///
/// Copyright (c) 2017-2022 Sensus Slovensko a.s.
///
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Config
{
    public static class Utils
    {
        /// <summary>
        /// Extract and return a DB server from a MySQL connection string.
        /// </summary>
        public static string GetDBServer(string connectionString)
        {
            return GetFromConnectionString(connectionString, new string[] { "SERVER=" });
        }

        /// <summary>
        /// Extract and return a DB name from a MySQL connection string.
        /// </summary>
        public static string GetDBName(string connectionString)
        {
            return GetFromConnectionString(connectionString, new string[] { "DATABASE=" });
        }

        /// <summary>
        /// Extract and return a username from a MySQL connection string
        /// </summary>
        public static string GetDBUser(string connectionString)
        {
            return GetFromConnectionString(connectionString, new string[] { "USER=", "UID=" });
        }

        /// <summary>
        /// Extract and return a password from a MySQL connection string
        /// </summary>
        public static string GetDBPassword(string connectionString)
        {
            return GetFromConnectionString(connectionString, new string[] { "PASSWORD=", "PWD=" });
        }

        /// <summary>
        /// Extract and return an element of a MySQL connection string
        /// (a host, a database, a user name or a password).
        /// Return an empty string on any error.
        /// </summary>
        public static string GetFromConnectionString(string connectionString, string[] patterns)
        {
            foreach (var pattern in patterns)
            {
                int startIx = connectionString.IndexOf(pattern);
                if (startIx >= 0)
                {
                    /// pattern found, extract the subsequent element
                    startIx += pattern.Length;
                    int endIx = connectionString.IndexOf(';', startIx);
                    return (endIx > 0) ? connectionString.Substring(startIx, endIx - startIx) : string.Empty;
                }
            }

            /// pattern NOT found
            return string.Empty;
        }
    }
}