Add additional logic to statistic api

src/main/kotlin/com/zufar/urlshortener/auth/entity/UserDetails.kt

@@ -8,7 +8,7 @@ import java.time.LocalDateTime
 data class UserDetails(
 
     @Id
-    val id: String,
+    val id: String? = null,
     val firstName: String,
     val lastName: String,
     val password: String,

src/main/kotlin/com/zufar/urlshortener/shorten/service/UrlDeleter.kt

@@ -28,7 +28,7 @@ class UrlDeleter(
         log.info("Deleted URL mapping for urlHash='{}' successfully", urlHash)
 
         val userDetails: UserDetails = userDetailsProvider.getUserEntity()
-        val userId = userDetails.id
+        val userId = userDetails.id ?: "anonymous"
 
         statisticsUpdater.update(userId, urlHash)
         log.info("Statistics was updated for 'DeleteUrl' operation with url={}", urlHash)

src/main/kotlin/com/zufar/urlshortener/shorten/service/UrlShortener.kt

@@ -28,11 +28,11 @@ class UrlShortener(
         val originalUrl = shortenUrlRequest.originalUrl
 
         var urlHash = StringEncoder.encode(originalUrl)
-        var urlMapping = urlRepository.findByUrlHash(urlHash)
+        val urlMappingOptional = urlRepository.findByUrlHash(urlHash)
 
-        if (!urlMapping.isEmpty) {
+        if (urlMappingOptional.isPresent) {
             log.info("ShortUrl found for the urlHash='{}' in database", urlHash)
-            return urlMapping.get().shortUrl
+            return urlMappingOptional.get().shortUrl
         }
 
         log.info("No existing shortUrl found for the urlHash='{}'. Creating a new one.", urlHash)
@@ -52,11 +52,11 @@ class UrlShortener(
         val newShortUrl = "$baseUrl/url/$urlHash"
         log.info("Generated new shortURL='{}' for originalURL='{}'", newShortUrl, originalUrl)
 
-        urlMapping = urlMappingEntityCreator.create(shortenUrlRequest, httpServletRequest, urlHash, newShortUrl)
-        urlRepository.save(urlMapping)
+        val createdUrl = urlMappingEntityCreator.create(shortenUrlRequest, httpServletRequest, urlHash, newShortUrl)
+        urlRepository.save(createdUrl)
         log.info("Saved URL mapping for urlHash='{}' in MongoDB", urlHash)
 
-        val userId = urlMapping.userId ?: "anonymous"
+        val userId = createdUrl.userId ?: "anonymous"
 
         statisticsUpdater.updateStatistics(userId, urlHash, newShortUrl, originalUrl)
         log.info("Statistics was updated for 'ShortenUrl' operation with url={}", urlHash)

src/main/kotlin/com/zufar/urlshortener/statistics/entity/Statistics.kt

@@ -2,16 +2,19 @@ package com.zufar.urlshortener.statistics.entity
 
 import org.springframework.data.annotation.Id
 import org.springframework.data.mongodb.core.mapping.Document
+import java.time.LocalDateTime
 
 @Document(collection = "statistics")
 data class Statistics(
 
     @Id
-    val id: String,
+    val id: String? = null,
     val userId: String,
     val totalShortLinksCount: Long = 0,
     val totalVisitsCount: Long = 0,
-    val urlStatistics: List<UrlStatistics> = emptyList()
+    val urlStatistics: List<UrlStatistics> = emptyList(),
+    val createdAt: LocalDateTime? = null,
+    val updatedAt: LocalDateTime? = null,
 )
 
 data class UrlStatistics(

src/main/kotlin/com/zufar/urlshortener/statistics/service/StatisticsProvider.kt

@@ -15,7 +15,7 @@ class StatisticsProvider(
 
     fun get(): UserStatisticsDto {
         val user = userDetailsProvider.getUserEntity()
-        val userId = user.id
+        val userId = user.id ?: "anonymous"
         val statistics = statisticsRepository.findByUserId(userId)
 
         return if (statistics != null) {

src/main/kotlin/com/zufar/urlshortener/statistics/service/updater/DeleteOperationStatisticsUpdater.kt

@@ -3,35 +3,54 @@ package com.zufar.urlshortener.statistics.service.updater
 import com.zufar.urlshortener.shorten.repository.UrlRepository
 import com.zufar.urlshortener.statistics.entity.Statistics
 import com.zufar.urlshortener.statistics.repository.StatisticsRepository
+import org.springframework.data.mongodb.core.MongoOperations
+import org.springframework.data.mongodb.core.query.Criteria
+import org.springframework.data.mongodb.core.query.Query
 import org.springframework.stereotype.Service
+import java.time.LocalDateTime
 
