/*
  KeePass Password Safe - The Open-Source Password Manager
  Copyright (C) 2003-2024 Dominik Reichl <dominik.reichl@t-online.de>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

using System;
using System.Collections.Generic;
using System.Diagnostics;

#if !KeePassUAP
using System.Drawing;
#endif

using KeePassLib.Collections;
using KeePassLib.Interfaces;
using KeePassLib.Security;
using KeePassLib.Utility;

namespace KeePassLib
{
	/// <summary>
	/// A class representing a password entry. A password entry consists of several
	/// fields like title, user name, password, etc. Each password entry has a
	/// unique ID (UUID).
	/// </summary>
	public sealed class PwEntry : ITimeLogger, IStructureItem, IDeepCloneable<PwEntry>
	{
		private PwUuid m_uuid = PwUuid.Zero;
		private PwGroup m_pParentGroup = null;
		private DateTime m_tParentGroupLastMod = PwDefs.DtDefaultNow;
		private PwUuid m_puPrevParentGroup = PwUuid.Zero;

		private ProtectedStringDictionary m_dStrings = new ProtectedStringDictionary();
		private ProtectedBinaryDictionary m_dBinaries = new ProtectedBinaryDictionary();
		private AutoTypeConfig m_cfgAutoType = new AutoTypeConfig();
		private PwObjectList<PwEntry> m_lHistory = new PwObjectList<PwEntry>();

		private PwIcon m_pwIcon = PwIcon.Key;
		private PwUuid m_puCustomIcon = PwUuid.Zero;

		private Color m_clrForeground = Color.Empty;
		private Color m_clrBackground = Color.Empty;

		private DateTime m_tCreation = PwDefs.DtDefaultNow;
		private DateTime m_tLastMod = PwDefs.DtDefaultNow;
		private DateTime m_tLastAccess = PwDefs.DtDefaultNow;
		private DateTime m_tExpire = PwDefs.DtDefaultNow;
		private bool m_bExpires = false;
		private ulong m_uUsageCount = 0;

		private string m_strOverrideUrl = string.Empty;
		private bool m_bQualityCheck = true;

		private List<string> m_lTags = new List<string>();

		private StringDictionaryEx m_dCustomData = new StringDictionaryEx();

		/// <summary>
		/// UUID of this entry.
		/// </summary>
		public PwUuid Uuid
		{
			get { return m_uuid; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_uuid = value;
			}
		}

		/// <summary>
		/// Reference to a group which contains the current entry.
		/// </summary>
		public PwGroup ParentGroup
		{
			get { return m_pParentGroup; }

			// Plugins: use <c>PwGroup.AddEntry</c> instead.
			internal set { m_pParentGroup = value; }
		}

		/// <summary>
		/// The date/time when the location of the object was last changed.
		/// </summary>
		public DateTime LocationChanged
		{
			get { return m_tParentGroupLastMod; }
			set { m_tParentGroupLastMod = value; }
		}

		public PwUuid PreviousParentGroup
		{
			get { return m_puPrevParentGroup; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_puPrevParentGroup = value;
			}
		}

		/// <summary>
		/// Get or set all entry strings.
		/// </summary>
		public ProtectedStringDictionary Strings
		{
			get { return m_dStrings; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_dStrings = value;
			}
		}

		/// <summary>
		/// Get or set all entry binaries.
		/// </summary>
		public ProtectedBinaryDictionary Binaries
		{
			get { return m_dBinaries; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_dBinaries = value;
			}
		}

		/// <summary>
		/// Get or set all auto-type window/keystroke sequence associations.
		/// </summary>
		public AutoTypeConfig AutoType
		{
			get { return m_cfgAutoType; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_cfgAutoType = value;
			}
		}

		/// <summary>
		/// Get all previous versions of this entry (backups).
		/// </summary>
		public PwObjectList<PwEntry> History
		{
			get { return m_lHistory; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_lHistory = value;
			}
		}

		/// <summary>
		/// Image ID specifying the icon that will be used for this entry.
		/// </summary>
		public PwIcon IconId
		{
			get { return m_pwIcon; }
			set { m_pwIcon = value; }
		}

