/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Data;
using System.Reflection;
using log4net;
using MySql.Data.MySqlClient;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;

namespace OpenSim.Data.MySQL
{
//    public class MySQLGenericHandler<T> : MySqlFramework where T: class, new()
    public class MySQLGenericHandler : MySqlFramework
    {
//        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        protected virtual Assembly Assembly
        {
            get { return GetType().Assembly; }
        }

        public MySQLGenericHandler(MySqlTransaction trans) : base(trans)
        {
            CommonConstruct();
        }

        public MySQLGenericHandler(string connectionString) : base(connectionString)
        {
            CommonConstruct();
        }

        protected void CommonConstruct()
        {
            // We always use a new connection for any Migrations
            using (MySqlConnection dbcon = new MySqlConnection(m_connectionString))
            {
                dbcon.Open();
            }
        }
/*
        private void CheckColumnNames(IDataReader reader)
        {
            if (m_ColumnNames != null)
                return;

            List<string> columnNames = new List<string>();

            DataTable schemaTable = reader.GetSchemaTable();
            foreach (DataRow row in schemaTable.Rows)
            {
                if (row["ColumnName"] != null)
                    columnNames.Add(row["ColumnName"].ToString());
            }

            m_ColumnNames = columnNames;
        }
*/
/*
        public virtual T[] Get(string table, string field, string key)
        {
            return Get(table, new string[] { field }, new string[] { key });
        }

        public virtual T[] Get(string table, string[] fields, string[] keys)
        {
            return Get(table, fields, keys, String.Empty);
        }

        public virtual T[] Get(string table, string[] fields, string[] keys, string options)
        {
            if (fields.Length != keys.Length)
                return new T[0];

            List<string> terms = new List<string>();

            using (MySqlCommand cmd = new MySqlCommand())
            {
                for (int i = 0 ; i < fields.Length ; i++)
                {
                    cmd.Parameters.AddWithValue(fields[i], keys[i]);
                    terms.Add("`" + fields[i] + "` = ?" + fields[i]);
                }

                string where = String.Join(" and ", terms.ToArray());

                string query = String.Format("select * from {0} where {1} {2}",
                                             table, where, options);

                cmd.CommandText = query;

                return DoQuery(cmd);
            }
        }

        protected T[] DoQuery(MySqlCommand cmd)
        {
            if (m_trans == null)
            {
                using (MySqlConnection dbcon = new MySqlConnection(m_connectionString))
                {
                    dbcon.Open();
                    T[] ret = DoQueryWithConnection(cmd, dbcon);
                    dbcon.Close();
                    return ret;
                }
            }
            else
            {
                return DoQueryWithTransaction(cmd, m_trans);
            }
        }

        protected T[] DoQueryWithTransaction(MySqlCommand cmd, MySqlTransaction trans)
        {
            cmd.Transaction = trans;

            return DoQueryWithConnection(cmd, trans.Connection);
        }

        protected T[] DoQueryWithConnection(MySqlCommand cmd, MySqlConnection dbcon)
        {
            List<T> result = new List<T>();

            cmd.Connection = dbcon;

            using (IDataReader reader = cmd.ExecuteReader())
            {
                if (reader == null)
                    return new T[0];
/*

                CheckColumnNames(reader);

                while (reader.Read())
                {
                    T row = new T();

                    foreach (string name in m_Fields.Keys)
                    {
                        if (reader[name] is DBNull)
                        {
                            continue;
                        }
                        if (m_Fields[name].FieldType == typeof(bool))
                        {
                            int v = Convert.ToInt32(reader[name]);
                            m_Fields[name].SetValue(row, v != 0 ? true : false);
                        }
                        else if (m_Fields[name].FieldType == typeof(UUID))
                        {
                            m_Fields[name].SetValue(row, DBGuid.FromDB(reader[name]));
                        }
                        else if (m_Fields[name].FieldType == typeof(int))
                        {
                            int v = Convert.ToInt32(reader[name]);
                            m_Fields[name].SetValue(row, v);
                        }
                        else if (m_Fields[name].FieldType == typeof(uint))
                        {
                            uint v = Convert.ToUInt32(reader[name]);
                            m_Fields[name].SetValue(row, v);
                        }
                        else
                        {
                            m_Fields[name].SetValue(row, reader[name]);
                        }
                    }

                    if (m_DataField != null)
                    {
                        Dictionary<string, string> data =
                            new Dictionary<string, string>();

