#import "RNFirebaseFirestoreCollectionReference.h"

@implementation RNFirebaseFirestoreCollectionReference

#if __has_include(<FirebaseFirestore/FirebaseFirestore.h>)

static NSMutableDictionary *_listeners;

- (id)initWithPathAndModifiers:(RCTEventEmitter *)emitter
                appDisplayName:(NSString *)appDisplayName
                          path:(NSString *)path
                       filters:(NSArray *)filters
                        orders:(NSArray *)orders
                       options:(NSDictionary *)options {
  self = [super init];
  if (self) {
    _emitter = emitter;
    _appDisplayName = appDisplayName;
    _path = path;
    _filters = filters;
    _orders = orders;
    _options = options;
    _query = [self buildQuery];
  }
  // Initialise the static listeners object if required
  if (!_listeners) {
    _listeners = [[NSMutableDictionary alloc] init];
  }
  return self;
}

- (void)get:(NSDictionary *)getOptions
   resolver:(RCTPromiseResolveBlock)resolve
   rejecter:(RCTPromiseRejectBlock)reject {
  FIRFirestoreSource source;
  if (getOptions && getOptions[@"source"]) {
    if ([getOptions[@"source"] isEqualToString:@"server"]) {
      source = FIRFirestoreSourceServer;
    } else if ([getOptions[@"source"] isEqualToString:@"cache"]) {
      source = FIRFirestoreSourceCache;
    } else {
      source = FIRFirestoreSourceDefault;
    }
  } else {
    source = FIRFirestoreSourceDefault;
  }
  [_query getDocumentsWithSource:source completion:^(FIRQuerySnapshot *_Nullable snapshot, NSError *_Nullable error) {
    if (error) {
      [RNFirebaseFirestore promiseRejectException:reject error:error];
    } else {
      NSDictionary *data = [RNFirebaseFirestoreCollectionReference snapshotToDictionary:snapshot];
      resolve(data);
    }
  }];
}

+ (void)offSnapshot:(NSString *)listenerId {
  id<FIRListenerRegistration> listener = _listeners[listenerId];
  if (listener) {
    [_listeners removeObjectForKey:listenerId];
    [listener remove];
  }
}

- (void)onSnapshot:(NSString *)listenerId
queryListenOptions:(NSDictionary *)queryListenOptions {
  if (_listeners[listenerId] == nil) {
    id listenerBlock = ^(FIRQuerySnapshot *_Nullable snapshot, NSError *_Nullable error) {
      if (error) {
        id<FIRListenerRegistration> listener = _listeners[listenerId];
        if (listener) {
          [_listeners removeObjectForKey:listenerId];
          [listener remove];
        }
        [self handleQuerySnapshotError:listenerId error:error];
      } else {
        [self handleQuerySnapshotEvent:listenerId querySnapshot:snapshot];
      }
    };

    bool includeMetadataChanges;
    if (queryListenOptions && queryListenOptions[@"includeMetadataChanges"]) {
      includeMetadataChanges = true;
    } else {
      includeMetadataChanges = false;
    }

    id<FIRListenerRegistration>
        listener = [_query addSnapshotListenerWithIncludeMetadataChanges:includeMetadataChanges listener:listenerBlock];
    _listeners[listenerId] = listener;
  }
}

- (FIRQuery *)buildQuery {
  FIRFirestore *firestore = [RNFirebaseFirestore getFirestoreForApp:_appDisplayName];
  FIRQuery *query = (FIRQuery *) [firestore collectionWithPath:_path];
  query = [self applyFilters:firestore query:query];
  query = [self applyOrders:query];
  query = [self applyOptions:firestore query:query];

  return query;
}

- (FIRQuery *)applyFilters:(FIRFirestore *)firestore
                     query:(FIRQuery *)query {
  for (NSDictionary *filter in _filters) {
    NSDictionary *fieldPathDictionary = filter[@"fieldPath"];
    NSString *fieldPathType = fieldPathDictionary[@"type"];
    NSString *operator = filter[@"operator"];
    NSDictionary *jsValue = filter[@"value"];
    id value = [RNFirebaseFirestoreDocumentReference parseJSTypeMap:firestore jsTypeMap:jsValue];

