x2log/X2Log.Observer.MonitorForm.pas

unit X2Log.Observer.MonitorForm;

interface
uses
  System.Classes,
  System.Generics.Collections,
  System.Types,
  Vcl.ActnList,
  Vcl.ComCtrls,
  Vcl.Controls,
  Vcl.Dialogs,
  Vcl.ExtCtrls,
  Vcl.Forms,
  Vcl.Grids,
  Vcl.ImgList,
  Vcl.Menus,
  Vcl.StdCtrls,
  Vcl.ToolWin,
  Vcl.ValEdit,
  VirtualTrees,
  Winapi.Messages,

  X2Log.Details.Intf,
  X2Log.Intf;


const
  CM_REENABLE = WM_APP + 1;


var
  DefaultMaxEntries: Cardinal = 1000;


type
  TX2LogObserverMonitorForm = class;
  TMonitorFormDictionary = TObjectDictionary<IX2LogObservable,TX2LogObserverMonitorForm>;

  TCopyHandler = procedure of object;


  TX2LogObserverMonitorForm = class(TForm, IX2LogObserver)
    vstLog: TVirtualStringTree;
    ilsLog: TImageList;
    splDetails: TSplitter;
    hcDetails: THeaderControl;
    pnlDetails: TPanel;
    reDetails: TRichEdit;
    pnlLog: TPanel;
    tbLog: TToolBar;
    tbDetails: TToolBar;
    pnlBorder: TPanel;
    tbClear: TToolButton;
    tbSaveDetails: TToolButton;
    sbStatus: TStatusBar;
    tbCopyDetails: TToolButton;
    alLog: TActionList;
    actClear: TAction;
    actCopyDetails: TAction;
    actSaveDetails: TAction;
    actPause: TAction;
    tbPause: TToolButton;
    sdDetails: TSaveDialog;
    tbShowVerbose: TToolButton;
    tbShowInfo: TToolButton;
    tbShowWarning: TToolButton;
    tbShowError: TToolButton;
    actShowVerbose: TAction;
    actShowInfo: TAction;
    actShowWarning: TAction;
    actShowError: TAction;
    lblFilter: TLabel;
    sbDetailsImage: TScrollBox;
    imgDetailsImage: TImage;
    tbWordWrap: TToolButton;
    tbDetailsSep1: TToolButton;
    actWordWrap: TAction;
    mmMain: TMainMenu;
    mmMainFile: TMenuItem;
    mmMainLog: TMenuItem;
    mmMainDetails: TMenuItem;
    mmMainWindow: TMenuItem;
    actClose: TAction;
    mmMainFileClose: TMenuItem;
    mmMainLogClear: TMenuItem;
    mmMainLogPause: TMenuItem;
    mmMainLogSep1: TMenuItem;
    mmMainLogVerbose: TMenuItem;
    mmMainLogInfo: TMenuItem;
    mmMainLogWarning: TMenuItem;
    mmMainLogError: TMenuItem;
    mmMainDetailsCopy: TMenuItem;
    mmMainDetailsSave: TMenuItem;
    mmMainDetailsWordWrap: TMenuItem;
    mmMainDetailsSep1: TMenuItem;
    actAlwaysOnTop: TAction;
    mmMainWindowAlwaysOnTop: TMenuItem;
    actSaveAs: TAction;
    mmMainFileSep1: TMenuItem;
    mmMainFileSaveAs: TMenuItem;
    sdSaveAs: TSaveDialog;
    vleDetailsDictionary: TValueListEditor;

