feat: added changes for seq_id

.gitignore

@@ -1,7 +1,7 @@
 # Xcode
 #
 # gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
-
+.vscode/
 
 ## Build generated
 Build/

Contentstack.xcodeproj/project.pbxproj

@@ -95,6 +95,7 @@
 		23A53F501E277BBE001DBE35 /* NSObject+Extensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 23A53F331E276BA5001DBE35 /* NSObject+Extensions.m */; };
 		23A53F5A1E277CD3001DBE35 /* Contentstack.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 230B38C01C16E98B00444A14 /* Contentstack.framework */; };
 		23B6F12A1B5662EE00A9E983 /* ISO8601DateFormatter.m in Sources */ = {isa = PBXBuildFile; fileRef = 23B6F1281B5662EE00A9E983 /* ISO8601DateFormatter.m */; };
+		47CD50872B7625B90032747B /* BSONObjectIdGenerator.m in Sources */ = {isa = PBXBuildFile; fileRef = 47CD50862B7625B90032747B /* BSONObjectIdGenerator.m */; };
 		565E11BB1BD76654005AD47F /* MMDocument.m in Sources */ = {isa = PBXBuildFile; fileRef = 565E11AA1BD76654005AD47F /* MMDocument.m */; };
 		565E11BC1BD76654005AD47F /* MMElement.m in Sources */ = {isa = PBXBuildFile; fileRef = 565E11AD1BD76654005AD47F /* MMElement.m */; };
 		565E11BD1BD76654005AD47F /* MMGenerator.m in Sources */ = {isa = PBXBuildFile; fileRef = 565E11AF1BD76654005AD47F /* MMGenerator.m */; };
@@ -205,6 +206,8 @@
 		23B6F1281B5662EE00A9E983 /* ISO8601DateFormatter.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ISO8601DateFormatter.m; sourceTree = "<group>"; };
 		23C545FB1C1976FE007BBD27 /* ios-build-framework-script.sh */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.script.sh; path = "ios-build-framework-script.sh"; sourceTree = "<group>"; };
 		3CF581B9F7526EDA48ED5C6F /* Pods-ContentstackTest.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-ContentstackTest.debug.xcconfig"; path = "Target Support Files/Pods-ContentstackTest/Pods-ContentstackTest.debug.xcconfig"; sourceTree = "<group>"; };
+		47CD50852B76243E0032747B /* BSONObjectIdGenerator.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = BSONObjectIdGenerator.h; sourceTree = "<group>"; };
+		47CD50862B7625B90032747B /* BSONObjectIdGenerator.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = BSONObjectIdGenerator.m; sourceTree = "<group>"; };
 		565E11A91BD76654005AD47F /* MMDocument.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MMDocument.h; sourceTree = "<group>"; };
 		565E11AA1BD76654005AD47F /* MMDocument.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MMDocument.m; sourceTree = "<group>"; };
 		565E11AB1BD76654005AD47F /* MMDocument_Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MMDocument_Private.h; sourceTree = "<group>"; };
@@ -383,6 +386,8 @@
 				23A53F311E276BA5001DBE35 /* CSIOURLCache.m */,
 				23A53F321E276BA5001DBE35 /* NSObject+Extensions.h */,
 				23A53F331E276BA5001DBE35 /* NSObject+Extensions.m */,
+				47CD50852B76243E0032747B /* BSONObjectIdGenerator.h */,
+				47CD50862B7625B90032747B /* BSONObjectIdGenerator.m */,
 			);
 			path = ContentstackInternal;
 			sourceTree = "<group>";
@@ -790,6 +795,7 @@
 				0FEAEF2A2361A18600985FF9 /* CSURLSessionManager.m in Sources */,
 				0FEAEF2C2361A18600985FF9 /* CSError.m in Sources */,
 				23B6F12A1B5662EE00A9E983 /* ISO8601DateFormatter.m in Sources */,
+				47CD50872B7625B90032747B /* BSONObjectIdGenerator.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

Contentstack/Stack.h

@@ -229,6 +229,27 @@ BUILT_ASSUME_NONNULL_BEGIN
 */
 - (void)sync:(void (^)(SyncStack * BUILT_NULLABLE_P syncStack, NSError  * BUILT_NULLABLE_P error))completionBlock;
 