		/// <summary>
		/// Get the custom icon ID. This value is 0, if no custom icon is
		/// being used (i.e. the icon specified by the <c>IconID</c> property
		/// should be displayed).
		/// </summary>
		public PwUuid CustomIconUuid
		{
			get { return m_puCustomIcon; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_puCustomIcon = value;
			}
		}

		/// <summary>
		/// Get or set the foreground color of this entry.
		/// </summary>
		public Color ForegroundColor
		{
			get { return m_clrForeground; }
			set { m_clrForeground = value; }
		}

		/// <summary>
		/// Get or set the background color of this entry.
		/// </summary>
		public Color BackgroundColor
		{
			get { return m_clrBackground; }
			set { m_clrBackground = value; }
		}

		/// <summary>
		/// The date/time when this entry was created.
		/// </summary>
		public DateTime CreationTime
		{
			get { return m_tCreation; }
			set { m_tCreation = value; }
		}

		/// <summary>
		/// The date/time when this entry was last modified.
		/// </summary>
		public DateTime LastModificationTime
		{
			get { return m_tLastMod; }
			set { m_tLastMod = value; }
		}

		/// <summary>
		/// The date/time when this entry was last accessed (read).
		/// </summary>
		public DateTime LastAccessTime
		{
			get { return m_tLastAccess; }
			set { m_tLastAccess = value; }
		}

		/// <summary>
		/// The date/time when this entry expires. Use the <c>Expires</c> property
		/// to specify if the entry does actually expire or not.
		/// </summary>
		public DateTime ExpiryTime
		{
			get { return m_tExpire; }
			set { m_tExpire = value; }
		}

		/// <summary>
		/// Specifies whether the entry expires or not.
		/// </summary>
		public bool Expires
		{
			get { return m_bExpires; }
			set { m_bExpires = value; }
		}

		/// <summary>
		/// Get or set the usage count of the entry. To increase the usage
		/// count by one, use the <c>Touch</c> function.
		/// </summary>
		public ulong UsageCount
		{
			get { return m_uUsageCount; }
			set { m_uUsageCount = value; }
		}

		/// <summary>
		/// Entry-specific override URL.
		/// </summary>
		public string OverrideUrl
		{
			get { return m_strOverrideUrl; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_strOverrideUrl = value;
			}
		}

		public bool QualityCheck
		{
			get { return m_bQualityCheck; }
			set { m_bQualityCheck = value; }
		}

		/// <summary>
		/// List of tags associated with this entry.
		/// </summary>
		public List<string> Tags
		{
			get { StrUtil.NormalizeTags(m_lTags); return m_lTags; }
			set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_lTags = value;
			}
		}

		/// <summary>
		/// Custom data container that can be used by plugins to store
		/// own data in KeePass entries.
		/// The data is stored in the encrypted part of encrypted
		/// database files.
		/// Use unique names for your items, e.g. "PluginName_ItemName".
		/// </summary>
		public StringDictionaryEx CustomData
		{
			get { return m_dCustomData; }
			internal set
			{
				if(value == null) { Debug.Assert(false); throw new ArgumentNullException("value"); }
				m_dCustomData = value;
			}
		}

		public static EventHandler<ObjectTouchedEventArgs> EntryTouched;
		public EventHandler<ObjectTouchedEventArgs> Touched;

		/// <summary>
		/// Construct a new, empty password entry. Member variables will be initialized
		/// to their default values.
		/// </summary>
		/// <param name="bCreateNewUuid">If <c>true</c>, a new UUID will be created
		/// for this entry. If <c>false</c>, the UUID is zero and you must set it
		/// manually later.</param>
		/// <param name="bSetTimes">If <c>true</c>, the creation, last modification
		/// and last access times will be set to the current system time.</param>
		public PwEntry(bool bCreateNewUuid, bool bSetTimes)
		{
			if(bCreateNewUuid) m_uuid = new PwUuid(true);

			if(bSetTimes)
			{
				DateTime dtNow = DateTime.UtcNow;
				m_tCreation = dtNow;
				m_tLastMod = dtNow;
				m_tLastAccess = dtNow;
				m_tParentGroupLastMod = dtNow;
			}
		}

