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unit SynEditMarkupCtrlMouseLink;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Graphics, SynEditMarkup, SynEditMiscClasses,
  SynEditMouseCmds, LazSynEditText, SynEditTypes, Controls, LCLProc;

type

  { TSynEditMarkupCtrlMouseLink }

  TSynEditMarkupCtrlMouseLink = class(TSynEditMarkup)
  private
    FCtrlMouseLine: Integer;
    FCtrlMouseX1: Integer;
    FCtrlMouseX2: Integer;
    FCtrlLinkable: Boolean;
    FCursor: TCursor;

    FLastControlIsPressed: boolean;
    FLastMouseCaret: TPoint;
    FLastMouseCaretLogical: TPoint;
    function GetIsMouseOverLink: Boolean;
    procedure SetCursor(AValue: TCursor);
    procedure SetLastMouseCaret(const AValue: TPoint);
    Procedure LinesChanged(Sender: TSynEditStrings; AIndex, ANewCount, AOldCount : Integer);
    function  IsCtrlMouseShiftState(AShift: TShiftState; OnlyShowLink: Boolean): Boolean;
    procedure InternalUpdateCtrlMouse;
    procedure UpdateSynCursor(Sender: TObject; const AMouseLocation: TSynMouseLocationInfo;
    var AnCursor: TCursor; var APriority: Integer; var AChangedBy: TObject);
  protected
    procedure SetLines(const AValue : TSynEditStrings); override;
    procedure DoMarkupChanged(AMarkup: TSynSelectedColor); override;
    procedure DoEnabledChanged(Sender: TObject); override;
  public
    procedure UpdateCtrlState(aShift: TShiftState);
    procedure UpdateCtrlMouse;
    property LastMouseCaret: TPoint read FLastMouseCaret write SetLastMouseCaret;
  public
    constructor Create(ASynEdit: TSynEditBase);
    destructor Destroy; override;

    function GetMarkupAttributeAtRowCol(const aRow: Integer;
                                        const aStartCol: TLazSynDisplayTokenBound;
                                        const AnRtlInfo: TLazSynDisplayRtlInfo): TSynSelectedColor; override;
    procedure GetNextMarkupColAfterRowCol(const aRow: Integer;
                                         const aStartCol: TLazSynDisplayTokenBound;
                                         const AnRtlInfo: TLazSynDisplayRtlInfo;
                                         out   ANextPhys, ANextLog: Integer); override;

    property CtrlMouseLine : Integer read FCtrlMouseLine write FCtrlMouseLine;
    property CtrlMouseX1 : Integer read FCtrlMouseX1 write FCtrlMouseX1;
    property CtrlMouseX2 : Integer read FCtrlMouseX2 write FCtrlMouseX2;
    property IsMouseOverLink: Boolean read GetIsMouseOverLink;
    property Cursor: TCursor read FCursor;
  end;

implementation
uses SynEdit;

const
  LINK_CURSOR_PRIORITY = 1;

{ TSynEditMarkupCtrlMouseLink }

procedure TSynEditMarkupCtrlMouseLink.SetLastMouseCaret(const AValue: TPoint);
begin
  if (FLastMouseCaret.X = AValue.X) and (FLastMouseCaret.Y = AValue.Y) then exit;
  FLastMouseCaret := AValue;
  if LastMouseCaret.y > 0
  then FLastMouseCaretLogical := Lines.PhysicalToLogicalPos(LastMouseCaret)
  else FLastMouseCaretLogical := LastMouseCaret;
  UpdateCtrlMouse;
end;

function TSynEditMarkupCtrlMouseLink.GetIsMouseOverLink: Boolean;
var
  NewCtrlIsPressed: Boolean;
begin
  // Normal checks only take Ctrl-State for ShowLink into account (since the cursor needs updates)
  // Here we need to check for Hiden-Links too
  NewCtrlIsPressed := IsCtrlMouseShiftState(GetKeyShiftState, False);
  if FLastControlIsPressed <> NewCtrlIsPressed then begin
    FLastControlIsPressed := NewCtrlIsPressed;
    InternalUpdateCtrlMouse;
  end;

