feat(boards2): add core flagging logic (#3451)

Add flagging support for boards2 realm.

Closes #3146

examples/gno.land/r/demo/boards2/board.gno

@@ -100,8 +100,13 @@ func (board *Board) Render() string {
 	s := "\\[" + newLink("post", board.GetPostFormURL()) + "]\n\n"
 	if board.threads.Size() > 0 {
 		board.threads.Iterate("", "", func(_ string, v interface{}) bool {
+			post := v.(*Post)
+			if post.isHidden {
+				return false
+			}
+
 			s += "----------------------------------------\n"
-			s += v.(*Post).RenderSummary() + "\n"
+			s += post.RenderSummary() + "\n"
 			return false
 		})
 	}

examples/gno.land/r/demo/boards2/flag.gno

@@ -0,0 +1,47 @@
+package boards2
+
+import (
+	"std"
+	"strconv"
+)
+
+const flagThreshold = 1
+
+type Flag struct {
+	User   std.Address
+	Reason string
+}
+
+func NewFlag(creator std.Address, reason string) Flag {
+	return Flag{
+		User:   creator,
+		Reason: reason,
+	}
+}
+
+type Flaggable interface {
+	// AddFlag adds a new flag to an item.
+	//
+	// Returns false if item was already flagged by user.
+	AddFlag(flag Flag) bool
+
+	// FlagsCount returns number of times item was flagged.
+	FlagsCount() int
+}
+
+// flagItem adds a flag to a flaggable item (post, thread, etc).
+//
+// Returns whether flag count threshold is reached and item can be hidden.
+//
+// Panics if flag count threshold was already reached.
+func flagItem(item Flaggable, flag Flag) bool {
+	if item.FlagsCount() >= flagThreshold {
+		panic("item flag count threshold exceeded: " + strconv.Itoa(flagThreshold))
+	}
+
+	if !item.AddFlag(flag) {
+		panic("item has been already flagged by a current user")
+	}
+
+	return item.FlagsCount() == flagThreshold
+}

examples/gno.land/r/demo/boards2/permission.gno

@@ -7,8 +7,10 @@ const (
 	PermissionThreadCreate            = "thread:create"
 	PermissionThreadEdit              = "thread:edit"
 	PermissionThreadDelete            = "thread:delete"
+	PermissionThreadFlag              = "thread:flag"
 	PermissionThreadRepost            = "thread:repost"
 	PermissionReplyDelete             = "reply:delete"
+	PermissionReplyFlag               = "reply:flag"
 	PermissionMemberInvite            = "member:invite"
 	PermissionMemberRemove            = "member:remove"
 )

examples/gno.land/r/demo/boards2/post.gno

@@ -30,12 +30,14 @@ type Post struct {
 	creator       std.Address
 	title         string // optional
 	body          string
+	isHidden      bool
 	replies       avl.Tree // Post.id -> *Post
 	repliesAll    avl.Tree // Post.id -> *Post (all replies, for top-level posts)
 	reposts       avl.Tree // Board.id -> Post.id
-	threadID      PostID   // original Post.id
-	parentID      PostID   // parent Post.id (if reply or repost)
-	repostBoardID BoardID  // original Board.id (if repost)
+	flags         []Flag
+	threadID      PostID  // original Post.id
+	parentID      PostID  // parent Post.id (if reply or repost)
+	repostBoardID BoardID // original Board.id (if repost)
 	createdAt     time.Time
 	updatedAt     time.Time
 }
@@ -97,6 +99,30 @@ func (post *Post) GetUpdatedAt() time.Time {
 	return post.updatedAt
 }
 
+func (post *Post) AddFlag(flag Flag) bool {
+	// TODO: sort flags for fast search in case of big thresholds
+	for _, v := range post.flags {
+		if v.User == flag.User {
+			return false
+		}
+	}
+
+	post.flags = append(post.flags, flag)
+	return true
+}
+
+func (post *Post) FlagsCount() int {
+	return len(post.flags)
+}
+
+func (post *Post) SetVisible(isVisible bool) {
+	post.isHidden = !isVisible
+}
+
+func (post *Post) IsHidden() bool {
+	return post.isHidden
+}
+
 func (post *Post) AddReply(creator std.Address, body string) *Post {
 	board := post.board
 	pid := board.incGetPostID()
@@ -219,6 +245,11 @@ func (post *Post) RenderSummary() string {
 		if !found {
 			return "reposted post does not exist"
 		}
+
+		if thread.isHidden {
+			return "reposted post was hidden"
+		}
+
 		return "Repost: " + post.GetSummary() + "\n" + thread.RenderSummary()
 	}
 
