/*
 * Copyright (C) 2015 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.tv.menu;

import android.content.Context;
import android.content.Intent;
import android.media.tv.TvInputInfo;
import android.view.View;

import com.android.tv.ApplicationSingletons;
import com.android.tv.R;
import com.android.tv.TvApplication;
import com.android.tv.analytics.Tracker;
import com.android.tv.common.feature.CommonFeatures;
import com.android.tv.data.Channel;
import com.android.tv.dvr.DvrDataManager;
import com.android.tv.recommendation.Recommender;
import com.android.tv.util.SetupUtils;
import com.android.tv.util.TvInputManagerHelper;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.List;

/**
 * An adapter of the Channels row.
 */
public class ChannelsRowAdapter extends ItemListRowView.ItemListAdapter<ChannelsRowItem> {
    // There are four special cards: guide, setup, dvr, applink.
    private static final int SIZE_OF_VIEW_TYPE = 5;

    private final Context mContext;
    private final Tracker mTracker;
    private final Recommender mRecommender;
    private final DvrDataManager mDvrDataManager;
    private final int mMaxCount;
    private final int mMinCount;

    private final View.OnClickListener mGuideOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mTracker.sendMenuClicked(R.string.channels_item_program_guide);
            getMainActivity().getOverlayManager().showProgramGuide();
        }
    };

    private final View.OnClickListener mSetupOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mTracker.sendMenuClicked(R.string.channels_item_setup);
            getMainActivity().getOverlayManager().showSetupFragment();
        }
    };

    private final View.OnClickListener mDvrOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mTracker.sendMenuClicked(R.string.channels_item_dvr);
            getMainActivity().getOverlayManager().showDvrManager();
        }
    };

    private final View.OnClickListener mAppLinkOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mTracker.sendMenuClicked(R.string.channels_item_app_link);
            Intent intent = ((AppLinkCardView) view).getIntent();
            if (intent != null) {
                getMainActivity().startActivitySafe(intent);
            }
        }
    };

    private final View.OnClickListener mChannelOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Always send the label "Channels" because the channel ID or name or number might be
            // sensitive.
            mTracker.sendMenuClicked(R.string.menu_title_channels);
            getMainActivity().tuneToChannel((Channel) view.getTag());
            getMainActivity().hideOverlaysForTune();
        }
    };

    public ChannelsRowAdapter(Context context, Recommender recommender,
            int minCount, int maxCount) {
        super(context);
        mContext = context;
        ApplicationSingletons appSingletons = TvApplication.getSingletons(context);
        mTracker = appSingletons.getTracker();
        if (CommonFeatures.DVR.isEnabled(context)) {
            mDvrDataManager = appSingletons.getDvrDataManager();
        } else {
            mDvrDataManager = null;
        }
        mRecommender = recommender;
        mMinCount = minCount;
        mMaxCount = maxCount;
        setHasStableIds(true);
    }

    @Override
    public int getItemViewType(int position) {
        return getItemList().get(position).getLayoutId();
    }

    @Override
    protected int getLayoutResId(int viewType) {
        return viewType;
    }

    @Override
    public long getItemId(int position) {
        return getItemList().get(position).getItemId();
    }

    @Override
    public void onBindViewHolder(MyViewHolder viewHolder, int position) {
        int viewType = getItemViewType(position);
        if (viewType == R.layout.menu_card_guide) {
            viewHolder.itemView.setOnClickListener(mGuideOnClickListener);
        } else if (viewType == R.layout.menu_card_setup) {
            viewHolder.itemView.setOnClickListener(mSetupOnClickListener);
        } else if (viewType == R.layout.menu_card_app_link) {
            viewHolder.itemView.setOnClickListener(mAppLinkOnClickListener);
        } else if (viewType == R.layout.menu_card_dvr) {
            viewHolder.itemView.setOnClickListener(mDvrOnClickListener);
            SimpleCardView view = (SimpleCardView) viewHolder.itemView;
            view.setText(R.string.channels_item_dvr);
        } else {
            viewHolder.itemView.setTag(getItemList().get(position).getChannel());
            viewHolder.itemView.setOnClickListener(mChannelOnClickListener);
        }
        super.onBindViewHolder(viewHolder, position);
    }

