/*
 * 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.tuner.tvinput;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.media.tv.TvContract;
import android.media.tv.TvInputManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Message;
import android.support.annotation.IntDef;
import android.support.annotation.MainThread;
import android.support.annotation.Nullable;
import android.util.Log;

import com.android.tv.TvApplication;
import com.android.tv.common.SoftPreconditions;
import com.android.tv.common.recording.RecordingCapability;
import com.android.tv.dvr.DvrStorageStatusManager;
import com.android.tv.dvr.RecordedProgram;
import com.android.tv.tuner.DvbDeviceAccessor;
import com.android.tv.tuner.data.PsipData;
import com.android.tv.tuner.data.TunerChannel;
import com.android.tv.tuner.exoplayer.ExoPlayerSampleExtractor;
import com.android.tv.tuner.exoplayer.SampleExtractor;
import com.android.tv.tuner.exoplayer.buffer.BufferManager;
import com.android.tv.tuner.exoplayer.buffer.DvrStorageManager;
import com.android.tv.tuner.source.TsDataSource;
import com.android.tv.tuner.source.TsDataSourceManager;
import com.android.tv.util.Utils;

import java.io.File;
import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.List;
import java.util.Locale;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * Implements a DVR feature.
 */
public class TunerRecordingSessionWorker implements PlaybackBufferListener,
        EventDetector.EventListener, SampleExtractor.OnCompletionListener,
        Handler.Callback {
    private static final String TAG = "TunerRecordingSessionW";
    private static final boolean DEBUG = false;

    private static final String SORT_BY_TIME = TvContract.Programs.COLUMN_START_TIME_UTC_MILLIS
            + ", " + TvContract.Programs.COLUMN_CHANNEL_ID + ", "
            + TvContract.Programs.COLUMN_END_TIME_UTC_MILLIS;
    private static final long STORAGE_MONITOR_INTERVAL_MS = TimeUnit.SECONDS.toMillis(4);
    private static final long MIN_PARTIAL_RECORDING_DURATION_MS = TimeUnit.SECONDS.toMillis(10);
    private static final long PREPARE_RECORDER_POLL_MS = 50;
    private static final int MSG_TUNE = 1;
    private static final int MSG_START_RECORDING = 2;
    private static final int MSG_PREPARE_RECODER = 3;
    private static final int MSG_STOP_RECORDING = 4;
    private static final int MSG_MONITOR_STORAGE_STATUS = 5;
    private static final int MSG_RELEASE = 6;
    private final RecordingCapability mCapabilities;

    public RecordingCapability getCapabilities() {
        return mCapabilities;
    }

    @IntDef({STATE_IDLE, STATE_TUNED, STATE_RECORDING})
    @Retention(RetentionPolicy.SOURCE)
    public @interface DvrSessionState {}
    private static final int STATE_IDLE = 1;
    private static final int STATE_TUNED = 2;
    private static final int STATE_RECORDING = 3;

    private static final long CHANNEL_ID_NONE = -1;

    private final Context mContext;
    private final ChannelDataManager mChannelDataManager;
    private final DvrStorageStatusManager mDvrStorageStatusManager;
    private final Handler mHandler;
    private final TsDataSourceManager mSourceManager;
    private final Random mRandom = new Random();

    private TsDataSource mTunerSource;
    private TunerChannel mChannel;
    private File mStorageDir;
    private long mRecordStartTime;
    private long mRecordEndTime;
    private boolean mRecorderRunning;
    private BufferManager mBufferManager;
    private SampleExtractor mRecorder;
    private final TunerRecordingSession mSession;
    @DvrSessionState private int mSessionState = STATE_IDLE;
    private final String mInputId;
    private Uri mProgramUri;

    public TunerRecordingSessionWorker(Context context, String inputId,
            ChannelDataManager dataManager, TunerRecordingSession session) {
        mRandom.setSeed(System.nanoTime());
        mContext = context;
        HandlerThread handlerThread = new HandlerThread(TAG);
        handlerThread.start();
        mHandler = new Handler(handlerThread.getLooper(), this);
        mDvrStorageStatusManager =
                TvApplication.getSingletons(context).getDvrStorageStatusManager();
        mChannelDataManager = dataManager;
        mChannelDataManager.checkDataVersion(context);
        mSourceManager = TsDataSourceManager.createSourceManager(true);
        mCapabilities = new DvbDeviceAccessor(context).getRecordingCapability(inputId);
        mInputId = inputId;
        if (DEBUG) Log.d(TAG, mCapabilities.toString());
        mSession = session;
    }

