Merge pull request #93 from jefft0/chore/add-reactions-support

chore: Add reactions support

realm/post.gno

@@ -22,6 +22,14 @@ func (pid PostID) String() string {
 	return strconv.Itoa(int(pid))
 }
 
+// Reaction is for the "enum" of ways to react to a post
+type Reaction int
+
+const (
+	Gnod Reaction = iota
+	MaxReaction
+)
+
 // A Post is a "thread" or a "reply" depending on context.
 // A thread is a Post of a UserPosts that holds other replies.
 // This is similar to boards.Post except that this doesn't have a title.
@@ -36,6 +44,7 @@ type Post struct {
 	threadID   PostID      // original PostID
 	parentID   PostID      // parent PostID (if reply or repost)
 	repostUser std.Address // UserPosts user std.Address of original post (if repost)
+	reactions  *avl.Tree   // Reaction -> *avl.Tree of std.Address -> "" (Use the avl.Tree keys as the "set" of addresses)
 	createdAt  time.Time
 }
 
@@ -51,6 +60,7 @@ func newPost(userPosts *UserPosts, id PostID, creator std.Address, body string,
 		threadID:   threadID,
 		parentID:   parentID,
 		repostUser: repostUser,
+		reactions:  avl.NewTree(),
 		createdAt:  debugNow(),
 	}
 }
@@ -103,6 +113,60 @@ func (post *Post) GetReply(pid PostID) *Post {
 	}
 }
 
+// Add the userAddr to the posts.reactions for reaction.
+// Create the reaction key in post.reactions if needed.
+// If userAddr is already added, do nothing.
+// If the userAddr is the post's creator, do nothing. (Don't react to one's own posts.)
+// Return a boolean indicating whether the userAddr was added (false if it was already added).
+func (post *Post) AddReaction(userAddr std.Address, reaction Reaction) bool {
+	validateReaction(reaction)
+
+	if userAddr == post.creator {
+		// Don't react to one's own posts.
+		return false
+	}
+	value := getOrCreateReactionValue(post.reactions, reaction)
+	if value.Has(userAddr.String()) {
+		// Already added.
+		return false
+	}
+
+	value.Set(userAddr.String(), "")
+	return true
+}
+
+// Remove the userAddr from the posts.reactions for reaction.
+// If userAddr is already removed, do nothing.
+// Return a boolean indicating whether the userAddr was found and removed.
+func (post *Post) RemoveReaction(userAddr std.Address, reaction Reaction) bool {
+	validateReaction(reaction)
+
+	if !post.reactions.Has(reactionKey(reaction)) {
+		// There is no entry for reaction, so don't create one.
+		return false
+	}
+
+	_, removed := getOrCreateReactionValue(post.reactions, reaction).Remove(userAddr.String())
+	return removed
+}
+
+// Return the count of reactions for the reaction.
+func (post *Post) GetReactionCount(reaction Reaction) int {
+	key := reactionKey(reaction)
+	valueI, exists := post.reactions.Get(key)
+	if exists {
+		return valueI.(*avl.Tree).Size()
+	} else {
+		return 0
+	}
+}
+
+func validateReaction(reaction Reaction) {
+	if reaction < 0 || reaction >= MaxReaction {
+		panic("invalid Reaction value: " + strconv.Itoa(int(reaction)))
+	}
+}
+
 func (post *Post) GetSummary() string {
 	return summaryOf(post.body, 80)
 }
@@ -117,6 +181,14 @@ func (post *Post) GetURL() string {
 	}
 }
 
+func (post *Post) GetGnodFormURL() string {
+	return "/r/berty/social?help&__func=AddReaction" +
+		"&userPostsAddr=" + post.userPosts.userAddr.String() +
+		"&threadid=" + post.threadID.String() +
+		"&postid=" + post.id.String() +
+		"&reaction=" + strconv.Itoa(int(Gnod))
+}
+
 func (post *Post) GetReplyFormURL() string {
 	return "/r/berty/social?help&__func=PostReply" +
 		"&userPostsAddr=" + post.userPosts.userAddr.String() +
@@ -149,6 +221,7 @@ func (post *Post) RenderSummary() string {
 	str += post.GetSummary() + "\n"
 	str += "\\- " + displayAddressMD(post.creator) + ","
 	str += " [" + post.createdAt.Format("2006-01-02 3:04pm MST") + "](" + post.GetURL() + ")"
+	str += " (" + strconv.Itoa(post.GetReactionCount(Gnod)) + " gnods)"
 	str += " (" + strconv.Itoa(post.replies.Size()) + " replies)"
 	str += " (" + strconv.Itoa(post.reposts.Size()) + " reposts)" + "\n"
 	return str
@@ -162,6 +235,8 @@ func (post *Post) RenderPost(indent string, levels int) string {
 	str += indentBody(indent, post.body) + "\n" // TODO: indent body lines.
 	str += indent + "\\- " + displayAddressMD(post.creator) + ", "
 	str += "[" + post.createdAt.Format("2006-01-02 3:04pm (MST)") + "](" + post.GetURL() + ")"
+	str += " - (" + strconv.Itoa(post.GetReactionCount(Gnod)) + " gnods) - "
+	str += " \\[[gnod](" + post.GetGnodFormURL() + ")]"
 	str += " \\[[reply](" + post.GetReplyFormURL() + ")]"
 	if post.IsThread() {
 		str += " \\[[repost](" + post.GetRepostFormURL() + ")]"
@@ -217,8 +292,9 @@ func (post *Post) MarshalJSON() ([]byte, error) {
 
 	json := new(bytes.Buffer)
 
