/*
    The MIT License (MIT)
    
    Copyright (c) 2014 Nir Hartmann
    
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
    
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
    
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
 */
package com.samsung.srpol.parallax;

import com.samsung.srpol.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ListView;

public class ParallaxListViewHelper implements OnScrollListener {

    private static final float DEFAULT_ALPHA_FACTOR = -1F;
    private static final float DEFAULT_PARALLAX_FACTOR = 1.9F;
    private static final boolean DEFAULT_IS_CIRCULAR = false;
    private float parallaxFactor = DEFAULT_PARALLAX_FACTOR;
    private float alphaFactor = DEFAULT_ALPHA_FACTOR;
    private ParallaxedView parallaxedView;
    private boolean isCircular;
    private OnScrollListener listener = null;
    private ListView listView;

    protected ParallaxListViewHelper(Context context, AttributeSet attrs,
            ListView listView) {
        init(context, attrs, listView);
    }

    protected void init(Context context, AttributeSet attrs, ListView listView) {
        this.listView = listView;
        TypedArray typeArray = context.obtainStyledAttributes(attrs,
                R.styleable.ParallaxScroll);
        this.parallaxFactor = typeArray.getFloat(
                R.styleable.ParallaxScroll_parallax_factor,
                DEFAULT_PARALLAX_FACTOR);
        this.alphaFactor = typeArray.getFloat(
                R.styleable.ParallaxScroll_alpha_factor, DEFAULT_ALPHA_FACTOR);
        this.isCircular = typeArray.getBoolean(
                R.styleable.ParallaxScroll_circular_parallax,
                DEFAULT_IS_CIRCULAR);
        typeArray.recycle();
    }

    protected void setOnScrollListener(OnScrollListener l) {
        this.listener = l;
    }

    protected void addParallaxedHeaderView(View v) {
        addParallaxedView(v);
    }

    protected void addParallaxedHeaderView(View v, Object data,
            boolean isSelectable) {
        addParallaxedView(v);
    }

    protected void addParallaxedView(View v) {
        this.parallaxedView = new ListViewParallaxedItem(v);
    }

    protected void parallaxScroll() {
        if (isCircular)
            circularParallax();
        else
            headerParallax();
    }

    private void circularParallax() {
        if (listView.getChildCount() > 0) {
            int top = -listView.getChildAt(0).getTop();
            if (top >= 0) {
                fillParallaxedViews();
                setFilters(top);
            }
        }
    }

    private void headerParallax() {
        if (parallaxedView != null) {
            if (listView.getChildCount() > 0) {
                int top = -listView.getChildAt(0).getTop();
                if (top >= 0) {
                    setFilters(top);
                }
            }
        }
    }

    private void setFilters(int top) {
        parallaxedView.setOffset((float) top / parallaxFactor);
        if (alphaFactor != DEFAULT_ALPHA_FACTOR) {
            float alpha = (top <= 0) ? 1 : (100 / ((float) top * alphaFactor));
            parallaxedView.setAlpha(alpha);
        }
        parallaxedView.animateNow();
    }

    private void fillParallaxedViews() {
        if (parallaxedView == null
                || parallaxedView.is(listView.getChildAt(0)) == false) {
            if (parallaxedView != null) {
                resetFilters();
                parallaxedView.setView(listView.getChildAt(0));
            } else {
                parallaxedView = new ListViewParallaxedItem(
                        listView.getChildAt(0));
            }
        }
    }

    private void resetFilters() {
        parallaxedView.setOffset(0);
        if (alphaFactor != DEFAULT_ALPHA_FACTOR)
            parallaxedView.setAlpha(1F);
        parallaxedView.animateNow();
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {
        parallaxScroll();
        if (this.listener != null)
            this.listener.onScroll(view, firstVisibleItem, visibleItemCount,
                    totalItemCount);
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        if (this.listener != null)
            this.listener.onScrollStateChanged(view, scrollState);
    }

    protected class ListViewParallaxedItem extends ParallaxedView {

        public ListViewParallaxedItem(View view) {
            super(view);
        }

        @Override
        protected void translatePreICS(View view, float offset) {
            addAnimation(new TranslateAnimation(0, 0, offset, offset));
        }
    }
}