    // PlaybackBufferListener
    @Override
    public void onBufferStartTimeChanged(long startTimeMs) { }

    @Override
    public void onBufferStateChanged(boolean available) { }

    @Override
    public void onDiskTooSlow() { }

    // EventDetector.EventListener
    @Override
    public void onChannelDetected(TunerChannel channel, boolean channelArrivedAtFirstTime) {
        if (mChannel == null || mChannel.compareTo(channel) != 0) {
            return;
        }
        mChannelDataManager.notifyChannelDetected(channel, channelArrivedAtFirstTime);
    }

    @Override
    public void onEventDetected(TunerChannel channel, List<PsipData.EitItem> items) {
        if (mChannel == null || mChannel.compareTo(channel) != 0) {
            return;
        }
        mChannelDataManager.notifyEventDetected(channel, items);
    }

    @Override
    public void onChannelScanDone() {
        // do nothing.
    }

    // SampleExtractor.OnCompletionListener
    @Override
    public void onCompletion(boolean success, long lastExtractedPositionUs) {
        onRecordingResult(success, lastExtractedPositionUs);
        reset();
    }

    /**
     * Tunes to {@code channelUri}.
     */
    @MainThread
    public void tune(Uri channelUri) {
        mHandler.removeCallbacksAndMessages(null);
        mHandler.obtainMessage(MSG_TUNE, channelUri).sendToTarget();
    }

    /**
     * Starts recording.
     */
    @MainThread
    public void startRecording(@Nullable Uri programUri) {
        mHandler.obtainMessage(MSG_START_RECORDING, programUri).sendToTarget();
    }

    /**
     * Stops recording.
     */
    @MainThread
    public void stopRecording() {
        mHandler.sendEmptyMessage(MSG_STOP_RECORDING);
    }

    /**
     * Releases all resources.
     */
    @MainThread
    public void release() {
        mHandler.removeCallbacksAndMessages(null);
        mHandler.sendEmptyMessage(MSG_RELEASE);
    }

    @Override
    public boolean handleMessage(Message msg) {
        switch (msg.what) {
            case MSG_TUNE: {
                Uri channelUri = (Uri) msg.obj;
                if (DEBUG) Log.d(TAG, "Tune to " + channelUri);
                if (doTune(channelUri)) {
                    mSession.onTuned(channelUri);
                } else {
                    reset();
                }
                return true;
            }
            case MSG_START_RECORDING: {
                if (DEBUG) Log.d(TAG, "Start recording");
                if (!doStartRecording((Uri) msg.obj)) {
                    reset();
                }
                return true;
            }
            case MSG_PREPARE_RECODER: {
                if (DEBUG) Log.d(TAG, "Preparing recorder");
                if (!mRecorderRunning) {
                    return true;
                }
                try {
                    if (!mRecorder.prepare()) {
                        mHandler.sendEmptyMessageDelayed(MSG_PREPARE_RECODER,
                                PREPARE_RECORDER_POLL_MS);
                    }
                } catch (IOException e) {
                    Log.w(TAG, "Failed to start recording. Couldn't prepare an extractor");
                    mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
                    reset();
                }
                return true;
            }
            case MSG_STOP_RECORDING: {
                if (DEBUG) Log.d(TAG, "Stop recording");
                if (mSessionState != STATE_RECORDING) {
                    mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
                    reset();
                    return true;
                }
                if (mRecorderRunning) {
                    stopRecorder();
                }
                return true;
            }
            case MSG_MONITOR_STORAGE_STATUS: {
                if (mSessionState != STATE_RECORDING) {
                    return true;
                }
                if (!mDvrStorageStatusManager.isStorageSufficient()) {
                    if (mRecorderRunning) {
                        stopRecorder();
                    }
                    new DeleteRecordingTask().execute(mStorageDir);
                    mSession.onError(TvInputManager.RECORDING_ERROR_INSUFFICIENT_SPACE);
                    reset();
                } else {
                    mHandler.sendEmptyMessageDelayed(MSG_MONITOR_STORAGE_STATUS,
                            STORAGE_MONITOR_INTERVAL_MS);
                }
                return true;
            }
            case MSG_RELEASE: {
                // Since release was requested, current recording will be cancelled
                // without notification.
                reset();
                mSourceManager.release();
                mHandler.removeCallbacksAndMessages(null);
                mHandler.getLooper().quitSafely();
                return true;
            }
        }
        return false;
    }

