/*
* Copyright (C) 2014 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.server.notification;

import android.app.Notification;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.ContactsContract.Contacts;
import android.provider.Settings;
import android.text.TextUtils;
import android.util.LruCache;
import android.util.Slog;

import java.util.ArrayList;
import java.util.LinkedList;

/**
 * This {@link NotificationSignalExtractor} attempts to validate
 * people references. Also elevates the priority of real people.
 */
public class ValidateNotificationPeople implements NotificationSignalExtractor {
    private static final String TAG = "ValidateNotificationPeople";
    private static final boolean INFO = true;
    private static final boolean DEBUG = false;

    private static final boolean ENABLE_PEOPLE_VALIDATOR = true;
    private static final String SETTING_ENABLE_PEOPLE_VALIDATOR =
            "validate_notification_people_enabled";
    private static final String[] LOOKUP_PROJECTION = { Contacts._ID, Contacts.STARRED };
    private static final int MAX_PEOPLE = 10;
    private static final int PEOPLE_CACHE_SIZE = 200;

    /** Indicates that the notification does not reference any valid contacts. */
    static final float NONE = 0f;

    /**
     * Affinity will be equal to or greater than this value on notifications
     * that reference a valid contact.
     */
    static final float VALID_CONTACT = 0.5f;

    /**
     * Affinity will be equal to or greater than this value on notifications
     * that reference a starred contact.
     */
    static final float STARRED_CONTACT = 1f;

    protected boolean mEnabled;
    private Context mContext;

    // maps raw person handle to resolved person object
    private LruCache<String, LookupResult> mPeopleCache;

    private RankingReconsideration validatePeople(final NotificationRecord record) {
        float affinity = NONE;
        Bundle extras = record.getNotification().extras;
        if (extras == null) {
            return null;
        }

        final String[] people = getExtraPeople(extras);
        if (people == null || people.length == 0) {
            return null;
        }

        if (INFO) Slog.i(TAG, "Validating: " + record.sbn.getKey());
        final LinkedList<String> pendingLookups = new LinkedList<String>();
        for (int personIdx = 0; personIdx < people.length && personIdx < MAX_PEOPLE; personIdx++) {
            final String handle = people[personIdx];
            if (TextUtils.isEmpty(handle)) continue;

            synchronized (mPeopleCache) {
                LookupResult lookupResult = mPeopleCache.get(handle);
                if (lookupResult == null || lookupResult.isExpired()) {
                    pendingLookups.add(handle);
                } else {
                    if (DEBUG) Slog.d(TAG, "using cached lookupResult: " + lookupResult.mId);
                }
                if (lookupResult != null) {
                    affinity = Math.max(affinity, lookupResult.getAffinity());
                }
            }
        }

        // record the best available data, so far:
        record.setContactAffinity(affinity);

        if (pendingLookups.isEmpty()) {
            if (INFO) Slog.i(TAG, "final affinity: " + affinity);
            return null;
        }

        if (DEBUG) Slog.d(TAG, "Pending: future work scheduled for: " + record.sbn.getKey());
        return new RankingReconsideration(record.getKey()) {
            float mContactAffinity = NONE;
            @Override
            public void work() {
                if (INFO) Slog.i(TAG, "Executing: validation for: " + record.getKey());
                for (final String handle: pendingLookups) {
                    LookupResult lookupResult = null;
                    final Uri uri = Uri.parse(handle);
                    if ("tel".equals(uri.getScheme())) {
                        if (DEBUG) Slog.d(TAG, "checking telephone URI: " + handle);
                        lookupResult = resolvePhoneContact(uri.getSchemeSpecificPart());
                    } else if ("mailto".equals(uri.getScheme())) {
                        if (DEBUG) Slog.d(TAG, "checking mailto URI: " + handle);
                        lookupResult = resolveEmailContact(uri.getSchemeSpecificPart());
                    } else if (handle.startsWith(Contacts.CONTENT_LOOKUP_URI.toString())) {
                        if (DEBUG) Slog.d(TAG, "checking lookup URI: " + handle);
                        lookupResult = searchContacts(uri);
                    } else {
                        lookupResult = new LookupResult();  // invalid person for the cache
                        Slog.w(TAG, "unsupported URI " + handle);
                    }
                    if (lookupResult != null) {
                        synchronized (mPeopleCache) {
                            mPeopleCache.put(handle, lookupResult);
                        }
                        mContactAffinity = Math.max(mContactAffinity, lookupResult.getAffinity());
                    }
                }
            }