    procedure FormShow(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure vstLogFreeNode(Sender: TBaseVirtualTree; Node: PVirtualNode);
    procedure vstLogGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType; var CellText: string);
    procedure vstLogGetImageIndex(Sender: TBaseVirtualTree; Node: PVirtualNode; Kind: TVTImageKind; Column: TColumnIndex; var Ghosted: Boolean; var ImageIndex: Integer);
    procedure vstLogFocusChanged(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex);
    procedure vleDetailsDictionaryKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
    procedure actCloseExecute(Sender: TObject);
    procedure actClearExecute(Sender: TObject);
    procedure actCopyDetailsExecute(Sender: TObject);
    procedure actSaveDetailsExecute(Sender: TObject);
    procedure actPauseExecute(Sender: TObject);
    procedure ToolbarCustomDraw(Sender: TToolBar; const ARect: TRect; var DefaultDraw: Boolean);
    procedure actShowVerboseExecute(Sender: TObject);
    procedure actShowInfoExecute(Sender: TObject);
    procedure actShowWarningExecute(Sender: TObject);
    procedure actShowErrorExecute(Sender: TObject);
    procedure actWordWrapExecute(Sender: TObject);
    procedure actAlwaysOnTopExecute(Sender: TObject);
    procedure actSaveAsExecute(Sender: TObject);
  private class var
    FInstances: TMonitorFormDictionary;
  private
    FFreeOnClose: Boolean;
    FClosed: Boolean;
    FLockCount: Integer;
    FLogObservable: IX2LogObservable;
    FLogAttached: Boolean;
    FPausedLogCount: Integer;
    FDetails: IX2LogDetails;
    FVisibleLevels: TX2LogLevels;
    FMaxEntries: Cardinal;
    FWordWrap: Boolean;
    FCopyHandler: TCopyHandler;
  protected
    class function GetInstance(ALog: IX2LogObservable; out AForm: TX2LogObserverMonitorForm): Boolean;
    class procedure RemoveInstance(AForm: TX2LogObserverMonitorForm);
    class procedure CleanupInstances;

    procedure CreateParams(var Params: TCreateParams); override;

    procedure WMEnable(var Msg: TWMEnable); message WM_ENABLE;
    procedure CMReenable(var Msg: TMessage); message CM_REENABLE;

    procedure AttachLog;
    procedure DetachLog;

    procedure UpdateUI;
    procedure UpdateStatus;
    procedure UpdateFilter;

    function GetPaused: Boolean;
    procedure ToggleVisibleLevel(AAction: TObject; ALevel: TX2LogLevel);

    procedure SetDetails(ADetails: IX2LogDetails);
    procedure SetBinaryDetails(ADetails: IX2LogDetailsBinary);
    procedure SetGraphicDetails(ADetails: IX2LogDetailsGraphic);
    procedure SetDictionaryDetails(ADetails: IX2LogDetailsDictionary);
    procedure CopyDictionaryDetails;

    procedure SetVisibleDetails(AControl: TControl);
    procedure SetWordWrap(AValue: Boolean);

    procedure ExportLog(ALog: IX2LogBase);

    property Closed: Boolean read FClosed;
    property Details: IX2LogDetails read FDetails;
    property LockCount: Integer read FLockCount;
    property LogObservable: IX2LogObservable read FLogObservable;
    property LogAttached: Boolean read FLogAttached;
    property Paused: Boolean read GetPaused;
    property PausedLogCount: Integer read FPausedLogCount write FPausedLogCount;
    property VisibleLevels: TX2LogLevels read FVisibleLevels write FVisibleLevels;
  public
    class function Instance(ALog: IX2LogObservable): TX2LogObserverMonitorForm;

    { Locked instances will always receive log messages, but will not be visible until
      ShowInstance is called and will hide instead of closing until UnlockInstance is called. }
    class procedure LockInstance(ALog: IX2LogObservable);
    class procedure UnlockInstance(ALog: IX2LogObservable);

    class procedure ShowInstance(ALog: IX2LogObservable);
    class procedure CloseInstance(ALog: IX2LogObservable);

    constructor Create(AOwner: TComponent; ALogObservable: IX2LogObservable = nil); reintroduce;
    destructor Destroy; override;

    procedure Lock;
    procedure Unlock;

    { IX2LogObserver }
    procedure Log(ALevel: TX2LogLevel; const AMessage, ACategory: string; ADetails: IX2LogDetails); overload;
    procedure Log(ALevel: TX2LogLevel; ADateTime: TDateTime; const AMessage, ACategory: string; ADetails: IX2LogDetails); overload;

    property FreeOnClose: Boolean read FFreeOnClose write FFreeOnClose;
    property MaxEntries: Cardinal read FMaxEntries write FMaxEntries;
  end;


implementation
uses
  System.DateUtils,
  System.Math,
  System.SysUtils,
  Vcl.Clipbrd,
  Vcl.Themes,
  Winapi.Windows,

  X2Log.Constants,
  X2Log.Observer.LogFile;