 @Service
 class DeleteOperationStatisticsUpdater(
     private val statisticsRepository: StatisticsRepository,
-    private val urlRepository: UrlRepository
+    private val urlRepository: UrlRepository,
+    private val mongoOperations: MongoOperations
 ) {
 
     fun update(userId: String, urlHash: String) {
         val statistics = statisticsRepository.findByUserId(userId)
+        val now = LocalDateTime.now()
 
         if (statistics == null) {
-            val totalShortLinksCount = urlRepository.countByUserId(userId) - 1 // Subtracting the deleted URL
+            val totalShortLinksCount = urlRepository.countByUserId(userId) - 1
             val newStatistics = Statistics(
                 userId = userId,
                 totalShortLinksCount = totalShortLinksCount,
                 totalVisitsCount = 0,
-                urlStatistics = mutableListOf()
+                urlStatistics = mutableListOf(),
+                createdAt = now,
+                updatedAt = now
             )
             statisticsRepository.save(newStatistics)
             return
         }
-        // Update existing statistics
-        statistics.totalShortLinksCount -= 1
+
         val urlStat = statistics.urlStatistics.find { it.urlHash == urlHash }
-        if (urlStat != null) {
-            statistics.totalVisitsCount -= urlStat.totalVisitsCount
-            statistics.urlStatistics.remove(urlStat)
-        }
-        statisticsRepository.save(statistics)
+        val totalVisitsToDecrement = urlStat?.totalVisitsCount ?: 0
+
+        val updatedStatistics = statistics.copy(
+            totalShortLinksCount = statistics.totalShortLinksCount - 1,
+            totalVisitsCount = statistics.totalVisitsCount - totalVisitsToDecrement,
+            updatedAt = now,
+            urlStatistics = statistics.urlStatistics.filter { it.urlHash != urlHash }
+        )
+
+        val query = Query(Criteria.where("userId").`is`(userId))
+        val update = org.springframework.data.mongodb.core.query.Update()
+            .set("totalShortLinksCount", updatedStatistics.totalShortLinksCount)
+            .set("totalVisitsCount", updatedStatistics.totalVisitsCount)
+            .set("modifiedDateTime", now)
+            .pull("urlStatistics", Query.query(Criteria.where("urlHash").`is`(urlHash)))
+
+        mongoOperations.updateFirst(query, update, Statistics::class.java)
     }
 }

src/main/kotlin/com/zufar/urlshortener/statistics/service/updater/RedirectOperationStatisticsUpdater.kt

@@ -3,12 +3,16 @@ package com.zufar.urlshortener.statistics.service.updater
 import com.zufar.urlshortener.shorten.repository.UrlRepository
 import com.zufar.urlshortener.statistics.entity.Statistics
 import com.zufar.urlshortener.statistics.entity.UrlStatistics
-import com.zufar.urlshortener.statistics.repository.StatisticsRepository
+import org.springframework.data.mongodb.core.MongoOperations
+import org.springframework.data.mongodb.core.query.Criteria
+import org.springframework.data.mongodb.core.query.Query
+import org.springframework.data.mongodb.core.query.Update
 import org.springframework.stereotype.Service
+import java.time.LocalDateTime
 
 @Service
 class RedirectOperationStatisticsUpdater(
-    private val statisticsRepository: StatisticsRepository,
+    private val mongoOperations: MongoOperations,
     private val urlRepository: UrlRepository
 ) {
 
@@ -18,37 +22,44 @@ class RedirectOperationStatisticsUpdater(
         shortenedUrl: String,
         originalUrl: String
     ) {
-        val statistics = statisticsRepository.findByUserId(userId)
+        val now = LocalDateTime.now()
 