		[Obsolete("Use a different constructor. To add an entry to a group, use the AddEntry method of PwGroup.")]
		public PwEntry(PwGroup pgParent, bool bCreateNewUuid, bool bSetTimes) :
			this(bCreateNewUuid, bSetTimes)
		{
			m_pParentGroup = pgParent;
		}

#if DEBUG
		// For display in debugger
		public override string ToString()
		{
			return ("PwEntry '" + m_dStrings.ReadSafe(PwDefs.TitleField) + "'");
		}
#endif

		/// <summary>
		/// Clone the current entry. The returned entry is an exact value copy
		/// of the current entry (including UUID and parent group reference).
		/// All mutable members are cloned.
		/// </summary>
		/// <returns>Exact value clone. All references to mutable values changed.</returns>
		public PwEntry CloneDeep()
		{
			PwEntry peNew = new PwEntry(false, false);

			peNew.m_uuid = m_uuid; // PwUuid is immutable
			peNew.m_pParentGroup = m_pParentGroup;
			peNew.m_tParentGroupLastMod = m_tParentGroupLastMod;
			peNew.m_puPrevParentGroup = m_puPrevParentGroup;

			peNew.m_dStrings = m_dStrings.CloneDeep();
			peNew.m_dBinaries = m_dBinaries.CloneDeep();
			peNew.m_cfgAutoType = m_cfgAutoType.CloneDeep();
			peNew.m_lHistory = m_lHistory.CloneDeep();

			peNew.m_pwIcon = m_pwIcon;
			peNew.m_puCustomIcon = m_puCustomIcon;

			peNew.m_clrForeground = m_clrForeground;
			peNew.m_clrBackground = m_clrBackground;

			peNew.m_tCreation = m_tCreation;
			peNew.m_tLastMod = m_tLastMod;
			peNew.m_tLastAccess = m_tLastAccess;
			peNew.m_tExpire = m_tExpire;
			peNew.m_bExpires = m_bExpires;
			peNew.m_uUsageCount = m_uUsageCount;

			peNew.m_strOverrideUrl = m_strOverrideUrl;
			peNew.m_bQualityCheck = m_bQualityCheck;

			peNew.m_lTags.AddRange(m_lTags);

			peNew.m_dCustomData = m_dCustomData.CloneDeep();

			return peNew;
		}

		public PwEntry CloneStructure()
		{
			PwEntry peNew = new PwEntry(false, false);

			peNew.m_uuid = m_uuid; // PwUuid is immutable
			peNew.m_tParentGroupLastMod = m_tParentGroupLastMod;
			// Do not assign m_pParentGroup

			return peNew;
		}

		private static PwCompareOptions BuildCmpOpt(bool bIgnoreParentGroup,
			bool bIgnoreLastMod, bool bIgnoreLastAccess, bool bIgnoreHistory,
			bool bIgnoreThisLastBackup)
		{
			PwCompareOptions pwOpt = PwCompareOptions.None;
			if(bIgnoreParentGroup) pwOpt |= PwCompareOptions.IgnoreParentGroup;
			if(bIgnoreLastMod) pwOpt |= PwCompareOptions.IgnoreLastMod;
			if(bIgnoreLastAccess) pwOpt |= PwCompareOptions.IgnoreLastAccess;
			if(bIgnoreHistory) pwOpt |= PwCompareOptions.IgnoreHistory;
			if(bIgnoreThisLastBackup) pwOpt |= PwCompareOptions.IgnoreLastBackup;
			return pwOpt;
		}

		[Obsolete]
		public bool EqualsEntry(PwEntry pe, bool bIgnoreParentGroup, bool bIgnoreLastMod,
			bool bIgnoreLastAccess, bool bIgnoreHistory, bool bIgnoreThisLastBackup)
		{
			return EqualsEntry(pe, BuildCmpOpt(bIgnoreParentGroup, bIgnoreLastMod,
				bIgnoreLastAccess, bIgnoreHistory, bIgnoreThisLastBackup),
				MemProtCmpMode.None);
		}

