#include "nm_device.h"
#include "nm_connection.h"
#include "logger/logger.h"
#include <cstring>
#include <iostream>
#include <stdexcept>

// Only include sdbus on Linux
#ifdef __linux__
#include <systemd/sd-bus.h>
#endif

namespace radiantwave::network {

// ─── Access Point Helper ───────────────────────────────────────────────

// Build an AccessPointInfo from raw D-Bus AccessPoint property values (see
// nm_device.h). The `ssid` argument carries the raw SSID bytes decoded from
// the AccessPoint.Ssid `ay` property as a std::string.
AccessPointInfo parseAccessPoint(
    const std::string& object_path,
    const std::string& ssid,
    uint8_t signal,
    uint32_t flags,
    uint32_t wpa_flags,
    uint32_t rsn_flags
) {
    AccessPointInfo ap;
    ap.object_path = object_path;
    ap.ssid = ssid;
    ap.ssid_bytes = ssidToBytes(ssid);
    ap.signal_strength = signal;
    ap.flags = flags;
    ap.wpa_flags = wpa_flags;
    ap.rsn_flags = rsn_flags;
    ap.security = detectSecurityType(flags, wpa_flags, rsn_flags);

    return ap;
}

// ─── WifiDevice Implementation ─────────────────────────────────────────

#ifdef __linux__

struct WifiDevice::Impl {
    std::string object_path;
    sd_bus* bus = nullptr;
    
    explicit Impl(const std::string& path) : object_path(path) {
        int r = sd_bus_open_system(&bus);
        if (r < 0) {
            throw std::runtime_error("Failed to open system bus: " + std::string(strerror(-r)));
        }
    }
    
    ~Impl() {
        if (bus) {
            sd_bus_unref(bus);
        }
    }
    
    // Helper: call a D-Bus method and get response
    sd_bus_message* callMethod(
        const char* dest,
        const char* path,
        const char* iface,
        const char* member,
        const char* type,
        ...
    ) {
        sd_bus_message* msg = nullptr;
        sd_bus_error error = SD_BUS_ERROR_NULL;
        
        int r = sd_bus_call_method(
            bus,
            dest,
            path,
            iface,
            member,
            &error,
            &msg,
            type
        );
        
        if (r < 0) {
            radiantwave::logger::Logger::instance().warning("WiFi",
                std::string("D-Bus call failed: ") +
                (error.message ? error.message : strerror(-r)));
            sd_bus_error_free(&error);
            return nullptr;
        }
        
        sd_bus_error_free(&error);
        return msg;
    }
    
    // Helper: get a property value
    sd_bus_message* getProperty(
        const char* dest,
        const char* path,
        const char* iface,
        const char* prop,
        const char* type
    ) {
        sd_bus_message* msg = nullptr;
        sd_bus_error error = SD_BUS_ERROR_NULL;
        
        int r = sd_bus_get_property(
            bus,
            dest,
            path,
            iface,
            prop,
            &error,
            &msg,
            type
        );
        
        if (r < 0) {
            // Transient D-Bus errors (e.g. a reply raced with a state change
            // while NetworkManager churns the device during a failed auth)
            // must never throw out of here — callers treat a null reply as
            // "unknown", which keeps the UI and wait loops running.
            radiantwave::logger::Logger::instance().warning("WiFi",
                "D-Bus property get failed on " + std::string(path) + "." +
                std::string(prop) + ": " +
                (error.message ? error.message : strerror(-r)));
            sd_bus_error_free(&error);
            return nullptr;
        }
        
        sd_bus_error_free(&error);
        return msg;
    }
};

WifiDevice::WifiDevice(const std::string& object_path)
    : impl_(std::make_unique<Impl>(object_path))
{
}

WifiDevice::~WifiDevice() = default;