@@ -267,8 +298,14 @@ func (post *Post) Render(indent string, levels int) string {
 	if levels > 0 {
 		if post.replies.Size() > 0 {
 			post.replies.Iterate("", "", func(_ string, value interface{}) bool {
+				reply := value.(*Post)
+				if reply.isHidden {
+					// TODO: change this in case of pagination
+					return false
+				}
+
 				s += indent + "\n"
-				s += value.(*Post).Render(indent+"> ", levels-1)
+				s += reply.Render(indent+"> ", levels-1)
 				return false
 			})
 		}

examples/gno.land/r/demo/boards2/post_test.gno

@@ -23,6 +23,27 @@ func TestPostUpdate(t *testing.T) {
 	uassert.False(t, post.GetUpdatedAt().IsZero())
 }
 
+func TestPostAddFlag(t *testing.T) {
+	addr := testutils.TestAddress("creator")
+	post := createTestThread(t)
+
+	flag := NewFlag(addr, "foobar")
+	uassert.True(t, post.AddFlag(flag))
+	uassert.False(t, post.AddFlag(flag), "should reject flag from duplicate user")
+	uassert.Equal(t, post.FlagsCount(), 1)
+}
+
+func TestPostSetVisible(t *testing.T) {
+	post := createTestThread(t)
+	uassert.False(t, post.IsHidden(), "post should be visible by default")
+
+	post.SetVisible(false)
+	uassert.True(t, post.IsHidden(), "post should be hidden")
+
+	post.SetVisible(true)
+	uassert.False(t, post.IsHidden(), "post should be visible")
+}
+
 func TestPostAddRepostTo(t *testing.T) {
 	cases := []struct {
 		name, title, body string

examples/gno.land/r/demo/boards2/public.gno

@@ -36,6 +36,21 @@ func CreateBoard(name string) BoardID {
 	return id
 }
 
+func FlagThread(bid BoardID, postID PostID, reason string) {
+	caller := std.GetOrigCaller()
+	board := mustGetBoard(bid)
+	assertHasBoardPermission(board, caller, PermissionThreadFlag)
+
+	t, ok := board.GetThread(postID)
+	if !ok {
+		panic("post doesn't exist")
+	}
+
+	if flagItem(t, NewFlag(caller, reason)) {
+		t.SetVisible(false)
+	}
+}
+
 func CreateThread(bid BoardID, title, body string) PostID {
 	assertIsUserCall()
 
@@ -57,21 +72,38 @@ func CreateReply(bid BoardID, threadID, replyID PostID, body string) PostID {
 	board := mustGetBoard(bid)
 	thread := mustGetThread(board, threadID)
 
+	assertThreadVisible(thread)
+
 	// TODO: Assert thread is not locked
 	// TODO: Assert that caller is a board member (when board type is invite only)
-
 	var reply *Post
 	if replyID == threadID {
 		// When the parent reply is the thread just add reply to thread
 		reply = thread.AddReply(caller, body)
 	} else {
 		// Try to get parent reply and add a new child reply
 		post := mustGetReply(thread, replyID)
+		assertReplyVisible(post)
+
 		reply = post.AddReply(caller, body)
 	}
 	return reply.id
 }
 
+func FlagReply(bid BoardID, threadID, replyID PostID, reason string) {
+	caller := std.GetOrigCaller()
+
+	board := mustGetBoard(bid)
+	assertHasBoardPermission(board, caller, PermissionThreadFlag)
+
+	thread := mustGetThread(board, threadID)
+	reply := mustGetReply(thread, replyID)
+
+	if hide := flagItem(reply, NewFlag(caller, reason)); hide {
+		reply.SetVisible(false)
+	}
+}
+
 func CreateRepost(bid BoardID, threadID PostID, title, body string, dstBoardID BoardID) PostID {
 	assertIsUserCall()
 
