feat(collections): add pagination to collections

Author: maniac-en

db/queries/collections.sql

@@ -1,8 +1,13 @@
 -- name: CreateCollection :one
 INSERT INTO collections (name) VALUES (?) RETURNING *;
 
--- name: GetAllCollections :many
-SELECT * FROM collections;
+-- name: GetCollectionsPaginated :many
+SELECT * FROM collections
+ORDER BY created_at DESC
+LIMIT ? OFFSET ?;
+
+-- name: CountCollections :one
+SELECT COUNT(*) FROM collections;
 
 -- name: UpdateCollectionName :one
 UPDATE collections

internal/collections/manager.go

@@ -96,10 +96,29 @@ func (c *CollectionsManager) Delete(ctx context.Context, id int64) error {
 }
 
 func (c *CollectionsManager) List(ctx context.Context) ([]CollectionEntity, error) {
-	log.Debug("listing all collections")
-	collections, err := c.DB.GetAllCollections(ctx)
+	log.Debug("listing all collections with default pagination")
+	paginated, err := c.ListPaginated(ctx, 50, 0)
 	if err != nil {
-		log.Error("failed to list collections", "error", err)
+		return nil, err
+	}
+	return paginated.Collections, nil
+}
+
+func (c *CollectionsManager) ListPaginated(ctx context.Context, limit, offset int64) (*PaginatedCollections, error) {
+	log.Debug("listing paginated collections", "limit", limit, "offset", offset)
+
+	total, err := c.DB.CountCollections(ctx)
+	if err != nil {
+		log.Error("failed to count collections", "error", err)
+		return nil, err
+	}
+
+	collections, err := c.DB.GetCollectionsPaginated(ctx, database.GetCollectionsPaginatedParams{
+		Limit:  limit,
+		Offset: offset,
+	})
+	if err != nil {
+		log.Error("failed to get paginated collections", "limit", limit, "offset", offset, "error", err)
 		return nil, err
 	}
 
@@ -108,6 +127,17 @@ func (c *CollectionsManager) List(ctx context.Context) ([]CollectionEntity, erro
 		entities[i] = CollectionEntity{Collection: collection}
 	}
 
-	log.Debug("listed collections", "count", len(entities))
-	return entities, nil
+	hasNext := offset+int64(len(collections)) < total
+	hasPrev := offset > 0
+
+	log.Debug("retrieved paginated collections", "total", total, "returned", len(entities), "has_next", hasNext, "has_prev", hasPrev)
+
+	return &PaginatedCollections{
+		Collections: entities,
+		Total:       total,
+		Offset:      offset,
+		Limit:       limit,
+		HasNext:     hasNext,
+		HasPrev:     hasPrev,
+	}, nil
 }

internal/collections/manager_test.go

@@ -3,6 +3,7 @@ package collections
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	"testing"
 
 	"github.com/maniac-en/req/internal/crud"
@@ -94,6 +95,39 @@ func TestCollectionsManagerCRUD(t *testing.T) {
 			t.Errorf("Expected at least 2 collections, got %d", len(collections))
 		}
 	})
+
+	t.Run("ListPaginated", func(t *testing.T) {
+		for i := 1; i <= 5; i++ {
+			manager.Create(ctx, fmt.Sprintf("Pagination Test %d", i))
+		}
+		
+		paginated, err := manager.ListPaginated(ctx, 2, 0)
+		if err != nil {
+			t.Fatalf("ListPaginated failed: %v", err)
+		}
+		
+		if len(paginated.Collections) != 2 {
+			t.Errorf("Expected 2 collections, got %d", len(paginated.Collections))
+		}
+		if paginated.Total < 5 {
+			t.Errorf("Expected total >= 5, got %d", paginated.Total)
+		}
+		if !paginated.HasNext {
+			t.Error("Expected HasNext to be true")
+		}
+		if paginated.HasPrev {
+			t.Error("Expected HasPrev to be false for offset 0")
+		}
+		
+		// Test second page
+		paginated2, err := manager.ListPaginated(ctx, 2, 2)
+		if err != nil {
+			t.Fatalf("ListPaginated page 2 failed: %v", err)
+		}
+		if !paginated2.HasPrev {
+			t.Error("Expected HasPrev to be true for offset > 0")
+		}
+	})
 }
 
 func TestCollectionsManagerValidation(t *testing.T) {

internal/collections/models.go

@@ -39,4 +39,13 @@ func (c CollectionEntity) GetUpdatedAt() time.Time {
 
 type CollectionsManager struct {
 	DB *database.Queries
+}
+
+type PaginatedCollections struct {
+	Collections []CollectionEntity `json:"collections"`
+	Total       int64              `json:"total"`
+	Offset      int64              `json:"offset"`
+	Limit       int64              `json:"limit"`
+	HasNext     bool               `json:"has_next"`
+	HasPrev     bool               `json:"has_prev"`
 }