		[Obsolete]
		public bool EqualsEntry(PwEntry pe, bool bIgnoreParentGroup, bool bIgnoreLastMod,
			bool bIgnoreLastAccess, bool bIgnoreHistory, bool bIgnoreThisLastBackup,
			MemProtCmpMode mpCmpStr)
		{
			return EqualsEntry(pe, BuildCmpOpt(bIgnoreParentGroup, bIgnoreLastMod,
				bIgnoreLastAccess, bIgnoreHistory, bIgnoreThisLastBackup), mpCmpStr);
		}

		public bool EqualsEntry(PwEntry pe, PwCompareOptions pwOpt,
			MemProtCmpMode mpCmpStr)
		{
			if(pe == null) { Debug.Assert(false); return false; }

			bool bNeEqStd = ((pwOpt & PwCompareOptions.NullEmptyEquivStd) !=
				PwCompareOptions.None);
			bool bIgnoreLastAccess = ((pwOpt & PwCompareOptions.IgnoreLastAccess) !=
				PwCompareOptions.None);
			bool bIgnoreLastMod = ((pwOpt & PwCompareOptions.IgnoreLastMod) !=
				PwCompareOptions.None);

			if(!m_uuid.Equals(pe.m_uuid)) return false;
			if((pwOpt & PwCompareOptions.IgnoreParentGroup) == PwCompareOptions.None)
			{
				if(m_pParentGroup != pe.m_pParentGroup) return false;
				if(!bIgnoreLastMod && !TimeUtil.EqualsFloor(m_tParentGroupLastMod,
					pe.m_tParentGroupLastMod))
					return false;
				if(!m_puPrevParentGroup.Equals(pe.m_puPrevParentGroup))
					return false;
			}

			if(!m_dStrings.EqualsDictionary(pe.m_dStrings, pwOpt, mpCmpStr))
				return false;
			if(!m_dBinaries.EqualsDictionary(pe.m_dBinaries)) return false;

			if(!m_cfgAutoType.Equals(pe.m_cfgAutoType)) return false;

			if((pwOpt & PwCompareOptions.IgnoreHistory) == PwCompareOptions.None)
			{
				bool bIgnoreLastBackup = ((pwOpt & PwCompareOptions.IgnoreLastBackup) !=
					PwCompareOptions.None);

				if(!bIgnoreLastBackup && (m_lHistory.UCount != pe.m_lHistory.UCount))
					return false;
				if(bIgnoreLastBackup && (m_lHistory.UCount == 0))
				{
					Debug.Assert(false);
					return false;
				}
				if(bIgnoreLastBackup && ((m_lHistory.UCount - 1) != pe.m_lHistory.UCount))
					return false;

				PwCompareOptions cmpSub = PwCompareOptions.IgnoreParentGroup;
				if(bNeEqStd) cmpSub |= PwCompareOptions.NullEmptyEquivStd;
				if(bIgnoreLastMod) cmpSub |= PwCompareOptions.IgnoreLastMod;
				if(bIgnoreLastAccess) cmpSub |= PwCompareOptions.IgnoreLastAccess;

				for(uint uHist = 0; uHist < pe.m_lHistory.UCount; ++uHist)
				{
					if(!m_lHistory.GetAt(uHist).EqualsEntry(pe.m_lHistory.GetAt(
						uHist), cmpSub, MemProtCmpMode.None))
						return false;
				}
			}

			if(m_pwIcon != pe.m_pwIcon) return false;
			if(!m_puCustomIcon.Equals(pe.m_puCustomIcon)) return false;

			if(m_clrForeground != pe.m_clrForeground) return false;
			if(m_clrBackground != pe.m_clrBackground) return false;

			if(!TimeUtil.EqualsFloor(m_tCreation, pe.m_tCreation)) return false;
			if(!bIgnoreLastMod && !TimeUtil.EqualsFloor(m_tLastMod, pe.m_tLastMod)) return false;
			if(!bIgnoreLastAccess && !TimeUtil.EqualsFloor(m_tLastAccess, pe.m_tLastAccess)) return false;
			if(!TimeUtil.EqualsFloor(m_tExpire, pe.m_tExpire)) return false;
			if(m_bExpires != pe.m_bExpires) return false;
			if(!bIgnoreLastAccess && (m_uUsageCount != pe.m_uUsageCount)) return false;

			if(m_strOverrideUrl != pe.m_strOverrideUrl) return false;
			if(m_bQualityCheck != pe.m_bQualityCheck) return false;

