Improve query findFollowsByTarget & add tests

src/main/kotlin/fr/dcproject/component/follow/database/FollowRepository.kt

@@ -74,21 +74,24 @@ sealed class FollowRepository<IN : TargetRef, OUT : TargetRef>(override var requ
         target: Entity,
         bulkSize: Int = 300
     ): Flow<FollowForView<IN>> = flow {
-        var nextPage = 1
-        do {
-            val paginate = findFollowsByTarget(target, nextPage, bulkSize)
-            paginate.result.forEach {
+        var lastId: UUID? = null
+        while (true) {
+            val result = findFollowsByTarget(target, lastId, bulkSize)
+            if (result.count() == 0) {
+                break
+            }
+            result.forEach {
                 emit(it)
             }
-            nextPage = paginate.currentPage + 1
-        } while (!paginate.isLastPage())
+            lastId = result.last().id
+        }
     }
 
     abstract fun findFollowsByTarget(
         target: Entity,
-        page: Int = 1,
+        lastId: UUID?,
         limit: Int = 300
-    ): Paginated<FollowForView<IN>>
+    ): List<FollowForView<IN>>
 }
 
 class FollowArticleRepository(requester: Requester) : FollowRepository<ArticleRef, ArticleForView>(requester) {
@@ -109,14 +112,14 @@ class FollowArticleRepository(requester: Requester) : FollowRepository<ArticleRe
 
     override fun findFollowsByTarget(
         target: Entity,
-        page: Int,
+        lastId: UUID?,
         limit: Int
-    ): Paginated<FollowForView<ArticleRef>> {
+    ): List<FollowForView<ArticleRef>> {
         return requester
             .getFunction("find_follows_article_by_target")
             .select(
-                page,
-                limit,
+                "start_id" to lastId,
+                "limit" to limit,
                 "target_id" to target.id
             )
     }
@@ -140,9 +143,9 @@ class FollowConstitutionRepository(requester: Requester) : FollowRepository<Cons
 
     override fun findFollowsByTarget(
         target: Entity,
-        page: Int,
+        lastId: UUID?,
         limit: Int
-    ): Paginated<FollowForView<ConstitutionRef>> {
+    ): List<FollowForView<ConstitutionRef>> {
         TODO("Not yet implemented")
     }
 }
@@ -165,9 +168,9 @@ class FollowCitizenRepository(requester: Requester) : FollowRepository<CitizenRe
 
     override fun findFollowsByTarget(
         target: Entity,
-        page: Int,
+        lastId: UUID?,
         limit: Int
-    ): Paginated<FollowForView<CitizenRef>> {
+    ): List<FollowForView<CitizenRef>> {
         TODO("Not yet implemented")
     }
 }

src/main/resources/sql/functions/follow/find_follows_article_by_target.sql

@@ -1,20 +1,21 @@
 create or replace function find_follows_article_by_target(
     _target_id uuid,
-    "limit" int default 50,
-    "offset" int default 0,
-    out resource json,
-    out total int
+    _limit int default 50,
+    _start_id uuid default null,
+    out resource json
 ) language plpgsql as
 $$
 declare
     _version_id uuid = (select version_id from article where id = _target_id);
+    _start_at timestamp default '2000-01-01 00:00:00'::timestamp;
+    _article_creator_id uuid = (select created_by_id from article where id = _target_id);
 begin
-    select json_agg(t), (
-        select count(f.id)
-        from follow f
-        join article a on f.target_id = a.id
-        where a.version_id = _version_id)
-    into resource, total
+    if _start_id is not null then
+        select created_at into _start_at from follow where id = _start_id;
+    end if;
+
+    select json_agg(t)
+    into resource
     from (
         select
             f.id,
@@ -22,11 +23,17 @@ begin
             f.target_reference,
             json_build_object('id', f.target_id) as target,
             find_citizen_by_id_with_user(f.created_by_id) as created_by
-        from follow_article as f
-        join article a on f.target_id = a.id
-        where a.version_id = _version_id
+        from follow as f
+        left join article a on f.target_reference = 'article'::regclass and f.target_id = a.id
+        where (
+            (f.target_reference = 'article'::regclass and a.version_id = _version_id)
+            or
+            (f.target_reference = 'citizen'::regclass and f.target_id = _article_creator_id)
+          )
+          and f.created_at >= _start_at
+          and (_start_id is null or f.id != _start_id)
         order by f.created_at
-        limit "limit" offset "offset"
+        limit _limit
     ) as t;
 end
 $$;