chore: initial commit of ai site platform

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/dbsync/echo.go

@@ -0,0 +1,77 @@
+package dbsync
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"time"
+)
+
+const FlagTable = "_ajz_sync_flag"
+
+// EnsureFlagTable：SQLite 用表标记「正在应用远端变更」，避免触发器回声。
+func EnsureFlagTable(ctx context.Context, db *sql.DB, driver Driver) error {
+	if driver != DriverSQLite {
+		return nil
+	}
+	_, err := db.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS `+FlagTable+` (
+  k TEXT PRIMARY KEY,
+  v INTEGER NOT NULL DEFAULT 0
+);`)
+	if err != nil {
+		return err
+	}
+	_, _ = db.ExecContext(ctx, `INSERT OR IGNORE INTO `+FlagTable+`(k,v) VALUES('applying',0)`)
+	return nil
+}
+
+// WithApplying 在写入目标库时置位，使触发器不写 outbox（防 A↔B 回声导致「多」）。
+func WithApplying(ctx context.Context, db *sql.DB, driver Driver, fn func() error) error {
+	switch driver {
+	case DriverSQLite:
+		if err := EnsureFlagTable(ctx, db, driver); err != nil {
+			return err
+		}
+		if _, err := db.ExecContext(ctx, `UPDATE `+FlagTable+` SET v=1 WHERE k='applying'`); err != nil {
+			return err
+		}
+		defer func() {
+			_, _ = db.ExecContext(context.Background(), `UPDATE `+FlagTable+` SET v=0 WHERE k='applying'`)
+		}()
+		return fn()
+	case DriverMySQL:
+		if _, err := db.ExecContext(ctx, `SET @ajz_applying = 1`); err != nil {
+			return err
+		}
+		defer func() { _, _ = db.ExecContext(context.Background(), `SET @ajz_applying = 0`) }()
+		return fn()
+	case DriverPostgres:
+		if _, err := db.ExecContext(ctx, `SELECT set_config('ajz.applying', '1', false)`); err != nil {
+			return err
+		}
+		defer func() {
+			_, _ = db.ExecContext(context.Background(), `SELECT set_config('ajz.applying', '0', false)`)
+		}()
+		return fn()
+	default:
+		return fn()
+	}
+}
+
+func EnqueueOutbox(ctx context.Context, db *sql.DB, driver Driver, table, pk, op, payload string, version int64) error {
+	if version <= 0 {
+		version = time.Now().UnixMilli()
+	}
+	switch driver {
+	case DriverPostgres:
+		_, err := db.ExecContext(ctx, fmt.Sprintf(`
+INSERT INTO %s(table_name,row_pk,op,payload,version) VALUES($1,$2,$3,$4,$5)`, OutboxTable),
+			table, pk, op, payload, version)
+		return err
+	default:
+		_, err := db.ExecContext(ctx, fmt.Sprintf(`
+INSERT INTO %s(table_name,row_pk,op,payload,version) VALUES(?,?,?,?,?)`, OutboxTable),
+			table, pk, op, payload, version)
+		return err
+	}
+}