WIP: load more comments for a post

Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>

comment.go

@@ -2,6 +2,7 @@ package reddit
 
 import (
 	"context"
+	"errors"
 	"net/http"
 	"net/url"
 )
@@ -63,3 +64,69 @@ func (s *CommentService) Edit(ctx context.Context, id string, text string) (*Com
 
 	return root, resp, nil
 }
+
+// LoadMoreReplies retrieves more replies that were left out when initially fetching the comment.
+func (s *CommentService) LoadMoreReplies(ctx context.Context, comment *Comment) (*Response, error) {
+	if comment == nil {
+		return nil, errors.New("comment: must not be nil")
+	}
+
+	if !comment.hasMore() {
+		return nil, nil
+	}
+
+	postID := comment.PostID
+	commentIDs := comment.Replies.MoreComments.Children
+
+	type query struct {
+		PostID  string   `url:"link_id"`
+		IDs     []string `url:"children,comma"`
+		APIType string   `url:"api_type"`
+	}
+
+	path := "api/morechildren"
+	path, err := addOptions(path, query{postID, commentIDs, "json"})
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := s.client.NewRequest(http.MethodGet, path, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	type rootResponse struct {
+		JSON struct {
+			Data struct {
+				Things Things `json:"things"`
+			} `json:"data"`
+		} `json:"json"`
+	}
+
+	root := new(rootResponse)
+	resp, err := s.client.Do(ctx, req, root)
+	if err != nil {
+		return resp, err
+	}
+
+	comments := root.JSON.Data.Things.Comments
+	for _, c := range comments {
+		addCommentToReplies(comment, c)
+	}
+
+	comment.Replies.MoreComments = nil
+	return resp, nil
+}
+
+// addCommentToReplies traverses the comment tree to find the one
+// that the 2nd comment is replying to. It then adds it to its replies.
+func addCommentToReplies(parent *Comment, comment *Comment) {
+	if parent.FullID == comment.ParentID {
+		parent.Replies.Comments = append(parent.Replies.Comments, comment)
+		return
+	}
+
+	for _, reply := range parent.Replies.Comments {
+		addCommentToReplies(reply, comment)
+	}
+}

post.go

@@ -65,20 +65,20 @@ type SubmitLinkOptions struct {
 // Get returns a post with its comments.
 // id is the ID36 of the post, not its full id.
 // Example: instead of t3_abc123, use abc123.
-func (s *PostService) Get(ctx context.Context, id string) (*Post, []*Comment, *Response, error) {
+func (s *PostService) Get(ctx context.Context, id string) (*PostAndComments, *Response, error) {
 	path := fmt.Sprintf("comments/%s", id)
 	req, err := s.client.NewRequest(http.MethodGet, path, nil)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, err
 	}
 
-	root := new(postAndComments)
+	root := new(PostAndComments)
 	resp, err := s.client.Do(ctx, req, root)
 	if err != nil {
-		return nil, nil, resp, err
+		return nil, resp, err
 	}
 
-	return root.Post, root.Comments, resp, nil
+	return root, resp, nil
 }
 
 func (s *PostService) submit(ctx context.Context, v interface{}) (*Submitted, *Response, error) {
@@ -433,24 +433,18 @@ func (s *PostService) DisableContestMode(ctx context.Context, id string) (*Respo
 	return s.client.Do(ctx, req, nil)
 }
 
-// More retrieves more comments that were left out when initially fetching the post.
+// LoadMoreComments retrieves more comments that were left out when initially fetching the post.
-// id is the post's full ID.
+func (s *PostService) LoadMoreComments(ctx context.Context, pc *PostAndComments) (*Response, error) {
-// commentIDs are the ID36s of comments.
+	if pc == nil {
-func (s *PostService) More(ctx context.Context, comment *Comment) (*Response, error) {
+		return nil, errors.New("pc: must not be nil")
-	if comment == nil {
-		return nil, errors.New("comment: must not be nil")
 	}
 
-	if comment.Replies.MoreComments == nil {
+	if !pc.hasMore() {
 		return nil, nil
 	}
 
-	postID := comment.PostID
+	postID := pc.Post.FullID
-	commentIDs := comment.Replies.MoreComments.Children
+	commentIDs := pc.moreComments.Children
-
-	if len(commentIDs) == 0 {
-		return nil, nil
-	}
 
 	type query struct {
 		PostID  string   `url:"link_id"`
@@ -485,22 +479,20 @@ func (s *PostService) More(ctx context.Context, comment *Comment) (*Response, er
 
 	comments := root.JSON.Data.Things.Comments
 	for _, c := range comments {
-		addCommentToReplies(comment, c)
+		addCommentToTree(pc, c)
 	}
 
-	comment.Replies.MoreComments = nil
+	pc.moreComments = nil
 	return resp, nil
 }
 