+/**
+ You can use the seq_id (that you receive after every sync call) to get the updated content next time.
+ The seq id is alternative to pagination token where it fetches all the events data in sequence, and the details of the content that was deleted or updated.
+
+     //Obj-C
+
+         NSString *seqId = @"seq_id"; //Seq id
+         [stack seqId:seqId completion:^(SyncStack * _Nullable syncStack, NSError * _Nullable error) {
+
+         }];
+
+     //Swift
+         var seqId = @"seq_id"; //Seq id
+         stack.seqId(seqId, completion: { ( syncStack:SyncStack, error: NSError) in
+
+         })
+
+ @param token Sync token from where to perform sync
+ @param completionBlock called synchronization is done.
+ */
+-(void)syncSeqId:(NSString *)seqId completion:(void (^)(SyncStack * BUILT_NULLABLE_P syncResult, NSError * BUILT_NULLABLE_P error))completionBlock;
 /**
  If the result of the initial sync (or subsequent sync) contains more than 100 records,
  the response would be paginated. It provides pagination token in the response. However,

Contentstack/Stack.m

@@ -160,6 +160,13 @@ -(void)sync:(void (^)(SyncStack * BUILT_NULLABLE_P syncResult, NSError * BUILT_N
     }];
 }
 
+-(void)syncSeqId:(NSString *)seqId completion:(void (^)(SyncStack * BUILT_NULLABLE_P syncResult, NSError * BUILT_NULLABLE_P error))completionBlock {
+    SyncStack *syncStack = [self getCurrentSyncStack:@{@"seq_id": seqId}];
+    [self sync:syncStack completion:^(SyncStack * _Nullable syncResult, NSError * _Nullable error) {
+        completionBlock(syncResult, error);
+    }];
+}
+
 -(void)syncToken:(NSString *)token completion:(void (^)(SyncStack * BUILT_NULLABLE_P syncResult, NSError * BUILT_NULLABLE_P error))completionBlock {
     SyncStack *syncStack = [self getCurrentSyncStack:@{@"sync_token": token}];
     [self sync:syncStack completion:^(SyncStack * _Nullable syncResult, NSError * _Nullable error) {
@@ -227,8 +234,6 @@ -(void)syncOnly:(NSString *)contentType locale:(NSString*)locale from:(NSDate *)
     [self sync:syncStack completion:^(SyncStack * _Nullable syncResult, NSError * _Nullable error) {
         completionBlock(syncResult, error);
     }];
-
-
 }
 
 -(void)syncOnly:(NSString *)contentType locale:(NSString*)locale from:(NSDate *)date publishType:(PublishType)publishType completion:(void (^)(SyncStack * _Nullable, NSError * _Nullable))completionBlock {
@@ -247,7 +252,7 @@ -(void)syncOnly:(NSString *)contentType locale:(NSString*)locale from:(NSDate *)
 
 - (void)sync:(SyncStack *)syncResult completion:(void (^)(SyncStack * BUILT_NULLABLE_P syncResult, NSError * BUILT_NULLABLE_P error))completionBlock {
     NSMutableDictionary *params = [NSMutableDictionary dictionaryWithDictionary:[syncResult getParameters]];
-    if (syncResult.paginationToken == nil && syncResult.syncToken == nil) {
+    if (syncResult.seqId == nil && syncResult.syncToken == nil) {
         [params setValue:self.environment forKey:@"environment"];
     }
     [self syncCallWithParams:params withCompletion:^(NSDictionary *responseDictionary, NSError *error) {

Contentstack/SyncStack.h

@@ -25,6 +25,10 @@ NS_ASSUME_NONNULL_BEGIN
  *Readonly property to delta sync.
  */
 @property (nonatomic, copy, readonly) NSString * _Nullable syncToken;
+/**
+ *Readonly property to sync.
+ */
+@property (nonatomic, copy, readonly) NSString * _Nullable seqId;
 /**
  *  Readonly property to check skip count
  */

Contentstack/SyncStack.m

@@ -8,6 +8,8 @@
 
 #import "SyncStack.h"
 #import "CSIOInternalHeaders.h"
+#import "BSONObjectIdGenerator.h"
+
 @implementation SyncStack
 