WifiDevice::WifiDevice(WifiDevice&& other) noexcept = default;
WifiDevice& WifiDevice::operator=(WifiDevice&& other) noexcept = default;

std::string WifiDevice::getInterfaceName() const {
    sd_bus_message* msg = impl_->getProperty(
        "org.freedesktop.NetworkManager",
        impl_->object_path.c_str(),
        "org.freedesktop.NetworkManager.Device",
        "Interface",
        "s"
    );

    if (!msg) {
        return "";
    }

    const char* iface = nullptr;
    sd_bus_message_read(msg, "s", &iface);
    std::string result = iface ? iface : "";
    sd_bus_message_unref(msg);
    
    return result;
}

uint32_t WifiDevice::getDeviceState() const {
    sd_bus_message* msg = impl_->getProperty(
        "org.freedesktop.NetworkManager",
        impl_->object_path.c_str(),
        "org.freedesktop.NetworkManager.Device",
        "State",
        "u"
    );

    if (!msg) {
        // Unknown state keeps callers polling/falling back gracefully instead
        // of aborting on a transient read failure.
        return nm_device_state::Unknown;
    }

    uint32_t state = 0;
    sd_bus_message_read(msg, "u", &state);
    sd_bus_message_unref(msg);
    
    return state;
}

std::string WifiDevice::getObjectPath() const {
    return impl_->object_path;
}

bool WifiDevice::requestScan() {
    sd_bus_error error = SD_BUS_ERROR_NULL;
    
    int r = sd_bus_call_method(
        impl_->bus,
        "org.freedesktop.NetworkManager",
        impl_->object_path.c_str(),
        "org.freedesktop.NetworkManager.Device.Wireless",
        "RequestScan",
        &error,
        nullptr,
        "a{sv}",
        0  // Empty options dict
    );

    if (r < 0) {
        radiantwave::logger::Logger::instance().warning("WiFi",
            "RequestScan failed on device " + impl_->object_path + ": " +
            (error.message ? error.message : strerror(-r)));
    }

    sd_bus_error_free(&error);
    return r >= 0;
}

std::vector<AccessPointInfo> WifiDevice::getAccessPoints() const {
    std::vector<AccessPointInfo> result;
    
    // Get access point paths
    sd_bus_message* msg = nullptr;
    sd_bus_error error = SD_BUS_ERROR_NULL;
    
    int r = sd_bus_get_property(
        impl_->bus,
        "org.freedesktop.NetworkManager",
        impl_->object_path.c_str(),
        "org.freedesktop.NetworkManager.Device.Wireless",
        "AccessPoints",
        &error,
        &msg,
        "ao"
    );
    
    if (r < 0) {
        radiantwave::logger::Logger::instance().warning("WiFi",
            "Failed to read AccessPoints on device " + impl_->object_path + ": " +
            (error.message ? error.message : strerror(-r)));
        sd_bus_error_free(&error);
        return result;
    }
    
    // Read array of object paths
    r = sd_bus_message_enter_container(msg, 'a', "o");
    if (r < 0) {
        sd_bus_message_unref(msg);
        return result;
    }
    
    // Read a single numeric AccessPoint property. Strength is a byte ("y"),
    // the security flag properties are uint32 ("u"). Leaves `out` untouched on
    // failure, so callers can rely on zero-initialized defaults.
    auto readApProperty = [this](const char* ap_path, const char* prop,
                                 const char* type, void* out) {
        sd_bus_message* prop_msg = nullptr;
        sd_bus_error prop_error = SD_BUS_ERROR_NULL;
        int pr = sd_bus_get_property(
            impl_->bus,
            "org.freedesktop.NetworkManager",
            ap_path,
            "org.freedesktop.NetworkManager.AccessPoint",
            prop,
            &prop_error,
            &prop_msg,
            type
        );
        if (pr >= 0 && prop_msg) {
            if (strcmp(type, "u") == 0) {
                sd_bus_message_read(prop_msg, "u", static_cast<uint32_t*>(out));
            } else {
                sd_bus_message_read(prop_msg, "y", static_cast<uint8_t*>(out));
            }
            sd_bus_message_unref(prop_msg);
        }
        sd_bus_error_free(&prop_error);
        return pr >= 0;
    };

    const char* ap_path = nullptr;
    while ((r = sd_bus_message_read(msg, "o", &ap_path)) > 0 && ap_path) {
        sd_bus_message* ap_msg = nullptr;
        sd_bus_error ap_error = SD_BUS_ERROR_NULL;