  Result := FCtrlLinkable and (FCtrlMouseLine >= 0);
end;

procedure TSynEditMarkupCtrlMouseLink.SetCursor(AValue: TCursor);
begin
  if FCursor = AValue then Exit;
  FCursor := AValue;
  TCustomSynEdit(SynEdit).UpdateCursorOverride;
end;

procedure TSynEditMarkupCtrlMouseLink.LinesChanged(Sender: TSynEditStrings; AIndex, ANewCount,
  AOldCount: Integer);
begin
  If LastMouseCaret.Y < 0 then exit;
  LastMouseCaret := Point(-1, -1);
  UpdateCtrlMouse;
end;

procedure TSynEditMarkupCtrlMouseLink.UpdateCtrlState(aShift: TShiftState);
var
  NewCtrlIsPressed: Boolean;
begin
  NewCtrlIsPressed := IsCtrlMouseShiftState(aShift, True);
  if FLastControlIsPressed <> NewCtrlIsPressed then begin
    FLastControlIsPressed := NewCtrlIsPressed;
    InternalUpdateCtrlMouse;
  end;
end;

procedure TSynEditMarkupCtrlMouseLink.UpdateCtrlMouse;
begin
  FLastControlIsPressed := IsCtrlMouseShiftState(GetKeyShiftState, True);
  InternalUpdateCtrlMouse;
end;

procedure TSynEditMarkupCtrlMouseLink.InternalUpdateCtrlMouse;

  procedure doNotShowLink;
  begin
    if FCtrlMouseLine >= 0 then
      InvalidateSynLines(FCtrlMouseLine, FCtrlMouseLine);
    SetCursor(crDefault);
    CtrlMouseLine:=-1;
    FCtrlLinkable := False;
  end;

var
  NewY, NewX1, NewX2: Integer;
begin
  if FLastControlIsPressed and (LastMouseCaret.X>0) and (LastMouseCaret.Y>0) then begin
    // show link
    NewY := LastMouseCaret.Y;
    TCustomSynEdit(SynEdit).GetWordBoundsAtRowCol(FLastMouseCaretLogical,NewX1,NewX2);
    if (NewY = CtrlMouseLine) and
       (NewX1 = CtrlMouseX1) and
       (NewX2 = CtrlMouseX2)
    then
      exit;
    if (FCtrlMouseLine >= 0) and (FCtrlMouseLine <> NewY) then
      InvalidateSynLines(FCtrlMouseLine, FCtrlMouseLine);
    FCtrlLinkable := TCustomSynEdit(SynEdit).IsLinkable(NewY, NewX1, NewX2);
    CtrlMouseLine := fLastMouseCaret.Y;
    CtrlMouseX1 := NewX1;
    CtrlMouseX2 := NewX2;
    InvalidateSynLines(FCtrlMouseLine, FCtrlMouseLine);
    if FCtrlLinkable then
      SetCursor(crHandPoint)
    else
      doNotShowLink;
  end else
    doNotShowLink;
end;

procedure TSynEditMarkupCtrlMouseLink.UpdateSynCursor(Sender: TObject;
  const AMouseLocation: TSynMouseLocationInfo; var AnCursor: TCursor; var APriority: Integer;
  var AChangedBy: TObject);
begin
  if (Cursor = crDefault) or (APriority > LINK_CURSOR_PRIORITY) then exit;
  AnCursor := Cursor;
  APriority := LINK_CURSOR_PRIORITY;
  AChangedBy := Self;
end;

function TSynEditMarkupCtrlMouseLink.IsCtrlMouseShiftState(AShift: TShiftState;
  OnlyShowLink: Boolean): Boolean;
var
  act: TSynEditMouseAction;
  i: Integer;
begin
  Result := False;

  if not (emUseMouseActions in TCustomSynEdit(SynEdit).MouseOptions) then begin
    Result := (emShowCtrlMouseLinks in TCustomSynEdit(SynEdit).MouseOptions) and
              (AShift * ([ssShift, ssCtrl, ssAlt] + [SYNEDIT_LINK_MODIFIER]) = [SYNEDIT_LINK_MODIFIER]);
    exit;
  end;