-        if (statistics == null) {
-            // Statistics data is absent, create new record
-            val totalShortLinksCount = urlRepository.countByUserId(userId)
-            val newStatistics = Statistics(
+        val query = Query(Criteria.where("userId").`is`(userId))
+
+        val update = Update()
+            .inc("totalVisitsCount", 1)
+            .set("modifiedDateTime", now)
+
+        val updateResult = mongoOperations.upsert(query, update, Statistics::class.java)
+
+        if (updateResult.upsertedId != null) {
+            val initialStatistics = Statistics(
                 userId = userId,
-                totalShortLinksCount = totalShortLinksCount,
+                totalShortLinksCount = urlRepository.countByUserId(userId),
                 totalVisitsCount = 1,
-                urlStatistics = mutableListOf(
-                    UrlStatistics(urlHash, shortenedUrl, originalUrl, totalVisitsCount = 1)
+                createdAt = now,
+                updatedAt = now,
+                urlStatistics = listOf(
+                    UrlStatistics(urlHash = urlHash, shortenedUrl = shortenedUrl, originalUrl = originalUrl, totalVisitsCount = 1)
                 )
             )
-            statisticsRepository.save(newStatistics)
+            mongoOperations.save(initialStatistics)
         } else {
-            // Update existing statistics
-            statistics.totalVisitsCount += 1
-            val urlStat = statistics.urlStatistics.find { it.urlHash == urlHash }
+            val urlStat = mongoOperations.findOne(query, Statistics::class.java)?.urlStatistics?.find {
+                it.urlHash == urlHash
+            }
             if (urlStat != null) {
-                urlStat.totalVisitsCount += 1
+                val urlUpdate = Update().inc("urlStatistics.$[elem].totalVisitsCount", 1)
+                    .filterArray(Criteria.where("elem.urlHash").`is`(urlHash))
+                    .set("modifiedDateTime", now)
+
+                mongoOperations.updateFirst(query, urlUpdate, Statistics::class.java)
             } else {
-                statistics.urlStatistics.add(
-                    UrlStatistics(
-                        urlHash = urlHash,
-                        shortenedUrl = shortenedUrl,
-                        originalUrl = originalUrl,
-                        totalVisitsCount = 1
-                    )
-                )
+                val addUrlStat = Update().push("urlStatistics", UrlStatistics(urlHash = urlHash, shortenedUrl = shortenedUrl, originalUrl = originalUrl, totalVisitsCount = 1))
+                    .set("modifiedDateTime", now)
+
+                mongoOperations.updateFirst(query, addUrlStat, Statistics::class.java)
             }
-            statisticsRepository.save(statistics)
         }
     }
 }

src/main/kotlin/com/zufar/urlshortener/statistics/service/updater/ShortenOperationStatisticsUpdater.kt

@@ -1,17 +1,17 @@
 package com.zufar.urlshortener.statistics.service.updater
 
-import com.zufar.urlshortener.shorten.repository.UrlRepository
 import com.zufar.urlshortener.statistics.entity.UrlStatistics
 import org.springframework.data.mongodb.core.MongoOperations
+import org.springframework.data.mongodb.core.aggregation.Aggregation
 import org.springframework.data.mongodb.core.query.Criteria
 import org.springframework.data.mongodb.core.query.Query
 import org.springframework.data.mongodb.core.query.Update
 import org.springframework.stereotype.Service
+import java.time.Instant
 
 @Service
 class ShortenOperationStatisticsUpdater(
-    private val mongoOperations: MongoOperations,
-    private val urlRepository: UrlRepository
+    private val mongoOperations: MongoOperations
 ) {
 
     fun updateStatistics(
@@ -20,30 +20,39 @@ class ShortenOperationStatisticsUpdater(
         shortenedUrl: String,
         originalUrl: String
     ) {
+        val currentTime = Instant.now()
+
         val query = Query(Criteria.where("userId").`is`(userId))
+
         val urlStatistics = UrlStatistics(
             urlHash = urlHash,
             shortenedUrl = shortenedUrl,
             originalUrl = originalUrl,
             totalVisitsCount = 0
         )
 
-        // Use upsert to atomically insert or update the document
         val update = Update()
             .inc("totalShortLinksCount", 1)
             .push("urlStatistics", urlStatistics)
+            .set("modifiedDateTime", currentTime)
 
         val updateResult = mongoOperations.upsert(query, update, "statistics")
 
-        // If the document didn't exist and was inserted, we need to ensure totalShortLinksCount is accurate
         if (updateResult.upsertedId != null) {
-            // Document was inserted; recalculate totalShortLinksCount
-            val totalShortLinksCount = urlRepository.countByUserId(userId)
-            mongoOperations.updateFirst(
-                query,
-                Update().set("totalShortLinksCount", totalShortLinksCount),
-                "statistics"
-            )
+            val totalShortLinksCount = mongoOperations.aggregate(
+                Aggregation.newAggregation(
+                    Aggregation.match(Criteria.where("userId").`is`(userId)),
+                    Aggregation.project("totalShortLinksCount")
+                ),
+                "statistics", Long::class.java
+            ).first()
+
+            val finalUpdate = Update()
+                .set("totalShortLinksCount", totalShortLinksCount)
+                .set("creationDateTime", currentTime)
+                .set("modifiedDateTime", currentTime)
+
+            mongoOperations.updateFirst(query, finalUpdate, "statistics")
         }
     }
 }