bool ix_socket_init() {
        #ifdef __APPLE__
        // macOS: ignore SIGPIPE globally
        signal(SIGPIPE, SIG_IGN);
        #endif
        return true;
    }
    
    inline void ix_socket_cleanup() {}
    
    inline ssize_t ix_send(socket_t s, const char* buf, size_t len, int flags) {
        return send(s, buf, len, flags);
    }
    
    inline ssize_t ix_recv(socket_t s, char* buf, size_t len, int flags) {
        return recv(s, buf, len, flags);
    }
#endif

// ═══════════════════════════════════════════════════════════════════════════
// Memory Mapping Abstraction
// ═══════════════════════════════════════════════════════════════════════════

#if IX_WINDOWS
    #include <windows.h>
    
    inline void* ix_mmap(void* addr, size_t length, int fd, size_t offset) {
        HANDLE hMap = CreateFileMapping((HANDLE)_get_osfhandle(fd), 
                                        NULL, PAGE_READONLY, 
                                        (DWORD)(length >> 32), (DWORD)length, NULL);
        if (!hMap) return nullptr;
        void* ptr = MapViewOfFile(hMap, FILE_MAP_READ, 
                                   (DWORD)(offset >> 32), (DWORD)offset, length);
        CloseHandle(hMap);
        return ptr;
    }
    
    inline int ix_munmap(void* addr, size_t length) {
        return UnmapViewOfFile(addr) ? 0 : -1;
    }
    
    inline void ix_madvise_sequential(void* addr, size_t length) {
        // No equivalent on Windows — VirtualLock could help but is limited
        (void)addr; (void)length;
    }

#else
    #include <sys/mman.h>
    
    inline void* ix_mmap(void* addr, size_t length, int fd, size_t offset) {
        return mmap(addr, length, PROT_READ, MAP_PRIVATE, fd, offset);
    }
    
    inline int ix_munmap(void* addr, size_t length) {
        return munmap(addr, length);
    }
    
    inline void ix_madvise_sequential(void* addr, size_t length) {
        madvise(addr, length, MADV_SEQUENTIAL);
    }
#endif

// ═══════════════════════════════════════════════════════════════════════════
// Threading Abstraction (minimal — we use C++17 <thread> mostly)
// ═══════════════════════════════════════════════════════════════════════════

#if IX_WINDOWS
    #include <windows.h>
    inline int ix_cpu_count() {
        SYSTEM_INFO si;
        GetSystemInfo(&si);
        return (int)si.dwNumberOfProcessors;
    }
    
    inline size_t ix_total_ram() {
        MEMORYSTATUSEX ms;
        ms.dwLength = sizeof(ms);
        GlobalMemoryStatusEx(&ms);
        return (size_t)ms.ullTotalPhys;
    }
#else
    #include <unistd.h>
    inline int ix_cpu_count() {
        return (int)sysconf(_SC_NPROCESSORS_ONLN);
    }
    
    inline size_t ix_total_ram() {
        long pages = sysconf(_SC_PHYS_PAGES);
        long page_size = sysconf(_SC_PAGE_SIZE);
        return (size_t)pages * page_size;
    }
#endif