    @Nullable
    private TunerChannel getChannel(Uri channelUri) {
        if (channelUri == null) {
            return null;
        }
        long channelId;
        try {
            channelId = ContentUris.parseId(channelUri);
        } catch (UnsupportedOperationException | NumberFormatException e) {
            channelId = CHANNEL_ID_NONE;
        }
        return (channelId == CHANNEL_ID_NONE) ? null : mChannelDataManager.getChannel(channelId);
    }

    private String getStorageKey() {
        long prefix = System.currentTimeMillis();
        int suffix = mRandom.nextInt();
        return String.format(Locale.ENGLISH, "%016x_%016x", prefix, suffix);
    }

    private void reset() {
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }
        if (mBufferManager != null) {
            mBufferManager.close();
            mBufferManager = null;
        }
        if (mTunerSource != null) {
            mSourceManager.releaseDataSource(mTunerSource);
            mTunerSource = null;
        }
        mSessionState = STATE_IDLE;
        mRecorderRunning = false;
    }

    private boolean doTune(Uri channelUri) {
        if (mSessionState != STATE_IDLE) {
            mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
            Log.e(TAG, "Tuning was requested from wrong status.");
            return false;
        }
        mChannel = getChannel(channelUri);
        if (mChannel == null) {
            mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
            Log.w(TAG, "Failed to start recording. Couldn't find the channel for " + mChannel);
            return false;
        }
        if (!mDvrStorageStatusManager.isStorageSufficient()) {
            mSession.onError(TvInputManager.RECORDING_ERROR_INSUFFICIENT_SPACE);
            Log.w(TAG, "Tuning failed due to insufficient storage.");
            return false;
        }
        mTunerSource = mSourceManager.createDataSource(mContext, mChannel, this);
        if (mTunerSource == null) {
            mSession.onError(TvInputManager.RECORDING_ERROR_RESOURCE_BUSY);
            Log.w(TAG, "Tuner stream cannot be created due to resource shortage.");
            return false;
        }
        mSessionState = STATE_TUNED;
        return true;
    }

    private boolean doStartRecording(@Nullable Uri programUri) {
        if (mSessionState != STATE_TUNED) {
            mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
            Log.e(TAG, "Recording session status abnormal");
            return false;
        }
        mStorageDir = mDvrStorageStatusManager.isStorageSufficient() ?
                new File(mDvrStorageStatusManager.getRecordingRootDataDirectory(),
                        getStorageKey()) : null;
        if (mStorageDir == null) {
            mSession.onError(TvInputManager.RECORDING_ERROR_INSUFFICIENT_SPACE);
            Log.w(TAG, "Failed to start recording due to insufficient storage.");
            return false;
        }
        // Since tuning might be happened a while ago, shifts the start position of tuned source.
        mTunerSource.shiftStartPosition(mTunerSource.getBufferedPosition());
        mBufferManager = new BufferManager(new DvrStorageManager(mStorageDir, true));
        mRecordStartTime = System.currentTimeMillis();
        mRecorder = new ExoPlayerSampleExtractor(Uri.EMPTY, mTunerSource, mBufferManager, this,
                true);
        mRecorder.setOnCompletionListener(this, mHandler);
        mProgramUri = programUri;
        mSessionState = STATE_RECORDING;
        mRecorderRunning = true;
        mHandler.sendEmptyMessage(MSG_PREPARE_RECODER);
        mHandler.removeMessages(MSG_MONITOR_STORAGE_STATUS);
        mHandler.sendEmptyMessageDelayed(MSG_MONITOR_STORAGE_STATUS,
                STORAGE_MONITOR_INTERVAL_MS);
        return true;
    }