        r = sd_bus_get_property(
            impl_->bus,
            "org.freedesktop.NetworkManager",
            ap_path,
            "org.freedesktop.NetworkManager.AccessPoint",
            "Ssid",
            &ap_error,
            &ap_msg,
            "ay"
        );

        if (r >= 0) {
            // Read the SSID byte array. sd_bus_get_property() already leaves
            // the message positioned at the array (inside the variant wrapper),
            // and sd_bus_message_read_array() enters AND exits the array
            // container itself. Do NOT call sd_bus_message_enter_container()
            // here first, or the read fails and every network silently drops
            // out of the scan list (it only ever shows up as an empty page with
            // no error logs).
            const uint8_t* ssid_data = nullptr;
            size_t ssid_len = 0;
            r = sd_bus_message_read_array(ap_msg, 'y', (const void**)&ssid_data, &ssid_len);

            std::string ssid;
            if (r >= 0 && ssid_data && ssid_len > 0) {
                ssid = std::string(reinterpret_cast<const char*>(ssid_data), ssid_len);
            }
            sd_bus_message_unref(ap_msg);

            // Remaining properties: signal strength plus the three flags that
            // drive detectSecurityType() (otherwise every network is reported
            // as Open and secured connections are built without a security
            // section).
            uint8_t signal = 0;
            uint32_t flags = 0, wpa_flags = 0, rsn_flags = 0;
            readApProperty(ap_path, "Strength", "y", &signal);
            readApProperty(ap_path, "Flags", "u", &flags);
            readApProperty(ap_path, "WpaFlags", "u", &wpa_flags);
            readApProperty(ap_path, "RsnFlags", "u", &rsn_flags);

            if (!ssid.empty()) {
                result.push_back(parseAccessPoint(ap_path, ssid, signal, flags, wpa_flags, rsn_flags));
            }
        }

        sd_bus_error_free(&ap_error);
    }
    
    sd_bus_message_exit_container(msg);
    sd_bus_message_unref(msg);
    
    return result;
}

AccessPointInfo WifiDevice::getActiveAccessPoint() const {
    sd_bus_message* msg = impl_->getProperty(
        "org.freedesktop.NetworkManager",
        impl_->object_path.c_str(),
        "org.freedesktop.NetworkManager.Device.Wireless",
        "ActiveAccessPoint",
        "o"
    );

    if (!msg) {
        return AccessPointInfo{};  // No active AP
    }

    const char* ap_path = nullptr;
    sd_bus_message_read(msg, "o", &ap_path);
    sd_bus_message_unref(msg);
    
    if (!ap_path || std::string(ap_path) == "/") {
        return AccessPointInfo{};  // No active AP
    }
    
    AccessPointInfo ap;
    ap.object_path = ap_path;

    // Read the active AP's SSID bytes so connectedSSID() (and the Home footer)
    // can report which network is in use.
    sd_bus_message* ssid_msg = nullptr;
    sd_bus_error ssid_error = SD_BUS_ERROR_NULL;
    int r = sd_bus_get_property(
        impl_->bus,
        "org.freedesktop.NetworkManager",
        ap_path,
        "org.freedesktop.NetworkManager.AccessPoint",
        "Ssid",
        &ssid_error,
        &ssid_msg,
        "ay"
    );
    if (r >= 0 && ssid_msg) {
        const uint8_t* ssid_data = nullptr;
        size_t ssid_len = 0;
        r = sd_bus_message_read_array(ssid_msg, 'y', (const void**)&ssid_data, &ssid_len);
        if (r >= 0 && ssid_data && ssid_len > 0) {
            ap.ssid = std::string(reinterpret_cast<const char*>(ssid_data), ssid_len);
        }
        sd_bus_message_unref(ssid_msg);
    }
    sd_bus_error_free(&ssid_error);

    return ap;
}

bool WifiDevice::isConnected() const {
    return getDeviceState() == nm_device_state::Activated;
}

std::string WifiDevice::connectedSSID() const {
    if (!isConnected()) {
        return "";
    }
    
