using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.SqlClient;
using DDTek.Oracle;
using NLog;

namespace DataModel.Db
{
    public class DbManager
    {
        private static readonly Logger logger = LogManager.GetCurrentClassLogger();

        private static readonly Dictionary<string, DbConnectionString> connectionStrings = new Dictionary<string, DbConnectionString>();


        public static void Initialize(List<DbConnectionString> dbConnectionStrings)
        {
            foreach (DbConnectionString dbConnectionString in dbConnectionStrings)
            {
                connectionStrings.Add(dbConnectionString.Name, dbConnectionString);
            }
        }

        public static DbConnection GetConnection(string name)
        {
            if (!connectionStrings.TryGetValue(name, out var connectionString))
            {
                throw new Exception($"DB Connection definition for '{name}' not found.");
            }

            DbConnection connection = connectionString.GetConnection();

            try
            {
                connection.Open();
            }
            catch (Exception error)
            {
                string errorMessage = $"Failed to open DB connection to '{name}': {error.Message}.";
                logger.Error(errorMessage);
                throw new Exception(errorMessage, error);
            }

            return connection;
        }
    }

    public enum DbTypes { SqlServer, Oracle }

    public class DbConnectionString
    {
        public string Environment { get; set; }
        public DbTypes DbType { get; set; }
        public string Name { get; set; }
        public string ConnectionString { get; set; }

        public DbConnection GetConnection()
        {
            switch (DbType)
            {
                case DbTypes.Oracle:
                    return new OracleConnection(ConnectionString);
                case DbTypes.SqlServer:
                    return new SqlConnection(ConnectionString);
                default:
                    return null;
            }
        }
    }
}