using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Sarand.Net.Standard.Base.App;
using Sarand.Net.Standard.Base.Dbas;
using Sarand.Net.Standard.Base.Security;
using Sarand.Net.Standard.Dbas.Data;

namespace Sarand.Net.Standard.Dbas.Security
{
	//=======================================================================
	internal partial class SaSecurityMgr_Dbas : SaSecurityMgr
	{
		//-------------------------------------------------------------------
		// Data members.

		//-------------------------------------------------------------------
		// Construction.
		internal SaSecurityMgr_Dbas(SaSecurityConsole_Dbas securityConsole) : base()
		{
			SecurityConsole = securityConsole;
			DbInfo = new DbDataItem.DatabaseInfo(securityConsole.Database);
		}

		//-------------------------------------------------------------------
		// Properties.
		internal SaSecurityConsole_Dbas SecurityConsole { get; }
		internal ISacsDatabase Database { get { return SecurityConsole.Database; } }
		private DbDataItem.DatabaseInfo DbInfo { get; }
		public String TableName_SecItem { get { return SaSecurityDbDfn.GetTableName(SaSecurityDbDfn.TableIdx.SaSecItem); } }
		public String TableName_SecLink { get { return SaSecurityDbDfn.GetTableName(SaSecurityDbDfn.TableIdx.SaSecLink); } }
		public override bool DatabaseIsValid { get { return (Database != null && Database.GetTableNames().Contains(TableName_SecItem) && Database.GetTableNames().Contains(TableName_SecLink)); } }
		public override bool CanUpdateDatabase { get { return DatabaseIsValid; } }

		// Database utilities.
		public override bool ColumnExists(SaSecurityDbDfn.ColumnIdx columnIdx)
		{
			String tableName = SaSecurityDbDfn.GetTableName(SaSecurityDbDfn.GetTableForColumn(columnIdx), false);
			String columnName = SaSecurityDbDfn.GetColumnName(columnIdx, false);
			return Database.ColumnExists(tableName, columnName);
		}

		//-------------------------------------------------------------------
		// Password utilities.

		public override bool PasswordIsBlank(SaSecurityItem securityItemUser)
		{
			if (securityItemUser == null) return false;
			SaSecurity.PasswordMethod method = securityItemUser.GetPasswordMethod();
			// MsSql method.
			if (method == SaSecurity.PasswordMethod.MsSql)
			{
				//...
			}
			// Legacy.
#pragma warning disable CS0618 // Deprecated property
			return EncryptPassword_Legacy("").Equals(securityItemUser.PasswordEncrypted);
#pragma warning restore CS0618 // Deprecated property
		}

		public override bool PasswordMatches(SaSecurityItem securityItemUser, String password)
		{
			if (securityItemUser == null) return false;
			SaSecurity.PasswordMethod method = securityItemUser.GetPasswordMethod();
			// MsSql method.
			if (method == SaSecurity.PasswordMethod.MsSql)
			{
				//...
			}
			// Legacy.
#pragma warning disable CS0618 // Deprecated property
			return (EncryptPassword_Legacy(password).Equals(securityItemUser.PasswordEncrypted));
#pragma warning restore CS0618 // Deprecated property
		}

		/// <summary>Store the password against against the user.</summary>
		public override bool SetPassword(SaSecurityItem securityItemUser, String password)
		{
			return false;
		}

		internal static String EncryptPassword_Legacy(String password)
		{
			// We know this is not very water-tight, but it at least
			// hides the contents of the password from prying eyes.
			String toBeEncrypted = password;
			// Password length goes in as first character:
			toBeEncrypted = ByteToString((byte)(128 - password.Length)) + toBeEncrypted;
			toBeEncrypted = string.Concat(toBeEncrypted.Reverse());
			// Pad out to fixed length (minimum 16, multiples of 8):
			int fixedLength = 16;
			if (password.Length / 8 > 2) fixedLength = 8 * (int)(password.Length / 8);
			while (toBeEncrypted.Length < fixedLength)
			{
				char charToAdd = (char)(password.Length > 0 ? password[(toBeEncrypted.Length % password.Length)] : 'A' + (toBeEncrypted.Length * 13) % 23);
				if (toBeEncrypted.Length % 2 != 0)
					toBeEncrypted += charToAdd;
				else toBeEncrypted = charToAdd + toBeEncrypted;
			}

			// Now perform a simple algorythm on each character to hide its true value:
			byte[] encryptedChars = new byte[toBeEncrypted.Length];
			for (int i = 0; i < toBeEncrypted.Length; i++)
			{
				int iData = toBeEncrypted[i];
				iData += 17 + i;
				if (iData > 255) iData -= (255 + 32);
				encryptedChars[i] = (byte)iData;
			}
			String result = Encoding_Ansi1252.GetString(encryptedChars);
#if DEBUG
			// Password: mgbgt
			// To encrypt: tbmggtgbgm{btggm
			// Encrypted:  133, 116, 128, 123, 124, 138, 126, 122, 128, 135, 150, 126, 145, 133, 134, 141
			//Logger.Info(fn + "\n\tPassword:   " + password + "\n\tTo encrypt: " + toBeEncrypted + "\n\tEncrypted:  " + encryptedChars.Select(i => i.ToString()).ToList().Concat(", "));
			//Logger.Debug(password + ": " + result);
#endif
			return result;
		}
		private static byte[] PasswordStringToBytes(String value)
		{
			byte[] values = new byte[value.Length];
			for (int idx = 0; idx < value.Length; idx++)
			{
				char c = value[idx];
				UInt32 ui = Convert.ToUInt32(c);
				SaLogger.Info(idx + ". " + ui.ToString("x8"));
				values[idx] = (byte)(c);
			}
			return values;
		}
		private static readonly Encoding Encoding_Ansi1252 = Encoding.GetEncoding(1252);
		private static String ByteToString(byte value)
		{
			return Encoding_Ansi1252.GetString(new[] { value });
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}