-// addCommentToReplies traverses the comment tree to find the one
+func addCommentToTree(pc *PostAndComments, comment *Comment) {
-// that the 2nd comment is replying to. It then adds it to its replies.
+	if pc.Post.FullID == comment.ParentID {
-func addCommentToReplies(parent *Comment, comment *Comment) {
+		pc.Comments = append(pc.Comments, comment)
-	if parent.FullID == comment.ParentID {
-		parent.Replies.Comments = append(parent.Replies.Comments, comment)
 		return
 	}
 
-	for _, reply := range parent.Replies.Comments {
+	for _, reply := range pc.Comments {
 		addCommentToReplies(reply, comment)
 	}
 }
@@ -516,7 +508,7 @@ func (s *PostService) random(ctx context.Context, subreddits ...string) (*Post,
 		return nil, nil, nil, err
 	}
 
-	root := new(postAndComments)
+	root := new(PostAndComments)
 	resp, err := s.client.Do(ctx, req, root)
 	if err != nil {
 		return nil, nil, resp, err

subreddit.go

@@ -294,7 +294,7 @@ func (s *SubredditService) getSticky(ctx context.Context, subreddit string, num
 		return nil, nil, nil, err
 	}
 
-	root := new(postAndComments)
+	root := new(PostAndComments)
 	resp, err := s.client.Do(ctx, req, root)
 	if err != nil {
 		return nil, nil, resp, err

things.go

@@ -58,7 +58,7 @@ type Listing struct {
 // Things are objects/entities coming from the Reddit API.
 type Things struct {
 	Comments     []*Comment
-	MoreComments []*More
+	MoreComments *More
 
 	Users      []*User
 	Posts      []*Post
@@ -71,9 +71,6 @@ func (t *Things) init() {
 	if t.Comments == nil {
 		t.Comments = make([]*Comment, 0)
 	}
-	if t.MoreComments == nil {
-		t.MoreComments = make([]*More, 0)
-	}
 	if t.Users == nil {
 		t.Users = make([]*User, 0)
 	}
@@ -110,7 +107,7 @@ func (t *Things) UnmarshalJSON(b []byte) error {
 		case kindMore:
 			v := new(More)
 			if err := json.Unmarshal(byteValue, v); err == nil {
-				t.MoreComments = append(t.MoreComments, v)
+				t.MoreComments = v
 			}
 		case kindAccount:
 			v := new(User)
@@ -190,6 +187,10 @@ type Comment struct {
 	Replies Replies `json:"replies"`
 }
 
+func (c *Comment) hasMore() bool {
+	return c.Replies.MoreComments != nil && len(c.Replies.MoreComments.Children) > 0
+}
+
 // Replies holds replies to a comment.
 // It contains both comments and "more" comments, which are entrypoints to other
 // comments that were left out.
@@ -214,9 +215,7 @@ func (r *Replies) UnmarshalJSON(data []byte) error {
 
 	if root.Data != nil {
 		r.Comments = root.Data.Things.Comments
-		if len(root.Data.Things.MoreComments) > 0 {
+		r.MoreComments = root.Data.Things.MoreComments
-			r.MoreComments = root.Data.Things.MoreComments[0]
-		}
 	}
 
 	return nil
@@ -329,6 +328,13 @@ func (rl *rootListing) getComments() *Comments {
 	return v
 }
 
+func (rl *rootListing) getMoreComments() *More {
+	if rl == nil || rl.Data == nil {
+		return nil
+	}
+	return rl.Data.Things.MoreComments
+}
+
 func (rl *rootListing) getUsers() *Users {
 	v := new(Users)
 	if rl != nil && rl.Data != nil {
@@ -404,17 +410,18 @@ type ModActions struct {
 	Before     string       `json:"before"`
 }
 
-// postAndComments is a post and its comments
+// PostAndComments is a post and its comments.
-type postAndComments struct {
+type PostAndComments struct {
-	Post     *Post
+	Post         *Post      `json:"post"`
-	Comments []*Comment
+	Comments     []*Comment `json:"comments"`
+	moreComments *More
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface.
 // When getting a sticky post, you get an array of 2 Listings
 // The 1st one contains the single post in its children array
 // The 2nd one contains the comments to the post
-func (pc *postAndComments) UnmarshalJSON(data []byte) error {
+func (pc *PostAndComments) UnmarshalJSON(data []byte) error {
 	var l []rootListing
 
 	err := json.Unmarshal(data, &l)
@@ -428,9 +435,17 @@ func (pc *postAndComments) UnmarshalJSON(data []byte) error {
 
 	post := l[0].getPosts().Posts[0]
 	comments := l[1].getComments().Comments
+	moreComments := l[1].getMoreComments()
 
 	pc.Post = post
 	pc.Comments = comments
+	pc.moreComments = moreComments
 
 	return nil
 }
+
+func (pc *PostAndComments) hasMore() bool {
+	return pc.moreComments != nil && len(pc.moreComments.Children) > 0
+}
+
+func (pc *PostAndComments) M() *More { return pc.moreComments }