{$R *.dfm}


type
  TLogEntryNodeData = record
    Time: TDateTime;
    Paused: Boolean;
    Level: TX2LogLevel;
    Category: string;
    Message: string;
    Details: IX2LogDetails;

    procedure Initialize(APaused: Boolean; ALevel: TX2LogLevel; ADateTime: TDateTime; const AMessage, ACategory: string; ADetails: IX2LogDetails);
  end;

  PLogEntryNodeData = ^TLogEntryNodeData;


const
  ColumnLevel = 0;
  ColumnTime = 1;
  ColumnCategory = 2;
  ColumnMessage = 3;

  LevelImageIndex: array[TX2LogLevel] of TImageIndex = (0, 1, 2, 3);


{ TLogEntryNode }
procedure TLogEntryNodeData.Initialize(APaused: Boolean; ALevel: TX2LogLevel; ADateTime: TDateTime; const AMessage, ACategory: string; ADetails: IX2LogDetails);
begin
  Self.Time := ADateTime;
  Self.Paused := APaused;
  Self.Level := ALevel;
  Self.Category := ACategory;
  Self.Message := AMessage;
  Self.Details := ADetails;
end;


{ TX2LogObserverMonitorForm }
class function TX2LogObserverMonitorForm.Instance(ALog: IX2LogObservable): TX2LogObserverMonitorForm;
var
  log: IX2LogObservable;

begin
  { Explicit cast ensures we're getting the same pointer every time if, for example,
    the implementing interface is a descendant of IX2Log }
  log := (ALog as IX2LogObservable);

  if not Assigned(FInstances) then
    FInstances := TMonitorFormDictionary.Create([doOwnsValues]);

  if not FInstances.TryGetValue(log, Result) then
  begin
    Result := TX2LogObserverMonitorForm.Create(nil, log);
    Result.FreeOnClose := True;

    FInstances.Add(log, Result);
  end;
end;


class procedure TX2LogObserverMonitorForm.LockInstance(ALog: IX2LogObservable);
begin
  Instance(ALog).Lock;
end;


class procedure TX2LogObserverMonitorForm.UnlockInstance(ALog: IX2LogObservable);
begin
  Instance(ALog).Unlock;
end;


class procedure TX2LogObserverMonitorForm.ShowInstance(ALog: IX2LogObservable);
begin
  Instance(ALog).Show;
end;


class procedure TX2LogObserverMonitorForm.CloseInstance(ALog: IX2LogObservable);
var
  monitorForm: TX2LogObserverMonitorForm;

begin
  if GetInstance(ALog, monitorForm) then
    monitorForm.Close;
end;


class function TX2LogObserverMonitorForm.GetInstance(ALog: IX2LogObservable; out AForm: TX2LogObserverMonitorForm): Boolean;
begin
  Result := False;

  if Assigned(FInstances) then
    Result := FInstances.TryGetValue(ALog as IX2Log, AForm);
end;


class procedure TX2LogObserverMonitorForm.RemoveInstance(AForm: TX2LogObserverMonitorForm);
var
  log: IX2LogObservable;

begin
  if Assigned(FInstances) then
  begin
    for log in FInstances.Keys do
    begin
      if FInstances[log] = AForm then
      begin
        FInstances.ExtractPair(log);
        break;
      end;
    end;
  end;
end;


class procedure TX2LogObserverMonitorForm.CleanupInstances;
begin
  if Assigned(FInstances) then
    FreeAndNil(FInstances);
end;


constructor TX2LogObserverMonitorForm.Create(AOwner: TComponent; ALogObservable: IX2LogObservable);
var
  captionFormat: string;

begin
  inherited Create(AOwner);

