/*
 * Copyright (C) 2011 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.
 */

package com.android.systemui.recent;

import android.animation.LayoutTransition;
import android.content.Context;
import android.content.res.Configuration;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;

import com.android.systemui.R;
import com.android.systemui.SwipeHelper;
import com.android.systemui.recent.RecentsPanelView.ActivityDescriptionAdapter;

public class RecentsHorizontalScrollView extends HorizontalScrollView
    implements SwipeHelper.Callback {
    private static final String TAG = RecentsPanelView.TAG;
    private static final boolean DEBUG = RecentsPanelView.DEBUG;
    private LinearLayout mLinearLayout;
    private ActivityDescriptionAdapter mAdapter;
    private RecentsCallback mCallback;
    protected int mLastScrollPosition;
    private SwipeHelper mSwipeHelper;
    private OnLongClickListener mOnLongClick = new OnLongClickListener() {
        public boolean onLongClick(View v) {
            final View anchorView = v.findViewById(R.id.app_description);
            mCallback.handleLongPress(v, anchorView);
            return true;
        }
    };

    public RecentsHorizontalScrollView(Context context) {
        this(context, null);
    }

    public RecentsHorizontalScrollView(Context context, AttributeSet attrs) {
        super(context, attrs, 0);
        float densityScale = getResources().getDisplayMetrics().density;
        float pagingTouchSlop = ViewConfiguration.get(mContext).getScaledPagingTouchSlop();
        mSwipeHelper = new SwipeHelper(SwipeHelper.Y, this, densityScale, pagingTouchSlop);
    }

    private int scrollPositionOfMostRecent() {
        return mLinearLayout.getWidth() - getWidth();
    }

    private void update() {
        mLinearLayout.removeAllViews();
        for (int i = 0; i < mAdapter.getCount(); i++) {
            final View view = mAdapter.getView(i, null, mLinearLayout);
            view.setLongClickable(true);
            view.setOnLongClickListener(mOnLongClick);

            final View thumbnail = getChildContentView(view);
            // thumbnail is set to clickable in the layout file
            thumbnail.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    mCallback.handleOnClick(view);
                }
            });
            mLinearLayout.addView(view);
        }
        // Scroll to end after layout.
        post(new Runnable() {
            public void run() {
                mLastScrollPosition = scrollPositionOfMostRecent();
                scrollTo(mLastScrollPosition, 0);
            }
        });
    }

    @Override
    public void removeViewInLayout(final View view) {
        dismissChild(view);
    }

    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (DEBUG) Log.v(TAG, "onInterceptTouchEvent()");
        return mSwipeHelper.onInterceptTouchEvent(ev) ||
            super.onInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return mSwipeHelper.onTouchEvent(ev) ||
            super.onTouchEvent(ev);
    }

    public boolean canChildBeDismissed(View v) {
        return true;
    }

    public void dismissChild(View v) {
        mSwipeHelper.dismissChild(v, 0);
    }

    public void onChildDismissed(View v) {
        mLinearLayout.removeView(v);
        mCallback.handleSwipe(v);
    }

    public void onBeginDrag(View v) {
    }

    public View getChildAtPosition(MotionEvent ev) {
        final float x = ev.getX() + getScrollX();
        final float y = ev.getY() + getScrollY();
        for (int i = 0; i < mLinearLayout.getChildCount(); i++) {
            View item = mLinearLayout.getChildAt(i);
            if (x >= item.getLeft() && x < item.getRight()
                && y >= item.getTop() && y < item.getBottom()) {
                return item;
            }
        }
        return null;
    }

    public View getChildContentView(View v) {
        return v.findViewById(R.id.app_thumbnail);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        setScrollbarFadingEnabled(true);
        mLinearLayout = (LinearLayout) findViewById(R.id.recents_linear_layout);
        final int leftPadding = mContext.getResources()
            .getDimensionPixelOffset(R.dimen.status_bar_recents_thumbnail_left_margin);
        setOverScrollEffectPadding(leftPadding, 0);
    }

    @Override
    protected void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        float densityScale = getResources().getDisplayMetrics().density;
        mSwipeHelper.setDensityScale(densityScale);
        float pagingTouchSlop = ViewConfiguration.get(mContext).getScaledPagingTouchSlop();
        mSwipeHelper.setPagingTouchSlop(pagingTouchSlop);
    }

    private void setOverScrollEffectPadding(int leftPadding, int i) {
        // TODO Add to (Vertical)ScrollView
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        // Keep track of the last visible item in the list so we can restore it
        // to the bottom when the orientation changes.
        mLastScrollPosition = scrollPositionOfMostRecent();

        // This has to happen post-layout, so run it "in the future"
        post(new Runnable() {
            public void run() {
                scrollTo(mLastScrollPosition, 0);
            }
        });
    }

    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        // scroll to bottom after reloading
        if (visibility == View.VISIBLE && changedView == this) {
            post(new Runnable() {
                public void run() {
                    update();
                }
            });
        }
    }

    public void setAdapter(ActivityDescriptionAdapter adapter) {
        mAdapter = adapter;
        mAdapter.registerDataSetObserver(new DataSetObserver() {
            public void onChanged() {
                update();
            }

            public void onInvalidated() {
                update();
            }
        });
    }

    @Override
    public void setLayoutTransition(LayoutTransition transition) {
        // The layout transition applies to our embedded LinearLayout
        mLinearLayout.setLayoutTransition(transition);
    }

    public void setCallback(RecentsCallback callback) {
        mCallback = callback;
    }
}