//
//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
//

NS_ASSUME_NONNULL_BEGIN

@class OWSLinkPreviewDraft;
@class OWSQuotedReplyModel;
@class OWSUnreadIndicator;
@class SignalAttachment;
@class TSContactThread;
@class TSGroupThread;
@class TSInteraction;
@class TSOutgoingMessage;
@class TSThread;
@class YapDatabaseConnection;
@class YapDatabaseReadTransaction;
@class YapDatabaseReadWriteTransaction;

@interface ThreadDynamicInteractions : NSObject

// Represents the "reverse index" of the focus message, if any.
// The "reverse index" is the distance of this interaction from
// the last interaction in the thread.  Therefore the last interaction
// will have a "reverse index" of zero.
//
// We use "reverse indices" because (among other uses) we use this to
// determine the initial load window size.
@property (nonatomic, nullable, readonly) NSNumber *focusMessagePosition;

@property (nonatomic, nullable, readonly) OWSUnreadIndicator *unreadIndicator;

- (void)clearUnreadIndicatorState;

@end

#pragma mark -

@interface ThreadUtil : NSObject

#pragma mark - dynamic interactions

// This method will create and/or remove any offers and indicators
// necessary for this thread.  This includes:
//
// * Block offers.
// * "Add to contacts" offers.
// * Unread indicators.
//
// Parameters:
//
// * hideUnreadMessagesIndicator: If YES, the "unread indicator" has
//   been cleared and should not be shown.
// * firstUnseenInteractionTimestamp: A snapshot of unseen message state
//   when we entered the conversation view.  See comments on
//   ThreadOffersAndIndicators.
// * maxRangeSize: Loading a lot of messages in conversation view is
//   slow and unwieldy.  This number represents the maximum current
//   size of the "load window" in that view. The unread indicator should
//   always be inserted within that window.
+ (ThreadDynamicInteractions *)ensureDynamicInteractionsForThread:(TSThread *)thread
                                                     dbConnection:(YapDatabaseConnection *)dbConnection
                                      hideUnreadMessagesIndicator:(BOOL)hideUnreadMessagesIndicator
                                              lastUnreadIndicator:(nullable OWSUnreadIndicator *)lastUnreadIndicator
                                                   focusMessageId:(nullable NSString *)focusMessageId
                                                     maxRangeSize:(int)maxRangeSize;

#pragma mark - Delete Content

+ (void)deleteAllContent;

#pragma mark - Find Content

+ (nullable TSInteraction *)findInteractionInThreadByTimestamp:(uint64_t)timestamp
                                                      authorId:(NSString *)authorId
                                                threadUniqueId:(NSString *)threadUniqueId
                                                   transaction:(YapDatabaseReadTransaction *)transaction;

@end

NS_ASSUME_NONNULL_END