firestore.dart

// Copyright 2022 Google LLC
//
// 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.

// ignore_for_file: non_constant_identifier_names, avoid_print

import'dart:math';

import'package:cloud_firestore/cloud_firestore.dart';
import'package:firebase_snippets_app/model/firestore_add_data_custom_objects_snippet.dart';
import'package:firebase_snippets_app/model/restaurant.dart';
import'package:firebase_snippets_app/snippets/snippet_base.dart';

classFirestoreSnippetsextendsDocSnippet {
@override
finalFirebaseFirestore db;

FirestoreSnippets(this.db);

@override
voidrunAll() {
getStarted_addData();
getStarted_addData2();
getStarted_readData();
dataModel_references();
dataModel_subCollections();
 }

voidgetStarted_addData() async {
// [START get_started_add_data_1]
// Create a new user with a first and last name
final user =<String, dynamic>{
"first":"Ada",
"last":"Lovelace",
"born":1815
 };

// Add a new document with a generated ID
 db.collection("users").add(user).then((DocumentReference doc) =>
print('DocumentSnapshot added with ID: ${doc.id}'));
// [END get_started_add_data_1]
 }

voidgetStarted_addData2() async {
// [START get_started_add_data_2]
// Create a new user with a first and last name
final user =<String, dynamic>{
"first":"Alan",
"middle":"Mathison",
"last":"Turing",
"born":1912
 };

// Add a new document with a generated ID
 db.collection("users").add(user).then((DocumentReference doc) =>
print('DocumentSnapshot added with ID: ${doc.id}'));
// [END get_started_add_data_2]
 }

voidgetStarted_readData() async {
// [START get_started_read_data]
await db.collection("users").get().then((event) {
for (var doc in event.docs) {
print("${doc.id} => ${doc.data()}");
 }
 });
// [END get_started_read_data]
 }

voiddataModel_references() {
// [START data_model_references]
final alovelaceDocumentRef = db.collection("users").doc("alovelace");
// [END data_model_references]

// [START data_model_references2]
final usersCollectionRef = db.collection("users");
// [END data_model_references2]

// [START data_model_references3]
final aLovelaceDocRef = db.doc("users/alovelace");
// [END data_model_references3]
 }

voiddataModel_subCollections() {
// [START data_model_sub_collections]
final messageRef = db
 .collection("rooms")
 .doc("roomA")
 .collection("messages")
 .doc("message1");
// [END data_model_sub_collections]
 }

voiddataBundles_loadingClientBundles() {
// [START data_bundles_loading_client_bundles]
// TODO - currently in scratch file
// [END data_bundles_loading_client_bundles]
 }

voidaddData_setADocument() {
// [START add_data_set_document_1]
final city =<String, String>{
"name":"Los Angeles",
"state":"CA",
"country":"USA"
 };

 db
 .collection("cities")
 .doc("LA")
 .set(city)
 .onError((e, _) =>print("Error writing document: $e"));
// [END add_data_set_document_1]
 }

voidaddData_setADocument2() {
// [START add_data_set_document_2]
// Update one field, creating the document if it does not already exist.
final data = {"capital":true};

 db.collection("cities").doc("BJ").set(data, SetOptions(merge:true));
// [END add_data_set_document_2]
 }

voidaddData_dataTypes() {
// [START add_data_data_types]
final docData = {
"stringExample":"Hello world!",
"booleanExample":true,
"numberExample":3.14159265,
"dateExample":Timestamp.now(),
"listExample": [1, 2, 3],
"nullExample":null
 };

final nestedData = {
"a":5,
"b":true,
 };

 docData["objectExample"] = nestedData;

 db
 .collection("data")
 .doc("one")
 .set(docData)
 .onError((e, _) =>print("Error writing document: $e"));
// [END add_data_data_types]
 }

voidaddData_customObjects() {
// [START add_data_custom_objects]
// TODO: is this supported in Dart yet?
// in the current docs, it isn't supported for about half the languages
// if it is, it will look like the code in [./custom_snippets/firestore_add_data_custom_objects_snippet.dart]

// This is how it's done in some other languages, but this doesn't seem like it should be included,
// because it isn't really a Firebase feature. I'm just converting Objects into a Map before submitting it.
 }

voidaddData_customObjects2() {
// [START add_data_custom_objects2]
// TODO: is this supported in Dart yet?
// in the current docs, it isn't supported for about half the languages
// See note above before including this in the docs.

