Memoh/internal/message/service.go

package message

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"math"
	"strings"
	"time"

	"github.com/jackc/pgx/v5/pgtype"

	dbpkg "github.com/memohai/memoh/internal/db"
	"github.com/memohai/memoh/internal/db/sqlc"
	"github.com/memohai/memoh/internal/message/event"
)

// DBService persists and reads bot history messages.
type DBService struct {
	queries   *sqlc.Queries
	logger    *slog.Logger
	publisher event.Publisher
}

// NewService creates a message service.
func NewService(log *slog.Logger, queries *sqlc.Queries, publishers ...event.Publisher) *DBService {
	if log == nil {
		log = slog.Default()
	}
	var publisher event.Publisher
	if len(publishers) > 0 {
		publisher = publishers[0]
	}
	return &DBService{
		queries:   queries,
		logger:    log.With(slog.String("service", "message")),
		publisher: publisher,
	}
}

// Persist writes a single message to bot_history_messages.
func (s *DBService) Persist(ctx context.Context, input PersistInput) (Message, error) {
	pgBotID, err := dbpkg.ParseUUID(input.BotID)
	if err != nil {
		return Message{}, fmt.Errorf("invalid bot id: %w", err)
	}

	pgSessionID, err := parseOptionalUUID(input.SessionID)
	if err != nil {
		return Message{}, fmt.Errorf("invalid session id: %w", err)
	}
	pgSenderChannelIdentityID, err := parseOptionalUUID(input.SenderChannelIdentityID)
	if err != nil {
		return Message{}, fmt.Errorf("invalid sender channel identity id: %w", err)
	}
	pgSenderUserID, err := parseOptionalUUID(input.SenderUserID)
	if err != nil {
		return Message{}, fmt.Errorf("invalid sender user id: %w", err)
	}
	pgModelID, err := parseOptionalUUID(input.ModelID)
	if err != nil {
		return Message{}, fmt.Errorf("invalid model id: %w", err)
	}

	metaBytes, err := json.Marshal(nonNilMap(input.Metadata))
	if err != nil {
		return Message{}, fmt.Errorf("marshal message metadata: %w", err)
	}

	content := input.Content
	if len(content) == 0 {
		content = []byte("{}")
	}

	row, err := s.queries.CreateMessage(ctx, sqlc.CreateMessageParams{
		BotID:                   pgBotID,
		SessionID:               pgSessionID,
		SenderChannelIdentityID: pgSenderChannelIdentityID,
		SenderUserID:            pgSenderUserID,
		ExternalMessageID:       toPgText(input.ExternalMessageID),
		SourceReplyToMessageID:  toPgText(input.SourceReplyToMessageID),
		Role:                    input.Role,
		Content:                 content,
		Metadata:                metaBytes,
		Usage:                   input.Usage,
		ModelID:                 pgModelID,
	})
	if err != nil {
		return Message{}, err
	}

	result := toMessageFromCreate(row)

	for _, ref := range input.Assets {
		pgMsgID := row.ID
		role := ref.Role
		if strings.TrimSpace(role) == "" {
			role = "attachment"
		}
		contentHash := strings.TrimSpace(ref.ContentHash)
		if contentHash == "" {
			s.logger.Warn("skip asset ref without content_hash")
			continue
		}
		if ref.Ordinal < math.MinInt32 || ref.Ordinal > math.MaxInt32 {
			return Message{}, fmt.Errorf("asset ordinal out of range: %d", ref.Ordinal)
		}
		if _, assetErr := s.queries.CreateMessageAsset(ctx, sqlc.CreateMessageAssetParams{
			MessageID:   pgMsgID,
			Role:        role,
			Ordinal:     int32(ref.Ordinal),
			ContentHash: contentHash,
			Name:        ref.Name,
			Metadata:    marshalMetadata(ref.Metadata),
		}); assetErr != nil {
			s.logger.Warn("create message asset link failed", slog.String("message_id", result.ID), slog.Any("error", assetErr))
		}
	}

	if len(input.Assets) > 0 {
		assets := make([]MessageAsset, 0, len(input.Assets))
		for _, ref := range input.Assets {
			ch := strings.TrimSpace(ref.ContentHash)
			if ch == "" {
				continue
			}
			assets = append(assets, MessageAsset{
				ContentHash: ch,
				Role:        coalesce(ref.Role, "attachment"),
				Ordinal:     ref.Ordinal,
				Mime:        ref.Mime,
				SizeBytes:   ref.SizeBytes,
				StorageKey:  ref.StorageKey,
				Name:        ref.Name,
				Metadata:    ref.Metadata,
			})
		}
		result.Assets = assets
	}

