package com.android.app_base.utils.rxbus;

import androidx.lifecycle.LifecycleOwner;
import com.uber.autodispose.AutoDispose;
import com.uber.autodispose.ObservableSubscribeProxy;
import com.uber.autodispose.android.lifecycle.AndroidLifecycleScopeProvider;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import io.reactivex.Observable;
import io.reactivex.subjects.PublishSubject;
import io.reactivex.subjects.Subject;

/**
 * @author Ljj
 * @date 2023.05.18. 21:54
 * @desc RxBus
 */
public class RxBus {
    private volatile static RxBus mDefaultInstance;
    //事件总线
    private final Subject<Object> mBus;
    //粘性事件存储
    private final Map<Class<?>, Object> mStickyEventMap;

    private RxBus() {
        mBus = PublishSubject.create().toSerialized();
        mStickyEventMap = new ConcurrentHashMap<>();
    }

    public static RxBus getInstance() {
        if (mDefaultInstance == null) {
            synchronized (RxBus.class) {
                if (mDefaultInstance == null) {
                    mDefaultInstance = new RxBus();
                }
            }
        }
        return mDefaultInstance;
    }

    /**
     * 发送事件
     */
    public void post(Object event) {
        mBus.onNext(event);
    }

    /**
     * 使用 AutoDispose解决RxJava引起的内存泄漏
     * 返回 ObservableSubscribeProxy，实际用处和Observable一样
     *
     */
    public <T> ObservableSubscribeProxy<T> toObservable(LifecycleOwner owner, final Class<T> eventType) {
        AndroidLifecycleScopeProvider provider = AndroidLifecycleScopeProvider.from(owner);
        return mBus.ofType(eventType).as(AutoDispose.autoDisposable(provider));
    }


    /**
     * 判断是否有订阅者
     */
    public boolean hasObservers() {
        return mBus.hasObservers();
    }

    public void reset() {
        mDefaultInstance = null;
    }

    /**
     * 发送一个新Sticky事件
     */
    public void postSticky(Object event) {
        synchronized (mStickyEventMap) {
            mStickyEventMap.put(event.getClass(), event);
        }
        post(event);
    }

    /**
     *  根据eventType获取Sticky事件，如果没有则返回null
     */
    public <T> ObservableSubscribeProxy<T> toObservableSticky(LifecycleOwner owner, final Class<T> eventType) {
        synchronized (mStickyEventMap) {
            AndroidLifecycleScopeProvider provider = AndroidLifecycleScopeProvider.from(owner);
            Observable<T> observable = mBus.ofType(eventType);
            final Object event = mStickyEventMap.get(eventType);
            if (event != null) {
                return observable.mergeWith(Observable.create(subscriber -> subscriber.onNext(eventType.cast(event)))).as(AutoDispose.autoDisposable(provider));
            } else {
                return observable.as(AutoDispose.autoDisposable(provider));
            }
        }
    }

    /**
     * 根据eventType获取Sticky事件
     */
    public <T> T getStickyEvent(Class<T> eventType) {
        synchronized (mStickyEventMap) {
            return eventType.cast(mStickyEventMap.get(eventType));
        }
    }

    /**
     * 移除指定eventType的Sticky事件
     */
    public <T> T removeStickyEvent(Class<T> eventType) {
        synchronized (mStickyEventMap) {
            return eventType.cast(mStickyEventMap.remove(eventType));
        }
    }

    /**
     * 移除所有的Sticky事件
     */
    public void removeAllStickyEvents() {
        synchronized (mStickyEventMap) {
            mStickyEventMap.clear();
        }
    }

}