/*
Copyright 2018 Wajahat Karim

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.wajahatkarim3.easyflipviewpager;

import androidx.viewpager.widget.ViewPager;
import android.view.View;

/**
 * A card based page flip animation PageTransformer implementation for ViewPager
 *
 * Set the object of this transformer to any ViewPager object.
 * For example, myViewPager.setPageTransformer(true, new CardFlipPageTransformer());
 *
 * @see <a href="http://github.com/wajahatkarim3/EasyFlipViewPager">EasyFlipViewPager</a>
 *
 * @author Wajahat Karim (http://wajahatkarim.com)
 */
public class CardFlipPageTransformer implements ViewPager.PageTransformer
{
    public final static int HORIZONTAL = 1;
    public final static int VERTICAL = 2;

    private boolean scalable = true;
    private int flipOrientation = VERTICAL;

    @Override
    public void transformPage(View page, float position)
    {
        float percentage = 1 - Math.abs(position);
        page.setCameraDistance(12000);
        setVisibility(page, position);
        setTranslation(page);
        setSize(page, position, percentage);
        setRotation(page, position, percentage);
    }

    private void setVisibility(View page, float position)
    {
        if (position < 0.5 && position > -0.5) {
            page.setVisibility(View.VISIBLE);
        } else {
            page.setVisibility(View.INVISIBLE);
        }
    }

    private void setTranslation(View page)
    {
        ViewPager viewPager = (ViewPager) page.getParent();
        int scroll = viewPager.getScrollX() - page.getLeft();
        page.setTranslationX(scroll);
    }

    private void setSize(View page, float position, float percentage)
    {
        // Do nothing, if its not scalable
        if (!scalable) return;

        page.setScaleX((position != 0 && position != 1) ? percentage : 1);
        page.setScaleY((position != 0 && position != 1) ? percentage : 1);
    }

    private void setRotation(View page, float position, float percentage)
    {
        if (flipOrientation == VERTICAL)
        {
            if (position > 0) {
                page.setRotationY(-180 * (percentage + 1));
            } else {
                page.setRotationY(180 * (percentage + 1));
            }
        }
        else
        {
            if (position > 0) {
                page.setRotationX(-180 * (percentage + 1));
            } else {
                page.setRotationX(180 * (percentage + 1));
            }
        }
    }

    public boolean isScalable() {
        return scalable;
    }

    public void setScalable(boolean scalable) {
        this.scalable = scalable;
    }

    public int getFlipOrientation() {
        return flipOrientation;
    }

    /**
     * Sets the Flip Orientation. Can be either CardFlipPageTransformer.HORIZONTAL or CardFlipPageTransformer.VERTICAL
     * @param flipOrientation Can be either CardFlipPageTransformer.HORIZONTAL or CardFlipPageTransformer.VERTICAL
     */
    public void setFlipOrientation(int flipOrientation) {
        this.flipOrientation = flipOrientation > 1 ? VERTICAL : HORIZONTAL;
    }
}