final city =City(
 name:"Los Angeles",
 state:"CA",
 country:"USA",
 capital:false,
 population:5000000,
 regions: ["west_coast", "socal"],
 );

 db.collection("cities").doc("LA").set(city.toFirestore());
// [END add_data_custom_objects2]
 }

voidaddData_addADocument() {
// [START add_data_add_a_document]
 db.collection("cities").doc("new-city-id").set({"name":"Chicago"});
// [END add_data_add_a_document]
 }

voidaddData_addADocument2() {
// [START add_data_add_a_document_2]
// Add a new document with a generated id.
final data = {"name":"Tokyo", "country":"Japan"};

 db.collection("cities").add(data).then((documentSnapshot) =>
print("Added Data with ID: ${documentSnapshot.id}"));
// [END add_data_add_a_document_2]
 }

voidaddData_addADocument3() {
// [START add_data_add_a_document_3]
// Add a new document with a generated id.
final data =<String, dynamic>{};

final newCityRef = db.collection("cities").doc();

// Later...
 newCityRef.set(data);

// [END add_data_add_a_document_3]
 }

voidaddData_updateADocument() {
// [START add_data_update_a_document]
final washingtonRef = db.collection("cites").doc("DC");
 washingtonRef.update({"capital":true}).then(
 (value) =>print("DocumentSnapshot successfully updated!"),
 onError: (e) =>print("Error updating document $e"));
// [END add_data_update_a_document]
 }

voidaddData_serverTimestamp() {
// [START add_data_server_timestamp]
final docRef = db.collection("objects").doc("some-id");
final updates =<String, dynamic>{
"timestamp":FieldValue.serverTimestamp(),
 };

 docRef.update(updates).then(
 (value) =>print("DocumentSnapshot successfully updated!"),
 onError: (e) =>print("Error updating document $e"));
// [END add_data_server_timestamp]
 }

voidaddData_updateFieldsInNestedObjects() {
// [START add_data_update_fields_in_nested_objects]
// Assume the document contains:
// {
// name: "Frank",
// favorites: { food: "Pizza", color: "Blue", subject: "recess" }
// age: 12
// }
 db
 .collection("users")
 .doc("frank")
 .update({"age":13, "favorites.color":"Red"});
// [END add_data_update_fields_in_nested_objects]
 }

voidaddData_updateElementsInArray() {
// [START add_data_update_elements_in_array]
final washingtonRef = db.collection("cities").doc("DC");

// Atomically add a new region to the "regions" array field.
 washingtonRef.update({
"regions":FieldValue.arrayUnion(["greater_virginia"]),
 });

// Atomically remove a region from the "regions" array field.
 washingtonRef.update({
"regions":FieldValue.arrayRemove(["east_coast"]),
 });
// [END add_data_update_elements_in_array]
 }

voidaddData_incrementANumericValue() {
// [START add_data_increment_a_numeric_value]
var washingtonRef = db.collection('cities').doc('DC');

// Atomically increment the population of the city by 50.
 washingtonRef.update(
 {"population":FieldValue.increment(50)},
 );
// [END add_data_increment_a_numeric_value]
 }

voidtransactions_updatingDataWithTransactions() {
// [START transactions_updating_data_with_transactions]
final sfDocRef = db.collection("cities").doc("SF");
 db.runTransaction((transaction) async {
final snapshot =await transaction.get(sfDocRef);
// Note: this could be done without a transaction
// by updating the population using FieldValue.increment()
final newPopulation = snapshot.get("population") +1;
 transaction.update(sfDocRef, {"population": newPopulation});
 }).then(
 (value) =>print("DocumentSnapshot successfully updated!"),
 onError: (e) =>print("Error updating document $e"),
 );
// [END transactions_updating_data_with_transactions]
 }

voidtransactions_passingInformationOutOfTransactions() {
// TODO: ewindmill@ - either the above example (using asnyc) or this example
// using (then) is "more correct". Figure out which one.
// [START transactions_passing_information_out_of_transactions]
final sfDocRef = db.collection("cities").doc("SF");
 db.runTransaction((transaction) {
return transaction.get(sfDocRef).then((sfDoc) {
final newPopulation = sfDoc.get("population") +1;
 transaction.update(sfDocRef, {"population": newPopulation});
return newPopulation;
 });
 }).then(
 (newPopulation) =>print("Population increased to $newPopulation"),
 onError: (e) =>print("Error updating document $e"),
 );
// [END transactions_passing_information_out_of_transactions]
 }

voidtransactions_batchedWrites() {
// [START transactions_batched_writes]
// Get a new write batch
final batch = db.batch();