  FClosed := True;
  FLogObservable := ALogObservable;
  FMaxEntries := DefaultMaxEntries;

  captionFormat := GetLogResourceString(@LogMonitorFormCaption);
  if Pos('%s', captionFormat) > 0 then
    Caption := Format(captionFormat, [Application.Title])
  else
    Caption := captionFormat;

  vstLog.NodeDataSize := SizeOf(TLogEntryNodeData);
  vstLog.Header.Columns[ColumnTime].Text := GetLogResourceString(@LogMonitorFormColumnTime);
  vstLog.Header.Columns[ColumnCategory].Text := GetLogResourceString(@LogMonitorFormColumnCategory);
  vstLog.Header.Columns[ColumnMessage].Text := GetLogResourceString(@LogMonitorFormColumnMessage);

  mmMainFile.Caption := GetLogResourceString(@LogMonitorFormMenuFile);
  mmMainLog.Caption := GetLogResourceString(@LogMonitorFormMenuLog);
  mmMainDetails.Caption := GetLogResourceString(@LogMonitorFormMenuDetails);
  mmMainWindow.Caption := GetLogResourceString(@LogMonitorFormMenuWindow);

  actSaveAs.Caption := GetLogResourceString(@LogMonitorFormMenuFileSaveAs);
  actClose.Caption := GetLogResourceString(@LogMonitorFormMenuFileClose);
  actClear.Caption := GetLogResourceString(@LogMonitorFormButtonClear);
  actPause.Caption := GetLogResourceString(@LogMonitorFormButtonPause);
  actCopyDetails.Caption := GetLogResourceString(@LogMonitorFormButtonCopyDetails);
  actSaveDetails.Caption := GetLogResourceString(@LogMonitorFormButtonSaveDetails);
  actAlwaysOnTop.Caption := GetLogResourceString(@LogMonitorFormMenuWindowAlwaysOnTop);

  sdDetails.Filter := GetLogResourceString(@LogMonitorFormSaveDetailsFilter);
  sdSaveAs.Filter := GetLogResourceString(@LogMonitorFormSaveDetailsSaveAs);

  lblFilter.Caption := '    ' + GetLogResourceString(@LogMonitorFormButtonFilter) + '  ';
  actShowVerbose.Caption := GetLogLevelText(TX2LogLevel.Verbose);
  actShowInfo.Caption := GetLogLevelText(TX2LogLevel.Info);
  actShowWarning.Caption := GetLogLevelText(TX2LogLevel.Warning);
  actShowError.Caption := GetLogLevelText(TX2LogLevel.Error);

  FVisibleLevels := [Low(TX2LogLevel)..High(TX2LogLevel)];
  SetVisibleDetails(nil);
  UpdateUI;
end;


procedure TX2LogObserverMonitorForm.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);

  Params.WndParent := 0;
end;


procedure TX2LogObserverMonitorForm.AttachLog;
begin
  if Assigned(FLogObservable) and (not FLogAttached) then
  begin
    FLogObservable.Attach(Self);
    FLogAttached := True;
  end;
end;


procedure TX2LogObserverMonitorForm.DetachLog;
begin
  if Assigned(FLogObservable) and FLogAttached then
  begin
    FLogObservable.Detach(Self);
    FLogAttached := False;
  end;
end;


procedure TX2LogObserverMonitorForm.Lock;
begin
  Inc(FLockCount);
  AttachLog;
end;


procedure TX2LogObserverMonitorForm.Unlock;
begin
  if FLockCount > 0 then
  begin
    Dec(FLockCount);

    { Lock may have prevented a proper close, try again }
    if Closed then
      Close;
  end;
end;


destructor TX2LogObserverMonitorForm.Destroy;
begin
  DetachLog;
  RemoveInstance(Self);

  inherited Destroy;
end;


procedure TX2LogObserverMonitorForm.FormShow(Sender: TObject);
begin
  FClosed := False;
  AttachLog;
end;


procedure TX2LogObserverMonitorForm.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  if LockCount = 0 then
  begin
    DetachLog;

    if FreeOnClose then
      Action := caFree
    else
      Action := caHide;
  end else
  begin
    Action := caHide;
    FClosed := True;
  end;
end;


procedure TX2LogObserverMonitorForm.Log(ALevel: TX2LogLevel; const AMessage, ACategory: string; ADetails: IX2LogDetails);
begin
  Log(ALevel, Now, AMessage, ACategory, ADetails);
end;


procedure TX2LogObserverMonitorForm.Log(ALevel: TX2LogLevel; ADateTime: TDateTime; const AMessage, ACategory: string; ADetails: IX2LogDetails);
var
  node: PVirtualNode;
  nodeData: PLogEntryNodeData;

begin
  { Ensure thread safety; TThread.Queue will run the procedure immediately
    if Log is called from the main thread, or queue it asynchronously }
  TThread.Queue(nil,
    procedure
    var
      scroll: Boolean;

    begin
      scroll := (not Paused) and (vstLog.RootNodeCount > 0) and (vstLog.BottomNode = vstLog.GetLast);

      vstLog.BeginUpdate;
      try
        node := vstLog.AddChild(nil);
        nodeData := vstLog.GetNodeData(node);

