package database
import (
"context"
"fmt"
"strings"
"github.com/ZanzyTHEbar/mcp-memory-libsql-go/internal/apptype"
"github.com/ZanzyTHEbar/mcp-memory-libsql-go/internal/metrics"
)
// CreateRelations creates multiple relations between entities
func (dm *DBManager) CreateRelations(ctx context.Context, projectName string, relations []apptype.Relation) error {
done := metrics.TimeOp("db_create_relations")
success := false
defer func() { done(success) }()
db, err := dm.getDB(projectName)
if err != nil {
return err
}
if len(relations) == 0 {
return nil
}
tx, err := db.BeginTx(ctx, nil)
if err != nil {
return fmt.Errorf("failed to begin transaction: %w", err)
}
defer tx.Rollback()
stmt, err := tx.PrepareContext(ctx,
"INSERT INTO relations (source, target, relation_type) VALUES (?, ?, ?)")
if err != nil {
return fmt.Errorf("failed to prepare statement: %w", err)
}
defer stmt.Close()
for _, relation := range relations {
if relation.From == "" || relation.To == "" || relation.RelationType == "" {
return fmt.Errorf("relation fields cannot be empty")
}
_, err := stmt.ExecContext(ctx, relation.From, relation.To, relation.RelationType)
if err != nil {
return fmt.Errorf("failed to insert relation (%s -> %s): %w", relation.From, relation.To, err)
}
}
if err := tx.Commit(); err != nil {
return err
}
success = true
return nil
}
// UpdateRelations updates relation tuples via delete/insert
func (dm *DBManager) UpdateRelations(ctx context.Context, projectName string, updates []apptype.UpdateRelationChange) error {
done := metrics.TimeOp("db_update_relations")
success := false
defer func() { done(success) }()
db, err := dm.getDB(projectName)
if err != nil {
return err
}
if len(updates) == 0 {
return nil
}
tx, err := db.BeginTx(ctx, nil)
if err != nil {
return fmt.Errorf("failed to begin transaction: %w", err)
}
defer tx.Rollback()
for _, up := range updates {
nf := strings.TrimSpace(up.NewFrom)
if nf == "" {
nf = strings.TrimSpace(up.From)
}
nt := strings.TrimSpace(up.NewTo)
if nt == "" {
nt = strings.TrimSpace(up.To)
}
nr := strings.TrimSpace(up.NewRelationType)
if nr == "" {
nr = strings.TrimSpace(up.RelationType)
}
if nf == "" || nt == "" || nr == "" {
return fmt.Errorf("relation endpoints and type cannot be empty")
}
rows, qerr := tx.QueryContext(ctx, "SELECT name FROM entities WHERE name IN (?, ?)", nf, nt)
if qerr != nil {
return fmt.Errorf("failed to verify relation endpoints: %w", qerr)
}
found := make(map[string]bool, 2)
for rows.Next() {
var name string
if err := rows.Scan(&name); err == nil {
found[name] = true
}
}
rows.Close()
missing := make([]string, 0, 2)
if !found[nf] {
missing = append(missing, nf)
}
if !found[nt] {
missing = append(missing, nt)
}
if len(missing) > 0 {
return fmt.Errorf("relation endpoints must exist before linking: missing %s", strings.Join(missing, ", "))
}
if _, err := tx.ExecContext(ctx, "DELETE FROM relations WHERE source = ? AND target = ? AND relation_type = ?", up.From, up.To, up.RelationType); err != nil {
return fmt.Errorf("failed to delete old relation: %w", err)
}
if _, err := tx.ExecContext(ctx, "INSERT INTO relations (source, target, relation_type) VALUES (?, ?, ?)", nf, nt, nr); err != nil {
return fmt.Errorf("failed to insert new relation: %w", err)
}
}
if err := tx.Commit(); err != nil {
return err
}
success = true
return nil
}