// Set the value of 'NYC'
var nycRef = db.collection("cities").doc("NYC");
 batch.set(nycRef, {"name":"New York City"});

// Update the population of 'SF'
var sfRef = db.collection("cities").doc("SF");
 batch.update(sfRef, {"population":1000000});

// Delete the city 'LA'
var laRef = db.collection("cities").doc("LA");
 batch.delete(laRef);

// Commit the batch
 batch.commit().then((_) {
// ...
 });
// [END transactions_batched_writes]
 }

voiddeleteData_deleteDocs() {
// [START delete_data_delete_docs]
 db.collection("cities").doc("DC").delete().then(
 (doc) =>print("Document deleted"),
 onError: (e) =>print("Error updating document $e"),
 );
// [END delete_data_delete_docs]
 }

voiddeleteData_deleteFields() {
// [START delete_data_delete_fields]
final docRef = db.collection("cities").doc("BJ");

// Remove the 'capital' field from the document
final updates =<String, dynamic>{
"capital":FieldValue.delete(),
 };

 docRef.update(updates);
// [END delete_data_delete_fields]
 }

voidgetDataOnce_exampleData() {
// [START get_data_once_example_data]
final cities = db.collection("cities");
final data1 =<String, dynamic>{
"name":"San Francisco",
"state":"CA",
"country":"USA",
"capital":false,
"population":860000,
"regions": ["west_coast", "norcal"]
 };
 cities.doc("SF").set(data1);

final data2 =<String, dynamic>{
"name":"Los Angeles",
"state":"CA",
"country":"USA",
"capital":false,
"population":3900000,
"regions": ["west_coast", "socal"],
 };
 cities.doc("LA").set(data2);

final data3 =<String, dynamic>{
"name":"Washington D.C.",
"state":null,
"country":"USA",
"capital":true,
"population":680000,
"regions": ["east_coast"]
 };
 cities.doc("DC").set(data3);

final data4 =<String, dynamic>{
"name":"Tokyo",
"state":null,
"country":"Japan",
"capital":true,
"population":9000000,
"regions": ["kanto", "honshu"]
 };
 cities.doc("TOK").set(data4);

final data5 =<String, dynamic>{
"name":"Beijing",
"state":null,
"country":"China",
"capital":true,
"population":21500000,
"regions": ["jingjinji", "hebei"],
 };
 cities.doc("BJ").set(data5);
// [END get_data_once_example_data]
 }

voidgetDataOnce_getADocument() {
// [START get_data_once_get_a_document]
final docRef = db.collection("cities").doc("SF");
 docRef.get().then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END get_data_once_get_a_document]
 }

voidgetDataOnce_sourceOptions() {
// [START get_data_once_source_options]
final docRef = db.collection("cities").doc("SF");

// Source can be CACHE, SERVER, or DEFAULT.
const source =Source.cache;

 docRef.get(constGetOptions(source: source)).then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END get_data_once_source_options]
 }

voidgetDataOnce_customObjects() {
// TODO: should this be included?
// This isn't really specific to Firestore, it's just serdes
// [START get_data_once_custom_objects]
final docRef = db.collection("cities").doc("BJ");
 docRef.get().then((documentSnapshot) {
final data = documentSnapshot.data() asMap<String, dynamic>;
final city =City(
 name: data['name'],
 );
 });
// [END get_data_once_custom_objects]
 }

voidgetDataOnce_multipleDocumentsFromACollection() {
// [START get_data_once_multiple_documents_from_a_collection]
 db.collection("cities").where("capital", isEqualTo:true).get().then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END get_data_once_multiple_documents_from_a_collection]
 }

voidgetDataOnce_getAllDocumentsInACollection() {
// [START get_data_once_get_all_documents_in_a_collection]
 db.collection("cities").get().then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END get_data_once_get_all_documents_in_a_collection]
 }

voidgetDataOnce_listSubCollections() {
// [START get_data_once_list_sub_collections]
// Not currently available in Dart SDK
// [END get_data_once_list_sub_collections]
 }

voidlistenToRealtimeUpdates_listenForUpdates() {
// [START listen_to_realtime_updates_listen_for_updates]
final docRef = db.collection("cities").doc("SF");
 docRef.snapshots().listen(
 (event) =>print("current data: ${event.data()}"),
 onError: (error) =>print("Listen failed: $error"),
 );

