#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>
#else
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <unistd.h>
#ifdef __linux__
#include <netpacket/packet.h>
#endif
#endif
#include <cstdint>
#include <cstddef>
#include <cstdio>
#include <cstring>
#include "SceTypes.hpp"
#include "prx/libc/include/General.hpp"
#include <fstream>
#include <memory>
#include <mutex>
#include <sstream>
#include <stdexcept>
#include <string>
#include <vector>

// Network-control state reflects host interface addressing, not PSN sign-in status.
static constexpr int SCE_NET_CTL_ERROR_CALLBACK_MAX = static_cast<int>(0x80412103);
static constexpr int SCE_NET_CTL_ERROR_INVALID_ID = static_cast<int>(0x80412105);
static constexpr int SCE_NET_CTL_ERROR_INVALID_CODE = static_cast<int>(0x80412106);
static constexpr int SCE_NET_CTL_ERROR_INVALID_ADDR = static_cast<int>(0x80412107);
static constexpr int SCE_NET_CTL_ERROR_NOT_CONNECTED = static_cast<int>(0x80412108);
static constexpr int NET_CTL_STATE_DISCONNECTED = 0;
static constexpr int NET_CTL_STATE_IPOBTAINED = 3;
static constexpr int NET_CTL_INFO_DEVICE = 1;
static constexpr int NET_CTL_INFO_ETHER_ADDR = 2;
static constexpr int NET_CTL_INFO_MTU = 3;
static constexpr int NET_CTL_INFO_LINK = 4;
static constexpr int NET_CTL_INFO_IP_CONFIG = 11;
static constexpr int NET_CTL_INFO_IP_ADDRESS = 14;
static constexpr int NET_CTL_INFO_NETMASK = 15;
static constexpr int NET_CTL_INFO_DEFAULT_ROUTE = 16;
static constexpr int NET_CTL_INFO_PRIMARY_DNS = 17;
static constexpr int NET_CTL_INFO_SECONDARY_DNS = 18;
static constexpr int NET_CTL_INFO_HTTP_PROXY_CONFIG = 19;
static constexpr int NET_CTL_INFO_HTTP_PROXY_PORT = 21;
static constexpr std::uint32_t NET_CTL_DEVICE_WIRED = 0;
static constexpr std::uint32_t NET_CTL_LINK_CONNECTED = 1;
static constexpr std::uint32_t NET_CTL_IP_DHCP = 0;
static constexpr std::uint32_t NET_CTL_HTTP_PROXY_OFF = 0;
static constexpr std::uint8_t NET_CTL_ETHER_ADDR[6] = {0x02, 0x50, 0x53, 0x35, 0x00, 0x01};
static constexpr std::size_t NET_CTL_IPV4_ADDR_STR_LEN = 16;
static constexpr int MAX_CALLBACKS = 8;

static std::mutex g_callbackLock;
static NetCtlCallback g_callbacks[MAX_CALLBACKS] = {};
static NetCtlCallback g_callbacksV6[MAX_CALLBACKS] = {};

static int RegisterCallback(NetCtlCallback (&callbacks)[MAX_CALLBACKS], NetCtlCallback func, int* cid) {
    if (!func || !cid) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    std::lock_guard lock(g_callbackLock);
    for (int index = 0; index < MAX_CALLBACKS; ++index) {
        if (!callbacks[index]) {
            callbacks[index] = func;
            *cid = index;
            return 0;
        }
    }
    return SCE_NET_CTL_ERROR_CALLBACK_MAX;
}

static int UnregisterCallback(NetCtlCallback (&callbacks)[MAX_CALLBACKS], int cid) {
    if (cid < 0 || cid >= MAX_CALLBACKS) return SCE_NET_CTL_ERROR_INVALID_ID;
    std::lock_guard lock(g_callbackLock);
    callbacks[cid] = nullptr;
    return 0;
}

