Implemented dedicated posts loading, part of #10

system/discourse/api/topics.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"strconv"
 )
 
 const TopicsBaseURL = "/t"
@@ -29,7 +30,8 @@ type LatestTopicsResponse struct {
 
 type SingleTopicResponse struct {
 	PostStream struct {
-		Posts []PostModel `json:"posts"`
+		Posts  []PostModel `json:"posts"`
+		Stream []int       `json:"stream"`
 	} `json:"post_stream"`
 
 	TopicModel
@@ -81,6 +83,11 @@ type TopicsService interface {
 		ctx context.Context,
 		id string,
 	) (*SingleTopicResponse, error)
+	ShowPosts(
+		ctx context.Context,
+		id string,
+		postIDs []int,
+	) (*SingleTopicResponse, error)
 	ListLatest(
 		ctx context.Context,
 		categorySlug string,
@@ -112,6 +119,33 @@ func (a *TopicServiceHandler) Show(
 	return response, nil
 }
 
+// ShowPosts
+func (a *TopicServiceHandler) ShowPosts(
+	ctx context.Context,
+	id string,
+	postIDs []int,
+) (*SingleTopicResponse, error) {
+	uri := TopicsBaseURL + "/" + id + "/posts.json"
+
+	req, err := a.client.NewRequest(ctx, http.MethodGet, uri, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	q := req.URL.Query()
+	for _, postID := range postIDs {
+		q.Add("post_ids[]", strconv.Itoa(postID))
+	}
+	req.URL.RawQuery = q.Encode()
+
+	response := new(SingleTopicResponse)
+	if err = a.client.Do(ctx, req, response); err != nil {
+		return nil, err
+	}
+
+	return response, nil
+}
+
 // List
 func (a *TopicServiceHandler) ListLatest(
 	ctx context.Context,

system/discourse/discourse.go

@@ -251,6 +251,23 @@ func (sys *System) LoadPost(p *post.Post) error {
 		return err
 	}
 
+	// API seems to return 20 posts by default. If the stream is greater than 20
+	// posts, we need to fetch the latest posts on our own, as we'd only get the
+	// first 20 posts otherwise.
+	if len(item.PostStream.Stream) > 20 {
+		replies, err := sys.client.Topics.ShowPosts(
+			context.Background(),
+			p.ID,
+			item.PostStream.Stream[len(item.PostStream.Stream)-20:],
+		)
+		if err != nil {
+			sys.logger.Error(err)
+			return err
+		}
+
+		item.PostStream.Posts = replies.PostStream.Posts
+	}
+
 	converter := md.NewConverter("", true, nil)
 
 	p.Replies = []reply.Reply{}