/*
 * 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.dialer.calllog;

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Handler;
import android.os.Message;
import android.provider.ContactsContract.PhoneLookup;
import android.text.TextUtils;
import android.view.View;
import android.view.ViewTreeObserver;

import com.android.dialer.util.ExpirableCache;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Objects;

import java.util.LinkedList;

/**
 * Adapter class to fill in data for the Call Log.
 */
public class CallLogAdapterHelper implements ViewTreeObserver.OnPreDrawListener {
    public interface Callback {
        void dataSetChanged();
        void updateContactInfo(String number, String countryIso,
                ContactInfo updatedInfo, ContactInfo callLogInfo);
    }

    /**
     * Stores a phone number of a call with the country code where it originally occurred.
     * <p>
     * Note the country does not necessarily specifies the country of the phone number itself, but
     * it is the country in which the user was in when the call was placed or received.
     */
    public static final class NumberWithCountryIso {
        public final String number;
        public final String countryIso;

        public NumberWithCountryIso(String number, String countryIso) {
            this.number = number;
            this.countryIso = countryIso;
        }

        @Override
        public boolean equals(Object o) {
            if (o == null) return false;
            if (!(o instanceof NumberWithCountryIso)) return false;
            NumberWithCountryIso other = (NumberWithCountryIso) o;
            return TextUtils.equals(number, other.number)
                    && TextUtils.equals(countryIso, other.countryIso);
        }

        @Override
        public int hashCode() {
            return (number == null ? 0 : number.hashCode())
                    ^ (countryIso == null ? 0 : countryIso.hashCode());
        }
    }

    /**
     * A request for contact details for the given number.
     */
    private static final class ContactInfoRequest {
        /** The number to look-up. */
        public final String number;
        /** The country in which a call to or from this number was placed or received. */
        public final String countryIso;
        /** The cached contact information stored in the call log. */
        public final ContactInfo callLogInfo;

        public ContactInfoRequest(String number, String countryIso, ContactInfo callLogInfo) {
            this.number = number;
            this.countryIso = countryIso;
            this.callLogInfo = callLogInfo;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) return true;
            if (obj == null) return false;
            if (!(obj instanceof ContactInfoRequest)) return false;

            ContactInfoRequest other = (ContactInfoRequest) obj;

            if (!TextUtils.equals(number, other.number)) return false;
            if (!TextUtils.equals(countryIso, other.countryIso)) return false;
            if (!Objects.equal(callLogInfo, other.callLogInfo)) return false;

            return true;
        }

        @Override
        public int hashCode() {
            final int prime = 31;
            int result = 1;
            result = prime * result + ((callLogInfo == null) ? 0 : callLogInfo.hashCode());
            result = prime * result + ((countryIso == null) ? 0 : countryIso.hashCode());
            result = prime * result + ((number == null) ? 0 : number.hashCode());
            return result;
        }
    }

    /*
     * Handles requests for contact name and number type.
     */
    private class QueryThread extends Thread {
        private volatile boolean mDone = false;

        public QueryThread() {
            super("CallLogAdapter.QueryThread");
        }

        public void stopProcessing() {
            mDone = true;
        }

        @Override
        public void run() {
            boolean needRedraw = false;
            while (true) {
                // Check if thread is finished, and if so return immediately.
                if (mDone) return;

                // Obtain next request, if any is available.
                // Keep synchronized section small.
                ContactInfoRequest req = null;
                synchronized (mRequests) {
                    if (!mRequests.isEmpty()) {
                        req = mRequests.removeFirst();
                    }
                }

                if (req != null) {
                    // Process the request. If the lookup succeeds, schedule a
                    // redraw.
                    needRedraw |= queryContactInfo(req.number, req.countryIso, req.callLogInfo);
                } else {
                    // Throttle redraw rate by only sending them when there are
                    // more requests.
                    if (needRedraw) {
                        needRedraw = false;
                        mHandler.sendEmptyMessage(REDRAW);
                    }

                    // Wait until another request is available, or until this
                    // thread is no longer needed (as indicated by being
                    // interrupted).
                    try {
                        synchronized (mRequests) {
                            mRequests.wait(1000);
                        }
                    } catch (InterruptedException ie) {
                        // Ignore, and attempt to continue processing requests.
                    }
                }
            }
        }
    }

    private static final int REDRAW = 1;
    private static final int START_THREAD = 2;

    /** The time in millis to delay starting the thread processing requests. */
    private static final int START_PROCESSING_REQUESTS_DELAY_MILLIS = 1000;

    /** The size of the cache of contact info. */
    private static final int CONTACT_INFO_CACHE_SIZE = 100;

    private Callback mCb;
    private final Context mContext;
    private final ContactInfoHelper mContactInfoHelper;
    private final PhoneNumberDisplayHelper mPhoneNumberHelper;