static bool HostHasAddress(int family) {
#ifdef _WIN32
    static const int socket_status = [] {
        WSADATA data{};
        return WSAStartup(MAKEWORD(2, 2), &data);
    }();
    if (socket_status != 0) return false;
    ULONG size = 0;
    const ULONG flags = GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER;
    if (GetAdaptersAddresses(family, flags, nullptr, nullptr, &size) != ERROR_BUFFER_OVERFLOW) return false;
    std::vector<std::uint8_t> storage(size);
    auto* adapters = reinterpret_cast<IP_ADAPTER_ADDRESSES*>(storage.data());
    if (GetAdaptersAddresses(family, flags, nullptr, adapters, &size) != NO_ERROR) return false;
    for (auto* adapter = adapters; adapter; adapter = adapter->Next) {
        if (adapter->OperStatus != IfOperStatusUp || adapter->IfType == IF_TYPE_SOFTWARE_LOOPBACK) continue;
        for (auto* address = adapter->FirstUnicastAddress; address; address = address->Next) {
            if (!address->Address.lpSockaddr) continue;
            if (address->Address.lpSockaddr->sa_family == AF_INET) {
                const auto* v4 = reinterpret_cast<const sockaddr_in*>(address->Address.lpSockaddr);
                const auto host = ntohl(v4->sin_addr.s_addr);
                if (host != 0 && (host >> 24) != 127) return true;
            } else if (address->Address.lpSockaddr->sa_family == AF_INET6) {
                const auto* v6 = reinterpret_cast<const sockaddr_in6*>(address->Address.lpSockaddr);
                if (!IN6_IS_ADDR_UNSPECIFIED(&v6->sin6_addr) && !IN6_IS_ADDR_LOOPBACK(&v6->sin6_addr)) return true;
            }
        }
    }
    return false;
#else
    ifaddrs* interfaces = nullptr;
    if (getifaddrs(&interfaces) != 0) return false;
    bool found = false;
    for (auto* item = interfaces; item && !found; item = item->ifa_next) {
        if (!item->ifa_addr || !(item->ifa_flags & IFF_UP) || (item->ifa_flags & IFF_LOOPBACK)) continue;
        const int address_family = item->ifa_addr->sa_family;
        if ((family == AF_UNSPEC || family == address_family) && address_family == AF_INET) {
            const auto* v4 = reinterpret_cast<const sockaddr_in*>(item->ifa_addr);
            const auto host = ntohl(v4->sin_addr.s_addr);
            found = host != 0 && (host >> 24) != 127;
        } else if ((family == AF_UNSPEC || family == address_family) && address_family == AF_INET6) {
            const auto* v6 = reinterpret_cast<const sockaddr_in6*>(item->ifa_addr);
            found = !IN6_IS_ADDR_UNSPECIFIED(&v6->sin6_addr) && !IN6_IS_ADDR_LOOPBACK(&v6->sin6_addr);
        }
    }
    freeifaddrs(interfaces);
    return found;
#endif
}

struct HostIpv4Interface {
    in_addr address{};
    in_addr netmask{};
    in_addr gateway{};
    std::uint32_t mtu = 0;
    std::vector<in_addr> dns;
};

static bool UsableIpv4(in_addr address) {
    const auto host = ntohl(address.s_addr);
    return host != 0 && (host >> 24) != 127;
}

#ifdef _WIN32
static const sockaddr_in* Ipv4Of(const SOCKET_ADDRESS& address) {
    if (!address.lpSockaddr || address.lpSockaddr->sa_family != AF_INET) return nullptr;
    return reinterpret_cast<const sockaddr_in*>(address.lpSockaddr);
}

static std::uint32_t PrefixMask(unsigned length) {
    if (length == 0) return 0;
    return htonl(length >= 32 ? 0xFFFFFFFFu : 0xFFFFFFFFu << (32 - length));
}
#else
struct HostDefaultRoute {
    std::string name;
    in_addr gateway{};
    unsigned long metric = 0;
};

static std::vector<HostDefaultRoute> HostDefaultRoutes() {
    std::ifstream table("/proc/net/route");
    if (!table) throw std::runtime_error("sceNetCtlGetInfo: the host routing table is unavailable");
    std::vector<HostDefaultRoute> routes;
    std::string line;
    std::getline(table, line);
    while (std::getline(table, line)) {
        std::istringstream fields(line);
        HostDefaultRoute route;
        unsigned long destination = 0;
        unsigned long gateway = 0;
        unsigned long flags = 0;
        unsigned long references = 0;
        unsigned long uses = 0;
        unsigned long mask = 0;
        if (!(fields >> route.name >> std::hex >> destination >> gateway >> flags >> std::dec >> references >> uses >> route.metric >> std::hex >> mask)) continue;
        if (destination != 0 || mask != 0 || !(flags & RTF_UP) || (flags & RTF_REJECT)) continue;
        route.gateway.s_addr = static_cast<std::uint32_t>(gateway);
        routes.push_back(route);
    }
    return routes;
}