@@ -216,3 +248,15 @@ func assertReplyExists(thread *Post, replyID PostID) {
 		panic("reply not found: " + replyID.String())
 	}
 }
+
+func assertThreadVisible(thread *Post) {
+	if thread.IsHidden() {
+		panic("thread with ID: " + thread.GetPostID().String() + " was hidden")
+	}
+}
+
+func assertReplyVisible(thread *Post) {
+	if thread.IsHidden() {
+		panic("reply with ID: " + thread.GetPostID().String() + " was hidden")
+	}
+}

examples/gno.land/r/demo/boards2/render.gno

@@ -59,7 +59,9 @@ func renderThread(res *mux.ResponseWriter, req *mux.Request) {
 	board := v.(*Board)
 	thread, found := board.GetThread(PostID(tID))
 	if !found {
-		res.Write("Thread does not exist with ID: " + req.GetVar("thread"))
+		res.Write("Thread does not exist with ID: " + rawID)
+	} else if thread.IsHidden() {
+		res.Write("Thread with ID: " + rawID + " has been flagged as inappropriate")
 	} else {
 		res.Write(thread.Render("", 5))
 	}
@@ -96,7 +98,9 @@ func renderReply(res *mux.ResponseWriter, req *mux.Request) {
 
 	reply, found := thread.GetReply(PostID(rID))
 	if !found {
-		res.Write("Reply does not exist with ID: " + req.GetVar("reply"))
+		res.Write("Reply does not exist with ID: " + rawID)
+	} else if reply.IsHidden() {
+		res.Write("Reply with ID: " + rawID + " was hidden")
 	} else {
 		res.Write(reply.RenderInner())
 	}

examples/gno.land/r/demo/boards2/z_2_a_filetest.gno

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/demo/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+func init() {
+	std.TestSetOrigCaller(owner)
+}
+
+func main() {
+	bid := boards2.CreateBoard("test1")
+	pid := boards2.CreateThread(bid, "thread", "thread")
+	boards2.FlagThread(bid, pid, "reason")
+	_ = boards2.CreateReply(bid, pid, pid, "reply")
+}
+
+// Error:
+// thread with ID: 1 was hidden

examples/gno.land/r/demo/boards2/z_2_b_filetest.gno

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/demo/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+func init() {
+	std.TestSetOrigCaller(owner)
+}
+
+func main() {
+	// ensure that nested replies denied if root thread is hidden.
+	bid := boards2.CreateBoard("test1")
+	pid := boards2.CreateThread(bid, "thread", "thread")
+	rid := boards2.CreateReply(bid, pid, pid, "reply1")
+
+	boards2.FlagThread(bid, pid, "reason")
+	_ = boards2.CreateReply(bid, pid, rid, "reply1.1")
+}
+
+// Error:
+// thread with ID: 1 was hidden

examples/gno.land/r/demo/boards2/z_2_c_filetest.gno

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/demo/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+func init() {
+	std.TestSetOrigCaller(owner)
+}
+
+func main() {
+	// ensure that nested replies denied if root thread is hidden.
+	bid := boards2.CreateBoard("test1")
+	pid := boards2.CreateThread(bid, "thread", "thread")
+	rid := boards2.CreateReply(bid, pid, pid, "reply1")
+
+	boards2.FlagReply(bid, pid, rid, "reason")
+	_ = boards2.CreateReply(bid, pid, rid, "reply1.1")
+}
+
+// Error:
+// reply with ID: 2 was hidden

examples/gno.land/r/demo/boards2/z_2_d_filetest.gno

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/demo/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+func init() {
+	std.TestSetOrigCaller(owner)
+}
+
+func main() {
+	// Only single user per flag can't be tested atm, as flagThreshold = 1.
+	bid := boards2.CreateBoard("test1")
+	pid := boards2.CreateThread(bid, "thread", "thread")
+
+	boards2.FlagThread(bid, pid, "reason1")
+	boards2.FlagThread(bid, pid, "reason2")
+}
+
+// Error:
+// item flag count threshold exceeded: 1