mapping

type ConnConfig struct {
	Type   string `yaml:"type"` // "postgres", "mssql", "sqlite"
	DSN    string `yaml:"dsn"`
	Schema string `yaml:"schema,omitempty"` // default schema; overridden by dotted table names
}

type ExecOptions struct {
	// DryRun performs the transformation without writing anything.
	DryRun bool

	// Quiet drops the per-target progress line. The caller reports the result
	// instead — a drain that consumes forty messages should not print forty
	// lines when the scheduler only wants the total.
	Quiet bool
	// Output receives the dry-run plan and progress. Nil keeps stdout for v1.
	Output io.Writer
}

type FieldMapping struct {
	From string            `yaml:"from"`
	To   string            `yaml:"to"`
	Enum map[string]string `yaml:"enum,omitempty"` // value remap: source value → target value
}

type InputSource struct {
	Type   string            `yaml:"type"` // "s3" | "broker"
	S3     *storage.S3Config `yaml:"s3,omitempty"`
	Broker *brokers.Config   `yaml:"broker,omitempty"`
}

type LoopGuard struct {
	SourceSystem string `yaml:"source_system"`
	TargetSystem string `yaml:"target_system"`
	MinInterval  string `yaml:"min_interval"` // e.g. "10s", "1m"
}

type MappingConfig struct {
	ID          string       `yaml:"id"`
	Version     string       `yaml:"version"`
	ApprovedBy  string       `yaml:"approved_by,omitempty"`
	LoopGuard   LoopGuard    `yaml:"loop_guard"`
	InputSource *InputSource `yaml:"input_source,omitempty"`
	TargetConn  ConnConfig   `yaml:"target_connection"`
	Targets     []Target     `yaml:"targets"`
}

type Target struct {
	ID        string         `yaml:"id"`
	Table     string         `yaml:"table"`
	UpsertKey string         `yaml:"upsert_key"` // field name used for ON CONFLICT
	Fields    []FieldMapping `yaml:"fields"`
}