        { BeginUpdate causes OnInitNode to be triggered on-demand,
          moved Initialize call here }
        Initialize(nodeData^);
        nodeData^.Initialize(Paused, ALevel, ADateTime, AMessage, ACategory, ADetails);

        vstLog.IsVisible[node] := (not Paused) and (ALevel in VisibleLevels);


        while vstLog.RootNodeCount > MaxEntries do
          vstLog.DeleteNode(vstLog.GetFirst);
      finally
        vstLog.EndUpdate;
      end;



      if scroll then
        vstLog.ScrollIntoView(node, False);

      UpdateUI;

      if Paused then
      begin
        PausedLogCount := PausedLogCount + 1;
        UpdateStatus;
      end;
    end);
end;


procedure TX2LogObserverMonitorForm.WMEnable(var Msg: TWMEnable);
begin
  if not Msg.Enabled then
    { Modal forms disable all other forms, ensure we're still accessible }
    PostMessage(Self.Handle, CM_REENABLE, 0, 0);
end;


procedure TX2LogObserverMonitorForm.CMReenable(var Msg: TMessage);
begin
  EnableWindow(Self.Handle, True);
end;


procedure TX2LogObserverMonitorForm.UpdateUI;
begin
  actClear.Enabled := (vstLog.RootNodeCount > 0);
  actSaveAs.Enabled := (vstLog.RootNodeCount > 0);
end;


procedure TX2LogObserverMonitorForm.UpdateStatus;
begin
  if Paused then
    sbStatus.SimpleText := ' ' + Format(GetLogResourceString(@LogMonitorFormStatusPaused), [PausedLogCount])
  else
    sbStatus.SimpleText := '';
end;


procedure TX2LogObserverMonitorForm.UpdateFilter;
var
  node: PVirtualNode;
  nodeData: PLogEntryNodeData;

begin
  vstLog.BeginUpdate;
  try
    for node in vstLog.Nodes do
    begin
      nodeData := vstLog.GetNodeData(node);
      vstLog.IsVisible[node] := (not nodeData^.Paused) and (nodeData^.Level in VisibleLevels);
    end;
  finally
    vstLog.EndUpdate;
  end;
end;


function TX2LogObserverMonitorForm.GetPaused: Boolean;
begin
  Result := actPause.Checked;
end;


procedure TX2LogObserverMonitorForm.ToggleVisibleLevel(AAction: TObject; ALevel: TX2LogLevel);
begin
  if ALevel in VisibleLevels then
    Exclude(FVisibleLevels, ALevel)
  else
    Include(FVisibleLevels, ALevel);

  (AAction as TCustomAction).Checked := (ALevel in VisibleLevels);
  UpdateFilter;
end;


procedure TX2LogObserverMonitorForm.SetDetails(ADetails: IX2LogDetails);
var
  logDetailsGraphic: IX2LogDetailsGraphic;
  logDetailsBinary: IX2LogDetailsBinary;
  logDetailsDictionary: IX2LogDetailsDictionary;
  logDetailsText: IX2LogDetailsText;
  canWrap: Boolean;

begin
  FDetails := ADetails;
  canWrap := False;
  FCopyHandler := nil;

  if Assigned(Details) then
  begin
    if Supports(ADetails, IX2LogDetailsGraphic, logDetailsGraphic) then
      SetGraphicDetails(logDetailsGraphic)

    else if Supports(ADetails, IX2LogDetailsBinary, logDetailsBinary) then
      SetBinaryDetails(logDetailsBinary)

    else if Supports(ADetails, IX2LogDetailsDictionary, logDetailsDictionary) then
      SetDictionaryDetails(logDetailsDictionary)

    else if Supports(ADetails, IX2LogDetailsText, logDetailsText) then
    begin
      reDetails.Text := logDetailsText.AsString;
      canWrap := True;
      SetVisibleDetails(reDetails);
    end;
  end else
    SetVisibleDetails(nil);


  actCopyDetails.Enabled := Assigned(FCopyHandler) or Supports(ADetails, IX2LogDetailsCopyable);
  actSaveDetails.Enabled := Supports(ADetails, IX2LogDetailsStreamable);
  actWordWrap.Enabled := canWrap;
  actWordWrap.Checked := canWrap and FWordWrap;

