From e8aa350c53acc6046401e5c5242199a064a577a1 Mon Sep 17 00:00:00 2001
From: ChronosX88 <chronosx88@gmail.com>
Date: Wed, 26 Jan 2022 00:29:30 +0300
Subject: [PATCH] Implement NEWGROUPS command

---
 README.md                           |  2 +-
 internal/backend/sqlite/sqlite.go   |  5 ++
 internal/backend/storage_backend.go |  1 +
 internal/protocol/constants.go      |  2 +
 internal/server/handler.go          | 74 +++++++++++++++++++++++++++--
 5 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 0567513..044bbaa 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@
 - :x: `IHAVE`
 - :x: `LAST`
 - :x: `LISTGROUP`
-- :x: `NEWGROUPS`
+- :heavy_check_mark: `NEWGROUPS`
 - :x: `NEWNEWS`
 - :x: `NEXT`
 - :x: `OVER`
diff --git a/internal/backend/sqlite/sqlite.go b/internal/backend/sqlite/sqlite.go
index cdfb3e5..b07c414 100644
--- a/internal/backend/sqlite/sqlite.go
+++ b/internal/backend/sqlite/sqlite.go
@@ -88,3 +88,8 @@ func (sb *SQLiteBackend) GetGroup(groupName string) (models.Group, error) {
 	var group models.Group
 	return group, sb.db.Get(&group, "SELECT * FROM groups WHERE group_name = ?", groupName)
 }
+
+func (sb *SQLiteBackend) GetNewGroupsSince(timestamp int64) ([]models.Group, error) {
+	var groups []models.Group
+	return groups, sb.db.Select(&groups, "SELECT * FROM groups WHERE created_at > ?", timestamp)
+}
diff --git a/internal/backend/storage_backend.go b/internal/backend/storage_backend.go
index 3a01bac..112aa5b 100644
--- a/internal/backend/storage_backend.go
+++ b/internal/backend/storage_backend.go
@@ -10,6 +10,7 @@ type StorageBackend interface {
 	ListGroups() ([]models.Group, error)
 	ListGroupsByPattern(pattern string) ([]models.Group, error)
 	GetGroup(groupName string) (models.Group, error)
+	GetNewGroupsSince(timestamp int64) ([]models.Group, error)
 	GetArticlesCount(g models.Group) (int, error)
 	GetGroupLowWaterMark(g models.Group) (int, error)
 	GetGroupHighWaterMark(g models.Group) (int, error)
diff --git a/internal/protocol/constants.go b/internal/protocol/constants.go
index 49a7f52..015f0cd 100644
--- a/internal/protocol/constants.go
+++ b/internal/protocol/constants.go
@@ -12,6 +12,7 @@ const (
 	CommandMode         = "MODE"
 	CommandList         = "LIST"
 	CommandGroup        = "GROUP"
+	CommandNewGroups    = "NEWGROUPS"
 )
 
 const (
@@ -34,6 +35,7 @@ const (
 	MessageUnknownCommand                    = "500 Unknown command"
 	MessageErrorHappened                     = "403 Failed to process command:"
 	MessageListOfNewsgroupsFollows           = "215 list of newsgroups follows"
+	MessageNewGroupsListOfNewsgroupsFollows  = "231 list of new newsgroups follows"
 	MessageSyntaxError                       = "501 Syntax Error"
 	MessageNoSuchGroup                       = "411 No such newsgroup"
 )
diff --git a/internal/server/handler.go b/internal/server/handler.go
index 7fb3260..2143567 100644
--- a/internal/server/handler.go
+++ b/internal/server/handler.go
@@ -25,6 +25,7 @@ func NewHandler(b backend.StorageBackend) *Handler {
 		protocol.CommandList:         h.handleList,
 		protocol.CommandMode:         h.handleModeReader,
 		protocol.CommandGroup:        h.handleGroup,
+		protocol.CommandNewGroups:    h.handleNewGroups,
 	}
 	return h
 }
@@ -157,19 +158,20 @@ func (h *Handler) handleGroup(s *Session, arguments []string, id uint) error {
 	if err != nil {
 		if err == sql.ErrNoRows {
 			return s.tconn.PrintfLine(protocol.MessageNoSuchGroup)
+		} else {
+			return err
 		}
-		return err
 	}
 	highWaterMark, err := h.backend.GetGroupHighWaterMark(g)
-	if err != nil {
+	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
 	lowWaterMark, err := h.backend.GetGroupLowWaterMark(g)
-	if err != nil {
+	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
 	articlesCount, err := h.backend.GetArticlesCount(g)
-	if err != nil {
+	if err != nil && err != sql.ErrNoRows {
 		return err
 	}
 
@@ -178,6 +180,70 @@ func (h *Handler) handleGroup(s *Session, arguments []string, id uint) error {
 	return s.tconn.PrintfLine("211 %d %d %d %s", articlesCount, lowWaterMark, highWaterMark, g.GroupName)
 }
 
+func (h *Handler) handleNewGroups(s *Session, arguments []string, id uint) error {
+	s.tconn.StartResponse(id)
+	defer s.tconn.EndResponse(id)
+
+	if len(arguments) < 2 || len(arguments) > 3 {
+		return s.tconn.PrintfLine(protocol.MessageSyntaxError)
+	}
+
+	dateString := arguments[0] + " " + arguments[1]
+	//isGMT := false
+	//if len(arguments) == 3 {
+	//	isGMT = true
+	//}
+
+	var date time.Time
+
+	var err error
+	if len(dateString) == 15 {
+		date, err = time.Parse("20060102 150405", dateString)
+		if err != nil {
+			return err
+		}
+	} else if len(dateString) == 13 {
+		date, err = time.Parse("060102 150405", dateString)
+		if err != nil {
+			return err
+		}
+	} else {
+		return s.tconn.PrintfLine(protocol.MessageSyntaxError)
+	}
+
+	g, err := h.backend.GetNewGroupsSince(date.Unix())
+	if err != nil {
+		return err
+	}
+
+	var sb strings.Builder
+
+	sb.Write([]byte(protocol.MessageListOfNewsgroupsFollows + protocol.CRLF))
+	for _, v := range g {
+		// TODO set actual post permission status
+		c, err := h.backend.GetArticlesCount(v)
+		if err != nil {
+			return err
+		}
+		if c > 0 {
+			highWaterMark, err := h.backend.GetGroupHighWaterMark(v)
+			if err != nil {
+				return err
+			}
+			lowWaterMark, err := h.backend.GetGroupLowWaterMark(v)
+			if err != nil {
+				return err
+			}
+			sb.Write([]byte(fmt.Sprintf("%s %d %d n"+protocol.CRLF, v.GroupName, highWaterMark, lowWaterMark)))
+		} else {
+			sb.Write([]byte(fmt.Sprintf("%s 0 1 n"+protocol.CRLF, v.GroupName)))
+		}
+	}
+	sb.Write([]byte(protocol.MultilineEnding))
+
+	return s.tconn.PrintfLine(sb.String())
+}
+
 func (h *Handler) Handle(s *Session, message string, id uint) error {
 	splittedMessage := strings.Split(message, " ")
 	for i, v := range splittedMessage {