package com.wd.player.adapter;

import static androidx.recyclerview.widget.RecyclerView.SCROLL_STATE_IDLE;

import android.content.Context;
import android.view.MotionEvent;
import android.view.View;

import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.PagerSnapHelper;
import androidx.recyclerview.widget.RecyclerView;

import com.wd.player.listener.OnViewPagerListener;
import com.wd.base.log.Logger;

/**
 * ViewPager效果的LayoutManager
 */
public class PagerLayoutManager extends LinearLayoutManager implements View.OnTouchListener {
    private static final String TAG = "PagerLayoutManager";

    private PagerSnapHelper mPagerSnapHelper;

    private OnViewPagerListener mOnViewPagerListener;

    private int mState;

    private int mdy;

    /**
     * 移动方向
     */
    private int direction;

    private boolean canScroll = true;

    public PagerLayoutManager(Context context) {
        super(context);
        init();
    }

    private void init() {
        mPagerSnapHelper = new PagerSnapHelper();
    }

    @Override
    public void onAttachedToWindow(RecyclerView recyclerView) {
        super.onAttachedToWindow(recyclerView);
        if (recyclerView.getOnFlingListener() == null) {
            mPagerSnapHelper.attachToRecyclerView(recyclerView);
        }
        recyclerView.addOnChildAttachStateChangeListener(mChildAttachStateChangeListener);
        recyclerView.setOnTouchListener(this);
        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                mState = newState;
                switch (mState) {
                    case SCROLL_STATE_IDLE:
                        View viewIdle = mPagerSnapHelper.findSnapView(PagerLayoutManager.this);
                        if (viewIdle == null) {
                            return;
                        }
                        int positionIdle = getPosition(viewIdle);
                        if (mOnViewPagerListener != null && getChildCount() == 1) {
                            mOnViewPagerListener.onPageSelected(positionIdle, positionIdle == getItemCount() - 1,
                                viewIdle);
                        }
                        break;
                    default:
                        break;
                }
            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                mdy = dy;
            }
        });
    }

    /**
     * 判断是否设置了监听
     */
    public boolean viewPagerListenerIsNull() {
        return mOnViewPagerListener == null;
    }

    /**
     * 监听竖直方向的相对偏移量
     */
    @Override
    public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
        this.direction = dy;
        return super.scrollVerticallyBy(dy, recycler, state);
    }

    /**
     * 监听水平方向的相对偏移量
     */
    @Override
    public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
        this.direction = dx;
        return super.scrollHorizontallyBy(dx, recycler, state);
    }

    /**
     * 设置监听
     */
    public void setOnViewPagerListener(OnViewPagerListener listener) {
        this.mOnViewPagerListener = listener;
    }

    public void clearOnViewPagerListener() {
        this.mOnViewPagerListener = null;
    }

    private RecyclerView.OnChildAttachStateChangeListener mChildAttachStateChangeListener =
        new RecyclerView.OnChildAttachStateChangeListener() {
            @Override
            public void onChildViewAttachedToWindow(View view) {
                if (mOnViewPagerListener != null && getChildCount() == 1) {
                    mOnViewPagerListener.onInitComplete();
                }
            }

            @Override
            public void onChildViewDetachedFromWindow(View view) {
                int position = getPosition(view);
                Logger.t(TAG).d("onChildViewDetachedFromWindow position:"+position);
                if (direction >= 0) {
                    if (mOnViewPagerListener != null) {
                        mOnViewPagerListener.onPageRelease(true, position, view);
                    }
                } else {
                    if (mOnViewPagerListener != null) {
                        mOnViewPagerListener.onPageRelease(false, position, view);
                    }
                }

            }
        };

    /**
     * 监听ouTouch事件，因为如果从第二个视频滑动到第一个视频(快速连续滑动),
     * onScrollStateChanged是不会触发SCROLL_STATE_IDLE状态的,会导致
     * 第一个视频不会播放的问题,不会调用onPageSelected监听回调。
     * 经反复测试发现,会回调onTouch的事件,所以在这里进行触发
     */
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_UP:
                if (mPagerSnapHelper != null) {
                    View snapView = mPagerSnapHelper.findSnapView(PagerLayoutManager.this);
                    if (snapView != null) {
                        int position = getPosition(snapView);
                        // 如果是第一个视频,并且
                        if (position == 0 && mdy < 0) {
                            if (mOnViewPagerListener != null && getChildCount() == 1) {
                                mOnViewPagerListener.onPageSelected(position, false, snapView);
                            }
                        }
                    }
                }
                break;
            default:
                break;
        }
        return false;
    }

    /**
     * bug java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder
     * https://stackoverflow.com/questions/31759171/recyclerview-and-java-lang-indexoutofboundsexception-inconsistency-detected-in
     */
    @Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
        try {
            super.onLayoutChildren(recycler, state);
        } catch (IndexOutOfBoundsException e) {
        }

    }

    public void setCanScroll(boolean canScroll) {
        this.canScroll = canScroll;
    }

    @Override
    public boolean canScrollVertically() {
        return canScroll && super.canScrollVertically();
    }

}