// [END listen_to_realtime_updates_listen_for_updates]
 }

voidlistenToRealtimeUpdates_eventsForLocalChanges() {
// [START listen_to_realtime_updates_events_for_local_changes]
final docRef = db.collection("cities").doc("SF");
 docRef.snapshots().listen(
 (event) {
final source = (event.metadata.hasPendingWrites) ?"Local":"Server";
print("$source data: ${event.data()}");
 },
 onError: (error) =>print("Listen failed: $error"),
 );

// [END listen_to_realtime_updates_events_for_local_changes]
 }

voidlistenToRealtimeUpdates_eventsOnMetadataChanges() {
// [START listen_to_realtime_updates_events_on_metadata_changes]
final docRef = db.collection("cities").doc("SF");
 docRef.snapshots(includeMetadataChanges:true).listen((event) {
// ...
 });
// [END listen_to_realtime_updates_events_on_metadata_changes]
 }

voidlistenToRealtimeUpdates_listToMultipleDocuments() {
// [START listen_to_realtime_updates_list_to_multiple_documents]
 db
 .collection("cities")
 .where("state", isEqualTo:"CA")
 .snapshots()
 .listen((event) {
final cities = [];
for (var doc in event.docs) {
 cities.add(doc.data()["name"]);
 }
print("cities in CA: ${cities.join(", ")}");
 });
// [END listen_to_realtime_updates_list_to_multiple_documents]
 }

voidlistenToRealtimeUpdates_viewUpdatesBetweenChanges() {
// [START listen_to_realtime_updates_view_updates_between_changes]
 db
 .collection("cities")
 .where("state", isEqualTo:"CA")
 .snapshots()
 .listen((event) {
for (var change in event.docChanges) {
switch (change.type) {
caseDocumentChangeType.added:
print("New City: ${change.doc.data()}");
break;
caseDocumentChangeType.modified:
print("Modified City: ${change.doc.data()}");
break;
caseDocumentChangeType.removed:
print("Removed City: ${change.doc.data()}");
break;
 }
 }
 });
// [END listen_to_realtime_updates_view_updates_between_changes]
 }

voidlistenToRealtimeUpdates_detachAListener() {
// [START listen_to_realtime_updates_detach_a_listener]
final collection = db.collection("cities");
final listener = collection.snapshots().listen((event) {
// ...
 });
 listener.cancel();
// [END listen_to_realtime_updates_detach_a_listener]
 }

voidlistenToRealtimeUpdates_handleListenErrors() {
// [START listen_to_realtime_updates_handle_listen_errors]
final docRef = db.collection("cities");
 docRef.snapshots().listen(
 (event) =>print("listener attached"),
 onError: (error) =>print("Listen failed: $error"),
 );
// [END listen_to_realtime_updates_handle_listen_errors]
 }

voidperformSimpleAndCompoundQueries_exampleData() {
// [START perform_simple_and_compound_queries_example_data]
final cities = db.collection("cities");
final data1 =<String, dynamic>{
"name":"San Francisco",
"state":"CA",
"country":"USA",
"capital":false,
"population":860000,
"regions": ["west_coast", "norcal"]
 };
 cities.doc("SF").set(data1);

final data2 =<String, dynamic>{
"name":"Los Angeles",
"state":"CA",
"country":"USA",
"capital":false,
"population":3900000,
"regions": ["west_coast", "socal"],
 };
 cities.doc("LA").set(data2);

final data3 =<String, dynamic>{
"name":"Washington D.C.",
"state":null,
"country":"USA",
"capital":true,
"population":680000,
"regions": ["east_coast"]
 };
 cities.doc("DC").set(data3);

final data4 =<String, dynamic>{
"name":"Tokyo",
"state":null,
"country":"Japan",
"capital":true,
"population":9000000,
"regions": ["kanto", "honshu"]
 };
 cities.doc("TOK").set(data4);

final data5 =<String, dynamic>{
"name":"Beijing",
"state":null,
"country":"China",
"capital":true,
"population":21500000,
"regions": ["jingjinji", "hebei"],
 };
 cities.doc("BJ").set(data5);
// [END perform_simple_and_compound_queries_example_data]
 }

voidperformSimpleAndCompoundQueries_simpleQueries() {
// [START perform_simple_and_compound_queries_simple_queries]
// Create a reference to the cities collection
final citiesRef = db.collection("cities");

