/*
 * Copyright 2006 Jozef Izso
 * 
 * Zdrojový kód je možné použiť ako inšpiráciu.
 * 
 * */

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;
using System.Data;

namespace izsaknet.Logging
{
	/// <summary>
	/// Trieda SimpleSqlLogItem formátuje do logovacieho výstupu informácie
	/// o objekte <see cref="SqlCommand"/>.
	/// </summary>
	/// <remarks>
	/// Ukážka formátovaného výstupu:
	/// 
	/// <example>
	/// [Log message] Nepodarilo sa získať informácie o užívateľovi.
	/// [SQL Command] SELECT id, meno, email FROM uzivatelia WHERE id = @ID AND meno = @meno
	///     [param] int @ID = 1
	///     [param] varchar meno = 'Administáror'
	/// 
	///     [Connection] DBSERVER\SQLEXPRESS:UkazkovaDB (Open)
	/// </example>
	/// 
	/// Formátovanie zatiaľ plne nepodporuje uložené procedúry.
	/// </remarks>
	public class SimpleSqlLogItem : SimpleLogItem
	{
		private SqlCommand _sql;

		public SimpleSqlLogItem(SqlCommand command, string message)
			: this(command, message, null)
		{ }

		public SimpleSqlLogItem(SqlCommand command, string message, params object[] args)
			: base(message, args)
		{
			_sql = command;
		}

		public override string ToString()
		{
			StringBuilder sb = new StringBuilder(30);

			// append log message
			sb.AppendLine(base.ToString());

			sb.Append("[SQL Command] ");

			if (this._sql == null)
			{
				sb.Append("(null)");
			}
			else
			{
				sb.AppendLine(this._sql.CommandText);
				// output SQL Command parameters
				if (this._sql.Parameters != null)
				{
					foreach (SqlParameter param in this._sql.Parameters)
					{
						// [out NULL param] Int ID = 2
						// [param] varchar Name = 'Jozef'
						sb.AppendFormat("\t[{0}param] {1} {2} = {3}",
							FormatParameterType(param),
							param.DbType,
							param.ParameterName,
							FormatParameterValue(param)
						);
						sb.AppendLine();
					}

					sb.AppendLine();
				}

				sb.Append("\t[Connection] ");
				SqlConnection conn = this._sql.Connection;

				if (conn == null)
				{
					sb.Append("(null)");
				}
				else
				{
					sb.AppendFormat("{0}\\{1}:{2} ({3})",
						conn.WorkstationId,
						conn.DataSource,
						conn.Database,
						conn.State
					);
				}
				sb.AppendLine();
			}

			return sb.ToString();
		}

		private string FormatParameterType(SqlParameter param)
		{
			StringBuilder sb = new StringBuilder();

			switch (param.Direction)
			{
				case ParameterDirection.Output:
					sb.Append("out");
					break;
				case ParameterDirection.ReturnValue:
					sb.Append("return");
					break;
				case ParameterDirection.InputOutput:
					sb.Append("in/out");
					break;
			}

			// indicates nullable parameter
			if (param.IsNullable)
			{
				sb.Append(" NULL");
			}

			return sb.ToString();
		}

		private string FormatParameterValue(SqlParameter param)
		{
			if (param.Value == null)
				return "(null)";
			if (param.Value is DBNull)
				return "(NULL)";

			// enclose string paramter in apostrophe
			if (param.Value is string)
				return String.Concat("'", param.Value.ToString().Replace("'", "''"), "'");

			return param.Value.ToString();
		}
	}
}