 -(instancetype)initWithParmas:(NSDictionary*) parmas {
@@ -17,6 +19,11 @@ -(instancetype)initWithParmas:(NSDictionary*) parmas {
         if ([[self.params objectForKey:@"sync_token"] isKindOfClass:[NSString class]]) {
             self.syncToken = [self.params objectForKey:@"sync_token"];
         }
+        if ([[self.params objectForKey:@"seq_id"]
+             isKindOfClass:[NSString
+                            class]]) {
+            self.seqId = [self.params objectForKey:@"seq_id"];
+        }
         self.items = [NSArray array];
     }
     return self;
@@ -27,8 +34,15 @@ -(void)parseSyncResult:(NSDictionary *)dictionary {
         self.syncToken = nil;
         self.paginationToken = nil;
         self.hasMorePages = false;
+
         if ([dictionary objectForKey:@"sync_token"]) {
-            self.syncToken = [dictionary objectForKey:@"sync_token"];
+            /* For existing persisted data sync token should be set to nil. Seq Id will be generated for sync with the help of event_at field.
+            */
+            [self setExistingTokensNilAndGenerateSeqId:@"sync_token" dict:dictionary];
+        }
+
+        if ([dictionary objectForKey:@"last_seq_id"]) {
+            self.seqId = [dictionary objectForKey:@"last_seq_id"];
         }
         if ([dictionary objectForKey:@"pagination_token"]) {
             self.hasMorePages = true;
@@ -44,21 +58,69 @@ -(void)parseSyncResult:(NSDictionary *)dictionary {
             self.limit = [[dictionary objectForKey:@"limit"] unsignedIntValue];
         }
         if ([dictionary objectForKey:@"items"] && [[dictionary objectForKey:@"items"] isKindOfClass:[NSArray class]]) {
-            self.items = [dictionary objectForKey:@"items"];//[[self.items mutableCopy] arrayByAddingObjectsFromArray:[dictionary objectForKey:@"items"]];
+            self.items = [dictionary objectForKey:@"items"];
+            if (self.items.count > 0) {
+                self.hasMorePages = true;
+            }
         }
     }
 }
 
 -(NSDictionary*)getParameters {
     NSMutableDictionary *syncParams = [NSMutableDictionary dictionary];
-    if (self.syncToken != nil) {
+    if (self.seqId != nil) {
+        [syncParams setValue:self.seqId forKey:@"seq_id"];
+    } else if (self.syncToken != nil) {
         [syncParams setValue:self.syncToken forKey:@"sync_token"];
-    }else if (self.paginationToken != nil) {
+    } else if (self.paginationToken != nil) {
         [syncParams setValue:self.paginationToken forKey:@"pagination_token"];
-    }else {
+    } else {
         syncParams = [NSMutableDictionary dictionaryWithDictionary:self.params];
+        [syncParams setValue:@"true" forKey:@"seq_id"];
         [syncParams setValue:@"true" forKey:@"init"];
     }
     return syncParams;
 }
+
+-(NSString*)generateSeqId:(NSString*) eventAt {
+    // Create a date formatter to parse the date string
+    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
+    dateFormatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
+    NSDate *date = [dateFormatter dateFromString:eventAt];
+    if (date) {
+        // Convert the NSDate object to an NSTimeInterval
+        NSTimeInterval timeInterval = [date timeIntervalSince1970];
+        NSInteger timeIntervalInSeconds = (NSInteger)timeInterval;
+
+        return [BSONObjectIdGenerator generate:timeIntervalInSeconds];
+    } else {
+        // Handle case where date conversion failed.
+        [NSException raise:@"Unable to parse date string" format:@"Invalid date format %@", eventAt];
+        return nil;
+    }
+}
+
+-(void)setExistingTokensNilAndGenerateSeqId:(NSString *) key dict:(NSDictionary *)dictionary {
+    NSMutableArray * items = [NSMutableArray array];
+    items = [dictionary objectForKey: @"items"];
+    if ([items isKindOfClass:[NSArray class]] && items.count > 0) {
+        // Get the last object's event_at
+        NSDictionary *lastObject = nil;
+        for (NSInteger i = items.count - 1; i >= 0; i--) {
+            id object = items[i];
+            if ([object isKindOfClass:[NSDictionary class]]) {
+                lastObject = object;
+                break;
+            }
+        }
+        self.seqId = [self generateSeqId:[lastObject objectForKey:@"event_at"]];
+    } else {
+        if ([key isEqual: @"sync_token"]) {
+            self.syncToken = [dictionary objectForKey:@"sync_token"];
+        } else {
+            self.paginationToken = [dictionary objectForKey:@"pagination_token"];
+        }
+    }
+}
+
 @end

ContentstackInternal/BSONObjectIdGenerator.h

@@ -0,0 +1,24 @@
+//
+//  BSONObjectIdGenerator.h
+//  Contentstack
+//
+//  Created by Vikram Kalta on 09/02/2024.
+//  Copyright © 2024 Contentstack. All rights reserved.
+//
+#ifndef BSONObjectIdGenerator_h
+#define BSONObjectIdGenerator_h
+
+#import <Foundation/Foundation.h>
+
+typedef union {
+    char bytes[12];
+    int ints[3];
+} bson_oid_t;
+
+@interface BSONObjectIdGenerator : NSObject
+
++ (NSString *)generate:(NSInteger)timestamp;
+
+@end
+
+#endif /* BSONObjectIdGenerator_h */

