/**
 * @license
 * Copyright 2020 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.
 */
import { Compat } from '@firebase/util';
import { Document } from '../model/document';
import { DocumentKey } from '../model/document_key';
import { FieldPath as InternalFieldPath } from '../model/path';
import { FirebaseFirestore } from './database';
import { FieldPath } from './field_path';
import { DocumentData, DocumentReference, Query, SetOptions } from './reference';
import { UntypedFirestoreDataConverter } from './user_data_reader';
import { AbstractUserDataWriter } from './user_data_writer';
/**
 * Converter used by `withConverter()` to transform user objects of type `T`
 * into Firestore data.
 *
 * Using the converter allows you to specify generic type arguments when
 * storing and retrieving objects from Firestore.
 *
 * @example
 * ```typescript
 * class Post {
 *   constructor(readonly title: string, readonly author: string) {}
 *
 *   toString(): string {
 *     return this.title + ', by ' + this.author;
 *   }
 * }
 *
 * const postConverter = {
 *   toFirestore(post: Post): firebase.firestore.DocumentData {
 *     return {title: post.title, author: post.author};
 *   },
 *   fromFirestore(snapshot: firebase.firestore.QueryDocumentSnapshot): Post {
 *     const data = snapshot.data(options)!;
 *     return new Post(data.title, data.author);
 *   }
 * };
 *
 * const postSnap = await firebase.firestore()
 *   .collection('posts')
 *   .withConverter(postConverter)
 *   .doc().get();
 * const post = postSnap.data();
 * if (post !== undefined) {
 *   post.title; // string
 *   post.toString(); // Should be defined
 *   post.someNonExistentProperty; // TS error
 * }
 * ```
 */
export interface FirestoreDataConverter<T> {
    /**
     * Called by the Firestore SDK to convert a custom model object of type `T`
     * into a plain Javascript object (suitable for writing directly to the
     * Firestore database). Used with {@link @firebase/firestore/lite#(setDoc:1)}, {@link @firebase/firestore/lite#(WriteBatch.set:1)}
     * and {@link @firebase/firestore/lite#(Transaction.set:1)}.
     */
    toFirestore(modelObject: T): DocumentData;
    /**
     * Called by the Firestore SDK to convert a custom model object of type `T`
     * into a plain Javascript object (suitable for writing directly to the
     * Firestore database). Used with {@link @firebase/firestore/lite#(setDoc:1)}, {@link @firebase/firestore/lite#(WriteBatch.set:1)}
     * and {@link @firebase/firestore/lite#(Transaction.set:1)} with `merge:true` or `mergeFields`.
     */
    toFirestore(modelObject: Partial<T>, options: SetOptions): DocumentData;
    /**
     * Called by the Firestore SDK to convert Firestore data into an object of
     * type T. You can access your data by calling: `snapshot.data()`.
     *
     * @param snapshot - A `QueryDocumentSnapshot` containing your data and
     * metadata.
     */
    fromFirestore(snapshot: QueryDocumentSnapshot<DocumentData>): T;
}
/**
 * A `DocumentSnapshot` contains data read from a document in your Firestore
 * database. The data can be extracted with `.data()` or `.get(<field>)` to
 * get a specific field.
 *
 * For a `DocumentSnapshot` that points to a non-existing document, any data
 * access will return 'undefined'. You can use the `exists()` method to
 * explicitly verify a document's existence.
 */
export declare class DocumentSnapshot<T = DocumentData> {
    _firestore: FirebaseFirestore;
    _userDataWriter: AbstractUserDataWriter;
    _key: DocumentKey;
    _document: Document | null;
    _converter: UntypedFirestoreDataConverter<T> | null;
    /** @hideconstructor protected */
    constructor(_firestore: FirebaseFirestore, _userDataWriter: AbstractUserDataWriter, _key: DocumentKey, _document: Document | null, _converter: UntypedFirestoreDataConverter<T> | null);
    /** Property of the `DocumentSnapshot` that provides the document's ID. */
    get id(): string;
    /**
     * The `DocumentReference` for the document included in the `DocumentSnapshot`.
     */
    get ref(): DocumentReference<T>;
    /**
     * Signals whether or not the document at the snapshot's location exists.
     *
     * @returns true if the document exists.
     */
    exists(): this is QueryDocumentSnapshot<T>;
    /**
     * Retrieves all fields in the document as an `Object`. Returns `undefined` if
     * the document doesn't exist.
     *
     * @returns An `Object` containing all fields in the document or `undefined`
     * if the document doesn't exist.
     */
    data(): T | undefined;
    /**
     * Retrieves the field specified by `fieldPath`. Returns `undefined` if the
     * document or field doesn't exist.
     *
     * @param fieldPath - The path (for example 'foo' or 'foo.bar') to a specific
     * field.
     * @returns The data at the specified field location or undefined if no such
     * field exists in the document.
     */
    get(fieldPath: string | FieldPath): any;
}
/**
 * A `QueryDocumentSnapshot` contains data read from a document in your
 * Firestore database as part of a query. The document is guaranteed to exist
 * and its data can be extracted with `.data()` or `.get(<field>)` to get a
 * specific field.
 *
 * A `QueryDocumentSnapshot` offers the same API surface as a
 * `DocumentSnapshot`. Since query results contain only existing documents, the
 * `exists` property will always be true and `data()` will never return
 * 'undefined'.
 */
export declare class QueryDocumentSnapshot<T = DocumentData> extends DocumentSnapshot<T> {
    /**
     * Retrieves all fields in the document as an `Object`.
     *
     * @override
     * @returns An `Object` containing all fields in the document.
     */
    data(): T;
}
/**
 * A `QuerySnapshot` contains zero or more `DocumentSnapshot` objects
 * representing the results of a query. The documents can be accessed as an
 * array via the `docs` property or enumerated using the `forEach` method. The
 * number of documents can be determined via the `empty` and `size`
 * properties.
 */
export declare class QuerySnapshot<T = DocumentData> {
    readonly _docs: Array<QueryDocumentSnapshot<T>>;
    /**
     * The query on which you called {@link getDocs} in order to get this
     * `QuerySnapshot`.
     */
    readonly query: Query<T>;
    /** @hideconstructor */
    constructor(_query: Query<T>, _docs: Array<QueryDocumentSnapshot<T>>);
    /** An array of all the documents in the `QuerySnapshot`. */
    get docs(): Array<QueryDocumentSnapshot<T>>;
    /** The number of documents in the `QuerySnapshot`. */
    get size(): number;
    /** True if there are no documents in the `QuerySnapshot`. */
    get empty(): boolean;
    /**
     * Enumerates all of the documents in the `QuerySnapshot`.
     *
     * @param callback - A callback to be called with a `QueryDocumentSnapshot` for
     * each document in the snapshot.
     * @param thisArg - The `this` binding for the callback.
     */
    forEach(callback: (result: QueryDocumentSnapshot<T>) => void, thisArg?: unknown): void;
}
/**
 * Returns true if the provided snapshots are equal.
 *
 * @param left - A snapshot to compare.
 * @param right - A snapshot to compare.
 * @returns true if the snapshots are equal.
 */
export declare function snapshotEqual<T>(left: DocumentSnapshot<T> | QuerySnapshot<T>, right: DocumentSnapshot<T> | QuerySnapshot<T>): boolean;
/**
 * Helper that calls fromDotSeparatedString() but wraps any error thrown.
 */
export declare function fieldPathFromArgument(methodName: string, arg: string | FieldPath | Compat<FieldPath>): InternalFieldPath;