  // todo: check FMouseSelActions if over selection?
  for i := 0 to TCustomSynEdit(SynEdit).MouseActions.Count - 1 do begin
    act := TCustomSynEdit(SynEdit).MouseActions.Items[i];
    if (act.Command = emcMouseLink) and
       ( (act.Option = emcoMouseLinkShow) or (not OnlyShowLink) ) and
       act.IsMatchingShiftState(AShift)
    then
      exit(True);
  end;

  for i := 0 to TCustomSynEdit(SynEdit).MouseTextActions.Count - 1 do begin
    act := TCustomSynEdit(SynEdit).MouseTextActions.Items[i];
    if (act.Command = emcMouseLink) and
       ( (act.Option = emcoMouseLinkShow) or (not OnlyShowLink) ) and
       act.IsMatchingShiftState(AShift)
    then
      exit(True);
  end;

  if not TCustomSynEdit(SynEdit).SelAvail then exit;

  for i := 0 to TCustomSynEdit(SynEdit).MouseSelActions.Count - 1 do begin
    act := TCustomSynEdit(SynEdit).MouseSelActions.Items[i];
    if (act.Command = emcMouseLink) and
       ( (act.Option = emcoMouseLinkShow) or (not OnlyShowLink) ) and
       act.IsMatchingShiftState(AShift)
    then
      exit(True);
  end;
end;

constructor TSynEditMarkupCtrlMouseLink.Create(ASynEdit: TSynEditBase);
begin
  inherited Create(ASynEdit);
  FLastControlIsPressed := false;
  FCtrlMouseLine:=-1;
  FCtrlLinkable := False;
  MarkupInfo.Style := [];
  MarkupInfo.StyleMask := [];
  MarkupInfo.Foreground := clBlue; {TODO:  invert blue to bg .... see below}
  MarkupInfo.Background := clNone;

  TCustomSynEdit(SynEdit).RegisterQueryMouseCursorHandler(@UpdateSynCursor);
end;

destructor TSynEditMarkupCtrlMouseLink.Destroy;
begin
  TCustomSynEdit(SynEdit).UnregisterQueryMouseCursorHandler(@UpdateSynCursor);
  if Lines <> nil then begin;
    Lines.RemoveModifiedHandler(senrLinesModified, @LinesChanged);
  end;
  inherited Destroy;
end;

procedure TSynEditMarkupCtrlMouseLink.SetLines(const AValue: TSynEditStrings);
begin
  inherited SetLines(AValue);
  if Lines <> nil then begin;
    Lines.AddModifiedHandler(senrLinesModified, @LinesChanged);
  end;
end;

procedure TSynEditMarkupCtrlMouseLink.DoMarkupChanged(AMarkup: TSynSelectedColor
  );
begin
  inherited DoMarkupChanged(AMarkup);
  if FCtrlMouseLine >= 0 then
    InvalidateSynLines(FCtrlMouseLine, FCtrlMouseLine);
end;

procedure TSynEditMarkupCtrlMouseLink.DoEnabledChanged(Sender: TObject);
begin
  inherited DoEnabledChanged(Sender);
  if FCtrlMouseLine >= 0 then
    InvalidateSynLines(FCtrlMouseLine, FCtrlMouseLine);
end;

function TSynEditMarkupCtrlMouseLink.GetMarkupAttributeAtRowCol(const aRow: Integer;
  const aStartCol: TLazSynDisplayTokenBound; const AnRtlInfo: TLazSynDisplayRtlInfo): TSynSelectedColor;
begin
  Result := nil;
  if (not FCtrlLinkable) or (aRow <> FCtrlMouseLine) or
     ((aStartCol.Logical < CtrlMouseX1) or (aStartCol.Logical >= CtrlMouseX2))
  then exit;
  Result := MarkupInfo;
  MarkupInfo.SetFrameBoundsLog(CtrlMouseX1, CtrlMouseX2);
end;

procedure TSynEditMarkupCtrlMouseLink.GetNextMarkupColAfterRowCol(const aRow: Integer;
  const aStartCol: TLazSynDisplayTokenBound; const AnRtlInfo: TLazSynDisplayRtlInfo; out ANextPhys,
  ANextLog: Integer);
begin
  ANextLog := -1;
  ANextPhys := -1;
  if FCtrlMouseLine <> aRow
  then exit;

  if aStartCol.Logical < CtrlMouseX1
  then ANextLog := CtrlMouseX1;
  if (aStartCol.Logical < CtrlMouseX2) and (aStartCol.Logical >= CtrlMouseX1)
  then ANextLog := CtrlMouseX2;
end;

end.