			// The Tags property normalizes
			if(!MemUtil.ListsEqual<string>(this.Tags, pe.Tags)) return false;

			if(!m_dCustomData.Equals(pe.m_dCustomData)) return false;

			return true;
		}

		/// <summary>
		/// Assign properties to the current entry based on a template entry.
		/// </summary>
		/// <param name="peTemplate">Template entry. Must not be <c>null</c>.</param>
		/// <param name="bOnlyIfNewer">Only set the properties of the template entry
		/// if it is newer than the current one.</param>
		/// <param name="bIncludeHistory">If <c>true</c>, the history will be
		/// copied, too.</param>
		/// <param name="bAssignLocationChanged">If <c>true</c>, the
		/// <c>LocationChanged</c> property is copied, otherwise not.</param>
		public void AssignProperties(PwEntry peTemplate, bool bOnlyIfNewer,
			bool bIncludeHistory, bool bAssignLocationChanged)
		{
			if(peTemplate == null) { Debug.Assert(false); throw new ArgumentNullException("peTemplate"); }

			if(bOnlyIfNewer && (TimeUtil.Compare(peTemplate.m_tLastMod,
				m_tLastMod, true) < 0))
				return;

			// Template UUID should be the same as the current one
			Debug.Assert(m_uuid.Equals(peTemplate.m_uuid));
			m_uuid = peTemplate.m_uuid;

			if(bAssignLocationChanged)
			{
				m_tParentGroupLastMod = peTemplate.m_tParentGroupLastMod;
				m_puPrevParentGroup = peTemplate.m_puPrevParentGroup;
			}

			m_dStrings = peTemplate.m_dStrings.CloneDeep();
			m_dBinaries = peTemplate.m_dBinaries.CloneDeep();
			m_cfgAutoType = peTemplate.m_cfgAutoType.CloneDeep();
			if(bIncludeHistory)
				m_lHistory = peTemplate.m_lHistory.CloneDeep();

			m_pwIcon = peTemplate.m_pwIcon;
			m_puCustomIcon = peTemplate.m_puCustomIcon; // Immutable

			m_clrForeground = peTemplate.m_clrForeground;
			m_clrBackground = peTemplate.m_clrBackground;

			m_tCreation = peTemplate.m_tCreation;
			m_tLastMod = peTemplate.m_tLastMod;
			m_tLastAccess = peTemplate.m_tLastAccess;
			m_tExpire = peTemplate.m_tExpire;
			m_bExpires = peTemplate.m_bExpires;
			m_uUsageCount = peTemplate.m_uUsageCount;

			m_strOverrideUrl = peTemplate.m_strOverrideUrl;
			m_bQualityCheck = peTemplate.m_bQualityCheck;

			m_lTags = new List<string>(peTemplate.m_lTags);

			m_dCustomData = peTemplate.m_dCustomData.CloneDeep();
		}

		/// <summary>
		/// Touch the entry. This function updates the internal last access
		/// time. If the <paramref name="bModified" /> parameter is <c>true</c>,
		/// the last modification time gets updated, too.
		/// </summary>
		/// <param name="bModified">Modify last modification time.</param>
		public void Touch(bool bModified)
		{
			Touch(bModified, true);
		}

