/**
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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.
 *
 * Modified by Vinay S Shenoy on 19/5/13
 */
package com.android.volley.toolbox;

import android.content.Context;
import android.content.res.TypedArray;
import android.text.TextUtils;
import android.util.AttributeSet;

import com.android.volley.Request;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.ImageLoader.ImageContainer;
import com.android.volley.toolbox.ImageLoader.ImageListener;
import com.vinaysshenoy.volleyenhanced.R;

/**
 * Handles fetching an image from a URL as well as the life-cycle of the
 * associated request.
 */
public class NetworkImageView extends AnimateImageView {

    /** The URL of the network image to load */
    private String         mUrl;

    /**
     * Resource ID of the image to be used as a placeholder until the network
     * image is loaded.
     */
    private int            mDefaultImageId;

    /**
     * Resource ID of the image to be used if the network response fails.
     */
    private int            mErrorImageId;

    /** Local copy of the ImageLoader. */
    private ImageLoader    mImageLoader;

    /** Current ImageContainer. (either in-flight or finished) */
    private ImageContainer mImageContainer;

    public NetworkImageView(Context context) {
        this(context, null);
        init(context, null);
    }

    public NetworkImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
        init(context, attrs);
    }

    public NetworkImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {

        if (attrs == null) {
            initializeWithDefaults();
        } else {
            TypedArray attributes = context.obtainStyledAttributes(attrs,
                    R.styleable.NetworkImageView);

            if (attributes == null) {
                initializeWithDefaults();
            }

            else {
                mDefaultImageId = attributes.getResourceId(
                        R.styleable.NetworkImageView_default_image, 0);
                mErrorImageId = attributes.getResourceId(
                        R.styleable.NetworkImageView_error_image, 0);
                attributes.recycle();

            }
        }
    }

    private void initializeWithDefaults() {

        mDefaultImageId = 0;
        mErrorImageId = 0;
    }

    /**
     * Sets URL of the image that should be loaded into this view. Note that
     * calling this will immediately either set the cached image (if available)
     * or the default image specified by
     * {@link NetworkImageView#setDefaultImageResId(int)} on the view.
     * 
     * NOTE: If applicable, {@link NetworkImageView#setDefaultImageResId(int)}
     * and {@link NetworkImageView#setErrorImageResId(int)} should be called
     * prior to calling this function.
     * 
     * @param url
     *            The URL that should be loaded into this ImageView.
     * @param imageLoader
     *            ImageLoader that will be used to make the request.
     */
    public void setImageUrl(String url, ImageLoader imageLoader) {
        mUrl = url;
        mImageLoader = imageLoader;
        // The URL has potentially changed. See if we need to load it.
        loadImageIfNecessary(false);
    }

    /**
     * Sets the default image resource ID to be used for this view until the
     * attempt to load it completes.
     */
    public void setDefaultImageResId(int defaultImage) {
        mDefaultImageId = defaultImage;
    }

    /**
     * Sets the error image resource ID to be used for this view in the event
     * that the image requested fails to load.
     */
    public void setErrorImageResId(int errorImage) {
        mErrorImageId = errorImage;
    }

    /**
     * Loads the image for the view if it isn't already loaded.
     * 
     * @param isInLayoutPass
     *            True if this was invoked from a layout pass, false otherwise.
     */
    private void loadImageIfNecessary(final boolean isInLayoutPass) {

        // if the URL to be loaded in this view is empty, cancel any old
        // requests and clear the
        // currently loaded image.
        if (TextUtils.isEmpty(mUrl)) {
            if (mImageContainer != null) {
                mImageContainer.cancelRequest();
                mImageContainer = null;
            }
            setImageBitmap(null);
            return;
        }

        // if there was an old request in this view, check if it needs to be
        // canceled.
        if (mImageContainer != null && mImageContainer.getRequestUrl() != null) {
            if (mImageContainer.getRequestUrl().equals(mUrl)) {
                // if the request is from the same URL, return.
                return;
            } else {
                // if there is a pre-existing request, cancel it if it's
                // fetching a different URL.
                mImageContainer.cancelRequest();
                setImageBitmap(null);
            }
        }

        // The pre-existing content of this view didn't match the current URL.
        // Load the new image
        // from the network.
        ImageContainer newContainer = mImageLoader.get(mUrl,
                new ImageListener() {
                    @Override
                    public void onErrorResponse(VolleyError error, Request<?> request) {
                        if (mErrorImageId != 0) {
                            setImageResource(mErrorImageId);
                        }
                    }

                    @Override
                    public void onResponse(final ImageContainer response, boolean isImmediate) {
                        // If this was an immediate response that was delivered
                        // inside of a layout
                        // pass do not set the image immediately as it will
                        // trigger a requestLayout
                        // inside of a layout. Instead, defer setting the image
                        // by posting back to
                        // the main thread.
                        if (isImmediate && isInLayoutPass) {
                            post(new Runnable() {
                                @Override
                                public void run() {
                                    onResponse(response, false);
                                }
                            });
                            return;
                        }

                        if (response.getBitmap() != null) {
                            setImageBitmap(response.getBitmap(), !isImmediate);
                        } else if (mDefaultImageId != 0) {
                            setImageResource(mDefaultImageId);
                        }
                    }
                }, getWidth(), getHeight());

        // update the ImageContainer to be the new bitmap container.
        mImageContainer = newContainer;
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        loadImageIfNecessary(true);
    }

    @Override
    protected void onDetachedFromWindow() {
        if (mImageContainer != null) {
            // If the view was bound to an image request, cancel it and clear
            // out the image from the view.
            mImageContainer.cancelRequest();
            setImageBitmap(null);
            // also clear out the container so we can reload the image if
            // necessary.
            mImageContainer = null;
        }
        super.onDetachedFromWindow();
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        invalidate();
    }

}