                        foreach (string col in m_ColumnNames)
                        {
                            data[col] = reader[col].ToString();
                            if (data[col] == null)
                                data[col] = String.Empty;
                        }

                        m_DataField.SetValue(row, data);
                    }
                    result.Add(row);
                }
*/
/*
            }
            cmd.Connection = null;
            return result.ToArray();
        }

        public virtual T[] Get(string table, string where)
        {
            using (MySqlCommand cmd = new MySqlCommand())
            {
                string query = String.Format("select * from {0} where {1}",
                                             table, where);

                cmd.CommandText = query;

                return DoQuery(cmd);
            }
        }
*/
        public virtual bool Delete(string table, string field, string key)
        {
            return Delete(table, new string[] { field }, new string[] { key });
        }

        public virtual bool Delete(string table, string[] fields, string[] keys)
        {
//            m_log.DebugFormat(
//                "[MYSQL GENERIC TABLE HANDLER]: Delete(string[] fields, string[] keys) invoked with {0}:{1}",
//                string.Join(",", fields), string.Join(",", keys));

            if (fields.Length != keys.Length)
                return false;

            List<string> terms = new List<string>();

            using (MySqlCommand cmd = new MySqlCommand())
            {
                for (int i = 0 ; i < fields.Length ; i++)
                {
                    cmd.Parameters.AddWithValue(fields[i], keys[i]);
                    terms.Add("`" + fields[i] + "` = ?" + fields[i]);
                }

                string where = String.Join(" and ", terms.ToArray());

                string query = String.Format("delete from {0} where {1}", table, where);

                cmd.CommandText = query;

                return ExecuteNonQuery(cmd) > 0;
            }
        }

        public long GetCount(string table, string field, string key)
        {
            return GetCount(table, new string[] { field }, new string[] { key });
        }

        public long GetCount(string table, string[] fields, string[] keys)
        {
            if (fields.Length != keys.Length)
                return 0;

            List<string> terms = new List<string>();

            using (MySqlCommand cmd = new MySqlCommand())
            {
                for (int i = 0; i < fields.Length; i++)
                {
                    cmd.Parameters.AddWithValue(fields[i], keys[i]);
                    terms.Add("`" + fields[i] + "` = ?" + fields[i]);
                }

                string where = String.Join(" and ", terms.ToArray());

                string query = String.Format("select count(*) from {0} where {1}",
                                             table, where);

                cmd.CommandText = query;

                Object result = DoQueryScalar(cmd);

                return Convert.ToInt64(result);
            }
        }

        public long GetCount(string table, string where)
        {
            using (MySqlCommand cmd = new MySqlCommand())
            {
                string query = String.Format("select count(*) from {0} where {1}",
                                             table, where);

                cmd.CommandText = query;

                object result = DoQueryScalar(cmd);

                return Convert.ToInt64(result);
            }
        }

        public long GetCount(string table)
        {
            using (MySqlCommand cmd = new MySqlCommand())
            {
                string query = String.Format("select count(*) from {0}", table);

                cmd.CommandText = query;

                object result = DoQueryScalar(cmd);

                return Convert.ToInt64(result);
            }
        }

        public object DoQueryScalar(MySqlCommand cmd)
        {
            if (m_trans == null)
            {
                using (MySqlConnection dbcon = new MySqlConnection(m_connectionString))
                {
                    dbcon.Open();
                    cmd.Connection = dbcon;

                    Object ret = cmd.ExecuteScalar();
                    cmd.Connection = null;
                    dbcon.Close();
                    return ret;
                }
            }
            else
            {
                cmd.Connection = m_trans.Connection;
                cmd.Transaction = m_trans;

                return cmd.ExecuteScalar();
            }
        }
    }
}