static std::uint32_t HostInterfaceMtu(const char* name) {
    const int descriptor = socket(AF_INET, SOCK_DGRAM, 0);
    if (descriptor < 0) throw std::runtime_error("sceNetCtlGetInfo: no socket to read the host interface MTU");
    ifreq request{};
    std::strncpy(request.ifr_name, name, IFNAMSIZ - 1);
    const int result = ioctl(descriptor, SIOCGIFMTU, &request);
    close(descriptor);
    if (result != 0) throw std::runtime_error(std::string("sceNetCtlGetInfo: no MTU for host interface ") + name);
    return static_cast<std::uint32_t>(request.ifr_mtu);
}

static std::vector<in_addr> HostDnsServers() {
    std::ifstream config("/etc/resolv.conf");
    std::vector<in_addr> servers;
    std::string line;
    while (std::getline(config, line)) {
        std::istringstream fields(line);
        std::string keyword;
        std::string value;
        in_addr server{};
        if (fields >> keyword >> value && keyword == "nameserver" && inet_pton(AF_INET, value.c_str(), &server) == 1) servers.push_back(server);
    }
    return servers;
}
#endif

static bool FindHostIpv4Interface(HostIpv4Interface& found) {
#ifdef _WIN32
    ULONG size = 0;
    const ULONG flags = GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_INCLUDE_GATEWAYS;
    if (GetAdaptersAddresses(AF_INET, flags, nullptr, nullptr, &size) != ERROR_BUFFER_OVERFLOW) return false;
    std::vector<std::uint8_t> storage(size);
    auto* adapters = reinterpret_cast<IP_ADAPTER_ADDRESSES*>(storage.data());
    if (GetAdaptersAddresses(AF_INET, flags, nullptr, adapters, &size) != NO_ERROR) return false;
    bool chosen = false;
    bool chosenHasGateway = false;
    ULONG chosenMetric = 0;
    for (auto* adapter = adapters; adapter; adapter = adapter->Next) {
        if (adapter->OperStatus != IfOperStatusUp || adapter->IfType == IF_TYPE_SOFTWARE_LOOPBACK) continue;
        auto* unicast = adapter->FirstUnicastAddress;
        while (unicast && !(Ipv4Of(unicast->Address) && UsableIpv4(Ipv4Of(unicast->Address)->sin_addr))) unicast = unicast->Next;
        if (!unicast) continue;
        auto* gateway = adapter->FirstGatewayAddress;
        while (gateway && !Ipv4Of(gateway->Address)) gateway = gateway->Next;
        if (chosen && !(gateway && (!chosenHasGateway || adapter->Ipv4Metric < chosenMetric))) continue;
        HostIpv4Interface candidate;
        candidate.address = Ipv4Of(unicast->Address)->sin_addr;
        candidate.netmask.s_addr = PrefixMask(unicast->OnLinkPrefixLength);
        if (gateway) candidate.gateway = Ipv4Of(gateway->Address)->sin_addr;
        candidate.mtu = adapter->Mtu;
        for (auto* server = adapter->FirstDnsServerAddress; server; server = server->Next) {
            if (Ipv4Of(server->Address)) candidate.dns.push_back(Ipv4Of(server->Address)->sin_addr);
        }
        found = std::move(candidate);
        chosen = true;
        chosenHasGateway = gateway != nullptr;
        chosenMetric = adapter->Ipv4Metric;
    }
    return chosen;
#else
    ifaddrs* list = nullptr;
    if (getifaddrs(&list) != 0) return false;
    const std::unique_ptr<ifaddrs, void (*)(ifaddrs*)> interfaces(list, freeifaddrs);
    const auto routes = HostDefaultRoutes();
    const ifaddrs* chosen = nullptr;
    const HostDefaultRoute* chosenRoute = nullptr;
    for (auto* item = list; item; item = item->ifa_next) {
        if (!item->ifa_addr || item->ifa_addr->sa_family != AF_INET || !(item->ifa_flags & IFF_UP) || (item->ifa_flags & IFF_LOOPBACK)) continue;
        if (!UsableIpv4(reinterpret_cast<const sockaddr_in*>(item->ifa_addr)->sin_addr)) continue;
        const HostDefaultRoute* route = nullptr;
        for (const auto& entry : routes) {
            if (entry.name == item->ifa_name && (!route || entry.metric < route->metric)) route = &entry;
        }
        if (chosen && !(route && (!chosenRoute || route->metric < chosenRoute->metric))) continue;
        chosen = item;
        chosenRoute = route;
    }
    if (!chosen) return false;
    found.address = reinterpret_cast<const sockaddr_in*>(chosen->ifa_addr)->sin_addr;
    if (chosen->ifa_netmask) found.netmask = reinterpret_cast<const sockaddr_in*>(chosen->ifa_netmask)->sin_addr;
    if (chosenRoute) found.gateway = chosenRoute->gateway;
    found.mtu = HostInterfaceMtu(chosen->ifa_name);
    found.dns = HostDnsServers();
    return true;
#endif
}

