feat(recent): add cursor + groupby support

src/application/services/recent_service.rs

@@ -1,6 +1,8 @@
-use crate::application::dtos::recent_dto::RecentItemDto;
+use crate::application::dtos::cursor::PageCursor;
+use crate::application::dtos::recent_dto::{RecentCursor, RecentItemDto, RecentResourceRow};
 use crate::application::ports::recent_ports::{RecentItemsRepositoryPort, RecentItemsUseCase};
 use crate::common::errors::{DomainError, ErrorKind, Result};
+use crate::domain::services::authorization::ResourceKind;
 use crate::infrastructure::repositories::pg::RecentItemsPgRepository;
 use std::sync::Arc;
 use tracing::info;
@@ -109,3 +111,99 @@ impl RecentItemsUseCase for RecentService {
         Ok(())
     }
 }
+
+impl RecentService {
+    /// No authz needed — recent items are strictly user-scoped; the repository
+    /// enforces `WHERE user_id = $1` so users can only see their own entries.
+    ///
+    /// Returns `(rows, next_cursor_encoded)`.
+    pub async fn list_resources_paged(
+        &self,
+        user_id: Uuid,
+        limit: usize,
+        cursor: Option<RecentCursor>,
+        order_by: &str,
+        kinds: Option<&[ResourceKind]>,
+        reverse: bool,
+    ) -> Result<(Vec<RecentResourceRow>, Option<String>)> {
+        // Fetch one extra row to detect whether a next page exists.
+        let mut rows = self
+            .repo
+            .list_resources_paged(
+                user_id,
+                limit + 1,
+                cursor.as_ref(),
+                order_by,
+                kinds,
+                reverse,
+            )
+            .await?;
+
+        let next_cursor = if rows.len() > limit {
+            let last = &rows[limit - 1];
+            let c = build_recent_cursor(last, order_by, reverse);
+            rows.truncate(limit);
+            Some(c.encode())
+        } else {
+            None
+        };
+
+        Ok((rows, next_cursor))
+    }
+}
+
+/// Build the next-page cursor from the last row of the current page.
+/// `reverse` is stored in the cursor so subsequent pages use the same direction.
+fn build_recent_cursor(row: &RecentResourceRow, order_by: &str, reverse: bool) -> RecentCursor {
+    match order_by {
+        "name" => RecentCursor {
+            order_by: "name".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: row.sort_str.clone(), // LOWER(name)
+            sort_int: row.sort_int,         // folder_first
+            sort_ts: None,
+            reverse,
+        },
+        "type" => RecentCursor {
+            order_by: "type".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: row.sort_str.clone(), // LOWER(name)
+            sort_int: row.sort_int,         // type_order
+            sort_ts: None,
+            reverse,
+        },
+        "modified_at" => RecentCursor {
+            order_by: "modified_at".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: None,
+            sort_int: None,
+            sort_ts: row.sort_ts, // modified_at timestamp
+            reverse,
+        },
+        "size" => RecentCursor {
+            order_by: "size".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: None,
+            sort_int: row.sort_int, // size in bytes
+            sort_ts: None,
+            reverse,
+        },
+        "owner" => RecentCursor {
+            order_by: "owner".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: row.sort_str.clone(), // LOWER(username)
+            sort_int: None,
+            sort_ts: row.sort_ts, // accessed_at timestamp (secondary)
+            reverse,
+        },
+        _ => RecentCursor {
+            // default: accessed_at DESC
+            order_by: "accessed_at".to_owned(),
+            resource_id: row.resource_id,
+            sort_str: None,
+            sort_int: None,
+            sort_ts: row.sort_ts, // accessed_at timestamp
+            reverse,
+        },
+    }
+}