/*
 * Copyright (C) 2020 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.appsearch;

import static android.app.appsearch.AppSearchResult.throwableToFailedResult;

import android.annotation.NonNull;
import android.app.appsearch.AppSearchBatchResult;
import android.app.appsearch.AppSearchResult;
import android.app.appsearch.AppSearchSchema;
import android.app.appsearch.GenericDocument;
import android.app.appsearch.IAppSearchBatchResultCallback;
import android.app.appsearch.IAppSearchManager;
import android.app.appsearch.IAppSearchResultCallback;
import android.app.appsearch.SearchResultPage;
import android.app.appsearch.SearchSpec;
import android.content.Context;
import android.os.Binder;
import android.os.Bundle;
import android.os.ParcelableException;
import android.os.RemoteException;
import android.os.UserHandle;
import android.util.Log;

import com.android.internal.util.Preconditions;
import com.android.server.SystemService;
import com.android.server.appsearch.external.localstorage.AppSearchImpl;

import java.util.ArrayList;
import java.util.List;

/**
 * TODO(b/142567528): add comments when implement this class
 */
public class AppSearchManagerService extends SystemService {
    private static final String TAG = "AppSearchManagerService";
    private static final char CALLING_NAME_DATABASE_DELIMITER = '$';

    public AppSearchManagerService(Context context) {
        super(context);
    }

    @Override
    public void onStart() {
        publishBinderService(Context.APP_SEARCH_SERVICE, new Stub());
    }

    private class Stub extends IAppSearchManager.Stub {
        @Override
        public void setSchema(
                @NonNull String databaseName,
                @NonNull List<Bundle> schemaBundles,
                @NonNull List<String> schemasNotPlatformSurfaceable,
                boolean forceOverride,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(schemaBundles);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                List<AppSearchSchema> schemas = new ArrayList<>(schemaBundles.size());
                for (int i = 0; i < schemaBundles.size(); i++) {
                    schemas.add(new AppSearchSchema(schemaBundles.get(i)));
                }
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                impl.setSchema(databaseName, schemas, schemasNotPlatformSurfaceable, forceOverride);
                invokeCallbackOnResult(callback,
                        AppSearchResult.newSuccessfulResult(/*result=*/ null));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void getSchema(
                @NonNull String databaseName,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                List<AppSearchSchema> schemas = impl.getSchema(databaseName);
                List<Bundle> schemaBundles = new ArrayList<>(schemas.size());
                for (int i = 0; i < schemas.size(); i++) {
                    schemaBundles.add(schemas.get(i).getBundle());
                }
                invokeCallbackOnResult(callback,
                        AppSearchResult.newSuccessfulResult(schemaBundles));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void putDocuments(
                @NonNull String databaseName,
                @NonNull List<Bundle> documentBundles,
                @NonNull IAppSearchBatchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(documentBundles);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchBatchResult.Builder<String, Void> resultBuilder =
                        new AppSearchBatchResult.Builder<>();
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                for (int i = 0; i < documentBundles.size(); i++) {
                    GenericDocument document = new GenericDocument(documentBundles.get(i));
                    try {
                        // TODO(b/173451571): reduce burden of binder thread by enqueue request onto
                        // a separate thread.
                        impl.putDocument(databaseName, document);
                        resultBuilder.setSuccess(document.getUri(), /*result=*/ null);
                    } catch (Throwable t) {
                        resultBuilder.setResult(document.getUri(), throwableToFailedResult(t));
                    }
                }
                invokeCallbackOnResult(callback, resultBuilder.build());
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void getDocuments(@NonNull String databaseName, @NonNull String namespace,
                @NonNull List<String> uris,
                @NonNull IAppSearchBatchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(namespace);
            Preconditions.checkNotNull(uris);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchBatchResult.Builder<String, Bundle> resultBuilder =
                        new AppSearchBatchResult.Builder<>();
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                for (int i = 0; i < uris.size(); i++) {
                    String uri = uris.get(i);
                    try {
                        GenericDocument document = impl.getDocument(databaseName, namespace, uri);
                        resultBuilder.setSuccess(uri, document.getBundle());
                    } catch (Throwable t) {
                        resultBuilder.setResult(uri, throwableToFailedResult(t));
                    }
                }
                invokeCallbackOnResult(callback, resultBuilder.build());
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        // TODO(sidchhabra): Do this in a threadpool.
        @Override
        public void query(
                @NonNull String databaseName,
                @NonNull String queryExpression,
                @NonNull Bundle searchSpecBundle,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(queryExpression);
            Preconditions.checkNotNull(searchSpecBundle);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                SearchResultPage searchResultPage = impl.query(
                        databaseName,
                        queryExpression,
                        new SearchSpec(searchSpecBundle));
                invokeCallbackOnResult(callback,
                        AppSearchResult.newSuccessfulResult(searchResultPage.getBundle()));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        public void globalQuery(
                @NonNull String queryExpression,
                @NonNull Bundle searchSpecBundle,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(queryExpression);
            Preconditions.checkNotNull(searchSpecBundle);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                SearchResultPage searchResultPage = impl.globalQuery(
                        queryExpression,
                        new SearchSpec(searchSpecBundle));
                invokeCallbackOnResult(callback,
                        AppSearchResult.newSuccessfulResult(searchResultPage.getBundle()));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void getNextPage(long nextPageToken,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            // TODO(b/162450968) check nextPageToken is being advanced by the same uid as originally
            // opened it
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                SearchResultPage searchResultPage = impl.getNextPage(nextPageToken);
                invokeCallbackOnResult(callback,
                        AppSearchResult.newSuccessfulResult(searchResultPage.getBundle()));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void invalidateNextPageToken(long nextPageToken) {
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                impl.invalidateNextPageToken(nextPageToken);
            } catch (Throwable t) {
                Log.d(TAG, "Unable to invalidate the query page token", t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void removeByUri(@NonNull String databaseName, @NonNull String namespace,
                @NonNull List<String> uris,
                @NonNull IAppSearchBatchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(uris);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            AppSearchBatchResult.Builder<String, Void> resultBuilder =
                    new AppSearchBatchResult.Builder<>();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                for (int i = 0; i < uris.size(); i++) {
                    String uri = uris.get(i);
                    try {
                        impl.remove(databaseName, namespace, uri);
                        resultBuilder.setSuccess(uri, /*result= */null);
                    } catch (Throwable t) {
                        resultBuilder.setResult(uri, throwableToFailedResult(t));
                    }
                }
                invokeCallbackOnResult(callback, resultBuilder.build());
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void removeByQuery(
                @NonNull String databaseName,
                @NonNull String queryExpression,
                @NonNull Bundle searchSpecBundle,
                @NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(databaseName);
            Preconditions.checkNotNull(queryExpression);
            Preconditions.checkNotNull(searchSpecBundle);
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                AppSearchImpl impl = ImplInstanceManager.getInstance(getContext(), callingUserId);
                databaseName = rewriteDatabaseNameWithUid(databaseName, callingUid);
                impl.removeByQuery(databaseName, queryExpression,
                        new SearchSpec(searchSpecBundle));
                invokeCallbackOnResult(callback, AppSearchResult.newSuccessfulResult(null));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        @Override
        public void initialize(@NonNull IAppSearchResultCallback callback) {
            Preconditions.checkNotNull(callback);
            int callingUid = Binder.getCallingUidOrThrow();
            int callingUserId = UserHandle.getUserId(callingUid);
            final long callingIdentity = Binder.clearCallingIdentity();
            try {
                ImplInstanceManager.getInstance(getContext(), callingUserId);
                invokeCallbackOnResult(callback, AppSearchResult.newSuccessfulResult(null));
            } catch (Throwable t) {
                invokeCallbackOnError(callback, t);
            } finally {
                Binder.restoreCallingIdentity(callingIdentity);
            }
        }

