/*
 * Copyright (C) 2017 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.am;

import static android.app.ActivityManager.START_SUCCESS;
import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;

import static com.android.server.am.ActivityManagerDebugConfig.TAG_AM;
import static com.android.server.am.ActivityManagerDebugConfig.TAG_WITH_CLASS_NAME;
import static com.android.server.am.ActivityManagerService.ALLOW_FULL_ONLY;

import android.app.IApplicationThread;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Binder;
import android.os.FactoryTest;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.provider.Settings;
import android.util.Slog;
import android.view.RemoteAnimationAdapter;

import com.android.internal.annotations.VisibleForTesting;
import com.android.server.am.ActivityStackSupervisor.PendingActivityLaunch;
import com.android.server.am.ActivityStarter.DefaultFactory;
import com.android.server.am.ActivityStarter.Factory;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

/**
 * Controller for delegating activity launches.
 *
 * This class' main objective is to take external activity start requests and prepare them into
 * a series of discrete activity launches that can be handled by an {@link ActivityStarter}. It is
 * also responsible for handling logic that happens around an activity launch, but doesn't
 * necessarily influence the activity start. Examples include power hint management, processing
 * through the pending activity list, and recording home activity launches.
 */
public class ActivityStartController {
    private static final String TAG = TAG_WITH_CLASS_NAME ? "ActivityStartController" : TAG_AM;

    private static final int DO_PENDING_ACTIVITY_LAUNCHES_MSG = 1;

    private final ActivityManagerService mService;
    private final ActivityStackSupervisor mSupervisor;

    /** Last home activity record we attempted to start. */
    private ActivityRecord mLastHomeActivityStartRecord;

    /** Temporary array to capture start activity results */
    private ActivityRecord[] tmpOutRecord = new ActivityRecord[1];

    /**The result of the last home activity we attempted to start. */
    private int mLastHomeActivityStartResult;

    /** A list of activities that are waiting to launch. */
    private final ArrayList<ActivityStackSupervisor.PendingActivityLaunch>
            mPendingActivityLaunches = new ArrayList<>();

    private final Factory mFactory;

    private final Handler mHandler;

    private final PendingRemoteAnimationRegistry mPendingRemoteAnimationRegistry;

    private final class StartHandler extends Handler {
        public StartHandler(Looper looper) {
            super(looper, null, true);
        }

        @Override
        public void handleMessage(Message msg) {
            switch(msg.what) {
                case DO_PENDING_ACTIVITY_LAUNCHES_MSG:
                    synchronized (mService) {
                        doPendingActivityLaunches(true);
                    }
                    break;
            }
        }
    }

    /**
     * TODO(b/64750076): Capture information necessary for dump and
     * {@link #postStartActivityProcessingForLastStarter} rather than keeping the entire object
     * around
     */
    private ActivityStarter mLastStarter;

    ActivityStartController(ActivityManagerService service) {
        this(service, service.mStackSupervisor,
                new DefaultFactory(service, service.mStackSupervisor,
                    new ActivityStartInterceptor(service, service.mStackSupervisor)));
    }

    @VisibleForTesting
    ActivityStartController(ActivityManagerService service, ActivityStackSupervisor supervisor,
            Factory factory) {
        mService = service;
        mSupervisor = supervisor;
        mHandler = new StartHandler(mService.mHandlerThread.getLooper());
        mFactory = factory;
        mFactory.setController(this);
        mPendingRemoteAnimationRegistry = new PendingRemoteAnimationRegistry(service,
                service.mHandler);
    }

