/*
 * Copyright 2018 Google
 *
 * 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 <FirebaseFirestore/FirebaseFirestore.h>

#import <XCTest/XCTest.h>

#import "Firestore/Source/API/FIRFieldValue+Internal.h"

#import "Firestore/Example/Tests/Util/FSTEventAccumulator.h"
#import "Firestore/Example/Tests/Util/FSTIntegrationTestCase.h"

/**
 * Note: Transforms are tested pretty thoroughly in FIRServerTimestampTests (via set, update,
 * transactions, nested in documents, multiple transforms together, etc.) and so these tests
 * mostly focus on the array transform semantics.
 */
@interface FIRArrayTransformTests : FSTIntegrationTestCase
@end

@implementation FIRArrayTransformTests {
  // A document reference to read and write to.
  FIRDocumentReference *_docRef;

  // Accumulator used to capture events during the test.
  FSTEventAccumulator<FIRDocumentSnapshot *> *_accumulator;

  // Listener registration for a listener maintained during the course of the test.
  id<FIRListenerRegistration> _listenerRegistration;
}

- (void)setUp {
  [super setUp];

  _docRef = [self documentRef];
  _accumulator = [FSTEventAccumulator accumulatorForTest:self];
  _listenerRegistration =
      [_docRef addSnapshotListenerWithIncludeMetadataChanges:YES
                                                    listener:_accumulator.valueEventHandler];

  // Wait for initial nil snapshot to avoid potential races.
  FIRDocumentSnapshot *initialSnapshot = [_accumulator awaitEventWithName:@"initial event"];
  XCTAssertFalse(initialSnapshot.exists);
}

- (void)tearDown {
  [_listenerRegistration remove];

  [super tearDown];
}

#pragma mark - Test Helpers

/** Writes some initial data and consumes the events generated. */
- (void)writeInitialData:(NSDictionary<NSString *, id> *)data {
  [self writeDocumentRef:_docRef data:data];
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, data);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, data);
}

#pragma mark - Test Cases

- (void)testCreateDocumentWithArrayUnion {
  [self writeDocumentRef:_docRef
                    data:@{
                      @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @1, @2 ]]
                    }];
  id expected = @{ @"array" : @[ @1, @2 ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testAppendToArrayViaUpdate {
  [self writeInitialData:@{ @"array" : @[ @1, @3 ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @2, @1, @4 ]]
                     }];

  id expected = @{ @"array" : @[ @1, @3, @2, @4 ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testAppendToArrayViaMergeSet {
  [self writeInitialData:@{ @"array" : @[ @1, @3 ] }];

  [self mergeDocumentRef:_docRef
                    data:@{
                      @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @2, @1, @4 ]]
                    }];

  id expected = @{ @"array" : @[ @1, @3, @2, @4 ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testAppendObjectToArrayViaUpdate {
  [self writeInitialData:@{ @"array" : @[ @{@"a" : @"hi"} ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue
                           fieldValueForArrayUnion:@[ @{@"a" : @"hi"}, @{@"a" : @"bye"} ]]
                     }];

  id expected = @{ @"array" : @[ @{@"a" : @"hi"}, @{@"a" : @"bye"} ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testRemoveFromArrayViaUpdate {
  [self writeInitialData:@{ @"array" : @[ @1, @3, @1, @3 ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayRemove:@[ @1, @4 ]]
                     }];

  id expected = @{ @"array" : @[ @3, @3 ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testRemoveFromArrayViaMergeSet {
  [self writeInitialData:@{ @"array" : @[ @1, @3, @1, @3 ] }];

  [self mergeDocumentRef:_docRef
                    data:@{
                      @"array" : [FIRFieldValue fieldValueForArrayRemove:@[ @1, @4 ]]
                    }];

  id expected = @{ @"array" : @[ @3, @3 ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