        /**
         * Rewrites the database name by adding a prefix of unique name for the given uid.
         *
         * <p>The current implementation returns the package name of the app with this uid in a
         * format like {@code com.example.package} or {@code com.example.sharedname:5678}.
         */
        @NonNull
        private String rewriteDatabaseNameWithUid(String databaseName, int callingUid) {
            // For regular apps, this call will return the package name. If callingUid is an
            // android:sharedUserId, this value may be another type of name and have a :uid suffix.
            String callingUidName = getContext().getPackageManager().getNameForUid(callingUid);
            if (callingUidName == null) {
                // Not sure how this is possible --- maybe app was uninstalled?
                throw new IllegalStateException(
                        "Failed to look up package name for uid " + callingUid);
            }
            return callingUidName + CALLING_NAME_DATABASE_DELIMITER + databaseName;
        }

        /**  Invokes the {@link IAppSearchResultCallback} with the result. */
        private void invokeCallbackOnResult(IAppSearchResultCallback callback,
                AppSearchResult result) {
            try {
                callback.onResult(result);
            } catch (RemoteException e) {
                Log.d(TAG, "Unable to send result to the callback", e);
            }
        }

        /**  Invokes the {@link IAppSearchBatchResultCallback} with the result. */
        private void invokeCallbackOnResult(IAppSearchBatchResultCallback callback,
                AppSearchBatchResult result) {
            try {
                callback.onResult(result);
            } catch (RemoteException e) {
                Log.d(TAG, "Unable to send result to the callback", e);
            }
        }

        /**
         *  Invokes the {@link IAppSearchResultCallback} with an throwable.
         *
         *  <p>The throwable is convert to a {@link AppSearchResult};
         */
        private void invokeCallbackOnError(IAppSearchResultCallback callback, Throwable throwable) {
            try {
                callback.onResult(throwableToFailedResult(throwable));
            } catch (RemoteException e) {
                Log.d(TAG, "Unable to send result to the callback", e);
            }
        }

        /**
         *  Invokes the {@link IAppSearchBatchResultCallback} with an throwable.
         *
         * <p>The throwable is converted to {@link ParcelableException}.
         */
        private void invokeCallbackOnError(IAppSearchBatchResultCallback callback,
                Throwable throwable) {
            try {
                callback.onSystemError(new ParcelableException(throwable));
            } catch (RemoteException e) {
                Log.d(TAG, "Unable to send error to the callback", e);
            }
        }
    }
}