    /**
     * @return A starter to configure and execute starting an activity. It is valid until after
     *         {@link ActivityStarter#execute} is invoked. At that point, the starter should be
     *         considered invalid and no longer modified or used.
     */
    ActivityStarter obtainStarter(Intent intent, String reason) {
        return mFactory.obtain().setIntent(intent).setReason(reason);
    }

    void onExecutionComplete(ActivityStarter starter) {
        if (mLastStarter == null) {
            mLastStarter = mFactory.obtain();
        }

        mLastStarter.set(starter);
        mFactory.recycle(starter);
    }

    /**
     * TODO(b/64750076): usage of this doesn't seem right. We're making decisions based off the
     * last starter for an arbitrary task record. Re-evaluate whether we can remove.
     */
    void postStartActivityProcessingForLastStarter(ActivityRecord r, int result,
            ActivityStack targetStack) {
        if (mLastStarter == null) {
            return;
        }

        mLastStarter.postStartActivityProcessing(r, result, targetStack);
    }

    void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason) {
        mSupervisor.moveHomeStackTaskToTop(reason);

        mLastHomeActivityStartResult = obtainStarter(intent, "startHomeActivity: " + reason)
                .setOutActivity(tmpOutRecord)
                .setCallingUid(0)
                .setActivityInfo(aInfo)
                .execute();
        mLastHomeActivityStartRecord = tmpOutRecord[0];
        if (mSupervisor.inResumeTopActivity) {
            // If we are in resume section already, home activity will be initialized, but not
            // resumed (to avoid recursive resume) and will stay that way until something pokes it
            // again. We need to schedule another resume.
            mSupervisor.scheduleResumeTopActivities();
        }
    }

    /**
     * Starts the "new version setup screen" if appropriate.
     */
    void startSetupActivity() {
        // Only do this once per boot.
        if (mService.getCheckedForSetup()) {
            return;
        }

        // We will show this screen if the current one is a different
        // version than the last one shown, and we are not running in
        // low-level factory test mode.
        final ContentResolver resolver = mService.mContext.getContentResolver();
        if (mService.mFactoryTest != FactoryTest.FACTORY_TEST_LOW_LEVEL &&
                Settings.Global.getInt(resolver,
                        Settings.Global.DEVICE_PROVISIONED, 0) != 0) {
            mService.setCheckedForSetup(true);

            // See if we should be showing the platform update setup UI.
            final Intent intent = new Intent(Intent.ACTION_UPGRADE_SETUP);
            final List<ResolveInfo> ris =
                    mService.mContext.getPackageManager().queryIntentActivities(intent,
                            PackageManager.MATCH_SYSTEM_ONLY | PackageManager.GET_META_DATA
                                    | ActivityManagerService.STOCK_PM_FLAGS);
            if (!ris.isEmpty()) {
                final ResolveInfo ri = ris.get(0);
                String vers = ri.activityInfo.metaData != null
                        ? ri.activityInfo.metaData.getString(Intent.METADATA_SETUP_VERSION)
                        : null;
                if (vers == null && ri.activityInfo.applicationInfo.metaData != null) {
                    vers = ri.activityInfo.applicationInfo.metaData.getString(
                            Intent.METADATA_SETUP_VERSION);
                }
                String lastVers = Settings.Secure.getString(
                        resolver, Settings.Secure.LAST_SETUP_SHOWN);
                if (vers != null && !vers.equals(lastVers)) {
                    intent.setFlags(FLAG_ACTIVITY_NEW_TASK);
                    intent.setComponent(new ComponentName(
                            ri.activityInfo.packageName, ri.activityInfo.name));
                    obtainStarter(intent, "startSetupActivity")
                            .setCallingUid(0)
                            .setActivityInfo(ri.activityInfo)
                            .execute();
                }
            }
        }
    }

    /**
     * If {@code validateIncomingUser} is true, check {@code targetUserId} against the real calling
     * user ID inferred from {@code realCallingUid}, then return the resolved user-id, taking into
     * account "current user", etc.
     *
     * If {@code validateIncomingUser} is false, it skips the above check, but instead
     * ensures {@code targetUserId} is a real user ID and not a special user ID such as
     * {@link android.os.UserHandle#USER_ALL}, etc.
     */
    private int checkTargetUser(int targetUserId, boolean validateIncomingUser,
            int realCallingPid, int realCallingUid, String reason) {
        if (validateIncomingUser) {
            return mService.mUserController.handleIncomingUser(realCallingPid, realCallingUid,
                    targetUserId, false, ALLOW_FULL_ONLY, reason, null);
        } else {
            mService.mUserController.ensureNotSpecialUser(targetUserId);
            return targetUserId;
        }
    }

    final int startActivityInPackage(int uid, int realCallingPid, int realCallingUid,
            String callingPackage, Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags, SafeActivityOptions options,
            int userId, TaskRecord inTask, String reason, boolean validateIncomingUser) {

        userId = checkTargetUser(userId, validateIncomingUser, realCallingPid, realCallingUid,
                reason);

