package notificationstore

import (
	"encoding/json"
	"fmt"
)

// marshalRecipientUserIDs returns the JSONB bytes for the
// `records.recipient_user_ids` column. A nil/empty slice round-trips as `[]`
// to keep the column NOT NULL across equality tests.
func marshalRecipientUserIDs(userIDs []string) ([]byte, error) {
	if userIDs == nil {
		userIDs = []string{}
	}
	payload, err := json.Marshal(userIDs)
	if err != nil {
		return nil, fmt.Errorf("marshal recipient user ids: %w", err)
	}
	return payload, nil
}

// unmarshalRecipientUserIDs decodes the JSONB recipient user-id list. nil
// payloads round-trip as a nil slice so the read path matches what the
// service layer accepts (`nil` and an empty `[]` are equivalent for
// audience_kind != user_set).
func unmarshalRecipientUserIDs(payload []byte) ([]string, error) {
	if len(payload) == 0 {
		return nil, nil
	}
	var userIDs []string
	if err := json.Unmarshal(payload, &userIDs); err != nil {
		return nil, fmt.Errorf("unmarshal recipient user ids: %w", err)
	}
	if len(userIDs) == 0 {
		return nil, nil
	}
	return userIDs, nil
}

// marshalRawFields returns the JSONB bytes for the
// `malformed_intents.raw_fields` column. The map is serialised verbatim so
// future operator queries can match arbitrary keys.
func marshalRawFields(fields map[string]any) ([]byte, error) {
	if fields == nil {
		fields = map[string]any{}
	}
	payload, err := json.Marshal(fields)
	if err != nil {
		return nil, fmt.Errorf("marshal raw fields: %w", err)
	}
	return payload, nil
}

// unmarshalRawFields decodes the malformed_intents.raw_fields column into a
// non-nil map (empty {} when the column is null/empty).
func unmarshalRawFields(payload []byte) (map[string]any, error) {
	out := map[string]any{}
	if len(payload) == 0 {
		return out, nil
	}
	if err := json.Unmarshal(payload, &out); err != nil {
		return nil, fmt.Errorf("unmarshal raw fields: %w", err)
	}
	return out, nil
}