	s.publishMessageCreated(result)
	return result, nil
}

// List returns all messages for a bot.
func (s *DBService) List(ctx context.Context, botID string) ([]Message, error) {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessages(ctx, pgBotID)
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromList(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListSince returns bot messages since a given time.
func (s *DBService) ListSince(ctx context.Context, botID string, since time.Time) ([]Message, error) {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesSince(ctx, sqlc.ListMessagesSinceParams{
		BotID:     pgBotID,
		CreatedAt: pgtype.Timestamptz{Time: since, Valid: true},
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromSince(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListActiveSince returns bot messages since a given time, excluding passive_sync messages.
func (s *DBService) ListActiveSince(ctx context.Context, botID string, since time.Time) ([]Message, error) {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListActiveMessagesSince(ctx, sqlc.ListActiveMessagesSinceParams{
		BotID:     pgBotID,
		CreatedAt: pgtype.Timestamptz{Time: since, Valid: true},
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromActiveSince(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListLatest returns the latest N bot messages (newest first in DB; caller may reverse for ASC).
func (s *DBService) ListLatest(ctx context.Context, botID string, limit int32) ([]Message, error) {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesLatest(ctx, sqlc.ListMessagesLatestParams{
		BotID:    pgBotID,
		MaxCount: limit,
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromLatest(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListBefore returns up to limit messages older than before (created_at < before), ordered oldest-first.
func (s *DBService) ListBefore(ctx context.Context, botID string, before time.Time, limit int32) ([]Message, error) {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesBefore(ctx, sqlc.ListMessagesBeforeParams{
		BotID:     pgBotID,
		CreatedAt: pgtype.Timestamptz{Time: before, Valid: true},
		MaxCount:  limit,
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromBefore(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// --- Session-scoped queries ---

// ListBySession returns all messages for a session.
func (s *DBService) ListBySession(ctx context.Context, sessionID string) ([]Message, error) {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesBySession(ctx, pgSessionID)
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromSessionList(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListSinceBySession returns session messages since a given time.
func (s *DBService) ListSinceBySession(ctx context.Context, sessionID string, since time.Time) ([]Message, error) {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesSinceBySession(ctx, sqlc.ListMessagesSinceBySessionParams{
		SessionID: pgSessionID,
		CreatedAt: pgtype.Timestamptz{Time: since, Valid: true},
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromSinceBySession(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListActiveSinceBySession returns session messages since a given time, excluding passive_sync messages.
func (s *DBService) ListActiveSinceBySession(ctx context.Context, sessionID string, since time.Time) ([]Message, error) {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListActiveMessagesSinceBySession(ctx, sqlc.ListActiveMessagesSinceBySessionParams{
		SessionID: pgSessionID,
		CreatedAt: pgtype.Timestamptz{Time: since, Valid: true},
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromActiveSinceBySession(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListLatestBySession returns the latest N session messages.
func (s *DBService) ListLatestBySession(ctx context.Context, sessionID string, limit int32) ([]Message, error) {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesLatestBySession(ctx, sqlc.ListMessagesLatestBySessionParams{
		SessionID: pgSessionID,
		MaxCount:  limit,
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromLatestBySession(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// ListBeforeBySession returns up to limit session messages older than before.
func (s *DBService) ListBeforeBySession(ctx context.Context, sessionID string, before time.Time, limit int32) ([]Message, error) {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return nil, err
	}
	rows, err := s.queries.ListMessagesBeforeBySession(ctx, sqlc.ListMessagesBeforeBySessionParams{
		SessionID: pgSessionID,
		CreatedAt: pgtype.Timestamptz{Time: before, Valid: true},
		MaxCount:  limit,
	})
	if err != nil {
		return nil, err
	}
	msgs := toMessagesFromBeforeBySession(rows)
	s.enrichAssets(ctx, msgs)
	return msgs, nil
}

// LinkAssets links asset refs to an existing persisted message.
func (s *DBService) LinkAssets(ctx context.Context, messageID string, assets []AssetRef) error {
	pgMsgID, err := dbpkg.ParseUUID(messageID)
	if err != nil {
		return fmt.Errorf("invalid message id: %w", err)
	}
	for _, ref := range assets {
		contentHash := strings.TrimSpace(ref.ContentHash)
		if contentHash == "" {
			continue
		}
		role := ref.Role
		if strings.TrimSpace(role) == "" {
			role = "attachment"
		}
		if ref.Ordinal < math.MinInt32 || ref.Ordinal > math.MaxInt32 {
			return fmt.Errorf("asset ordinal out of range: %d", ref.Ordinal)
		}
		if _, assetErr := s.queries.CreateMessageAsset(ctx, sqlc.CreateMessageAssetParams{
			MessageID:   pgMsgID,
			Role:        role,
			Ordinal:     int32(ref.Ordinal),
			ContentHash: contentHash,
			Name:        ref.Name,
			Metadata:    marshalMetadata(ref.Metadata),
		}); assetErr != nil {
			s.logger.Warn("link asset failed", slog.String("message_id", messageID), slog.Any("error", assetErr))
		}
	}
	return nil
}