		/// <summary>
		/// Touch the entry. This function updates the internal last access
		/// time. If the <paramref name="bModified" /> parameter is <c>true</c>,
		/// the last modification time gets updated, too.
		/// </summary>
		/// <param name="bModified">Modify last modification time.</param>
		/// <param name="bTouchParents">If <c>true</c>, all parent objects
		/// get touched, too.</param>
		public void Touch(bool bModified, bool bTouchParents)
		{
			m_tLastAccess = DateTime.UtcNow;
			++m_uUsageCount;

			if(bModified) m_tLastMod = m_tLastAccess;

			if(this.Touched != null)
				this.Touched(this, new ObjectTouchedEventArgs(this,
					bModified, bTouchParents));
			if(PwEntry.EntryTouched != null)
				PwEntry.EntryTouched(this, new ObjectTouchedEventArgs(this,
					bModified, bTouchParents));

			if(bTouchParents && (m_pParentGroup != null))
				m_pParentGroup.Touch(bModified, true);
		}

		/// <summary>
		/// Create a backup of this entry. The backup item doesn't contain any
		/// history items.
		/// </summary>
		[Obsolete]
		public void CreateBackup()
		{
			CreateBackup(null);
		}

		/// <summary>
		/// Create a backup of this entry. The backup item doesn't contain any
		/// history items.
		/// <param name="pwHistMntcSettings">If this parameter isn't <c>null</c>,
		/// the history list is maintained automatically (i.e. old backups are
		/// deleted if there are too many or the history size is too large).
		/// This parameter may be <c>null</c> (no maintenance then).</param>
		/// </summary>
		public void CreateBackup(PwDatabase pwHistMntcSettings)
		{
			PwEntry peCopy = CloneDeep();
			peCopy.m_lHistory.Clear();

			m_lHistory.Add(peCopy); // Must be added at end, see EqualsEntry

			if(pwHistMntcSettings != null) MaintainBackups(pwHistMntcSettings);
		}

		/// <summary>
		/// Restore an entry snapshot from backups.
		/// </summary>
		/// <param name="uBackupIndex">Index of the backup item, to which
		/// should be reverted.</param>
		[Obsolete]
		public void RestoreFromBackup(uint uBackupIndex)
		{
			RestoreFromBackup(uBackupIndex, null);
		}

		/// <summary>
		/// Restore an entry snapshot from backups.
		/// </summary>
		/// <param name="uBackupIndex">Index of the backup item, to which
		/// should be reverted.</param>
		/// <param name="pwHistMntcSettings">If this parameter isn't <c>null</c>,
		/// the history list is maintained automatically (i.e. old backups are
		/// deleted if there are too many or the history size is too large).
		/// This parameter may be <c>null</c> (no maintenance then).</param>
		public void RestoreFromBackup(uint uBackupIndex, PwDatabase pwHistMntcSettings)
		{
			if(uBackupIndex >= m_lHistory.UCount)
			{
				Debug.Assert(false);
				throw new ArgumentOutOfRangeException("uBackupIndex");
			}

			PwEntry pe = m_lHistory.GetAt(uBackupIndex);
			if(pe == null) { Debug.Assert(false); throw new InvalidOperationException(); }

			CreateBackup(pwHistMntcSettings); // Backup current data before restoring
			AssignProperties(pe, false, false, false);
		}

		public bool HasBackupOfData(PwEntry peData, bool bIgnoreLastMod,
			bool bIgnoreLastAccess)
		{
			if(peData == null) { Debug.Assert(false); return false; }

			PwCompareOptions cmpOpt = (PwCompareOptions.IgnoreParentGroup |
				PwCompareOptions.IgnoreHistory | PwCompareOptions.NullEmptyEquivStd);
			if(bIgnoreLastMod) cmpOpt |= PwCompareOptions.IgnoreLastMod;
			if(bIgnoreLastAccess) cmpOpt |= PwCompareOptions.IgnoreLastAccess;

			foreach(PwEntry pe in m_lHistory)
			{
				if(pe.EqualsEntry(peData, cmpOpt, MemProtCmpMode.None)) return true;
			}

			return false;
		}

		/// <summary>
		/// Delete old history entries if there are too many or the
		/// history size is too large.
		/// <returns>If one or more history entries have been deleted,
		/// <c>true</c> is returned. Otherwise <c>false</c>.</returns>
		/// </summary>
		public bool MaintainBackups(PwDatabase pwSettings)
		{
			if(pwSettings == null) { Debug.Assert(false); return false; }