  SetWordWrap(actWordWrap.Checked);
end;


procedure TX2LogObserverMonitorForm.SetBinaryDetails(ADetails: IX2LogDetailsBinary);
const
  BufferSize = 4096;

  BytesPerLine = 16;
  HexSplitPos = 7;
  HexSplitSpacing = 1;

  HexDigits = 2;
  TextDigits = 1;
  HexSpacing = 0;
  HexTextSpacing = 2;

  ReadableCharacters = [32..126, 161..255];
  UnreadableCharacter = '.';


  procedure ResetLine(var ALine: string);
  var
    linePos: Integer;

  begin
    for linePos := 1 to Length(ALine) do
      ALine[linePos] := ' ';
  end;


var
  stream: TStream;
  buffer: array[0..Pred(BufferSize)] of Byte;
  readBytes: Integer;
  linePosition: Integer;
  line: string;
  bufferIndex: Integer;
  hexValue: string;
  hexPos: Integer;
  textPos: Integer;

begin
  stream := ADetails.AsStream;
  linePosition := 0;

  SetLength(line, (BytesPerLine * (HexDigits + HexSpacing + TextDigits)) + HexTextSpacing +
                  IfThen(HexSplitPos < BytesPerLine, HexSplitSpacing, 0));
  ResetLine(line);

  reDetails.Lines.BeginUpdate;
  try
    reDetails.Lines.Clear;

    while True do
    begin
      readBytes := stream.Read(buffer, SizeOf(buffer));
      if readBytes = 0 then
        break;

      for bufferIndex := 0 to Pred(readBytes) do
      begin
        hexValue := IntToHex(buffer[bufferIndex], HexDigits);

        if linePosition >= BytesPerLine then
        begin
          reDetails.Lines.Add(line);

          ResetLine(line);
          linePosition := 0;
        end;

        hexPos := (linePosition * (HexDigits + HexSpacing));
        if linePosition > HexSplitPos then
          Inc(hexPos, HexSplitSpacing);

        line[hexPos + 1] := hexValue[1];
        line[hexPos + 2] := hexValue[2];

        textPos := (BytesPerLine * (HexDigits + HexSpacing)) + HexTextSpacing + (linePosition * TextDigits);
        if HexSplitPos < BytesPerLine then
          Inc(textPos, HexSplitSpacing);

        if buffer[bufferIndex] in ReadableCharacters then
          line[textPos] := Chr(buffer[bufferIndex])
        else
          line[textPos] := UnreadableCharacter;

        Inc(linePosition);
      end;
    end;

    if linePosition > 0 then
      reDetails.Lines.Add(line);
  finally
    reDetails.Lines.EndUpdate;

    SetVisibleDetails(reDetails);
  end;
end;


procedure TX2LogObserverMonitorForm.SetGraphicDetails(ADetails: IX2LogDetailsGraphic);
begin
  imgDetailsImage.Picture.Assign(ADetails.AsGraphic);
  SetVisibleDetails(sbDetailsImage);
end;


procedure TX2LogObserverMonitorForm.SetDictionaryDetails(ADetails: IX2LogDetailsDictionary);
var
  key: string;

begin
  vleDetailsDictionary.Strings.Clear;

  for key in ADetails.Keys do
    vleDetailsDictionary.Values[key] := ADetails.DisplayValue[key];

  FCopyHandler := CopyDictionaryDetails;
  SetVisibleDetails(vleDetailsDictionary);
end;


procedure TX2LogObserverMonitorForm.CopyDictionaryDetails;
var
  y: Integer;
  x: Integer;
  selectedText: TStringBuilder;

begin
  selectedText := TStringBuilder.Create;
  try
    for y := vleDetailsDictionary.Selection.Top to vleDetailsDictionary.Selection.Bottom do
    begin
      for x := vleDetailsDictionary.Selection.Left to vleDetailsDictionary.Selection.Right do
        selectedText.Append(vleDetailsDictionary.Cells[x, y]);
    end;