// DeleteByBot deletes all messages for a bot.
func (s *DBService) DeleteByBot(ctx context.Context, botID string) error {
	pgBotID, err := dbpkg.ParseUUID(botID)
	if err != nil {
		return err
	}
	return s.queries.DeleteMessagesByBot(ctx, pgBotID)
}

// DeleteBySession deletes all messages for a session.
func (s *DBService) DeleteBySession(ctx context.Context, sessionID string) error {
	pgSessionID, err := dbpkg.ParseUUID(sessionID)
	if err != nil {
		return err
	}
	return s.queries.DeleteMessagesBySession(ctx, pgSessionID)
}

// --- Conversion helpers ---

func toMessageFromCreate(row sqlc.CreateMessageRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		pgtype.Text{},
		pgtype.Text{},
		extractPlatformFromMetadata(row.Metadata),
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func extractPlatformFromMetadata(metadata []byte) pgtype.Text {
	m := parseJSONMap(metadata)
	if v, ok := m["platform"].(string); ok && strings.TrimSpace(v) != "" {
		return pgtype.Text{String: strings.TrimSpace(v), Valid: true}
	}
	return pgtype.Text{}
}

func toMessageFromListRow(row sqlc.ListMessagesRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromSessionListRow(row sqlc.ListMessagesBySessionRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromSinceRow(row sqlc.ListMessagesSinceRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromSinceBySessionRow(row sqlc.ListMessagesSinceBySessionRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromActiveSinceRow(row sqlc.ListActiveMessagesSinceRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromActiveSinceBySessionRow(row sqlc.ListActiveMessagesSinceBySessionRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromLatestRow(row sqlc.ListMessagesLatestRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromLatestBySessionRow(row sqlc.ListMessagesLatestBySessionRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromBeforeRow(row sqlc.ListMessagesBeforeRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFromBeforeBySessionRow(row sqlc.ListMessagesBeforeBySessionRow) Message {
	return toMessageFields(
		row.ID,
		row.BotID,
		row.SessionID,
		row.SenderChannelIdentityID,
		row.SenderUserID,
		row.SenderDisplayName,
		row.SenderAvatarUrl,
		row.Platform,
		row.ExternalMessageID,
		row.SourceReplyToMessageID,
		row.Role,
		row.Content,
		row.Metadata,
		row.Usage,
		row.CreatedAt,
	)
}

func toMessageFields(
	id pgtype.UUID,
	botID pgtype.UUID,
	sessionID pgtype.UUID,
	senderChannelIdentityID pgtype.UUID,
	senderUserID pgtype.UUID,
	senderDisplayName pgtype.Text,
	senderAvatarURL pgtype.Text,
	platform pgtype.Text,
	externalMessageID pgtype.Text,
	sourceReplyToMessageID pgtype.Text,
	role string,
	content []byte,
	metadata []byte,
	usage []byte,
	createdAt pgtype.Timestamptz,
) Message {
	return Message{
		ID:                      id.String(),
		BotID:                   botID.String(),
		SessionID:               sessionID.String(),
		SenderChannelIdentityID: senderChannelIdentityID.String(),
		SenderUserID:            senderUserID.String(),
		SenderDisplayName:       dbpkg.TextToString(senderDisplayName),
		SenderAvatarURL:         dbpkg.TextToString(senderAvatarURL),
		Platform:                dbpkg.TextToString(platform),
		ExternalMessageID:       dbpkg.TextToString(externalMessageID),
		SourceReplyToMessageID:  dbpkg.TextToString(sourceReplyToMessageID),
		Role:                    role,
		Content:                 json.RawMessage(content),
		Metadata:                parseJSONMap(metadata),
		Usage:                   json.RawMessage(usage),
		CreatedAt:               createdAt.Time,
	}
}

func toMessagesFromList(rows []sqlc.ListMessagesRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromListRow(row))
	}
	return messages
}

func toMessagesFromSessionList(rows []sqlc.ListMessagesBySessionRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromSessionListRow(row))
	}
	return messages
}

func toMessagesFromSince(rows []sqlc.ListMessagesSinceRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromSinceRow(row))
	}
	return messages
}

func toMessagesFromSinceBySession(rows []sqlc.ListMessagesSinceBySessionRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromSinceBySessionRow(row))
	}
	return messages
}

func toMessagesFromActiveSince(rows []sqlc.ListActiveMessagesSinceRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromActiveSinceRow(row))
	}
	return messages
}

func toMessagesFromActiveSinceBySession(rows []sqlc.ListActiveMessagesSinceBySessionRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromActiveSinceBySessionRow(row))
	}
	return messages
}

func toMessagesFromLatest(rows []sqlc.ListMessagesLatestRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromLatestRow(row))
	}
	return messages
}

func toMessagesFromLatestBySession(rows []sqlc.ListMessagesLatestBySessionRow) []Message {
	messages := make([]Message, 0, len(rows))
	for _, row := range rows {
		messages = append(messages, toMessageFromLatestBySessionRow(row))
	}
	return messages
}