// Create a query against the collection.
final query = citiesRef.where("state", isEqualTo:"CA");
// [END perform_simple_and_compound_queries_simple_queries]
 }

voidperformSimpleAndCompoundQueries_simpleQueries2() {
// [START perform_simple_and_compound_queries_simple_queries2]
final capitalcities =
 db.collection("cities").where("capital", isEqualTo:true);
// [END perform_simple_and_compound_queries_simple_queries2]
 }

voidperformSimpleAndCompoundQueries_executeAQuery() {
// [START perform_simple_and_compound_queries_execute_a_query]
 db.collection("cities").where("capital", isEqualTo:true).get().then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END perform_simple_and_compound_queries_execute_a_query]
 }

voidperformSimpleAndCompoundQueries_queryOperators() {
// [START perform_simple_and_compound_queries_query_operators]
final citiesRef = db.collection("cities");
final stateQuery = citiesRef.where("state", isEqualTo:"CA");
final populationQuery = citiesRef.where("population", isLessThan:100000);
final nameQuery = citiesRef.where("name", isEqualTo:"San Francisco");
// [END perform_simple_and_compound_queries_query_operators]
 }

voidperformSimpleAndCompoundQueries_notEqual() {
// [START perform_simple_and_compound_queries_not_equal]
final citiesRef = db.collection("cities");
final notCapitals = citiesRef.where("capital", isNotEqualTo:true);
// [END perform_simple_and_compound_queries_not_equal]
 }

voidperformSimpleAndCompoundQueries_arrayMembership() {
// [START perform_simple_and_compound_queries_array_membership]
final citiesRef = db.collection("cities");
final westCoastcities =
 citiesRef.where("regions", arrayContains:"west_coast");
// [END perform_simple_and_compound_queries_array_membership]
 }

voidperformSimpleAndCompoundQueries_inNotInArrayContainsAny() {
// [START perform_simple_and_compound_queries_in_not_in_array_contains_any]
final citiesRef = db.collection("cities");
final cities = citiesRef.where("regions", whereIn: ["USA", "Japan"]);
// [END perform_simple_and_compound_queries_in_not_in_array_contains_any]
 }

voidperformSimpleAndCompoundQueries_notIn() {
// [START perform_simple_and_compound_queries_not_in]
final citiesRef = db.collection("cities");
final cities = citiesRef.where("regions", whereNotIn: ["USA", "Japan"]);
// [END perform_simple_and_compound_queries_not_in]
 }

voidperformSimpleAndCompoundQueries_arrayContainsAny() {
// [START perform_simple_and_compound_queries_array_contains_any]
final citiesRef = db.collection("cities");
final cities = citiesRef
 .where("regions", arrayContainsAny: ["west_coast", "east_coast"]);
// [END perform_simple_and_compound_queries_array_contains_any]
 }

voidperformSimpleAndCompoundQueries_compoundQueries() {
// [START perform_simple_and_compound_queries_compound_queries]
final citiesRef = db.collection("cities");
 citiesRef
 .where("state", isEqualTo:"CO")
 .where("name", isEqualTo:"Denver");
 citiesRef
 .where("state", isEqualTo:"CA")
 .where("population", isLessThan:1000000);
// [END perform_simple_and_compound_queries_compound_queries]
 }

// TODO: remember to document this naming convention in README
voidperformSimpleAndCompoundQueries_compoundQueries_validRangeFilters() {
// [START perform_simple_and_compound_queries_compound_queries_valid_range_filters]
final citiesRef = db.collection("cities");
 citiesRef
 .where("state", isGreaterThanOrEqualTo:"CA")
 .where("state", isLessThanOrEqualTo:"IN");
 citiesRef
 .where("state", isEqualTo:"CA")
 .where("population", isGreaterThan:1000000);
// [END perform_simple_and_compound_queries_compound_queries_valid_range_filters]
 }

voidperformSimpleAndCompoundQueries_compoundQueries_invalidRangeFilters() {
// [START perform_simple_and_compound_queries_compound_queries_invalid_range_filters]
final citiesRef = db.collection("cities");
 citiesRef
 .where("state", isGreaterThanOrEqualTo:"CA")
 .where("population", isGreaterThan:1000000);
// [END perform_simple_and_compound_queries_compound_queries_invalid_range_filters]
 }

