/*
 * Copyright (C) 2015 Paul Burke
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.ypx.imagepicker.helper.recyclerviewitemhelper;

import android.graphics.Canvas;

import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;


/**
 * An implementation of {@link ItemTouchHelper.Callback} that enables basic drag & drop and
 * swipe-to-dismiss. Drag events are automatically started by an item long-press.<br/>
 * </br/>
 * Expects the <code>RecyclerView.Adapter</code> to listen for {@link
 * ItemTouchHelperAdapter} callbacks and the <code>RecyclerView.ViewHolder</code> to implement
 * {@link ItemTouchHelperViewHolder}.
 *
 * @author Paul Burke (ipaulpro)
 */
public class SimpleItemTouchHelperCallback extends ItemTouchHelper.Callback {
    public static final float ALPHA_FULL = 1.0f;
    private boolean moveFreely = false;
    private boolean lastActive = false;
    // 移动时，item 的放大系数
    private float moveScaleFactor = 1.1f;
    private final ItemTouchHelperAdapter mAdapter;
    private OnSelectChangedListener mOnSelectChangedListener;

    public SimpleItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
        mAdapter = adapter;
    }

    public void setOnSelectChangedListener(OnSelectChangedListener mOnSelectChangedListener) {
        this.mOnSelectChangedListener = mOnSelectChangedListener;
    }

    public void setMoveScaleFactor(float moveScaleFactor) {
        this.moveScaleFactor = moveScaleFactor;
    }

    @Override
    public boolean isItemViewSwipeEnabled() {
        return mAdapter.isItemViewSwipeEnabled();
    }

    public interface OnSelectChangedListener {
        /**
         * @param viewHolder
         * @param dX
         * @param dY
         * @param actionState
         * @param isCurrentlyActive
         */
        void onSelectedChanged(RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive);

        /**
         * @param viewHolder
         * @param actionState
         */
        void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState);
    }

    @Override
    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        // Set movement flags based on the layout manager
        if (moveFreely) {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
            return makeMovementFlags(dragFlags, swipeFlags);
        } else if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            final int swipeFlags = 0;
            return makeMovementFlags(dragFlags, swipeFlags);
        } else if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
            LinearLayoutManager linear = (LinearLayoutManager) recyclerView.getLayoutManager();
            if (linear.getOrientation() == RecyclerView.HORIZONTAL) {
                final int dragFlags = ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
                final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
                return makeMovementFlags(dragFlags, swipeFlags);
            } else {
                final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
                final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
                return makeMovementFlags(dragFlags, swipeFlags);
            }
        } else {
            final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
            final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
            return makeMovementFlags(dragFlags, swipeFlags);
        }
    }

    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder source, RecyclerView.ViewHolder target) {
        if (source.getItemViewType() != target.getItemViewType()) {
            return false;
        }

        // Notify the adapter of the move
        mAdapter.onItemMove(source.getAdapterPosition(), target.getAdapterPosition());
        return true;
    }

    @Override
    public void onMoved(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, int fromPos, RecyclerView.ViewHolder target, int toPos, int x, int y) {
        super.onMoved(recyclerView, viewHolder, fromPos, target, toPos, x, y);
        viewHolder.itemView.setAlpha(1f);
        target.itemView.setAlpha(1f);
    }

    @Override
    public void onSwiped(RecyclerView.ViewHolder viewHolder, int i) {
        // Notify the adapter of the dismissal
        mAdapter.onItemDismiss(viewHolder.getAdapterPosition());
    }

    @Override
    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
            // Fade out the view as it is swiped out of the parent's bounds
            final float alpha = ALPHA_FULL - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
            viewHolder.itemView.setAlpha(alpha);
            viewHolder.itemView.setTranslationX(dX);
        } else if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
            if (isCurrentlyActive) {
                viewHolder.itemView.setAlpha(0.5f);
                viewHolder.itemView.setScaleX(moveScaleFactor);
                viewHolder.itemView.setScaleY(moveScaleFactor);
            } else {
                viewHolder.itemView.setAlpha(1f);
                viewHolder.itemView.setScaleX(1f);
                viewHolder.itemView.setScaleY(1f);
            }
            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
        } else {
            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
        }

        // 从拖动到释放的过程
        if (null != mOnSelectChangedListener && !isCurrentlyActive && lastActive) {
            mOnSelectChangedListener.onSelectedChanged(viewHolder, dX, dY, actionState, isCurrentlyActive);
        }
        lastActive = isCurrentlyActive;
    }

    @Override
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
        // We only want the active item to change
        if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
            if (viewHolder instanceof ItemTouchHelperViewHolder) {
                // Let the view holder know that this item is being moved or dragged
                ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
                itemViewHolder.onItemSelected();
            }
        }
        super.onSelectedChanged(viewHolder, actionState);

        if (null != mOnSelectChangedListener) {
            mOnSelectChangedListener.onSelectedChanged(viewHolder, actionState);
        }
    }

    @Override
    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        super.clearView(recyclerView, viewHolder);
        viewHolder.itemView.setAlpha(ALPHA_FULL);
        if (viewHolder instanceof ItemTouchHelperViewHolder) {
            // Tell the view holder it's time to restore the idle state
            ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
            itemViewHolder.onItemClear();
        }
    }

    public void setMoveFreely(boolean moveFreely) {
        this.moveFreely = moveFreely;
    }
}