    @Override
    public void update() {
        if (getItemCount() == 0) {
            createItems();
        } else {
            updateItems();
        }
    }

    private void createItems() {
        List<ChannelsRowItem> items = new ArrayList<>();
        items.add(ChannelsRowItem.GUIDE_ITEM);
        if (needToShowSetupItem()) {
            items.add(ChannelsRowItem.SETUP_ITEM);
        }
        if (needToShowDvrItem()) {
            items.add(ChannelsRowItem.DVR_ITEM);
        }
        if (needToShowAppLinkItem()) {
            ChannelsRowItem.APP_LINK_ITEM.setChannel(
                    new Channel.Builder(getMainActivity().getCurrentChannel()).build());
            items.add(ChannelsRowItem.APP_LINK_ITEM);
        }
        for (Channel channel : getRecentChannels()) {
            items.add(new ChannelsRowItem(channel, R.layout.menu_card_channel));
        }
        setItemList(items);
    }

    private void updateItems() {
        List<ChannelsRowItem> items = getItemList();
        // The current index of the item list to iterate. It starts from 1 because the first item
        // (GUIDE) is always visible and not updated.
        int currentIndex = 1;
        if (updateItem(needToShowSetupItem(), ChannelsRowItem.SETUP_ITEM, currentIndex)) {
            ++currentIndex;
        }
        if (updateItem(needToShowDvrItem(), ChannelsRowItem.DVR_ITEM, currentIndex)) {
            ++currentIndex;
        }
        if (updateItem(needToShowAppLinkItem(), ChannelsRowItem.APP_LINK_ITEM, currentIndex)) {
            if (!getMainActivity().getCurrentChannel()
                    .hasSameReadOnlyInfo(ChannelsRowItem.APP_LINK_ITEM.getChannel())) {
                ChannelsRowItem.APP_LINK_ITEM.setChannel(
                        new Channel.Builder(getMainActivity().getCurrentChannel()).build());
                notifyItemChanged(currentIndex);
            }
            ++currentIndex;
        }
        int numOldChannels = items.size() - currentIndex;
        if (numOldChannels > 0) {
            while (items.size() > currentIndex) {
                items.remove(items.size() - 1);
            }
            notifyItemRangeRemoved(currentIndex, numOldChannels);
        }
        for (Channel channel : getRecentChannels()) {
            items.add(new ChannelsRowItem(channel, R.layout.menu_card_channel));
        }
        int numNewChannels = items.size() - currentIndex;
        if (numNewChannels > 0) {
            notifyItemRangeInserted(currentIndex, numNewChannels);
        }
    }

    /**
     * Returns {@code true} if the item should be shown.
     */
    private boolean updateItem(boolean needToShow, ChannelsRowItem item, int index) {
        List<ChannelsRowItem> items = getItemList();
        boolean isItemInList = index < items.size() && item.equals(items.get(index));
        if (needToShow && !isItemInList) {
            items.add(index, item);
            notifyItemInserted(index);
        } else if (!needToShow && isItemInList) {
            items.remove(index);
            notifyItemRemoved(index);
        }
        return needToShow;
    }

    private boolean needToShowSetupItem() {
        TvInputManagerHelper inputManager =
                TvApplication.getSingletons(mContext).getTvInputManagerHelper();
        return SetupUtils.getInstance(mContext).hasNewInput(inputManager);
    }

    private boolean needToShowDvrItem() {
        TvInputManagerHelper inputManager =
                TvApplication.getSingletons(mContext).getTvInputManagerHelper();
        if (mDvrDataManager != null) {
            for (TvInputInfo info : inputManager.getTvInputInfos(true, true)) {
                if (info.canRecord()) {
                    return true;
                }
            }
        }
        return false;
    }

    private boolean needToShowAppLinkItem() {
        TvInputManagerHelper inputManager =
                TvApplication.getSingletons(mContext).getTvInputManagerHelper();
        Channel currentChannel = getMainActivity().getCurrentChannel();
        return currentChannel != null
                && currentChannel.getAppLinkType(mContext) != Channel.APP_LINK_TYPE_NONE
                // Sometimes applicationInfo can be null. b/28932537
                && inputManager.getTvInputAppInfo(currentChannel.getInputId()) != null;
    }

    private List<Channel> getRecentChannels() {
        List<Channel> channelList = new ArrayList<>();
        long currentChannelId = getMainActivity().getCurrentChannelId();
        ArrayDeque<Long> recentChannels = getMainActivity().getRecentChannels();
        // Add the last watched channel as the first one.
        for (long channelId : recentChannels) {
            if (addChannelToList(
                    channelList, mRecommender.getChannel(channelId), currentChannelId)) {
                break;
            }
        }
        // Add the recommended channels.
        for (Channel channel : mRecommender.recommendChannels(mMaxCount)) {
            if (channelList.size() >= mMaxCount) {
                break;
            }
            addChannelToList(channelList, channel, currentChannelId);
        }
        // If the number of recommended channels is not enough, add more from the recent channel
        // list.
        for (long channelId : recentChannels) {
            if (channelList.size() >= mMinCount) {
                break;
            }
            addChannelToList(channelList, mRecommender.getChannel(channelId), currentChannelId);
        }
        return channelList;
    }

    private static boolean addChannelToList(
            List<Channel> channelList, Channel channel, long currentChannelId) {
        if (channel == null || channel.getId() == currentChannelId
                || channelList.contains(channel) || !channel.isBrowsable()) {
            return false;
        }
        channelList.add(channel);
        return true;
    }
}