Implement PathToRoot and PathToLeaf with one query

After fetching all of a conversation's messages, we traverse the
message's Parent or SelectedReply fields to build the message "path"
in-memory

pkg/lmcli/store.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -299,48 +300,107 @@ func (s *SQLStore) CloneBranch(messageToClone model.Message) (*model.Message, ui
 	return &newMessage, replyCount, nil
 }
 
-// PathToRoot traverses message Parent until reaching the tree root
-func (s *SQLStore) PathToRoot(message *model.Message) ([]model.Message, error) {
-	if message == nil {
-		return nil, fmt.Errorf("Message is nil")
+func fetchMessages(db *gorm.DB) ([]model.Message, error) {
+	var messages []model.Message
+	if err := db.Find(&messages).Error; err != nil {
+		return nil, fmt.Errorf("Could not fetch messages: %v", err)
 	}
+
+	messageMap := make(map[uint]model.Message)
+	for i, message := range messages {
+		messageMap[messages[i].ID] = message
+	}
+
+	// Create a map to store replies by their parent ID
+	repliesMap := make(map[uint][]model.Message)
+	for i, message := range messages {
+		if messages[i].ParentID != nil {
+			repliesMap[*messages[i].ParentID] = append(repliesMap[*messages[i].ParentID], message)
+		}
+	}
+
+	// Assign replies, parent, and selected reply to each message
+	for i := range messages {
+		if replies, exists := repliesMap[messages[i].ID]; exists {
+			messages[i].Replies = make([]model.Message, len(replies))
+			for j, m := range replies {
+				messages[i].Replies[j] = m
+			}
+		}
+		if messages[i].ParentID != nil {
+			if parent, exists := messageMap[*messages[i].ParentID]; exists {
+				messages[i].Parent = &parent
+			}
+		}
+		if messages[i].SelectedReplyID != nil {
+			if selectedReply, exists := messageMap[*messages[i].SelectedReplyID]; exists {
+				messages[i].SelectedReply = &selectedReply
+			}
+		}
+	}
+	return messages, nil
+}
+
+func (s *SQLStore) buildPath(message *model.Message, getNext func(*model.Message) *uint) ([]model.Message, error) {
+	var messages []model.Message
+	messages, err := fetchMessages(s.db.Where("conversation_id = ?", message.ConversationID))
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a map to store messages by their ID
+	messageMap := make(map[uint]*model.Message)
+	for i := range messages {
+		messageMap[messages[i].ID] = &messages[i]
+	}
+
+	// Build the path
 	var path []model.Message
-	current := message
+	nextID := &message.ID
+
 	for {
-		path = append([]model.Message{*current}, path...)
-		if current.Parent == nil {
-			break
+		current, exists := messageMap[*nextID]
+		if !exists {
+			return nil, fmt.Errorf("Message with ID %d not found in conversation", *nextID)
 		}
 
-		var err error
-		current, err = s.MessageByID(*current.ParentID)
-		if err != nil {
-			return nil, fmt.Errorf("finding parent message: %w", err)
+		path = append(path, *current)
+
+		nextID = getNext(current)
+		if nextID == nil {
+			break
 		}
 	}
+
+	return path, nil
+}
+
+// PathToRoot traverses message Parent until reaching the tree root
+func (s *SQLStore) PathToRoot(message *model.Message) ([]model.Message, error) {
+	if message == nil || message.ID <= 0 {
+		return nil, fmt.Errorf("Message is nil or has invalid ID")
+	}
+
+	path, err := s.buildPath(message, func(m *model.Message) *uint {
+		return m.ParentID
+	})
+	if err != nil {
+		return nil, err
+	}
+	slices.Reverse(path)
+
 	return path, nil
 }
 
 // PathToLeaf traverses message SelectedReply until reaching a tree leaf
 func (s *SQLStore) PathToLeaf(message *model.Message) ([]model.Message, error) {
-	if message == nil {
-		return nil, fmt.Errorf("Message is nil")
+	if message == nil || message.ID <= 0 {
+		return nil, fmt.Errorf("Message is nil or has invalid ID")
 	}
-	var path []model.Message
-	current := message
-	for {
-		path = append(path, *current)
-		if current.SelectedReplyID == nil {
-			break
-		}
 
-		var err error
-		current, err = s.MessageByID(*current.SelectedReplyID)
-		if err != nil {
-			return nil, fmt.Errorf("finding selected reply: %w", err)
-		}
-	}
-	return path, nil
+	return s.buildPath(message, func(m *model.Message) *uint {
+		return m.SelectedReplyID
+	})
 }
 
 func (s *SQLStore) LatestConversationMessages() ([]model.Message, error) {