package com.android.app_base.base.viewmodel;

import android.app.Application;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.lifecycle.AndroidViewModel;
import androidx.lifecycle.DefaultLifecycleObserver;
import androidx.lifecycle.LifecycleOwner;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;

import com.android.app_base.base.StateViewEnum;
import com.android.app_base.base.model.BaseModel;

import io.reactivex.disposables.CompositeDisposable;
import io.reactivex.disposables.Disposable;

/**
 * ViewModel基类
 */
public abstract class BaseViewModel<M extends BaseModel> extends AndroidViewModel implements DefaultLifecycleObserver {

    protected Application application;
    /**
     * 数据仓库model
     */
    protected M model;
    /**
     * 控制状态视图的LiveData
     */
    protected MutableLiveData<StateViewEnum> stateViewLiveData = new MutableLiveData<>();
    protected MutableLiveData<String> messageLiveData = new MutableLiveData<>();
    //管理RxJava，主要针对RxJava异步操作造成的内存泄漏
    private CompositeDisposable mCompositeDisposable;

    public BaseViewModel(@NonNull Application application) {
        super(application);
        this.application = application;
        model = initModel();
        mCompositeDisposable = new CompositeDisposable();
    }

    /**
     * 数据仓库初始化，由子类实现返回
     */
    protected abstract M initModel();

    /**
     * Rxjava的异步操作都要调用此方法添加到 mCompositeDisposable里，
     */
    protected void addSubscribe(Disposable disposable) {
        if (mCompositeDisposable == null) {
            mCompositeDisposable = new CompositeDisposable();
        }
        mCompositeDisposable.add(disposable);
    }

    /**
     * 获取状态视图LiveData
     */
    public LiveData<StateViewEnum> getStateViewLiveData() {
        if(stateViewLiveData == null){
            stateViewLiveData = new MutableLiveData<>();
        }
        return stateViewLiveData;
    }
    public MutableLiveData<String> getMessageLivaData(){
        if(messageLiveData == null){
            messageLiveData = new MutableLiveData<>();
        }
        return messageLiveData;
    }
    /**
     * 更改状态视图的状态
     */
    public void changeStateView(StateViewEnum state) {
        stateViewLiveData.postValue(state);
    }

    @Override
    protected void onCleared() {
        super.onCleared();
        if (model != null) {
            model.onCleared();
        }
        //ViewModel销毁时会执行，同时取消所有异步任务
        if (mCompositeDisposable != null) {
            mCompositeDisposable.clear();
        }
    }


    /**
     * 子类可以重写生命周期方法，便于生命周期的考虑
     */
    @Override
    public void onCreate(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onCreate(owner);
    }

    @Override
    public void onStart(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onStart(owner);
    }

    @Override
    public void onResume(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onResume(owner);
    }


    @Override
    public void onPause(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onPause(owner);
    }

    @Override
    public void onStop(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onStop(owner);
    }

    @Override
    public void onDestroy(@NonNull LifecycleOwner owner) {
        DefaultLifecycleObserver.super.onDestroy(owner);
    }

    protected void onCreate(Bundle savedInstanceState) {
    }
}