ContentstackInternal/BSONObjectIdGenerator.m

@@ -0,0 +1,102 @@
+//
+//  BSONObjectIdGenerator.m
+//  ThirdPartyExtension
+//
+//  Created by Vikram Kalta on 09/02/2024.
+//  Copyright © 2024 Contentstack. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import <CommonCrypto/CommonDigest.h>
+#import "BSONObjectIdGenerator.h"
+
+@implementation BSONObjectIdGenerator
+static int _incr = 0;
+
++ (NSString *) generate:(NSInteger)timestamp {
+    int i = _incr++;
+    bson_oid_t *oid = malloc(sizeof(bson_oid_t));
+    time_t t = time(NULL);
+
+    // Grab the PID
+    int pid = [NSProcessInfo processInfo].processIdentifier;
+
+    // Get a device identifier. The specification usually has this as the MAC address
+    // or hostname but we already have a unique device identifier.
+    //
+    NSString *identifier = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
+
+    // MD5 hash the device identifier
+    NSString *md5HashOfIdentifier = [self md5HashFromString:identifier];
+    const char *cIdentifier = [md5HashOfIdentifier cStringUsingEncoding:NSUTF8StringEncoding];
+
+    // Copy bytes over to our object id. Specification taken from http://www.mongodb.org/display/DOCS/Object+IDs
+    bson_swap_endian_len(&oid->bytes[0], &timestamp, 4);
+    bson_swap_endian_len(&oid->bytes[4], &cIdentifier, 3);
+    bson_swap_endian_len(&oid->bytes[7], &pid, 2);
+    bson_swap_endian_len(&oid->bytes[9], &i, 3);
+    NSString *str = [self bson_oid_to_string:oid];
+
+    free(oid);
+
+    return str;
+}
+
+/**
+ @discussion Given an NSString, returns the MD5 hash of it. Taken from
+ http://stackoverflow.com/questions/1524604/md5-algorithm-in-objective-c
+ @param source The source string
+ @return MD5 hash as a string
+ */
++ (NSString *) md5HashFromString:(NSString *)source {
+    const char *cStr = [source UTF8String];
+    unsigned char result[16];
+    CC_MD5(cStr, strlen(cStr), result);
+    return [NSString stringWithFormat:
+                @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
+            result[0], result[1], result[2], result[3],
+            result[4], result[5], result[6], result[7],
+            result[8], result[9], result[10], result[11],
+            result[12], result[13], result[14], result[15]
+    ];
+}
+
+/**
+ @discussion Converts a bson_oid_t to an NSString. Mostly taken from https://github.com/mongodb/mongo-c-driver/blob/master/src/bson.c
+ @param oid The bson_oid_t to convert
+ @return Autoreleased NSString of 24 hex characters
+ */
++ (NSString *) bson_oid_to_string:(bson_oid_t *)oid {
+    char *str = malloc(sizeof(char) * 25);
+    static const char hex[16] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};
+    int i;
+    for ( i=0; i<12; i++ ) {
+        str[2*i]     = hex[( oid->bytes[i] & 0xf0 ) >> 4];
+        str[2*i + 1] = hex[ oid->bytes[i] & 0x0f      ];
+    }
+    str[24] = '\0';
+    NSString *string = [NSString stringWithCString:str encoding:NSUTF8StringEncoding];
+    free(str);
+    return string;
+}
+
+
+/**
+ @discussion The ARM architecture is little endian while intel macs are big Endian, so we need to swap endianness if we're compiling on a big Endian architecture.
+ @param outp The destination pointer
+ @param inp The source pointer
+ @param len The length to copy
+ */
+void bson_swap_endian_len(void *outp, const void *inp, int len) {
+    const char *in = (const char *)inp;
+    char *out = (char *)outp;
+    for (int i = 0; i < len; i ++) {
+        #if __DARWIN_BIG_ENDIAN
+        out[i] = in[len - 1 - i];
+        #elif __DARWIN_LITTLE_ENDIAN
+        out[i] = in[i];
+        #endif
+    }
+}
+
+@end

ContentstackInternal/CSIOInternalHeaders.h

@@ -100,6 +100,7 @@
 @property (nonatomic, copy) NSArray *items;
 @property (nonatomic, copy) NSString *paginationToken;
 @property (nonatomic, copy) NSString *syncToken;
+@property (nonatomic, copy) NSString *seqId;
 
 @property (nonatomic, assign) BOOL hasMorePages;
 @property (nonatomic, assign) unsigned int skip;