/*
 * 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.search;

import android.content.Context;
import android.content.Intent;
import android.media.tv.TvContentRating;
import android.media.tv.TvContract;
import android.media.tv.TvContract.Programs;
import android.media.tv.TvInputManager;
import android.os.SystemClock;
import android.support.annotation.MainThread;
import android.text.TextUtils;
import android.util.Log;

import com.android.tv.ApplicationSingletons;
import com.android.tv.TvApplication;
import com.android.tv.data.Channel;
import com.android.tv.data.ChannelDataManager;
import com.android.tv.data.Program;
import com.android.tv.data.ProgramDataManager;
import com.android.tv.search.LocalSearchProvider.SearchResult;
import com.android.tv.util.MainThreadExecutor;
import com.android.tv.util.Utils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

/**
 * An implementation of {@link SearchInterface} to search query from {@link ChannelDataManager}
 * and {@link ProgramDataManager}.
 */
public class DataManagerSearch implements SearchInterface {
    private static final String TAG = "TvProviderSearch";
    private static final boolean DEBUG = false;

    private final Context mContext;
    private final TvInputManager mTvInputManager;
    private final ChannelDataManager mChannelDataManager;
    private final ProgramDataManager mProgramDataManager;

    DataManagerSearch(Context context) {
        mContext = context;
        mTvInputManager = (TvInputManager) context.getSystemService(Context.TV_INPUT_SERVICE);
        ApplicationSingletons appSingletons = TvApplication.getSingletons(context);
        mChannelDataManager = appSingletons.getChannelDataManager();
        mProgramDataManager = appSingletons.getProgramDataManager();
    }

    @Override
    public List<SearchResult> search(final String query, final int limit, final int action) {
        Future<List<SearchResult>> future = MainThreadExecutor.getInstance()
                .submit(new Callable<List<SearchResult>>() {
                    @Override
                    public List<SearchResult> call() throws Exception {
                        return searchFromDataManagers(query, limit, action);
                    }
                });

        try {
            return future.get();
        } catch (InterruptedException e) {
            Thread.interrupted();
            return Collections.EMPTY_LIST;
        } catch (ExecutionException e) {
            Log.w(TAG, "Error searching for " + query, e);
            return Collections.EMPTY_LIST;
        }
    }

    @MainThread
    private List<SearchResult> searchFromDataManagers(String query, int limit, int action) {
        List<SearchResult> results = new ArrayList<>();
        if (!mChannelDataManager.isDbLoadFinished()) {
            return results;
        }
        if (action == ACTION_TYPE_SWITCH_CHANNEL
                || action == ACTION_TYPE_SWITCH_INPUT) {
            // Voice search query should be handled by the a system TV app.
            return results;
        }
        if (DEBUG) Log.d(TAG, "Searching channels: '" + query + "'");
        long time = SystemClock.elapsedRealtime();
        Set<Long> channelsFound = new HashSet<>();
        List<Channel> channelList = mChannelDataManager.getBrowsableChannelList();
        query = query.toLowerCase();
        if (TextUtils.isDigitsOnly(query)) {
            for (Channel channel : channelList) {
                if (channelsFound.contains(channel.getId())) {
                    continue;
                }
                if (contains(channel.getDisplayNumber(), query)) {
                    addResult(results, channelsFound, channel, null);
                }
                if (results.size() >= limit) {
                    if (DEBUG) {
                        Log.d(TAG, "Found " + results.size() + " channels. Elapsed time for" +
                                " searching channels: " + (SystemClock.elapsedRealtime() - time) +
                                "(msec)");
                    }
                    return results;
                }
            }
            // TODO: recently watched channels may have higher priority.
        }
        for (Channel channel : channelList) {
            if (channelsFound.contains(channel.getId())) {
                continue;
            }
            if (contains(channel.getDisplayName(), query)
                    || contains(channel.getDescription(), query)) {
                addResult(results, channelsFound, channel, null);
            }
            if (results.size() >= limit) {
                if (DEBUG) {
                    Log.d(TAG, "Found " + results.size() + " channels. Elapsed time for" +
                            " searching channels: " + (SystemClock.elapsedRealtime() - time) +
                            "(msec)");
                }
                return results;
            }
        }
        if (DEBUG) {
            Log.d(TAG, "Found " + results.size() + " channels. Elapsed time for" +
                    " searching channels: " + (SystemClock.elapsedRealtime() - time) + "(msec)");
        }
        int channelResult = results.size();
        if (DEBUG) Log.d(TAG, "Searching programs: '" + query + "'");
        time = SystemClock.elapsedRealtime();
        for (Channel channel : channelList) {
            if (channelsFound.contains(channel.getId())) {
                continue;
            }
            Program program = mProgramDataManager.getCurrentProgram(channel.getId());
            if (program == null) {
                continue;
            }
            if (contains(program.getTitle(), query)
                    && !isRatingBlocked(program.getContentRatings())) {
                addResult(results, channelsFound, channel, program);
            }
            if (results.size() >= limit) {
                if (DEBUG) {
                    Log.d(TAG, "Found " + (results.size() - channelResult) + " programs. Elapsed" +
                            " time for searching programs: " +
                            (SystemClock.elapsedRealtime() - time) + "(msec)");
                }
                return results;
            }
        }
        for (Channel channel : channelList) {
            if (channelsFound.contains(channel.getId())) {
                continue;
            }
            Program program = mProgramDataManager.getCurrentProgram(channel.getId());
            if (program == null) {
                continue;
            }
            if (contains(program.getDescription(), query)
                    && !isRatingBlocked(program.getContentRatings())) {
                addResult(results, channelsFound, channel, program);
            }
            if (results.size() >= limit) {
                if (DEBUG) {
                    Log.d(TAG, "Found " + (results.size() - channelResult) + " programs. Elapsed" +
                            " time for searching programs: " +
                            (SystemClock.elapsedRealtime() - time) + "(msec)");
                }
                return results;
            }
        }
        if (DEBUG) {
            Log.d(TAG, "Found " + (results.size() - channelResult) + " programs. Elapsed time for" +
                    " searching programs: " + (SystemClock.elapsedRealtime() - time) + "(msec)");
        }
        return results;
    }