    Clipboard.AsText := selectedText.ToString;
  finally
    FreeAndNil(selectedText);
  end;
end;


procedure TX2LogObserverMonitorForm.SetVisibleDetails(AControl: TControl);
var
  text: string;

begin
  if Assigned(AControl) then
  begin
    AControl.BringToFront;

    if (AControl = reDetails) and (not reDetails.HandleAllocated) then
    begin
      // TRichEdit clears it's text when it is first shown, at least on Delphi XE2
      text := reDetails.Text;
      reDetails.Visible := True;
      reDetails.Text := text;
    end else
      AControl.Visible := True;
  end;

  reDetails.Visible := (AControl = reDetails);
  sbDetailsImage.Visible := (AControl = sbDetailsImage);
  vleDetailsDictionary.Visible := (AControl = vleDetailsDictionary);

  if not reDetails.Visible then
    reDetails.Clear;

  if not sbDetailsImage.Visible then
    imgDetailsImage.Picture.Assign(nil);

  if not vleDetailsDictionary.Visible then
    vleDetailsDictionary.Strings.Clear;
end;


procedure TX2LogObserverMonitorForm.SetWordWrap(AValue: Boolean);
begin
  reDetails.WordWrap := AValue;

  if AValue then
    reDetails.ScrollBars := ssVertical
  else
    reDetails.ScrollBars := ssBoth;
end;


procedure TX2LogObserverMonitorForm.ExportLog(ALog: IX2LogBase);
var
  node: PVirtualNode;
  nodeData: PLogEntryNodeData;

begin
  for node in vstLog.Nodes do
  begin
    nodeData := vstLog.GetNodeData(node);
    ALog.Log(nodeData^.Level, nodeData^.Time, nodeData^.Message, nodeData^.Category, nodeData^.Details);
  end;
end;


procedure TX2LogObserverMonitorForm.vstLogFreeNode(Sender: TBaseVirtualTree; Node: PVirtualNode);
var
  nodeData: PLogEntryNodeData;

begin
  nodeData := Sender.GetNodeData(Node);
  Finalize(nodeData^);
end;


procedure TX2LogObserverMonitorForm.vstLogGetText(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex;
                                                  TextType: TVSTTextType; var CellText: string);
var
  nodeData: PLogEntryNodeData;

begin
  CellText := '';
  nodeData := Sender.GetNodeData(Node);

  case Column of
    ColumnTime:
      CellText := DateTimeToStr(nodeData^.Time);

    ColumnCategory:
      CellText := nodeData^.Category;

    ColumnMessage:
      CellText := nodeData^.Message;
  end;
end;


procedure TX2LogObserverMonitorForm.vstLogGetImageIndex(Sender: TBaseVirtualTree; Node: PVirtualNode; Kind: TVTImageKind;
                                                        Column: TColumnIndex; var Ghosted: Boolean; var ImageIndex: Integer);
var
  nodeData: PLogEntryNodeData;

begin
  if Kind in [ikNormal, ikSelected] then
  begin
    nodeData := Sender.GetNodeData(Node);

    case Column of
      ColumnLevel:
        ImageIndex := LevelImageIndex[nodeData^.Level];

      ColumnMessage:
        if Assigned(nodeData^.Details) then
          ImageIndex := 4;
    end;
  end;
end;


procedure TX2LogObserverMonitorForm.vstLogFocusChanged(Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex);
var
  nodeData: PLogEntryNodeData;

begin
  if Assigned(Node) then
  begin
    nodeData := Sender.GetNodeData(Node);
    SetDetails(nodeData^.Details);
  end else
    SetDetails(nil);

  UpdateUI;
end;


procedure TX2LogObserverMonitorForm.vleDetailsDictionaryKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
begin
  if (Shift = [ssCtrl]) and (Key = Ord('C')) then
  begin
    CopyDictionaryDetails;
    Key := 0;
  end;
end;


procedure TX2LogObserverMonitorForm.actCloseExecute(Sender: TObject);
begin
  Close;
end;


procedure TX2LogObserverMonitorForm.actClearExecute(Sender: TObject);
begin
  vstLog.Clear;
  SetDetails(nil);

