fix: better pagination (#2)

* remove checks

* remove pointless assertion

* sort newest-first by default

* modifications

* fix pagination

* rm newline

* spacing/inlining

api/p/memeland/memeland.gno

@@ -50,7 +50,6 @@ func (m *Memeland) PostMeme(data string, timestamp int64) string {
 	}
 
 	m.Posts = append(m.Posts, newPost)
-
 	return id
 }
 
@@ -60,18 +59,13 @@ func (m *Memeland) Upvote(id string) string {
 		panic("post with specified ID does not exist")
 	}
 
-	p, ok := post.(*Post)
-	if !ok {
-		panic("error casting post")
-	}
-
 	caller := std.PrevRealm().Addr().String()
 
-	if _, exists := p.UpvoteTracker.Get(caller); exists {
+	if _, exists := post.UpvoteTracker.Get(caller); exists {
 		panic("user has already upvoted this post")
 	}
 
-	p.UpvoteTracker.Set(caller, struct{}{})
+	post.UpvoteTracker.Set(caller, struct{}{})
 
 	return "upvote successful"
 }
@@ -103,25 +97,26 @@ func (m *Memeland) GetPostsInRange(startTimestamp, endTimestamp int64, page, pag
 	case "UPVOTES":
 		sort.Sort(UpvoteSorter(filteredPosts))
 	default:
-		break
+		// Sort by timestamp, beginning with newest
+		filteredPosts = reversePosts(filteredPosts)
 	}
 
 	// Pagination
 	startIndex := (page - 1) * pageSize
 	endIndex := startIndex + pageSize
 
+	// If page does not contain any posts
 	if startIndex >= len(filteredPosts) {
-		panic("page size too large")
+		return "[]"
 	}
 
+	// If page contains fewer posts than the page size
 	if endIndex > len(filteredPosts) {
 		endIndex = len(filteredPosts)
 	}
 
-	paginatedPosts := filteredPosts[startIndex:endIndex]
-
 	// Return JSON representation of paginated and sorted posts
-	return PostsToJSONString(paginatedPosts)
+	return PostsToJSONString(filteredPosts[startIndex:endIndex])
 }
 
 // PostsToJSONString converts a slice of Post structs into a JSON string representation.
@@ -136,8 +131,8 @@ func PostsToJSONString(posts []*Post) string {
 
 		sb.WriteString(PostToJSONString(post))
 	}
-
 	sb.WriteString("]")
+
 	return sb.String()
 }
 
@@ -170,6 +165,13 @@ func (m *Memeland) getPost(id string) *Post {
 	return nil
 }
 
+func reversePosts(posts []*Post) []*Post {
+	for i, j := 0, len(posts)-1; i < j; i, j = i+1, j-1 {
+		posts[i], posts[j] = posts[j], posts[i]
+	}
+	return posts
+}
+
 func (a UpvoteSorter) Len() int      { return len(a) }
 func (a UpvoteSorter) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
 func (a UpvoteSorter) Less(i, j int) bool {

api/p/memeland/memeland_test.gno

@@ -42,11 +42,12 @@ func TestGetPostsInRangePagination(t *testing.T) {
 		pageSize           int
 		expectedNumOfPosts int
 	}{
-		{page: 1, pageSize: 1, expectedNumOfPosts: 1},                   // one per page
-		{page: 2, pageSize: 1, expectedNumOfPosts: 1},                   // one on second page
-		{page: 1, pageSize: numOfPosts, expectedNumOfPosts: numOfPosts}, // all posts on single page
-		//{page: 10, pageSize: 10, expectedNumOfPosts: 0}, // todo fix
-		{page: 5, pageSize: numOfPosts / 5, expectedNumOfPosts: 2}, // evenly distribute posts per page
+		{page: 1, pageSize: 1, expectedNumOfPosts: 1},                       // one per page
+		{page: 2, pageSize: 1, expectedNumOfPosts: 1},                       // one on second page
+		{page: 1, pageSize: numOfPosts, expectedNumOfPosts: numOfPosts},     // all posts on single page
+		{page: 12, pageSize: 1, expectedNumOfPosts: 0},                      // empty page
+		{page: 1, pageSize: numOfPosts + 1, expectedNumOfPosts: numOfPosts}, // page with fewer posts than its size
+		{page: 5, pageSize: numOfPosts / 5, expectedNumOfPosts: 2},          // evenly distribute posts per page
 	}
 
 	for _, tc := range testCases {
@@ -66,7 +67,7 @@ func TestGetPostsInRangeByTimestamp(t *testing.T) {
 	m := NewMemeland()
 	now := time.Now()
 
-	numOfPosts := 10
+	numOfPosts := 5
 	var memeData []string
 	for i := 1; i <= numOfPosts; i++ {
 		// Prep meme data
@@ -107,7 +108,6 @@ func TestGetPostsInRangeByTimestamp(t *testing.T) {
 	}
 
 	// todo add test to check order
-
 }
 
 func TestGetPostsInRangeByUpvote(t *testing.T) {

api/r/memeland/memeland.gno

@@ -8,36 +8,23 @@ import (
 var m = memeland.NewMemeland()
 
 func PostMeme(data string, timestamp int64) string {
-	if m == nil {
-		return "memeland does not exist"
-	}
 	return m.PostMeme(data, timestamp)
 }
 
 func Upvote(id string) string {
-	if m == nil {
-		return "memeland does not exist"
-	}
 	return m.Upvote(id)
 }
 
 func GetPostsInRange(startTimestamp, endTimestamp int64, page, pageSize int, sortBy string) string {
-	if m == nil {
-		return "memeland does not exist"
-	}
-
 	return m.GetPostsInRange(startTimestamp, endTimestamp, page, pageSize, sortBy)
 }
 
 func Render(path string) string {
 	numOfMemes := int(m.MemeCounter)
 	if numOfMemes == 0 {
-		return "no memes yet :c"
+		return "No memes posted yet! :/"
 	}
 
 	// Default render is get Posts since year 2000 to now
-	postsJson := m.GetPostsInRange(952733931, time.Now().Unix(), 1, numOfMemes, "DATE_CREATED")
-	if postsJson == "[]" {
-	}
-	return postsJson
+	return m.GetPostsInRange(0, time.Now().Unix(), 1, numOfMemes, "DATE_CREATED")
 }