package cn.sinata.xldutils.netstatus;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;
import android.net.NetworkRequest;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;

import androidx.annotation.RequiresApi;

import java.util.ArrayList;
import java.util.List;

/**
 * 网络状态监听
 */
public class NetStateReceiver extends BroadcastReceiver {

    public final static String CUSTOM_ANDROID_NET_CHANGE_ACTION = "cn.sinata.xldutils.net.conn.CONNECTIVITY_CHANGE";
    private final static String ANDROID_NET_CHANGE_ACTION = "android.net.conn.CONNECTIVITY_CHANGE";
    private static boolean isNetAvailable = false;
    private static NetUtils.NetType mNetType;
    private static ArrayList<NetChangeObserver> mNetChangeObservers = new ArrayList<NetChangeObserver>();
    private static BroadcastReceiver mBroadcastReceiver;
    // 保存应用级上下文，避免页面上下文被静态监听器持有 由AI生成
    private static Context mAppContext;
    // 记录注册次数，防止多个页面互相注销同一个全局监听 由AI生成
    private static int mRegisterCount = 0;
    // 网络回调对象用于 Android 5.0 及以上系统监听网络变化 由AI生成
    private static ConnectivityManager.NetworkCallback mNetworkCallback;
    // 主线程 Handler 用于把网络回调分发回 UI 安全线程 由AI生成
    private static final Handler MAIN_HANDLER = new Handler(Looper.getMainLooper());

    private static BroadcastReceiver getReceiver() {
        if (null == mBroadcastReceiver) {
            synchronized (NetStateReceiver.class) {
                if (null == mBroadcastReceiver) {
                    mBroadcastReceiver = new NetStateReceiver();
                }
            }
        }
        return mBroadcastReceiver;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        mBroadcastReceiver = NetStateReceiver.this;
        if (intent.getAction().equalsIgnoreCase(ANDROID_NET_CHANGE_ACTION) || intent.getAction().equalsIgnoreCase(CUSTOM_ANDROID_NET_CHANGE_ACTION)) {
//            Utils.systemErr("111111111");
            updateNetworkState(context);
            notifyObserver();
        }
    }

    public static void registerNetworkStateReceiver(Context mContext) {
        if (mContext == null) {
            return;
        }
        mAppContext = mContext.getApplicationContext();
        if (mRegisterCount++ > 0) {
            updateNetworkState(mAppContext);
            return;
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            registerNetworkCallback(mAppContext);
        } else {
            IntentFilter filter = new IntentFilter();
            filter.addAction(CUSTOM_ANDROID_NET_CHANGE_ACTION);
            filter.addAction(ANDROID_NET_CHANGE_ACTION);
            mAppContext.registerReceiver(getReceiver(), filter);
        }
        updateNetworkState(mAppContext);
    }

    public static void checkNetworkState(Context mContext) {
        if (mContext == null) {
            return;
        }
        updateNetworkState(mContext);
        notifyObserver();
    }

    public static void unRegisterNetworkStateReceiver(Context mContext) {
        if (mContext == null || mRegisterCount <= 0) {
            return;
        }
        mRegisterCount--;
        if (mRegisterCount > 0) {
            return;
        }
        Context appContext = mContext.getApplicationContext();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && mNetworkCallback != null) {
            try {
                ConnectivityManager connectivityManager = (ConnectivityManager) appContext.getSystemService(Context.CONNECTIVITY_SERVICE);
                if (connectivityManager != null) {
                    connectivityManager.unregisterNetworkCallback(mNetworkCallback);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                mNetworkCallback = null;
            }
            return;
        }
        if (mBroadcastReceiver != null) {
            try {
                appContext.unregisterReceiver(mBroadcastReceiver);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

    public static boolean isNetworkAvailable() {
        return isNetAvailable;
    }

    public static NetUtils.NetType getAPNType() {
        return mNetType;
    }

    private static void notifyObserver() {
        if (!mNetChangeObservers.isEmpty()) {
            List<NetChangeObserver> observers = new ArrayList<NetChangeObserver>(mNetChangeObservers);
            for (NetChangeObserver observer : observers) {
                if (observer != null) {
                    if (isNetworkAvailable()) {
                        observer.onNetConnected(mNetType);
                    } else {
                        observer.onNetDisConnect();
                    }
                }
            }
        }
    }

    public static void registerObserver(NetChangeObserver observer) {
        if (mNetChangeObservers == null) {
            mNetChangeObservers = new ArrayList<NetChangeObserver>();
        }
        if (observer != null && !mNetChangeObservers.contains(observer)) {
            mNetChangeObservers.add(observer);
        }
    }

    public static void removeRegisterObserver(NetChangeObserver observer) {
        if (mNetChangeObservers != null) {
            if (mNetChangeObservers.contains(observer)) {
                mNetChangeObservers.remove(observer);
            }
        }
    }