    if ([fieldPathType isEqualToString:@"string"]) {
      NSString *fieldPath = fieldPathDictionary[@"string"];
      if ([operator isEqualToString:@"EQUAL"]) {
        query = [query queryWhereField:fieldPath isEqualTo:value];
      } else if ([operator isEqualToString:@"GREATER_THAN"]) {
        query = [query queryWhereField:fieldPath isGreaterThan:value];
      } else if ([operator isEqualToString:@"GREATER_THAN_OR_EQUAL"]) {
        query = [query queryWhereField:fieldPath isGreaterThanOrEqualTo:value];
      } else if ([operator isEqualToString:@"LESS_THAN"]) {
        query = [query queryWhereField:fieldPath isLessThan:value];
      } else if ([operator isEqualToString:@"LESS_THAN_OR_EQUAL"]) {
        query = [query queryWhereField:fieldPath isLessThanOrEqualTo:value];
      } else if ([operator isEqualToString:@"ARRAY_CONTAINS"]) {
        query = [query queryWhereField:fieldPath arrayContains:value];
      }
    } else {
      NSArray *fieldPathElements = fieldPathDictionary[@"elements"];
      FIRFieldPath *fieldPath = [[FIRFieldPath alloc] initWithFields:fieldPathElements];
      if ([operator isEqualToString:@"EQUAL"]) {
        query = [query queryWhereFieldPath:fieldPath isEqualTo:value];
      } else if ([operator isEqualToString:@"GREATER_THAN"]) {
        query = [query queryWhereFieldPath:fieldPath isGreaterThan:value];
      } else if ([operator isEqualToString:@"GREATER_THAN_OR_EQUAL"]) {
        query = [query queryWhereFieldPath:fieldPath isGreaterThanOrEqualTo:value];
      } else if ([operator isEqualToString:@"LESS_THAN"]) {
        query = [query queryWhereFieldPath:fieldPath isLessThan:value];
      } else if ([operator isEqualToString:@"LESS_THAN_OR_EQUAL"]) {
        query = [query queryWhereFieldPath:fieldPath isLessThanOrEqualTo:value];
      } else if ([operator isEqualToString:@"ARRAY_CONTAINS"]) {
        query = [query queryWhereFieldPath:fieldPath arrayContains:value];
      }
    }
  }

  return query;
}

- (FIRQuery *)applyOrders:(FIRQuery *)query {
  for (NSDictionary *order in _orders) {
    NSString *direction = order[@"direction"];
    NSDictionary *fieldPathDictionary = order[@"fieldPath"];
    NSString *fieldPathType = fieldPathDictionary[@"type"];

    if ([fieldPathType isEqualToString:@"string"]) {
      NSString *fieldPath = fieldPathDictionary[@"string"];
      query = [query queryOrderedByField:fieldPath descending:([direction isEqualToString:@"DESCENDING"])];
    } else {
      NSArray *fieldPathElements = fieldPathDictionary[@"elements"];
      FIRFieldPath *fieldPath = [[FIRFieldPath alloc] initWithFields:fieldPathElements];
      query = [query queryOrderedByFieldPath:fieldPath descending:([direction isEqualToString:@"DESCENDING"])];
    }
  }
  return query;
}

- (FIRQuery *)applyOptions:(FIRFirestore *)firestore
                     query:(FIRQuery *)query {
  if (_options[@"endAt"]) {
    query =
        [query queryEndingAtValues:[RNFirebaseFirestoreDocumentReference parseJSArray:firestore jsArray:_options[@"endAt"]]];
  }
  if (_options[@"endBefore"]) {
    query =
        [query queryEndingBeforeValues:[RNFirebaseFirestoreDocumentReference parseJSArray:firestore jsArray:_options[@"endBefore"]]];
  }
  if (_options[@"limit"]) {
    query = [query queryLimitedTo:[_options[@"limit"] intValue]];
  }
  if (_options[@"offset"]) {
    // iOS doesn't support offset
  }
  if (_options[@"selectFields"]) {
    // iOS doesn't support selectFields
  }
  if (_options[@"startAfter"]) {
    query =
        [query queryStartingAfterValues:[RNFirebaseFirestoreDocumentReference parseJSArray:firestore jsArray:_options[@"startAfter"]]];
  }
  if (_options[@"startAt"]) {
    query =
        [query queryStartingAtValues:[RNFirebaseFirestoreDocumentReference parseJSArray:firestore jsArray:_options[@"startAt"]]];
  }
  return query;
}