voidperformSimpleAndCompoundQueries_collectionGroups() {
// [START perform_simple_and_compound_queries_collection_groups]
final citiesRef = db.collection("cities");

final ggbData = {"name":"Golden Gate Bridge", "type":"bridge"};
 citiesRef.doc("SF").collection("landmarks").add(ggbData);

final lohData = {"name":"Legion of Honor", "type":"museum"};
 citiesRef.doc("SF").collection("landmarks").add(lohData);

final gpData = {"name":"Griffth Park", "type":"park"};
 citiesRef.doc("LA").collection("landmarks").add(gpData);

final tgData = {"name":"The Getty", "type":"museum"};
 citiesRef.doc("LA").collection("landmarks").add(tgData);

final lmData = {"name":"Lincoln Memorial", "type":"memorial"};
 citiesRef.doc("DC").collection("landmarks").add(lmData);

final nasaData = {
"name":"National Air and Space Museum",
"type":"museum"
 };
 citiesRef.doc("DC").collection("landmarks").add(nasaData);

final upData = {"name":"Ueno Park", "type":"park"};
 citiesRef.doc("TOK").collection("landmarks").add(upData);

final nmData = {
"name":"National Musuem of Nature and Science",
"type":"museum"
 };
 citiesRef.doc("TOK").collection("landmarks").add(nmData);

final jpData = {"name":"Jingshan Park", "type":"park"};
 citiesRef.doc("BJ").collection("landmarks").add(jpData);

final baoData = {"name":"Beijing Ancient Observatory", "type":"musuem"};
 citiesRef.doc("BJ").collection("landmarks").add(baoData);
// [END perform_simple_and_compound_queries_collection_groups]
 }

voidperformSimpleAndCompoundQueries_collectionGroups2() {
// [START perform_simple_and_compound_queries_collection_groups2]
 db
 .collectionGroup("landmarks")
 .where("type", isEqualTo:"museum")
 .get()
 .then(
 (res) =>print("Successfully completed"),
 onError: (e) =>print("Error completing: $e"),
 );
// [END perform_simple_and_compound_queries_collection_groups2]
 }

voidorderAndLimitData_orderAndLimitData() {
// [START order_and_limit_data_order_and_limit_data]
final citiesRef = db.collection("cities");
 citiesRef.orderBy("name").limit(3);
// [END order_and_limit_data_order_and_limit_data]
 }

voidorderAndLimitData_orderAndLimitData2() {
// [START order_and_limit_data_order_and_limit_data2]
final citiesRef = db.collection("cities");
 citiesRef.orderBy("name", descending:true).limit(3);
// [END order_and_limit_data_order_and_limit_data2]
 }

voidorderAndLimitData_orderAndLimitData3() {
// [START order_and_limit_data_order_and_limit_data3]
final citiesRef = db.collection("cities");
 citiesRef.orderBy("state").orderBy("population", descending:true);
// [END order_and_limit_data_order_and_limit_data3]
 }

voidorderAndLimitData_orderAndLimitData4() {
// [START order_and_limit_data_order_and_limit_data4]
final citiesRef = db.collection("cities");
 citiesRef
 .where("population", isGreaterThan:100000)
 .orderBy("population")
 .limit(2);
// [END order_and_limit_data_order_and_limit_data4]
 }

voidorderAndLimitData_limitations_valid() {
// [START order_and_limit_data_limitations_valid]
final citiesRef = db.collection("cities");
 citiesRef.where("population", isGreaterThan:100000).orderBy("population");
// [END order_and_limit_data_limitations_valid]
 }

voidorderAndLimitData_limitations_invalid() {
// [START order_and_limit_data_limitations_invalid]
final citiesRef = db.collection("cities");
 citiesRef.where("population", isGreaterThan:100000).orderBy("country");
// [END order_and_limit_data_limitations_invalid]
 }

voidpaginateData_addASimpleCursor() {
// [START paginate_data_add_a_simple_cursor]
 db.collection("cities").orderBy("population").startAt([1000000]);
// [END paginate_data_add_a_simple_cursor]
 }

voidpaginateData_addASimpleCursor2() {
// [START paginate_data_add_a_simple_cursor2]
 db.collection("cities").orderBy("population").startAt([1000000]);
// [END paginate_data_add_a_simple_cursor2]
 }