-	json.WriteString(ufmt.Sprintf(`{"id": %d, "createdAt": %s, "creator": "%s", "n_replies": %d, "n_replies_all": %d, "parent_id": %d`,
-		uint64(post.id), string(createdAt), post.creator.String(), post.replies.Size(), post.repliesAll.Size(), uint64(post.parentID)))
+	json.WriteString(ufmt.Sprintf(`{"id": %d, "createdAt": %s, "creator": "%s", "n_gnods": %d, "n_replies": %d, "n_replies_all": %d, "parent_id": %d`,
+		uint64(post.id), string(createdAt), post.creator.String(), post.GetReactionCount(Gnod), post.replies.Size(), post.repliesAll.Size(),
+		uint64(post.parentID)))
 	if post.repostUser != "" {
 		json.WriteString(ufmt.Sprintf(`, "repost_user": %s`, strconv.Quote(post.repostUser.String())))
 	}

realm/public.gno

@@ -256,6 +256,66 @@ func Unfollow(followedAddr std.Address) {
 	userPosts.Unfollow(followedAddr)
 }
 
+// Add the reaction by the caller to the post of userPostsAddr, where threadid is the ID
+// returned by the original call to PostMessage. If postid == threadid then add the reaction
+// to a top-level post for the threadid, otherwise add the reaction to the postid "sub reply".
+// (This function's arguments are similar to PostReply.)
+// The caller must already be registered with /r/demo/users Register.
+// Return a boolean indicating whether the userAddr was added. See Post.AddReaction.
+func AddReaction(userPostsAddr std.Address, threadid, postid PostID, reaction Reaction) bool {
+	caller := std.GetOrigCaller()
+	if usernameOf(caller) == "" {
+		panic("please register")
+	}
+	userPosts := getUserPosts(userPostsAddr)
+	if userPosts == nil {
+		panic("posts for userPostsAddr do not exist")
+	}
+	thread := userPosts.GetThread(threadid)
+	if thread == nil {
+		panic("threadid in user posts does not exist")
+	}
+	if postid == threadid {
+		return thread.AddReaction(caller, reaction)
+	} else {
+		post := thread.GetReply(postid)
+		if post == nil {
+			panic("postid does not exist")
+		}
+		return post.AddReaction(caller, reaction)
+	}
+}
+
+// Remove the reaction by the caller to the post of userPostsAddr, where threadid is the ID
+// returned by the original call to PostMessage. If postid == threadid then remove the reaction
+// from a top-level post for the threadid, otherwise remove the reaction from the postid "sub reply".
+// (This function's arguments are similar to PostReply.)
+// The caller must already be registered with /r/demo/users Register.
+// Return a boolean indicating whether the userAddr was removed. See Post.RemoveReaction.
+func RemoveReaction(userPostsAddr std.Address, threadid, postid PostID, reaction Reaction) bool {
+	caller := std.GetOrigCaller()
+	if usernameOf(caller) == "" {
+		panic("please register")
+	}
+	userPosts := getUserPosts(userPostsAddr)
+	if userPosts == nil {
+		panic("posts for userPostsAddr do not exist")
+	}
+	thread := userPosts.GetThread(threadid)
+	if thread == nil {
+		panic("threadid in user posts does not exist")
+	}
+	if postid == threadid {
+		return thread.RemoveReaction(caller, reaction)
+	} else {
+		post := thread.GetReply(postid)
+		if post == nil {
+			panic("postid does not exist")
+		}
+		return post.RemoveReaction(caller, reaction)
+	}
+}
+
 // Call users.GetUserByAddress and return the result as JSON, or "" if not found.
 // (This is a temporary utility until gno.land supports returning structured data directly.)
 func GetJsonUserByAddress(addr std.Address) string {

realm/util.gno

@@ -5,6 +5,7 @@ import (
 	"strconv"
 	"strings"
 
+	"gno.land/p/demo/avl"
 	"gno.land/p/demo/ufmt"
 	p_users "gno.land/p/demo/users"
 	"gno.land/r/demo/users"
@@ -60,6 +61,24 @@ func postIDKey(pid PostID) string {
 	return padZero(uint64(pid), 10)
 }
 
+func reactionKey(reaction Reaction) string {
+	return strconv.Itoa(int(reaction))
+}
+
+// If reactions has an value for the given reaction, then return it.
+// Otherwise, add the reaction key to reactions, set the value to an empty avl.Tree and return it.
+func getOrCreateReactionValue(reactions *avl.Tree, reaction Reaction) *avl.Tree {
+	key := reactionKey(reaction)
+	valueI, exists := reactions.Get(key)
+	if exists {
+		return valueI.(*avl.Tree)
+	} else {
+		value := avl.NewTree()
+		reactions.Set(key, value)
+		return value
+	}
+}
+
 func indentBody(indent string, body string) string {
 	lines := strings.Split(body, "\n")
 	res := ""