- (void)testRemoveObjectFromArrayViaUpdate {
  [self writeInitialData:@{ @"array" : @[ @{@"a" : @"hi"}, @{@"a" : @"bye"} ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayRemove:@[ @{@"a" : @"hi"} ]]
                     }];

  id expected = @{ @"array" : @[ @{@"a" : @"bye"} ] };
  XCTAssertEqualObjects([_accumulator awaitLocalEvent].data, expected);
  XCTAssertEqualObjects([_accumulator awaitRemoteEvent].data, expected);
}

@end

/**
 * Unlike the FIRArrayTransformTests above, these tests intentionally avoid having any ongoing
 * listeners so that we can test what gets stored in the offline cache based purely on the write
 * acknowledgement (without receiving an updated document via watch). As such they also rely on
 * persistence being enabled so documents remain in the cache after the write.
 */
@interface FIRArrayTransformServerApplicationTests : FSTIntegrationTestCase
@end

@implementation FIRArrayTransformServerApplicationTests {
  // A document reference to read and write to.
  FIRDocumentReference *_docRef;
}

- (void)setUp {
  [super setUp];

  _docRef = [self documentRef];
}

/**
 * Helper that uses a temporary listener to read from cache (returning nil if no document seems
 * to be in cache). Can probably be replaced with get(source=cache) in the future.
 */
- (FIRDocumentSnapshot *_Nullable)getFromCache {
  FSTEventAccumulator *accumulator = [FSTEventAccumulator accumulatorForTest:self];
  id<FIRListenerRegistration> listenerRegistration =
      [_docRef addSnapshotListener:accumulator.valueEventHandler];
  FIRDocumentSnapshot *snapshot = [accumulator awaitEventWithName:@"listenForOneEvent"];
  [listenerRegistration remove];
  if (snapshot.metadata.fromCache) {
    return snapshot;
  } else {
    return nil;
  }
}

- (void)testServerApplicationOfSetWithNoCachedBaseDoc {
  [self writeDocumentRef:_docRef
                    data:@{
                      @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @1, @2 ]]
                    }];
  id expected = @{ @"array" : @[ @1, @2 ] };
  XCTAssertEqualObjects([self getFromCache].data, expected);
}

- (void)testServerApplicationOfUpdateWithNoCachedBaseDoc {
  // Write an initial document out-of-band so it's not in our cache
  [self writeDocumentRef:[[self firestore] documentWithPath:_docRef.path]
                    data:@{
                      @"array" : @[ @42 ]
                    }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @1, @2 ]]
                     }];

  // Nothing should be cached since it was an update and we had no base doc.
  XCTAssertNil([self getFromCache]);
}

- (void)testServerApplicationOfMergeSetWithNoCachedBaseDoc {
  // Write an initial document out-of-band so it's not in our cache
  [self writeDocumentRef:[[self firestore] documentWithPath:_docRef.path]
                    data:@{
                      @"array" : @[ @42 ]
                    }];

  [self mergeDocumentRef:_docRef
                    data:@{
                      @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @1, @2 ]]
                    }];

  // Document will be cached but we'll be missing 42.
  id expected = @{ @"array" : @[ @1, @2 ] };
  XCTAssertEqualObjects([self getFromCache].data, expected);
}

- (void)testServerApplicationOfArrayUnionUpdateWithCachedBaseDoc {
  // Cache a document with an array.
  [self writeDocumentRef:_docRef data:@{ @"array" : @[ @42 ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayUnion:@[ @1, @2 ]]
                     }];

  // Should have merged the update with the cached doc.
  id expected = @{ @"array" : @[ @42, @1, @2 ] };
  XCTAssertEqualObjects([self getFromCache].data, expected);
}

- (void)testServerApplicationOfArrayRemoveUpdateWithCachedBaseDoc {
  // Cache a document with an array.
  [self writeDocumentRef:_docRef data:@{ @"array" : @[ @42, @1, @2 ] }];

  [self updateDocumentRef:_docRef
                     data:@{
                       @"array" : [FIRFieldValue fieldValueForArrayRemove:@[ @1, @2 ]]
                     }];

  // Should have merged the update with the cached doc.
  id expected = @{ @"array" : @[ @42 ] };
  XCTAssertEqualObjects([self getFromCache].data, expected);
}
@end