magistrala/pkg/postgres/common.go

// Copyright (c) Abstract Machines
// SPDX-License-Identifier: Apache-2.0

package postgres

import (
	"context"
	"encoding/json"
	"fmt"
)

// CreateMetadataQuery creates a query to filter by metadata.
//
// For example:
//
//	query, param, err := CreateMetadataQuery("", map[string]any{
//		"key": "value",
//	})
func CreateMetadataQuery(entity string, um map[string]any) (string, []byte, error) {
	if len(um) == 0 {
		return "", nil, nil
	}

	param, err := json.Marshal(um)
	if err != nil {
		return "", nil, err
	}
	query := fmt.Sprintf("%smetadata @> :metadata", entity)

	return query, param, nil
}

// Total returns the total number of rows.
//
// For example:
//
//	total, err := Total(ctx, db, "SELECT COUNT(*) FROM table", nil)
func Total(ctx context.Context, db Database, query string, params any) (uint64, error) {
	rows, err := db.NamedQueryContext(ctx, query, params)
	if err != nil {
		return 0, err
	}
	defer rows.Close()

	total := uint64(0)
	if rows.Next() {
		if err := rows.Scan(&total); err != nil {
			return 0, err
		}
	}

	return total, nil
}