			// Fix UUIDs of history entries; should not be necessary
			PwUuid pu = m_uuid;
			foreach(PwEntry pe in m_lHistory)
			{
				if(!pe.Uuid.Equals(pu)) { Debug.Assert(false); pe.Uuid = pu; }
			}

			bool bDeleted = false;

			int nMaxItems = pwSettings.HistoryMaxItems;
			if(nMaxItems >= 0)
			{
				while(m_lHistory.UCount > (uint)nMaxItems)
				{
					RemoveOldestBackup();
					bDeleted = true;
				}
			}

			long lMaxSize = pwSettings.HistoryMaxSize;
			if(lMaxSize >= 0)
			{
				while(true)
				{
					ulong uHistSize = 0;
					foreach(PwEntry pe in m_lHistory) { uHistSize += pe.GetSize(); }

					if(uHistSize > (ulong)lMaxSize)
					{
						RemoveOldestBackup();
						bDeleted = true;
					}
					else break;
				}
			}

			return bDeleted;
		}

		private void RemoveOldestBackup()
		{
			DateTime dtMin = TimeUtil.SafeMaxValueUtc;
			uint idxRemove = uint.MaxValue;

			for(uint u = 0; u < m_lHistory.UCount; ++u)
			{
				PwEntry pe = m_lHistory.GetAt(u);
				if(TimeUtil.Compare(pe.LastModificationTime, dtMin, true) < 0)
				{
					idxRemove = u;
					dtMin = pe.LastModificationTime;
				}
			}

			if(idxRemove != uint.MaxValue) m_lHistory.RemoveAt(idxRemove);
		}

		// Cf. AutoType.GetEnabledText
		public bool GetAutoTypeEnabled()
		{
			if(!m_cfgAutoType.Enabled) return false;

			if(m_pParentGroup != null)
				return m_pParentGroup.GetAutoTypeEnabledInherited();

			return PwGroup.DefaultAutoTypeEnabled;
		}

		public string GetAutoTypeSequence()
		{
			string strSeq = m_cfgAutoType.DefaultSequence;

			PwGroup pg = m_pParentGroup;
			while(pg != null)
			{
				if(strSeq.Length != 0) break;

				strSeq = pg.DefaultAutoTypeSequence;
				pg = pg.ParentGroup;
			}

			if(strSeq.Length != 0) return strSeq;

			if(PwDefs.IsTanEntry(this)) return PwDefs.DefaultAutoTypeSequenceTan;
			return PwDefs.DefaultAutoTypeSequence;
		}

		public bool GetSearchingEnabled()
		{
			if(m_pParentGroup != null)
				return m_pParentGroup.GetSearchingEnabledInherited();

			return PwGroup.DefaultSearchingEnabled;
		}

		/// <summary>
		/// Approximate the total size (in process memory) of this entry
		/// in bytes (including strings, binaries and history entries).
		/// </summary>
		/// <returns>Size in bytes.</returns>
		public ulong GetSize()
		{
			// This method assumes 64-bit pointers/references and Unicode
			// strings (i.e. 2 bytes per character)

			ulong cb = 276; // Number of bytes; approx. fixed length data
			ulong cc = 0; // Number of characters

			cb += (ulong)m_dStrings.UCount * 40;
			foreach(KeyValuePair<string, ProtectedString> kvpStr in m_dStrings)
				cc += (ulong)kvpStr.Key.Length + (ulong)kvpStr.Value.Length;

			cb += (ulong)m_dBinaries.UCount * 65;
			foreach(KeyValuePair<string, ProtectedBinary> kvpBin in m_dBinaries)
			{
				cc += (ulong)kvpBin.Key.Length;
				cb += (ulong)kvpBin.Value.Length;
			}

			cc += (ulong)m_cfgAutoType.DefaultSequence.Length;
			cb += (ulong)m_cfgAutoType.AssociationsCount * 24;
			foreach(AutoTypeAssociation a in m_cfgAutoType.Associations)
				cc += (ulong)a.WindowName.Length + (ulong)a.Sequence.Length;