// toMessagesFromBefore returns messages in oldest-first order (ListMessagesBefore returns DESC; we reverse).
func toMessagesFromBefore(rows []sqlc.ListMessagesBeforeRow) []Message {
	messages := make([]Message, 0, len(rows))
	for i := len(rows) - 1; i >= 0; i-- {
		messages = append(messages, toMessageFromBeforeRow(rows[i]))
	}
	return messages
}

func toMessagesFromBeforeBySession(rows []sqlc.ListMessagesBeforeBySessionRow) []Message {
	messages := make([]Message, 0, len(rows))
	for i := len(rows) - 1; i >= 0; i-- {
		messages = append(messages, toMessageFromBeforeBySessionRow(rows[i]))
	}
	return messages
}

func parseOptionalUUID(id string) (pgtype.UUID, error) {
	if strings.TrimSpace(id) == "" {
		return pgtype.UUID{}, nil
	}
	return dbpkg.ParseUUID(id)
}

func toPgText(value string) pgtype.Text {
	value = strings.TrimSpace(value)
	if value == "" {
		return pgtype.Text{}
	}
	return pgtype.Text{String: value, Valid: true}
}

func nonNilMap(m map[string]any) map[string]any {
	if m == nil {
		return map[string]any{}
	}
	return m
}

func coalesce(values ...string) string {
	for _, v := range values {
		if strings.TrimSpace(v) != "" {
			return v
		}
	}
	return ""
}

func parseJSONMap(data []byte) map[string]any {
	if len(data) == 0 {
		return nil
	}
	var m map[string]any
	_ = json.Unmarshal(data, &m)
	return m
}

func (s *DBService) publishMessageCreated(message Message) {
	if s.publisher == nil {
		return
	}
	payload, err := json.Marshal(message)
	if err != nil {
		if s.logger != nil {
			s.logger.Warn("marshal message event failed", slog.Any("error", err))
		}
		return
	}
	s.publisher.Publish(event.Event{
		Type:  event.EventTypeMessageCreated,
		BotID: strings.TrimSpace(message.BotID),
		Data:  payload,
	})
}

// enrichAssets batch-loads asset links for a list of messages (single-table query).
func (s *DBService) enrichAssets(ctx context.Context, messages []Message) {
	if len(messages) == 0 {
		return
	}
	ids := make([]pgtype.UUID, 0, len(messages))
	for _, m := range messages {
		pgID, err := dbpkg.ParseUUID(m.ID)
		if err != nil {
			continue
		}
		ids = append(ids, pgID)
	}
	if len(ids) == 0 {
		return
	}
	rows, err := s.queries.ListMessageAssetsBatch(ctx, ids)
	if err != nil {
		s.logger.Warn("enrich assets failed, returning messages without assets", slog.Any("error", err))
		ensureAssetsSlice(messages)
		return
	}
	assetMap := map[string][]MessageAsset{}
	for _, row := range rows {
		msgID := row.MessageID.String()
		contentHash := strings.TrimSpace(row.ContentHash)
		if contentHash == "" {
			continue
		}
		assetMap[msgID] = append(assetMap[msgID], MessageAsset{
			ContentHash: contentHash,
			Role:        row.Role,
			Ordinal:     int(row.Ordinal),
			Name:        row.Name,
			Metadata:    unmarshalMetadata(row.Metadata),
		})
	}
	for i := range messages {
		if assets, ok := assetMap[messages[i].ID]; ok {
			messages[i].Assets = assets
		} else {
			messages[i].Assets = []MessageAsset{}
		}
	}
}

func ensureAssetsSlice(messages []Message) {
	for i := range messages {
		if messages[i].Assets == nil {
			messages[i].Assets = []MessageAsset{}
		}
	}
}

func marshalMetadata(m map[string]any) []byte {
	if len(m) == 0 {
		return []byte("{}")
	}
	b, err := json.Marshal(m)
	if err != nil {
		return []byte("{}")
	}
	return b
}

func unmarshalMetadata(b []byte) map[string]any {
	if len(b) == 0 {
		return nil
	}
	var m map[string]any
	if err := json.Unmarshal(b, &m); err != nil || len(m) == 0 {
		return nil
	}
	return m
}