    private void stopRecorder() {
        // Do not change session status.
        if (mRecorder != null) {
            mRecorder.release();
            mRecordEndTime = System.currentTimeMillis();
            mRecorder = null;
        }
        mRecorderRunning = false;
        mHandler.removeMessages(MSG_MONITOR_STORAGE_STATUS);
        Log.i(TAG, "Recording stopped");
    }

    private static class Program {
        private final long mChannelId;
        private final String mTitle;
        private String mSeriesId;
        private final String mSeasonTitle;
        private final String mEpisodeTitle;
        private final String mSeasonNumber;
        private final String mEpisodeNumber;
        private final String mDescription;
        private final String mPosterArtUri;
        private final String mThumbnailUri;
        private final String mCanonicalGenres;
        private final String mContentRatings;
        private final long mStartTimeUtcMillis;
        private final long mEndTimeUtcMillis;
        private final int mVideoWidth;
        private final int mVideoHeight;
        private final byte[] mInternalProviderData;

        private static final String[] PROJECTION = {
                TvContract.Programs.COLUMN_CHANNEL_ID,
                TvContract.Programs.COLUMN_TITLE,
                TvContract.Programs.COLUMN_SEASON_TITLE,
                TvContract.Programs.COLUMN_EPISODE_TITLE,
                TvContract.Programs.COLUMN_SEASON_DISPLAY_NUMBER,
                TvContract.Programs.COLUMN_EPISODE_DISPLAY_NUMBER,
                TvContract.Programs.COLUMN_SHORT_DESCRIPTION,
                TvContract.Programs.COLUMN_POSTER_ART_URI,
                TvContract.Programs.COLUMN_THUMBNAIL_URI,
                TvContract.Programs.COLUMN_CANONICAL_GENRE,
                TvContract.Programs.COLUMN_CONTENT_RATING,
                TvContract.Programs.COLUMN_START_TIME_UTC_MILLIS,
                TvContract.Programs.COLUMN_END_TIME_UTC_MILLIS,
                TvContract.Programs.COLUMN_VIDEO_WIDTH,
                TvContract.Programs.COLUMN_VIDEO_HEIGHT,
                TvContract.Programs.COLUMN_INTERNAL_PROVIDER_DATA
        };

        public Program(Cursor cursor) {
            int index = 0;
            mChannelId = cursor.getLong(index++);
            mTitle = cursor.getString(index++);
            mSeasonTitle = cursor.getString(index++);
            mEpisodeTitle = cursor.getString(index++);
            mSeasonNumber = cursor.getString(index++);
            mEpisodeNumber = cursor.getString(index++);
            mDescription = cursor.getString(index++);
            mPosterArtUri = cursor.getString(index++);
            mThumbnailUri = cursor.getString(index++);
            mCanonicalGenres = cursor.getString(index++);
            mContentRatings = cursor.getString(index++);
            mStartTimeUtcMillis = cursor.getLong(index++);
            mEndTimeUtcMillis = cursor.getLong(index++);
            mVideoWidth = cursor.getInt(index++);
            mVideoHeight = cursor.getInt(index++);
            mInternalProviderData = cursor.getBlob(index++);
            SoftPreconditions.checkArgument(index == PROJECTION.length);
        }

        public Program(long channelId) {
            mChannelId = channelId;
            mTitle = "Unknown";
            mSeasonTitle = "";
            mEpisodeTitle = "";
            mSeasonNumber = "";
            mEpisodeNumber = "";
            mDescription = "Unknown";
            mPosterArtUri = null;
            mThumbnailUri = null;
            mCanonicalGenres = null;
            mContentRatings = null;
            mStartTimeUtcMillis = 0;
            mEndTimeUtcMillis = 0;
            mVideoWidth = 0;
            mVideoHeight = 0;
            mInternalProviderData = null;
        }

        public static Program onQuery(Cursor c) {
            Program program = null;
            if (c != null && c.moveToNext()) {
                program = new Program(c);
            }
            return program;
        }

