Merge pull request #130 from SEMOSAN/feat/#127-course-altitude-stats

[feat] 코스 응답에 누적 상승/하강/최고 고도 추가

Author: JangInho

src/main/java/com/semosan/api/domain/mountain/dto/response/CourseDetailResponse.java

@@ -18,6 +18,9 @@ public record CourseDetailResponse(
         Integer duration,
         String startName,
         String endName,
+        Double ascent,
+        Double descent,
+        Double maxAltitude,
         @JsonRawValue String polyline,
         @JsonRawValue String altitudes
 ) {
@@ -30,6 +33,9 @@ public static CourseDetailResponse from(CourseDetailProjection p) {
                 p.getDuration(),
                 p.getStartName(),
                 p.getEndName(),
+                p.getAscent(),
+                p.getDescent(),
+                p.getMaxAltitude(),
                 p.getPolyline(),
                 p.getAltitudes()
         );

src/main/java/com/semosan/api/domain/mountain/entity/Course.java

@@ -47,6 +47,18 @@ public class Course extends BaseEntity {
     @Column(name = "end_name", length = 100)
     private String endName;
 
+    /** 누적 상승 고도(m). Σ max(0, current - previous). altitudes 없거나 점 1개 이하면 null. */
+    @Column(name = "ascent")
+    private Double ascent;
+
+    /** 누적 하강 고도(m). Σ max(0, previous - current). altitudes 없거나 점 1개 이하면 null. */
+    @Column(name = "descent")
+    private Double descent;
+
+    /** 코스 최고 고도(m). altitudes 의 max. null 가능. */
+    @Column(name = "max_altitude")
+    private Double maxAltitude;
+
     @Column(name = "polyline", columnDefinition = "geography(LineString, 4326)")
     private LineString polyline;
 

src/main/java/com/semosan/api/domain/mountain/repository/CourseRepository.java

@@ -35,6 +35,9 @@ public interface CourseRepository extends JpaRepository<Course, Long> {
                         c.duration      AS duration,
                         c.start_name    AS startName,
                         c.end_name      AS endName,
+                        c.ascent        AS ascent,
+                        c.descent       AS descent,
+                        c.max_altitude  AS maxAltitude,
                         ST_AsGeoJSON(c.polyline)::text AS polyline,
                         c.altitudes::text              AS altitudes
                     FROM courses c

src/main/java/com/semosan/api/domain/mountain/repository/projection/CourseDetailProjection.java

@@ -13,6 +13,12 @@ public interface CourseDetailProjection {
     Integer getDuration();
     String getStartName();
     String getEndName();
+    /** 누적 상승 고도(m). altitudes 없거나 점 1개 이하면 null. */
+    Double getAscent();
+    /** 누적 하강 고도(m). altitudes 없거나 점 1개 이하면 null. */
+    Double getDescent();
+    /** 코스 최고 고도(m). null 가능. */
+    Double getMaxAltitude();
     /** GeoJSON LineString 문자열 (ST_AsGeoJSON 결과). null 가능. */
     String getPolyline();
     /** 점별 고도 배열 jsonb 문자열. null 가능. */

src/main/resources/db/migration/V23__add_course_altitude_stats.sql

@@ -0,0 +1,41 @@
+-- 코스 누적 상승/하강 고도 + 최고 고도 컬럼 추가.
+-- altitudes(jsonb 숫자 배열) 를 풀어 다음 정의로 백필한다.
+--   ascent       = Σ max(0, current - previous)
+--   descent      = Σ max(0, previous - current)
+--   max_altitude = max(altitudes)
+-- altitudes 가 null 이거나 점이 1개 이하인 코스는 셋 다 NULL 로 남김.
+
+ALTER TABLE courses
+    ADD COLUMN ascent       DOUBLE PRECISION,
+    ADD COLUMN descent      DOUBLE PRECISION,
+    ADD COLUMN max_altitude DOUBLE PRECISION;
+
+WITH altitude_pairs AS (
+    SELECT
+        c.id AS course_id,
+        (a.value #>> '{}')::numeric AS altitude,
+        LAG((a.value #>> '{}')::numeric)
+            OVER (PARTITION BY c.id ORDER BY a.ordinality) AS prev_altitude
+    FROM courses c
+    CROSS JOIN LATERAL
+        jsonb_array_elements(c.altitudes) WITH ORDINALITY AS a(value, ordinality)
+    WHERE c.altitudes IS NOT NULL
+      AND jsonb_array_length(c.altitudes) > 1
+),
+calculated AS (
+    -- prev_altitude IS NULL 인 첫 점도 포함시켜 MAX(altitude) 가 모든 점을 보게 한다.
+    -- ascent/descent 의 GREATEST(0, x - NULL) 은 PostgreSQL 이 NULL 을 무시해 0 으로 처리하므로 SUM 결과에 영향 없음.
+    SELECT
+        course_id,
+        SUM(GREATEST(0, altitude - prev_altitude)) AS ascent,
+        SUM(GREATEST(0, prev_altitude - altitude)) AS descent,
+        MAX(altitude)                              AS max_altitude
+    FROM altitude_pairs
+    GROUP BY course_id
+)
+UPDATE courses c
+SET ascent       = calc.ascent,
+    descent      = calc.descent,
+    max_altitude = calc.max_altitude
+FROM calculated calc
+WHERE c.id = calc.course_id;