static void WriteInfoWord(NetCtlInfo* info, std::uint32_t value) {
    std::memcpy(info->opaque, &value, sizeof(value));
}

static void WriteInfoAddress(NetCtlInfo* info, in_addr address) {
    const auto* bytes = reinterpret_cast<const std::uint8_t*>(&address.s_addr);
    char text[NET_CTL_IPV4_ADDR_STR_LEN] = {};
    std::snprintf(text, sizeof(text), "%u.%u.%u.%u", static_cast<unsigned>(bytes[0]), static_cast<unsigned>(bytes[1]), static_cast<unsigned>(bytes[2]), static_cast<unsigned>(bytes[3]));
    std::memcpy(info->opaque, text, sizeof(text));
}

extern "C" std::uint64_t NetCtlReadByteCounter_nid_no_patch(const char* path) {
    std::ifstream file(path);
    std::uint64_t value = 0;
    if (!(file >> value)) throw std::runtime_error(std::string("sceNetCtlGetIfStat: no byte counter in ") + path);
    return value;
}

static void HostTraffic(std::uint64_t& sent, std::uint64_t& received) {
    sent = 0;
    received = 0;
#ifdef _WIN32
    MIB_IF_TABLE2* table = nullptr;
    if (GetIfTable2(&table) != NO_ERROR) throw std::runtime_error("sceNetCtlGetIfStat: the host interface table is unavailable");
    for (ULONG index = 0; index < table->NumEntries; ++index) {
        const auto& row = table->Table[index];
        if (row.OperStatus != IfOperStatusUp || row.Type == IF_TYPE_SOFTWARE_LOOPBACK || !row.InterfaceAndOperStatusFlags.HardwareInterface) continue;
        sent += row.OutOctets;
        received += row.InOctets;
    }
    FreeMibTable(table);
#elif defined(__linux__)
    ifaddrs* interfaces = nullptr;
    if (getifaddrs(&interfaces) != 0) throw std::runtime_error("sceNetCtlGetIfStat: the host interface list is unavailable");
    for (auto* item = interfaces; item; item = item->ifa_next) {
        if (!item->ifa_addr || item->ifa_addr->sa_family != AF_PACKET) continue;
        if (!(item->ifa_flags & IFF_UP) || (item->ifa_flags & IFF_LOOPBACK)) continue;
        const std::string statistics = std::string("/sys/class/net/") + item->ifa_name + "/statistics/";
        sent += NetCtlReadByteCounter_nid_no_patch((statistics + "tx_bytes").c_str());
        received += NetCtlReadByteCounter_nid_no_patch((statistics + "rx_bytes").c_str());
    }
    freeifaddrs(interfaces);
#else
    throw std::runtime_error("sceNetCtlGetIfStat: host interface byte counters are not implemented on this platform");
#endif
}