  UpdateUI;
end;


procedure TX2LogObserverMonitorForm.actCopyDetailsExecute(Sender: TObject);
var
  logDetailsCopyable: IX2LogDetailsCopyable;

begin
  if Assigned(FCopyHandler) then
    FCopyHandler

  else if Supports(Details, IX2LogDetailsCopyable, logDetailsCopyable) then
    logDetailsCopyable.CopyToClipboard;
end;


procedure TX2LogObserverMonitorForm.actSaveDetailsExecute(Sender: TObject);
var
  logDetailsStreamable: IX2LogDetailsStreamable;
  outputStream: TFileStream;

begin
  if Supports(Details, IX2LogDetailsStreamable, logDetailsStreamable) then
  begin
    if sdDetails.Execute then
    begin
      outputStream := TFileStream.Create(sdDetails.FileName, fmCreate or fmShareDenyWrite);
      try
        logDetailsStreamable.SaveToStream(outputStream);
      finally
        FreeAndNil(outputStream);
      end;
    end;
  end;
end;


procedure TX2LogObserverMonitorForm.actWordWrapExecute(Sender: TObject);
begin
  FWordWrap := actWordWrap.Checked;
  SetWordWrap(FWordWrap);
end;


procedure TX2LogObserverMonitorForm.actPauseExecute(Sender: TObject);
var
  node: PVirtualNode;
  nodeData: PLogEntryNodeData;

begin
  if not Paused then
  begin
    { Clear Paused status from nodes }
    vstLog.BeginUpdate;
    try
      for node in vstLog.Nodes do
      begin
        nodeData := vstLog.GetNodeData(node);

        if nodeData^.Paused then
        begin
          nodeData^.Paused := False;
          vstLog.IsVisible[node] := (nodeData^.Level in VisibleLevels);
        end;
      end;
    finally
      vstLog.EndUpdate;
    end;
  end;

  PausedLogCount := 0;
  UpdateStatus;
end;


procedure TX2LogObserverMonitorForm.actShowVerboseExecute(Sender: TObject);
begin
  ToggleVisibleLevel(Sender, TX2LogLevel.Verbose);
end;


procedure TX2LogObserverMonitorForm.actShowInfoExecute(Sender: TObject);
begin
  ToggleVisibleLevel(Sender, TX2LogLevel.Info);
end;


procedure TX2LogObserverMonitorForm.actShowWarningExecute(Sender: TObject);
begin
  ToggleVisibleLevel(Sender, TX2LogLevel.Warning);
end;


procedure TX2LogObserverMonitorForm.actShowErrorExecute(Sender: TObject);
begin
  ToggleVisibleLevel(Sender, TX2LogLevel.Error);
end;


procedure TX2LogObserverMonitorForm.actAlwaysOnTopExecute(Sender: TObject);
begin
  actAlwaysOnTop.Checked := not actAlwaysOnTop.Checked;

  if actAlwaysOnTop.Checked then
    SetWindowPos(Self.Handle, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE or SWP_NOACTIVATE)
  else
    SetWindowPos(Self.Handle, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE or SWP_NOACTIVATE);
end;


procedure TX2LogObserverMonitorForm.actSaveAsExecute(Sender: TObject);
var
  logFile: IX2LogBase;

begin
  if sdSaveAs.Execute then
  begin
    { Default behaviour of the LogFile observer is to append }
    System.SysUtils.DeleteFile(sdSaveAs.FileName);

    logFile := TX2LogFileObserver.Create(sdSaveAs.FileName, X2LogLevelsAll);
    ExportLog(logFile);
  end;
end;


procedure TX2LogObserverMonitorForm.ToolbarCustomDraw(Sender: TToolBar; const ARect: TRect; var DefaultDraw: Boolean);
var
  element: TThemedElementDetails;
  rect: TRect;

begin
  if StyleServices.Enabled then
  begin
    rect := Sender.ClientRect;
    if Assigned(Self.Menu) then
      Dec(rect.Top, GetSystemMetrics(SM_CYMENU));

    element := StyleServices.GetElementDetails(trRebarRoot);
    StyleServices.DrawElement(Sender.Canvas.Handle, element, rect);
  end;
end;


initialization
finalization
  TX2LogObserverMonitorForm.CleanupInstances;

end.