using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using FirebirdSql.Data.FirebirdClient;
using FireBirdUtil.SqlUtils;
using System.Diagnostics;
using System.Data;

namespace FireBirdUtil.SqlHelpers
{
	public class SqlHelper : IDisposable
	{
		private string _Database;
		private FbConnection _Connection;
		private FbTransaction _Transaction;
		public SqlHelper(string database)
		{
#if DEBUG
			if (string.IsNullOrEmpty(database))
				throw new ArgumentException("构造函数参数不允许为空");
#endif
			_Database = database;
			CreateConnection();
		}

		~SqlHelper()
		{
			Dispose();
		}

		private FbConnection CreateConnection()
		{
			_Connection = new FbConnection(SQLExecuteUtil.GetConnectionString(_Database));
			_Connection.Open();
			return _Connection;
		}

		public FbTransaction CreateTransaction()
		{
			_Transaction = _Connection.BeginTransaction();
			return _Transaction;
		}
		/// <summary>
		/// 提交事务。注意：提交之后，事务就为空了
		/// </summary>
		public void Commit()
		{
			_Transaction.Commit();
		}
		/// <summary>
		/// Rollback
		/// </summary>
		public void Rollback()
		{
			_Transaction.Rollback();
		}

		public void Insert(string tableName, IDictionary<string, object> fieldsValues)
		{
			new InsertHelper(_Database, _Connection, _Transaction).Insert(tableName, fieldsValues);
		}

		public void Delete(string tableName, string conditions)
		{
			new DeleteHelper(_Database, _Connection, _Transaction).Delete(tableName, conditions);
		}

		public void Update(string tableName, Dictionary<string, object> newValues, string conditions)
		{
			new UpdateHelper(_Database, _Connection, _Transaction).Update(tableName, newValues, conditions);
		}

		public TResult Query<TResult>(string sql, Func<object, TResult> DealResult)
		{
			return SqlExecuteBaseUtil.ExecuteScalar<TResult>(_Connection, _Transaction, sql, DealResult);
		}

		/// <summary>
		/// 查询当前id。主要用于事务中
		/// </summary>
		/// <param name="idVar">要查询的表的表名</param>
		public long GetCurrentID(string tableName)
		{
			return Query<long>("SELECT GEN_ID(" + SqlUtil.GetGeneratorName(tableName) + ", 0) FROM RDB$DATABASE;", idStr => { return (long)idStr; });
		}

		public DataTable Query(string sql)
		{
			return SqlExecuteBaseUtil.ExecuteReader(_Connection, _Transaction, sql);
		}

		public void ExecuteNonQuery(string sql)
		{
			SqlExecuteBaseUtil.ExecuteNonQuery(_Connection, _Transaction, sql);
		}

		public void ExecuteNonQuery(string sql, out bool success)
		{
			string errorMessage;
			ExecuteNonQuery(sql, out success, out errorMessage);
		}
		public string ExecuteNonQuery2(string sql, out bool success)
		{
			string errorMessage;
			ExecuteNonQuery(sql, out success, out errorMessage);
			return errorMessage;
		}

		public void ExecuteNonQuery(string sql, out bool success, out string errorMessage)
		{
			success = false;
			errorMessage = string.Empty;
			try {
				ExecuteNonQuery(sql);
				success = true;
			} catch (Exception ex) {
				success = false;
				errorMessage = ex.ToString();
			}
		}

		public void Dispose()
		{
			if (_Connection != null && _Connection.State == ConnectionState.Open)
				_Connection.Close();
		}
	}
}