        // TODO: Switch to user app stacks here.
        return obtainStarter(intent, reason)
                .setCallingUid(uid)
                .setRealCallingPid(realCallingPid)
                .setRealCallingUid(realCallingUid)
                .setCallingPackage(callingPackage)
                .setResolvedType(resolvedType)
                .setResultTo(resultTo)
                .setResultWho(resultWho)
                .setRequestCode(requestCode)
                .setStartFlags(startFlags)
                .setActivityOptions(options)
                .setMayWait(userId)
                .setInTask(inTask)
                .execute();
    }

    /**
     * Start intents as a package.
     *
     * @param uid Make a call as if this UID did.
     * @param callingPackage Make a call as if this package did.
     * @param intents Intents to start.
     * @param userId Start the intents on this user.
     * @param validateIncomingUser Set true to skip checking {@code userId} with the calling UID.
     */
    final int startActivitiesInPackage(int uid, String callingPackage, Intent[] intents,
            String[] resolvedTypes, IBinder resultTo, SafeActivityOptions options, int userId,
            boolean validateIncomingUser) {

        final String reason = "startActivityInPackage";

        userId = checkTargetUser(userId, validateIncomingUser, Binder.getCallingPid(),
                Binder.getCallingUid(), reason);

        // TODO: Switch to user app stacks here.
        return startActivities(null, uid, callingPackage, intents, resolvedTypes, resultTo, options,
                userId, reason);
    }

    int startActivities(IApplicationThread caller, int callingUid, String callingPackage,
            Intent[] intents, String[] resolvedTypes, IBinder resultTo, SafeActivityOptions options,
            int userId, String reason) {
        if (intents == null) {
            throw new NullPointerException("intents is null");
        }
        if (resolvedTypes == null) {
            throw new NullPointerException("resolvedTypes is null");
        }
        if (intents.length != resolvedTypes.length) {
            throw new IllegalArgumentException("intents are length different than resolvedTypes");
        }

        final int realCallingPid = Binder.getCallingPid();
        final int realCallingUid = Binder.getCallingUid();

        int callingPid;
        if (callingUid >= 0) {
            callingPid = -1;
        } else if (caller == null) {
            callingPid = realCallingPid;
            callingUid = realCallingUid;
        } else {
            callingPid = callingUid = -1;
        }
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mService) {
                ActivityRecord[] outActivity = new ActivityRecord[1];
                for (int i=0; i < intents.length; i++) {
                    Intent intent = intents[i];
                    if (intent == null) {
                        continue;
                    }

                    // Refuse possible leaked file descriptors
                    if (intent != null && intent.hasFileDescriptors()) {
                        throw new IllegalArgumentException("File descriptors passed in Intent");
                    }

                    boolean componentSpecified = intent.getComponent() != null;

                    // Don't modify the client's object!
                    intent = new Intent(intent);

                    // Collect information about the target of the Intent.
                    ActivityInfo aInfo = mSupervisor.resolveActivity(intent, resolvedTypes[i], 0,
                            null, userId, realCallingUid);
                    // TODO: New, check if this is correct
                    aInfo = mService.getActivityInfoForUser(aInfo, userId);

                    if (aInfo != null &&
                            (aInfo.applicationInfo.privateFlags
                                    & ApplicationInfo.PRIVATE_FLAG_CANT_SAVE_STATE)  != 0) {
                        throw new IllegalArgumentException(
                                "FLAG_CANT_SAVE_STATE not supported here");
                    }

                    final boolean top = i == intents.length - 1;
                    final SafeActivityOptions checkedOptions = top
                            ? options
                            : null;
                    final int res = obtainStarter(intent, reason)
                            .setCaller(caller)
                            .setResolvedType(resolvedTypes[i])
                            .setActivityInfo(aInfo)
                            .setResultTo(resultTo)
                            .setRequestCode(-1)
                            .setCallingPid(callingPid)
                            .setCallingUid(callingUid)
                            .setCallingPackage(callingPackage)
                            .setRealCallingPid(realCallingPid)
                            .setRealCallingUid(realCallingUid)
                            .setActivityOptions(checkedOptions)
                            .setComponentSpecified(componentSpecified)
                            .setOutActivity(outActivity)