    // 注册系统网络回调以替代高版本系统上不可靠的 CONNECTIVITY_CHANGE 广播 由AI生成
    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    private static void registerNetworkCallback(final Context context) {
        // 获取系统网络服务用于注册 NetworkCallback 由AI生成
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        // 网络服务为空时保持原有状态并直接返回 由AI生成
        if (connectivityManager == null) {
            return;
        }
        // 避免重复创建网络回调对象 由AI生成
        if (mNetworkCallback != null) {
            return;
        }
        // 创建网络变化回调对象 由AI生成
        mNetworkCallback = new ConnectivityManager.NetworkCallback() {
            // 网络可用时刷新当前网络状态 由AI生成
            @Override
            public void onAvailable(Network network) {
                // 切回主线程分发，避免页面回调在 Binder 线程更新 UI 由AI生成
                dispatchNetworkChanged(context);
            }

            // 网络能力变化时刷新当前网络状态 由AI生成
            @Override
            public void onCapabilitiesChanged(Network network, NetworkCapabilities networkCapabilities) {
                // 切回主线程分发最新联网能力 由AI生成
                dispatchNetworkChanged(context);
            }

            // 网络丢失时重新查询当前活动网络，兼容 Wi-Fi 与移动网络切换 由AI生成
            @Override
            public void onLost(Network network) {
                // 切回主线程后再通知观察者 由AI生成
                dispatchNetworkChanged(context);
            }
        };
        try {
            // 只监听具备互联网能力的网络，减少无效网络状态回调 由AI生成
            NetworkRequest request = new NetworkRequest.Builder().addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
            // 向系统注册网络变化回调 由AI生成
            connectivityManager.registerNetworkCallback(request, mNetworkCallback);
        } catch (Exception e) {
            // 注册失败时打印异常并回退到旧广播路径 由AI生成
            e.printStackTrace();
            // 清空失败的回调对象，避免后续注销不存在的系统回调 由AI生成
            mNetworkCallback = null;
            // 使用旧广播监听作为兜底方案 由AI生成
            registerLegacyReceiver(context);
        }
    }

    // 注册旧版网络广播监听作为低版本或异常兜底 由AI生成
    private static void registerLegacyReceiver(Context context) {
        // 创建网络广播过滤器 由AI生成
        IntentFilter filter = new IntentFilter();
        // 监听应用内部主动检查网络的广播 由AI生成
        filter.addAction(CUSTOM_ANDROID_NET_CHANGE_ACTION);
        // 监听系统网络变化广播 由AI生成
        filter.addAction(ANDROID_NET_CHANGE_ACTION);
        try {
            // 使用应用上下文注册广播，避免持有页面实例 由AI生成
            context.getApplicationContext().registerReceiver(getReceiver(), filter);
        } catch (Exception e) {
            // 注册失败时输出异常，避免影响业务启动 由AI生成
            e.printStackTrace();
        }
    }

    // 刷新网络状态并通知所有观察者 由AI生成
    private static void dispatchNetworkChanged(final Context context) {
        // 主线程执行状态更新，保证观察者回调线程一致 由AI生成
        MAIN_HANDLER.post(new Runnable() {
            // 执行网络状态查询和分发 由AI生成
            @Override
            public void run() {
                // 根据系统当前网络刷新缓存状态 由AI生成
                updateNetworkState(context);
                // 把最新状态通知业务观察者 由AI生成
                notifyObserver();
            }
        });
    }

    // 根据当前系统网络刷新缓存状态 由AI生成
    private static void updateNetworkState(Context context) {
        // 上下文为空时标记为无网络 由AI生成
        if (context == null) {
            isNetAvailable = false;
            mNetType = NetUtils.NetType.NONE;
            return;
        }
        // Android 6.0 及以上优先用 NetworkCapabilities 判断真实互联网能力 由AI生成
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            ConnectivityManager connectivityManager = (ConnectivityManager) context.getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
            if (connectivityManager == null) {
                isNetAvailable = false;
                mNetType = NetUtils.NetType.NONE;
                return;
            }
            Network activeNetwork = connectivityManager.getActiveNetwork();
            NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(activeNetwork);
            isNetAvailable = capabilities != null
                    && capabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
            mNetType = isNetAvailable ? NetUtils.getAPNType(context) : NetUtils.NetType.NONE;
            return;
        }
        // 旧系统保持原有 NetworkInfo 判断逻辑 由AI生成
        if (!NetUtils.isNetworkAvailable(context)) {
            isNetAvailable = false;
            mNetType = NetUtils.NetType.NONE;
        } else {
            isNetAvailable = true;
            mNetType = NetUtils.getAPNType(context);
        }
    }
}