        public ContentValues buildValues() {
            ContentValues values = new ContentValues();
            int index = 0;
            values.put(PROJECTION[index++], mChannelId);
            values.put(PROJECTION[index++], mTitle);
            values.put(PROJECTION[index++], mSeasonTitle);
            values.put(PROJECTION[index++], mEpisodeTitle);
            values.put(PROJECTION[index++], mSeasonNumber);
            values.put(PROJECTION[index++], mEpisodeNumber);
            values.put(PROJECTION[index++], mDescription);
            values.put(PROJECTION[index++], mPosterArtUri);
            values.put(PROJECTION[index++], mThumbnailUri);
            values.put(PROJECTION[index++], mCanonicalGenres);
            values.put(PROJECTION[index++], mContentRatings);
            values.put(PROJECTION[index++], mStartTimeUtcMillis);
            values.put(PROJECTION[index++], mEndTimeUtcMillis);
            values.put(PROJECTION[index++], mVideoWidth);
            values.put(PROJECTION[index++], mVideoHeight);
            values.put(PROJECTION[index++], mInternalProviderData);
            SoftPreconditions.checkArgument(index == PROJECTION.length);
            return values;
        }
    }

    private Program getRecordedProgram() {
        ContentResolver resolver = mContext.getContentResolver();
        Uri programUri = mProgramUri;
        if (mProgramUri == null) {
            long avg = mRecordStartTime / 2 + mRecordEndTime / 2;
            programUri = TvContract.buildProgramsUriForChannel(mChannel.getChannelId(), avg, avg);
        }
        try (Cursor c = resolver.query(programUri, Program.PROJECTION, null, null, SORT_BY_TIME)) {
            if (c != null) {
                Program result = Program.onQuery(c);
                if (DEBUG) {
                    Log.v(TAG, "Finished query for " + this);
                }
                return result;
            } else {
                if (c == null) {
                    Log.e(TAG, "Unknown query error for " + this);
                } else {
                    if (DEBUG) Log.d(TAG, "Canceled query for " + this);
                }
                return null;
            }
        }
    }

    private Uri insertRecordedProgram(Program program, long channelId, String storageUri,
            long totalBytes, long startTime, long endTime) {
        // TODO: Set title even though program is null.
        RecordedProgram recordedProgram = RecordedProgram.builder()
                .setInputId(mInputId)
                .setChannelId(channelId)
                .setDataUri(storageUri)
                .setDurationMillis(endTime - startTime)
                .setDataBytes(totalBytes)
                // startTime and endTime could be overridden by program's start and end value.
                .setStartTimeUtcMillis(startTime)
                .setEndTimeUtcMillis(endTime)
                .build();
        ContentValues values = RecordedProgram.toValues(recordedProgram);
        if (program != null) {
            values.putAll(program.buildValues());
        }
        return mContext.getContentResolver().insert(TvContract.RecordedPrograms.CONTENT_URI,
                values);
    }

    private void onRecordingResult(boolean success, long lastExtractedPositionUs) {
        if (mSessionState != STATE_RECORDING) {
            // Error notification is not needed.
            Log.e(TAG, "Recording session status abnormal");
            return;
        }
        if (mRecorderRunning) {
            // In case of recorder not being stopped, because of premature termination of recording.
            stopRecorder();
        }
        if (!success && lastExtractedPositionUs <
                TimeUnit.MILLISECONDS.toMicros(MIN_PARTIAL_RECORDING_DURATION_MS)) {
            new DeleteRecordingTask().execute(mStorageDir);
            mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
            Log.w(TAG, "Recording failed during recording");
            return;
        }
        Log.i(TAG, "recording finished " + (success ? "completely" : "partially"));
        Uri uri = insertRecordedProgram(getRecordedProgram(), mChannel.getChannelId(),
                Uri.fromFile(mStorageDir).toString(), 1024 * 1024, mRecordStartTime,
                mRecordStartTime + TimeUnit.MICROSECONDS.toMillis(lastExtractedPositionUs));
        if (uri == null) {
            new DeleteRecordingTask().execute(mStorageDir);
            mSession.onError(TvInputManager.RECORDING_ERROR_UNKNOWN);
            Log.e(TAG, "Inserting a recording to DB failed");
            return;
        }
        mSession.onRecordFinished(uri);
    }

    private static class DeleteRecordingTask extends AsyncTask<File, Void, Void> {

        @Override
        public Void doInBackground(File... files) {
            if (files == null || files.length == 0) {
                return null;
            }
            for(File file : files) {
                Utils.deleteDirOrFile(file);
            }
            return null;
        }
    }
}