    auto ap = getActiveAccessPoint();
    return ap.ssid;
}

std::unique_ptr<WifiDevice> WifiDevice::findFirstDevice() {
    sd_bus* bus = nullptr;
    int r = sd_bus_open_system(&bus);
    if (r < 0) {
        return nullptr;
    }
    
    sd_bus_message* msg = nullptr;
    sd_bus_error error = SD_BUS_ERROR_NULL;
    
    r = sd_bus_call_method(
        bus,
        "org.freedesktop.NetworkManager",
        "/org/freedesktop/NetworkManager",
        "org.freedesktop.NetworkManager",
        "GetDevices",
        &error,
        &msg,
        ""
    );
    
    if (r < 0) {
        sd_bus_error_free(&error);
        sd_bus_unref(bus);
        return nullptr;
    }
    
    // Read device paths
    r = sd_bus_message_enter_container(msg, 'a', "o");
    if (r < 0) {
        sd_bus_message_unref(msg);
        sd_bus_unref(bus);
        return nullptr;
    }
    
    const char* dev_path = nullptr;
    std::string wifi_path;
    
    while ((r = sd_bus_message_read(msg, "o", &dev_path)) > 0 && dev_path) {
        // Check device type
        sd_bus_message* type_msg = nullptr;
        sd_bus_error type_error = SD_BUS_ERROR_NULL;
        uint32_t dev_type = 0;
        
        r = sd_bus_get_property(
            bus,
            "org.freedesktop.NetworkManager",
            dev_path,
            "org.freedesktop.NetworkManager.Device",
            "DeviceType",
            &type_error,
            &type_msg,
            "u"
        );
        
        if (r >= 0) {
            sd_bus_message_read(type_msg, "u", &dev_type);
            sd_bus_message_unref(type_msg);
            
            // NM_DEVICE_TYPE_WIFI = 2
            if (dev_type == 2) {
                wifi_path = dev_path;
                break;
            }
        }
        
        sd_bus_error_free(&type_error);
    }
    
    sd_bus_message_exit_container(msg);
    sd_bus_message_unref(msg);
    sd_bus_unref(bus);
    
    if (wifi_path.empty()) {
        return nullptr;
    }
    
    return std::make_unique<WifiDevice>(wifi_path);
}

#else // !__linux__

// ─── Stub implementation for non-Linux platforms ───────────────────────

struct WifiDevice::Impl {
    std::string object_path;
    
    explicit Impl(const std::string& path) : object_path(path) {}
};

WifiDevice::WifiDevice(const std::string& object_path)
    : impl_(std::make_unique<Impl>(object_path))
{
}

WifiDevice::~WifiDevice() = default;

WifiDevice::WifiDevice(WifiDevice&& other) noexcept = default;
WifiDevice& WifiDevice::operator=(WifiDevice&& other) noexcept = default;

std::string WifiDevice::getInterfaceName() const {
    return "wlan0";  // Stub
}

uint32_t WifiDevice::getDeviceState() const {
    return nm_device_state::Disconnected;  // Stub
}

std::string WifiDevice::getObjectPath() const {
    return impl_->object_path;
}

bool WifiDevice::requestScan() {
    std::cerr << "[WifiDevice] Stub: requestScan() called on non-Linux platform\n";
    return false;
}

std::vector<AccessPointInfo> WifiDevice::getAccessPoints() const {
    std::cerr << "[WifiDevice] Stub: getAccessPoints() called on non-Linux platform\n";
    return {};
}

AccessPointInfo WifiDevice::getActiveAccessPoint() const {
    std::cerr << "[WifiDevice] Stub: getActiveAccessPoint() called on non-Linux platform\n";
    return {};
}

bool WifiDevice::isConnected() const {
    return false;
}

std::string WifiDevice::connectedSSID() const {
    return "";
}

std::unique_ptr<WifiDevice> WifiDevice::findFirstDevice() {
    std::cerr << "[WifiDevice] Stub: findFirstDevice() called on non-Linux platform\n";
    return nullptr;
}

#endif // __linux__

} // namespace radiantwave::network