voidpaginateData_useADocSnapshotToDefineCursorQuery() {
// [START paginate_data_use_a_doc_snapshot_to_define_cursor_query]
 db.collection("cities").doc("SF").get().then(
 (documentSnapshot) {
final biggerThanSf = db
 .collection("cities")
 .orderBy("population")
 .startAt([documentSnapshot]);
 },
 onError: (e) =>print("Error: $e"),
 );
// [END paginate_data_use_a_doc_snapshot_to_define_cursor_query]
 }

voidpaginateData_paginateAQuery() {
// [START paginate_data_paginate_a_query]
// Construct query for first 25 cities, ordered by population
final first = db.collection("cities").orderBy("population").limit(25);

 first.get().then(
 (documentSnapshots) {
// Get the last visible document
final lastVisible = documentSnapshots.docs[documentSnapshots.size -1];

// Construct a new query starting at this document,
// get the next 25 cities.
final next = db
 .collection("cities")
 .orderBy("population")
 .startAfter([lastVisible]).limit(25);

// Use the query for pagination
// ...
 },
 onError: (e) =>print("Error completing: $e"),
 );
// [END paginate_data_paginate_a_query]
 }

voidpaginateData_setCursorBasedOnMultipleFields() {
// [START paginate_data_set_cursor_based_on_multiple_fields]
// Will return all Springfields
 db
 .collection("cities")
 .orderBy("name")
 .orderBy("state")
 .startAt(["Springfield"]);

// Will return "Springfield, Missouri" and "Springfield, Wisconsin"
 db
 .collection("cities")
 .orderBy("name")
 .orderBy("state")
 .startAt(["Springfield", "Missouri"]);
// [END paginate_data_set_cursor_based_on_multiple_fields]
 }

voidaccessDataOffline_listenToOfflineData() {
// [START access_data_offline_listen_to_offline_data]
 db
 .collection("cities")
 .where("state", isEqualTo:"CA")
 .snapshots(includeMetadataChanges:true)
 .listen((querySnapshot) {
for (var change in querySnapshot.docChanges) {
if (change.type ==DocumentChangeType.added) {
final source =
 (querySnapshot.metadata.isFromCache) ?"local cache":"server";

print("Data fetched from $source}");
 }
 }
 });
// [END access_data_offline_listen_to_offline_data]
 }

voidaccessDataOffline_disableNetwork() {
// [START access_data_offline_disable_network]
 db.disableNetwork().then((_) {
// Do offline things
 });
// [END access_data_offline_disable_network]
 }

voidaccessDataOffline_enableNetwork() {
// [START access_data_offline_enable_network]
 db.disableNetwork().then((_) {
// Do offline things
 });
// [END access_data_offline_enable_network]
 }

voidsolutions_aggregationQueries() {
// [START solutions_aggregation_queries]
 db
 .collection("restaurants")
 .doc("arinell-pizza")
 .collection("ratings")
 .get();
// [END solutions_aggregation_queries]
 }

voidsolutions_aggregationQueries2() {
// [START solutions_aggregation_queries_2]
final arinellDoc = {
'name':'Arinell Pizza',
'avgRating':4.65,
'numRatings':683
 };
// [END solutions_aggregation_queries_2]
 }

voidsolutions_aggregationQueries3() {
// [START solutions_aggregation_queries_3]
voidaddRating(DocumentReference restaurantRef, double rating) async {
// Create reference for new rating, for use inside the transaction
final ratingRef = restaurantRef.collection("ratings").doc();

// In a transaction, add the new rating and update the aggregate totals
return db.runTransaction((transaction) async {
final restaurant =await transaction.get(restaurantRef).then((snap) {
final data = snap.data() asMap<String, dynamic>;
returnRestaurant.fromFirestore(data);
 });

// Compute new number of ratings
final newNumRatings = restaurant.numRatings +1;

// Compute new average rating
final oldRatingTotal = restaurant.avgRating * restaurant.numRatings;
final newAvgRating = (oldRatingTotal + rating) / newNumRatings;

// Set new restaurant info
 restaurant.numRatings = newNumRatings;
 restaurant.avgRating = newAvgRating;

// Update restaurant
 transaction.set(restaurantRef, restaurant);

// Update rating
final data = {
"rating": rating,
 };

 transaction.set(ratingRef, data, SetOptions(merge:true));
 });
 }

// [END solutions_aggregation_queries_3]
final docRef = db.collection("restaurants").doc("arinell-pizza");
addRating(docRef, 2.3);
 }

voidsolutions_distributedCounters2() {