- (void)handleQuerySnapshotError:(NSString *)listenerId
                           error:(NSError *)error {
  NSMutableDictionary *event = [[NSMutableDictionary alloc] init];
  [event setValue:_appDisplayName forKey:@"appName"];
  [event setValue:_path forKey:@"path"];
  [event setValue:listenerId forKey:@"listenerId"];
  [event setValue:[RNFirebaseFirestore getJSError:error] forKey:@"error"];

  [RNFirebaseUtil sendJSEvent:self.emitter name:FIRESTORE_COLLECTION_SYNC_EVENT body:event];
}

- (void)handleQuerySnapshotEvent:(NSString *)listenerId
                   querySnapshot:(FIRQuerySnapshot *)querySnapshot {
  NSMutableDictionary *event = [[NSMutableDictionary alloc] init];
  [event setValue:_appDisplayName forKey:@"appName"];
  [event setValue:_path forKey:@"path"];
  [event setValue:listenerId forKey:@"listenerId"];
  [event setValue:[RNFirebaseFirestoreCollectionReference snapshotToDictionary:querySnapshot] forKey:@"querySnapshot"];

  [RNFirebaseUtil sendJSEvent:self.emitter name:FIRESTORE_COLLECTION_SYNC_EVENT body:event];
}

+ (NSDictionary *)snapshotToDictionary:(FIRQuerySnapshot *)querySnapshot {
  NSMutableDictionary *snapshot = [[NSMutableDictionary alloc] init];
  [snapshot setValue:[self documentChangesToArray:querySnapshot.documentChanges] forKey:@"changes"];
  [snapshot setValue:[self documentSnapshotsToArray:querySnapshot.documents] forKey:@"documents"];
  if (querySnapshot.metadata) {
    NSMutableDictionary *metadata = [[NSMutableDictionary alloc] init];
    [metadata setValue:@(querySnapshot.metadata.fromCache) forKey:@"fromCache"];
    [metadata setValue:@(querySnapshot.metadata.hasPendingWrites) forKey:@"hasPendingWrites"];
    [snapshot setValue:metadata forKey:@"metadata"];
  }

  return snapshot;
}

+ (NSArray *)documentChangesToArray:(NSArray<FIRDocumentChange *> *)documentChanges {
  NSMutableArray *changes = [[NSMutableArray alloc] init];
  for (FIRDocumentChange *change in documentChanges) {
    [changes addObject:[self documentChangeToDictionary:change]];
  }

  return changes;
}

+ (NSDictionary *)documentChangeToDictionary:(FIRDocumentChange *)documentChange {
  NSMutableDictionary *change = [[NSMutableDictionary alloc] init];
  [change setValue:[RNFirebaseFirestoreDocumentReference snapshotToDictionary:documentChange.document] forKey:@"document"];
  [change setValue:@(documentChange.newIndex) forKey:@"newIndex"];
  [change setValue:@(documentChange.oldIndex) forKey:@"oldIndex"];

  if (documentChange.type == FIRDocumentChangeTypeAdded) {
    [change setValue:@"added" forKey:@"type"];
  } else if (documentChange.type == FIRDocumentChangeTypeRemoved) {
    [change setValue:@"removed" forKey:@"type"];
  } else if (documentChange.type == FIRDocumentChangeTypeModified) {
    [change setValue:@"modified" forKey:@"type"];
  }

  return change;
}

+ (NSArray *)documentSnapshotsToArray:(NSArray<FIRDocumentSnapshot *> *)documentSnapshots {
  NSMutableArray *snapshots = [[NSMutableArray alloc] init];
  for (FIRDocumentSnapshot *snapshot in documentSnapshots) {
    [snapshots addObject:[RNFirebaseFirestoreDocumentReference snapshotToDictionary:snapshot]];
  }

  return snapshots;
}

#endif

@end