            @Override
            public void applyChangesLocked(NotificationRecord operand) {
                float affinityBound = operand.getContactAffinity();
                operand.setContactAffinity(Math.max(mContactAffinity, affinityBound));
                if (INFO) Slog.i(TAG, "final affinity: " + operand.getContactAffinity());
            }
        };
    }

    private String[] getExtraPeople(Bundle extras) {
        Object people = extras.get(Notification.EXTRA_PEOPLE);
        if (people instanceof String[]) {
            return (String[]) people;
        }

        if (people instanceof ArrayList) {
            ArrayList arrayList = (ArrayList) people;

            if (arrayList.isEmpty()) {
                return null;
            }

            if (arrayList.get(0) instanceof String) {
                ArrayList<String> stringArray = (ArrayList<String>) arrayList;
                return stringArray.toArray(new String[stringArray.size()]);
            }

            if (arrayList.get(0) instanceof CharSequence) {
                ArrayList<CharSequence> charSeqList = (ArrayList<CharSequence>) arrayList;
                final int N = charSeqList.size();
                String[] array = new String[N];
                for (int i = 0; i < N; i++) {
                    array[i] = charSeqList.get(i).toString();
                }
                return array;
            }

            return null;
        }

        if (people instanceof String) {
            String[] array = new String[1];
            array[0] = (String) people;
            return array;
        }

        if (people instanceof char[]) {
            String[] array = new String[1];
            array[0] = new String((char[]) people);
            return array;
        }

        if (people instanceof CharSequence) {
            String[] array = new String[1];
            array[0] = ((CharSequence) people).toString();
            return array;
        }

        if (people instanceof CharSequence[]) {
            CharSequence[] charSeqArray = (CharSequence[]) people;
            final int N = charSeqArray.length;
            String[] array = new String[N];
            for (int i = 0; i < N; i++) {
                array[i] = charSeqArray[i].toString();
            }
            return array;
        }

        return null;
    }

    private LookupResult resolvePhoneContact(final String number) {
        Uri phoneUri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI,
                Uri.encode(number));
        return searchContacts(phoneUri);
    }

    private LookupResult resolveEmailContact(final String email) {
        Uri numberUri = Uri.withAppendedPath(
                ContactsContract.CommonDataKinds.Email.CONTENT_LOOKUP_URI,
                Uri.encode(email));
        return searchContacts(numberUri);
    }

    private LookupResult searchContacts(Uri lookupUri) {
        LookupResult lookupResult = new LookupResult();
        Cursor c = null;
        try {
            c = mContext.getContentResolver().query(lookupUri, LOOKUP_PROJECTION, null, null, null);
            if (c != null && c.getCount() > 0) {
                c.moveToFirst();
                lookupResult.readContact(c);
            }
        } catch(Throwable t) {
            Slog.w(TAG, "Problem getting content resolver or performing contacts query.", t);
        } finally {
            if (c != null) {
                c.close();
            }
        }
        return lookupResult;
    }

    public void initialize(Context context) {
        if (DEBUG) Slog.d(TAG, "Initializing  " + getClass().getSimpleName() + ".");
        mContext = context;
        mPeopleCache = new LruCache<String, LookupResult>(PEOPLE_CACHE_SIZE);
        mEnabled = ENABLE_PEOPLE_VALIDATOR && 1 == Settings.Global.getInt(
                mContext.getContentResolver(), SETTING_ENABLE_PEOPLE_VALIDATOR, 1);
    }

    public RankingReconsideration process(NotificationRecord record) {
        if (!mEnabled) {
            if (INFO) Slog.i(TAG, "disabled");
            return null;
        }
        if (record == null || record.getNotification() == null) {
            if (INFO) Slog.i(TAG, "skipping empty notification");
            return null;
        }
        return validatePeople(record);
    }

    private static class LookupResult {
        private static final long CONTACT_REFRESH_MILLIS = 60 * 60 * 1000;  // 1hr
        public static final int INVALID_ID = -1;

        private final long mExpireMillis;
        private int mId;
        private boolean mStarred;

        public LookupResult() {
            mId = INVALID_ID;
            mStarred = false;
            mExpireMillis = System.currentTimeMillis() + CONTACT_REFRESH_MILLIS;
        }

        public void readContact(Cursor cursor) {
            final int idIdx = cursor.getColumnIndex(Contacts._ID);
            if (idIdx >= 0) {
                mId = cursor.getInt(idIdx);
                if (DEBUG) Slog.d(TAG, "contact _ID is: " + mId);
            } else {
                if (DEBUG) Slog.d(TAG, "invalid cursor: no _ID");
            }
            final int starIdx = cursor.getColumnIndex(Contacts.STARRED);
            if (starIdx >= 0) {
                mStarred = cursor.getInt(starIdx) != 0;
                if (DEBUG) Slog.d(TAG, "contact STARRED is: " + mStarred);
            } else {
                if (DEBUG) Slog.d(TAG, "invalid cursor: no STARRED");
            }
        }

        public boolean isExpired() {
            return mExpireMillis < System.currentTimeMillis();
        }

        public boolean isInvalid() {
            return mId == INVALID_ID || isExpired();
        }

        public float getAffinity() {
            if (isInvalid()) {
                return NONE;
            } else if (mStarred) {
                return STARRED_CONTACT;
            } else {
                return VALID_CONTACT;
            }
        }

        public LookupResult setStarred(boolean starred) {
            mStarred = starred;
            return this;
        }

        public LookupResult setId(int id) {
            mId = id;
            return this;
        }
    }
}