extern "C" {

int APS5_VABI sceNetCtlCheckCallback(void) {
    return 0;
}

int APS5_VABI sceNetCtlGetIfStat(NetCtlIfStat* stat) {
    if (!stat) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    if (!HostHasAddress(AF_UNSPEC)) return SCE_NET_CTL_ERROR_NOT_CONNECTED;
    *stat = {};
    HostTraffic(stat->tx_bytes, stat->rx_bytes);
    return 0;
}

int APS5_VABI sceNetCtlGetInfo(int code, NetCtlInfo* info) {
    if (!info) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    if (code < NET_CTL_INFO_DEVICE || code > NET_CTL_INFO_HTTP_PROXY_PORT) return SCE_NET_CTL_ERROR_INVALID_CODE;
    HostIpv4Interface host;
    if (!FindHostIpv4Interface(host)) return SCE_NET_CTL_ERROR_NOT_CONNECTED;
    switch (code) {
        case NET_CTL_INFO_DEVICE: WriteInfoWord(info, NET_CTL_DEVICE_WIRED); break;
        case NET_CTL_INFO_ETHER_ADDR: std::memcpy(info->opaque, NET_CTL_ETHER_ADDR, sizeof(NET_CTL_ETHER_ADDR)); break;
        case NET_CTL_INFO_MTU: WriteInfoWord(info, host.mtu); break;
        case NET_CTL_INFO_LINK: WriteInfoWord(info, NET_CTL_LINK_CONNECTED); break;
        case NET_CTL_INFO_IP_CONFIG: WriteInfoWord(info, NET_CTL_IP_DHCP); break;
        case NET_CTL_INFO_IP_ADDRESS: WriteInfoAddress(info, host.address); break;
        case NET_CTL_INFO_NETMASK: WriteInfoAddress(info, host.netmask); break;
        case NET_CTL_INFO_DEFAULT_ROUTE: WriteInfoAddress(info, host.gateway); break;
        case NET_CTL_INFO_PRIMARY_DNS: WriteInfoAddress(info, host.dns.size() > 0 ? host.dns[0] : in_addr{}); break;
        case NET_CTL_INFO_SECONDARY_DNS: WriteInfoAddress(info, host.dns.size() > 1 ? host.dns[1] : in_addr{}); break;
        case NET_CTL_INFO_HTTP_PROXY_CONFIG: WriteInfoWord(info, NET_CTL_HTTP_PROXY_OFF); break;
        default: throw std::runtime_error("sceNetCtlGetInfo: info code " + std::to_string(code) + " is not implemented");
    }
    return 0;
}

int APS5_VABI sceNetCtlGetNatInfo(NetCtlNatInfo* nat_info) {
    (void)nat_info;
    return SCE_NET_CTL_ERROR_NOT_CONNECTED;
}

int APS5_VABI sceNetCtlGetResult(int event_type, int* error_code) {
    (void)event_type;
    if (!error_code) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    *error_code = 0;
    return 0;
}

int APS5_VABI sceNetCtlGetState(int* state) {
    if (!state) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    *state = HostHasAddress(AF_UNSPEC) ? NET_CTL_STATE_IPOBTAINED : NET_CTL_STATE_DISCONNECTED;
    return 0;
}

int APS5_VABI sceNetCtlGetStateV6(int* state) {
    if (!state) return SCE_NET_CTL_ERROR_INVALID_ADDR;
    *state = HostHasAddress(AF_INET6) ? NET_CTL_STATE_IPOBTAINED : NET_CTL_STATE_DISCONNECTED;
    return 0;
}

int APS5_VABI sceNetCtlInit(void) {
    return 0;
}

int APS5_VABI sceNetCtlRegisterCallback(NetCtlCallback func, void* arg, int* cid) {
    return RegisterCallback(g_callbacks, func, cid);
}

int APS5_VABI sceNetCtlRegisterCallbackV6(NetCtlCallback func, void* arg, int* cid) {
    return RegisterCallback(g_callbacksV6, func, cid);
}

void APS5_VABI sceNetCtlTerm(void) {
}

int APS5_VABI sceNetCtlUnregisterCallback(int cid) {
    return UnregisterCallback(g_callbacks, cid);
}

int APS5_VABI sceNetCtlUnregisterCallbackV6(int cid) {
    return UnregisterCallback(g_callbacksV6, cid);
}

}