[FEATURE] #140 : 설문 시각 계산 로직 추가

core/model/src/main/java/com/wap/wapp/core/model/survey/Survey.kt

@@ -1,6 +1,9 @@
 package com.wap.wapp.core.model.survey
 
+import java.time.Duration
 import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
 
 /*
 회원이 작성하는 설문 모델
@@ -15,4 +18,33 @@ data class Survey(
     val content: String,
     val surveyAnswerList: List<SurveyAnswer>,
     val surveyedAt: LocalDateTime,
-)
+) {
+    fun calculateSurveyedAt(): String {
+        val currentDateTime = LocalDateTime.now(TIME_ZONE_SEOUL)
+        val duration = Duration.between(surveyedAt, currentDateTime)
+
+        if (duration.toMinutes() == 0L) {
+            return "방금"
+        } else if (duration.toMinutes() < 60) {
+            val leftMinutes = duration.toMinutes().toString()
+            return leftMinutes + "분 전 작성"
+        }
+
+        if (duration.toHours() < 24) {
+            val leftHours = duration.toHours().toString()
+            return leftHours + "시간 전 작성"
+        }
+
+        if (duration.toDays() < 31) {
+            val leftDays = duration.toDays().toString()
+            return leftDays + "일 전 작성"
+        }
+
+        return surveyedAt.format(yyyyMMddFormatter) + " 작성"
+    }
+
+    companion object {
+        val yyyyMMddFormatter = DateTimeFormatter.ofPattern("yyyy.MM.dd")
+        val TIME_ZONE_SEOUL = ZoneId.of("Asia/Seoul")
+    }
+}