                            // Top activity decides on animation being run, so we allow only for the
                            // top one as otherwise an activity below might consume it.
                            .setAllowPendingRemoteAnimationRegistryLookup(top /* allowLookup*/)
                            .execute();

                    if (res < 0) {
                        return res;
                    }

                    resultTo = outActivity[0] != null ? outActivity[0].appToken : null;
                }
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }

        return START_SUCCESS;
    }

    void schedulePendingActivityLaunches(long delayMs) {
        mHandler.removeMessages(DO_PENDING_ACTIVITY_LAUNCHES_MSG);
        Message msg = mHandler.obtainMessage(DO_PENDING_ACTIVITY_LAUNCHES_MSG);
        mHandler.sendMessageDelayed(msg, delayMs);
    }

    void doPendingActivityLaunches(boolean doResume) {
        while (!mPendingActivityLaunches.isEmpty()) {
            final PendingActivityLaunch pal = mPendingActivityLaunches.remove(0);
            final boolean resume = doResume && mPendingActivityLaunches.isEmpty();
            final ActivityStarter starter = obtainStarter(null /* intent */,
                    "pendingActivityLaunch");
            try {
                starter.startResolvedActivity(pal.r, pal.sourceRecord, null, null, pal.startFlags,
                        resume, null, null, null /* outRecords */);
            } catch (Exception e) {
                Slog.e(TAG, "Exception during pending activity launch pal=" + pal, e);
                pal.sendErrorResult(e.getMessage());
            }
        }
    }

    void addPendingActivityLaunch(PendingActivityLaunch launch) {
        mPendingActivityLaunches.add(launch);
    }

    boolean clearPendingActivityLaunches(String packageName) {
        final int pendingLaunches = mPendingActivityLaunches.size();

        for (int palNdx = pendingLaunches - 1; palNdx >= 0; --palNdx) {
            final PendingActivityLaunch pal = mPendingActivityLaunches.get(palNdx);
            final ActivityRecord r = pal.r;
            if (r != null && r.packageName.equals(packageName)) {
                mPendingActivityLaunches.remove(palNdx);
            }
        }
        return mPendingActivityLaunches.size() < pendingLaunches;
    }

    void registerRemoteAnimationForNextActivityStart(String packageName,
            RemoteAnimationAdapter adapter) {
        mPendingRemoteAnimationRegistry.addPendingAnimation(packageName, adapter);
    }

    PendingRemoteAnimationRegistry getPendingRemoteAnimationRegistry() {
        return mPendingRemoteAnimationRegistry;
    }

    void dump(PrintWriter pw, String prefix, String dumpPackage) {
        pw.print(prefix);
        pw.print("mLastHomeActivityStartResult=");
        pw.println(mLastHomeActivityStartResult);

        if (mLastHomeActivityStartRecord != null) {
            pw.print(prefix);
            pw.println("mLastHomeActivityStartRecord:");
            mLastHomeActivityStartRecord.dump(pw, prefix + "  ");
        }

        final boolean dumpPackagePresent = dumpPackage != null;

        if (mLastStarter != null) {
            final boolean dump = !dumpPackagePresent
                    || mLastStarter.relatedToPackage(dumpPackage)
                    || (mLastHomeActivityStartRecord != null
                            && dumpPackage.equals(mLastHomeActivityStartRecord.packageName));

            if (dump) {
                pw.print(prefix);
                mLastStarter.dump(pw, prefix + "  ");

                if (dumpPackagePresent) {
                    return;
                }
            }
        }

        if (dumpPackagePresent) {
            pw.print(prefix);
            pw.println("(nothing)");
        }
    }
}