			cb += (ulong)m_lHistory.UCount * 8;
			foreach(PwEntry peHistory in m_lHistory)
				cb += peHistory.GetSize();

			cc += (ulong)m_strOverrideUrl.Length;

			cb += (ulong)m_lTags.Count * 8;
			foreach(string strTag in m_lTags)
				cc += (ulong)strTag.Length;

			cb += (ulong)m_dCustomData.Count * 16;
			foreach(KeyValuePair<string, string> kvp in m_dCustomData)
				cc += (ulong)kvp.Key.Length + (ulong)kvp.Value.Length;

			return (cb + (cc << 1));
		}

		public bool HasTag(string strTag)
		{
			if(string.IsNullOrEmpty(strTag)) { Debug.Assert(false); return false; }

			// this.Tags normalizes
			return this.Tags.Contains(StrUtil.NormalizeTag(strTag));
		}

		public bool AddTag(string strTag)
		{
			if(string.IsNullOrEmpty(strTag)) { Debug.Assert(false); return false; }

			strTag = StrUtil.NormalizeTag(strTag);
			if(this.Tags.Contains(strTag)) return false; // this.Tags normalizes

			m_lTags.Add(strTag);
			return true;
		}

		public bool RemoveTag(string strTag)
		{
			if(string.IsNullOrEmpty(strTag)) { Debug.Assert(false); return false; }

			// this.Tags normalizes
			return this.Tags.Remove(StrUtil.NormalizeTag(strTag));
		}

		internal List<string> GetTagsInherited()
		{
			List<string> l = ((m_pParentGroup != null) ?
				m_pParentGroup.GetTagsInherited(false) : new List<string>());
			l.AddRange(this.Tags);
			StrUtil.NormalizeTags(l);
			return l;
		}

		public bool IsContainedIn(PwGroup pgContainer)
		{
			PwGroup pgCur = m_pParentGroup;
			while(pgCur != null)
			{
				if(pgCur == pgContainer) return true;

				pgCur = pgCur.ParentGroup;
			}

			return false;
		}

		public void SetUuid(PwUuid pwNewUuid, bool bAlsoChangeHistoryUuids)
		{
			this.Uuid = pwNewUuid;

			if(bAlsoChangeHistoryUuids)
			{
				foreach(PwEntry peHist in m_lHistory)
					peHist.Uuid = pwNewUuid;
			}
		}

		public void SetCreatedNow()
		{
			DateTime dt = DateTime.UtcNow;

			m_tCreation = dt;
			m_tLastAccess = dt;
		}

		public PwEntry Duplicate()
		{
			PwEntry pe = CloneDeep();

			pe.SetUuid(new PwUuid(true), true);
			pe.SetCreatedNow();

			return pe;
		}

		internal static PwEntry CreateVirtual(PwGroup pgParent,
			ProtectedStringDictionary dStrings)
		{
			PwEntry pe = new PwEntry(true, true);

			pe.ParentGroup = pgParent; // Do not add to group
			if(dStrings != null) pe.Strings = dStrings; // No clone

			return pe;
		}
	}

	public sealed class PwEntryComparer : IComparer<PwEntry>
	{
		private readonly string m_strFieldName;
		private readonly bool m_bCaseInsensitive;
		private readonly bool m_bCompareNaturally;

		public PwEntryComparer(string strFieldName, bool bCaseInsensitive,
			bool bCompareNaturally)
		{
			if(strFieldName == null) throw new ArgumentNullException("strFieldName");

			m_strFieldName = strFieldName;
			m_bCaseInsensitive = bCaseInsensitive;
			m_bCompareNaturally = bCompareNaturally;
		}

		public int Compare(PwEntry a, PwEntry b)
		{
			string strA = a.Strings.ReadSafe(m_strFieldName);
			string strB = b.Strings.ReadSafe(m_strFieldName);

			if(m_bCompareNaturally) return StrUtil.CompareNaturally(strA, strB);

			return string.Compare(strA, strB, m_bCaseInsensitive);
		}
	}
}