    /**
     * A cache of the contact details for the phone numbers in the call log.
     * <p>
     * The content of the cache is expired (but not purged) whenever the application comes to
     * the foreground.
     * <p>
     * The key is number with the country in which the call was placed or received.
     */
    private ExpirableCache<NumberWithCountryIso, ContactInfo> mContactInfoCache;

    private QueryThread mCallerIdThread;
    /** Can be set to true by tests to disable processing of requests. */
    private volatile boolean mRequestProcessingDisabled = false;

    /**
     * List of requests to update contact details.
     * <p>
     * Each request is made of a phone number to look up, and the contact info currently stored in
     * the call log for this number.
     * <p>
     * The requests are added when displaying the contacts and are processed by a background
     * thread.
     */
    private final LinkedList<ContactInfoRequest> mRequests;

    private ViewTreeObserver mViewTreeObserver = null;

    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case REDRAW:
                    mCb.dataSetChanged();
                    break;
                case START_THREAD:
                    startRequestProcessing();
                    break;
            }
        }
    };

    /**
     * Enqueues a request to look up the contact details for the given phone number.
     * <p>
     * It also provides the current contact info stored in the call log for this number.
     * <p>
     * If the {@code immediate} parameter is true, it will start immediately the thread that looks
     * up the contact information (if it has not been already started). Otherwise, it will be
     * started with a delay. See {@link #START_PROCESSING_REQUESTS_DELAY_MILLIS}.
     */
    @VisibleForTesting
    void enqueueRequest(String number, String countryIso, ContactInfo callLogInfo,
            boolean immediate) {
        ContactInfoRequest request = new ContactInfoRequest(number, countryIso, callLogInfo);
        synchronized (mRequests) {
            if (!mRequests.contains(request)) {
                mRequests.add(request);
                mRequests.notifyAll();
            }
        }
        if (immediate) startRequestProcessing();
    }

    @Override
    public boolean onPreDraw() {
        // We only wanted to listen for the first draw (and this is it).
        unregisterPreDrawListener();

        // Only schedule a thread-creation message if the thread hasn't been
        // created yet. This is purely an optimization, to queue fewer messages.
        if (mCallerIdThread == null) {
            mHandler.sendEmptyMessageDelayed(START_THREAD, START_PROCESSING_REQUESTS_DELAY_MILLIS);
        }

        return true;
    }

    public void registerOnPreDrawListener(View v) {
        // Listen for the first draw
        if (mViewTreeObserver == null) {
            mViewTreeObserver = v.getViewTreeObserver();
            mViewTreeObserver.addOnPreDrawListener(this);
        }
    }

    /**
     * Stop receiving onPreDraw() notifications.
     */
    private void unregisterPreDrawListener() {
        if (mViewTreeObserver != null && mViewTreeObserver.isAlive()) {
            mViewTreeObserver.removeOnPreDrawListener(this);
        }
        mViewTreeObserver = null;
    }

    public void invalidateCache() {
        mContactInfoCache.expireAll();

        // Restart the request-processing thread after the next draw.
        stopRequestProcessing();
        unregisterPreDrawListener();
    }

    /**
     * Starts a background thread to process contact-lookup requests, unless one
     * has already been started.
     */
    private synchronized void startRequestProcessing() {
        // For unit-testing.
        if (mRequestProcessingDisabled) return;

        // Idempotence... if a thread is already started, don't start another.
        if (mCallerIdThread != null) return;

        mCallerIdThread = new QueryThread();
        mCallerIdThread.setPriority(Thread.MIN_PRIORITY);
        mCallerIdThread.start();
    }

    /**
     * Stops the background thread that processes updates and cancels any
     * pending requests to start it.
     */
    public synchronized void stopRequestProcessing() {
        // Remove any pending requests to start the processing thread.
        mHandler.removeMessages(START_THREAD);
        if (mCallerIdThread != null) {
            // Stop the thread; we are finished with it.
            mCallerIdThread.stopProcessing();
            mCallerIdThread.interrupt();
            mCallerIdThread = null;
        }
    }

    /**
     * Queries the appropriate content provider for the contact associated with the number.
     * <p>
     * Upon completion it also updates the cache in the call log, if it is different from
     * {@code callLogInfo}.
     * <p>
     * The number might be either a SIP address or a phone number.
     * <p>
     * It returns true if it updated the content of the cache and we should therefore tell the
     * view to update its content.
     */
    private boolean queryContactInfo(String number, String countryIso, ContactInfo callLogInfo) {
        final ContactInfo info = mContactInfoHelper.lookupNumber(number, countryIso);

        if (info == null) {
            // The lookup failed, just return without requesting to update the view.
            return false;
        }

        // Check the existing entry in the cache: only if it has changed we should update the
        // view.
        NumberWithCountryIso numberCountryIso = new NumberWithCountryIso(number, countryIso);
        ContactInfo existingInfo = mContactInfoCache.getPossiblyExpired(numberCountryIso);
        boolean updated = (existingInfo != ContactInfo.EMPTY) && !info.equals(existingInfo);

        // Store the data in the cache so that the UI thread can use to display it. Store it
        // even if it has not changed so that it is marked as not expired.
        mContactInfoCache.put(numberCountryIso, info);
        mCb.updateContactInfo(number, countryIso, info, callLogInfo);
        return updated;
    }