    // It assumes that query is already lower cases.
    private boolean contains(String string, String query) {
        return string != null && string.toLowerCase().contains(query);
    }

    /**
     * If query is matched to channel, {@code program} should be null.
     */
    private void addResult(List<SearchResult> results, Set<Long> channelsFound, Channel channel,
            Program program) {
        if (program == null) {
            program = mProgramDataManager.getCurrentProgram(channel.getId());
            if (program != null && isRatingBlocked(program.getContentRatings())) {
                program = null;
            }
        }

        SearchResult result = new SearchResult();

        long channelId = channel.getId();
        result.channelId = channelId;
        result.channelNumber = channel.getDisplayNumber();
        if (program == null) {
            result.title = channel.getDisplayName();
            result.description = channel.getDescription();
            result.imageUri = TvContract.buildChannelLogoUri(channelId).toString();
            result.intentAction = Intent.ACTION_VIEW;
            result.intentData = buildIntentData(channelId);
            result.contentType = Programs.CONTENT_ITEM_TYPE;
            result.isLive = true;
            result.progressPercentage = LocalSearchProvider.PROGRESS_PERCENTAGE_HIDE;
        } else {
            result.title = program.getTitle();
            result.description = buildProgramDescription(channel.getDisplayNumber(),
                    channel.getDisplayName(), program.getStartTimeUtcMillis(),
                    program.getEndTimeUtcMillis());
            result.imageUri = program.getPosterArtUri();
            result.intentAction = Intent.ACTION_VIEW;
            result.intentData = buildIntentData(channelId);
            result.contentType = Programs.CONTENT_ITEM_TYPE;
            result.isLive = true;
            result.videoWidth = program.getVideoWidth();
            result.videoHeight = program.getVideoHeight();
            result.duration = program.getDurationMillis();
            result.progressPercentage = getProgressPercentage(
                    program.getStartTimeUtcMillis(), program.getEndTimeUtcMillis());
        }
        if (DEBUG) {
            Log.d(TAG, "Add a result : channel=" + channel + " program=" + program);
        }
        results.add(result);
        channelsFound.add(channel.getId());
    }

    private String buildProgramDescription(String channelNumber, String channelName,
            long programStartUtcMillis, long programEndUtcMillis) {
        return Utils.getDurationString(mContext, programStartUtcMillis, programEndUtcMillis, false)
                + System.lineSeparator() + channelNumber + " " + channelName;
    }

    private int getProgressPercentage(long startUtcMillis, long endUtcMillis) {
        long current = System.currentTimeMillis();
        if (startUtcMillis > current || endUtcMillis <= current) {
            return LocalSearchProvider.PROGRESS_PERCENTAGE_HIDE;
        }
        return (int)(100 * (current - startUtcMillis) / (endUtcMillis - startUtcMillis));
    }

    private String buildIntentData(long channelId) {
        return TvContract.buildChannelUri(channelId).toString();
    }

    private boolean isRatingBlocked(TvContentRating[] ratings) {
        if (ratings == null || ratings.length == 0
                || !mTvInputManager.isParentalControlsEnabled()) {
            return false;
        }
        for (TvContentRating rating : ratings) {
            try {
                if (mTvInputManager.isRatingBlocked(rating)) {
                    return true;
                }
            } catch (IllegalArgumentException e) {
                // Do nothing.
            }
        }
        return false;
    }
}