    /*
     * Get the number from the Contacts, if available, since sometimes
     * the number provided by caller id may not be formatted properly
     * depending on the carrier (roaming) in use at the time of the
     * incoming call.
     * Logic : If the caller-id number starts with a "+", use it
     *         Else if the number in the contacts starts with a "+", use that one
     *         Else if the number in the contacts is longer, use that one
     */
    public String getBetterNumberFromContacts(String number, String countryIso) {
        String matchingNumber = null;
        // Look in the cache first. If it's not found then query the Phones db
        NumberWithCountryIso numberCountryIso = new NumberWithCountryIso(number, countryIso);
        ContactInfo ci = mContactInfoCache.getPossiblyExpired(numberCountryIso);
        if (ci != null && ci != ContactInfo.EMPTY) {
            matchingNumber = ci.number;
        } else {
            try {
                Cursor phonesCursor = mContext.getContentResolver().query(
                        Uri.withAppendedPath(PhoneLookup.CONTENT_FILTER_URI, number),
                        PhoneQuery._PROJECTION, null, null, null);
                if (phonesCursor != null) {
                    if (phonesCursor.moveToFirst()) {
                        matchingNumber = phonesCursor.getString(PhoneQuery.MATCHED_NUMBER);
                    }
                    phonesCursor.close();
                }
            } catch (Exception e) {
                // Use the number from the call log
            }
        }
        if (!TextUtils.isEmpty(matchingNumber) &&
                (matchingNumber.startsWith("+")
                        || matchingNumber.length() > number.length())) {
            number = matchingNumber;
        }
        return number;
    }

    /** Checks whether the contact info from the call log matches the one from the contacts db. */
    private boolean callLogInfoMatches(ContactInfo callLogInfo, ContactInfo info) {
        // The call log only contains a subset of the fields in the contacts db.
        // Only check those.
        return TextUtils.equals(callLogInfo.name, info.name)
                && callLogInfo.type == info.type
                && TextUtils.equals(callLogInfo.label, info.label);
    }


    public ContactInfo lookupContact(String number, int numberPresentation,
            String countryIso, ContactInfo cachedContactInfo) {
        NumberWithCountryIso numberCountryIso = new NumberWithCountryIso(number, countryIso);
        ExpirableCache.CachedValue<ContactInfo> cachedInfo =
                mContactInfoCache.getCachedValue(numberCountryIso);
        ContactInfo info = cachedInfo == null ? null : cachedInfo.getValue();
        if (!PhoneNumberUtilsWrapper.canPlaceCallsTo(number, numberPresentation)
                || new PhoneNumberUtilsWrapper().isVoicemailNumber(number)) {
            // If this is a number that cannot be dialed, there is no point in looking up a contact
            // for it.
            info = ContactInfo.EMPTY;
        } else if (cachedInfo == null) {
            mContactInfoCache.put(numberCountryIso, ContactInfo.EMPTY);
            // Use the cached contact info from the call log.
            info = cachedContactInfo;
            // The db request should happen on a non-UI thread.
            // Request the contact details immediately since they are currently missing.
            enqueueRequest(number, countryIso, cachedContactInfo, true);
            // We will format the phone number when we make the background request.
        } else {
            if (cachedInfo.isExpired()) {
                // The contact info is no longer up to date, we should request it. However, we
                // do not need to request them immediately.
                enqueueRequest(number, countryIso, cachedContactInfo, false);
            } else  if (!callLogInfoMatches(cachedContactInfo, info)) {
                // The call log information does not match the one we have, look it up again.
                // We could simply update the call log directly, but that needs to be done in a
                // background thread, so it is easier to simply request a new lookup, which will, as
                // a side-effect, update the call log.
                enqueueRequest(number, countryIso, cachedContactInfo, false);
            }

            if (info == ContactInfo.EMPTY) {
                // Use the cached contact info from the call log.
                info = cachedContactInfo;
            }
        }

        return info;
    }

    public CallLogAdapterHelper(Context context, Callback cb,
            ContactInfoHelper contactInfoHelper,
            PhoneNumberDisplayHelper phoneNumberHelper) {
        mContext = context;
        mCb = cb;
        mContactInfoHelper = contactInfoHelper;
        mPhoneNumberHelper = phoneNumberHelper;

        mContactInfoCache = ExpirableCache.create(CONTACT_INFO_CACHE_SIZE);
        mRequests = new LinkedList<ContactInfoRequest>();
    }

    /**
     * Sets whether processing of requests for contact details should be enabled.
     * <p>
     * This method should be called in tests to disable such processing of requests when not
     * needed.
     */
    @VisibleForTesting
    void disableRequestProcessingForTest() {
        mRequestProcessingDisabled = true;
    }

    @VisibleForTesting
    void injectContactInfoForTest(String number, String countryIso, ContactInfo contactInfo) {
        NumberWithCountryIso numberCountryIso = new NumberWithCountryIso(number, countryIso);
        mContactInfoCache.put(numberCountryIso, contactInfo);
    }
}