/// <summary>
/// Unit contains logic for checking if currently loaded studies need updating.
/// If a serie in specific study is modified in some way then it will be refreshed
/// based on DB.
/// </summary>

unit pm.View.DB.SeriesUpdateFetcher;

interface

uses
  pmViewImageStorage,
  pm.DB.ThreadInstances,
  IBX.IBCustomDataSet,
  System.Generics.Collections,
  pmDICOMTypes;

type

  TPmSeriesUpdateEvent = procedure(
    ASender                   : TObject;
    const AStudyID, ASeriesIDs: TList<Int64>) of object;

  TPmSerieUpdateChecker = class
  private
    FOnSerieNeedsUpdating: TPmSeriesUpdateEvent;
    function FetchStudyDBData: TIBDataSet;
    function NeedsSerieUpdatingOrAdding(
      const AStudy       : TPmStudyNode;
      var ASeriesToUpdate: TList<Int64>): Boolean;
  public
    property OnSerieNeedsUpdate: TPmSeriesUpdateEvent read FOnSerieNeedsUpdating write FOnSerieNeedsUpdating;
    /// <summary>
    /// Downloads series updates fo studies loaded into pmview
    /// </summary>
    /// <returns>Number of series that need update.</returns>
    function DownloadUpdates: Integer;
  end;

implementation

uses
  System.SysUtils,
  daDB;

{ TPmSerieUpdateChecker }

function TPmSerieUpdateChecker.DownloadUpdates: Integer;
var
  LNavi       : TPmStudyTreeNavigator;
  LDBStudyData: TIBDataSet;
  LImgType    : TPmImageType;
  LStudyDBDiff: TPmDCMStudyDB;
  LI          : Integer;
begin
  try
    LStudyDBDiff := TPmDCMStudyDB.Create(nil);
    LNavi        := TPmStudyTreeNavigator.Create();
    // exit and clear, if no data is available
    if (LNavi.ImageIndex < 0) then
    begin
      Exit(0);
    end;

    LStudyDBDiff.DB := GetdaserverThreadDB();
    // Check for updates
    LDBStudyData := FetchStudyDBData;

    if not Assigned(LDBStudyData) then
      Exit(0);

    repeat
      // match DB record with current Study node in navtree
      { TODO : DBID needs to be added to TpmStudyTreeNAvigator.Study class, StudyUID seems to be not unique enough }
      if LDBStudyData.Locate('id', LNavi.Study.DBID) then
      begin
        { TODO : LastTransfer needs to be added to TpmStudyTreeNAvigator.Study class }
        // process further only if lasttransferdate is not equal with currently loaded data
        if LNavi.Study.LastTransferDate < LDBStudyData.FieldByName('LastTransfer').AsDateTime then
        begin
          // load study object form making diff for update process
          LStudyDBDiff.Load(LDBStudyData.FieldByName('id').AsInteger, True);

          repeat
            { TODO : DBID needs to be added }
            if LStudyDBDiff.Series.SerieById[LNavi.Series.DBID] <> nil then
            begin
              if LNavi.Series.ImageCount <> LStudyDBDiff.Series.SerieById[LNavi.Series.DBID].Images.Count then
              begin
                repeat
                  if LStudyDBDiff.Series.SerieById[LNavi.Series.DBID].Images.ImageById[LNavi.Image.DBID] <> nil then
                  begin
                    LStudyDBDiff.Series.SerieById[LNavi.Series.DBID].Images.Delete
                      (LStudyDBDiff.Series.SerieById[LNavi.Series.DBID].Images.ImageById[LNavi.Image.DBID].Index);
                  end;

                until LNavi.NextImage;
              end
              else
              begin
                LStudyDBDiff.Series.Delete(LStudyDBDiff.Series.SerieById[LNavi.Series.DBID].Index);
              end;
            end;

          until LNavi.NextSeries;

        end;

        if LStudyDBDiff.StudyId <> 0 then
          if Assigned(OnSerieNeedsUpdate) then
          begin
            // call event and pass study diff object to create download task
            // every study frequency was choosen for better ux
            OnSerieNeedsUpdate(Self, LStudyDBDiff);
          end;
      end;

      // next study
    until (not LNavi.NextStudy);

  finally
    FreeAndNil(LNavi);
  end;
end;

function TPmSerieUpdateChecker.FetchStudyDBData: TIBDataSet;
var
  LStudyIDSet: String;
  LPatNode   : TPmPatientNode;
  LStudyNode : TPmStudyNode;
begin
  // list all DaPatIDs e.g. = 15,34,12,204
  for LPatNode in TPmImageStorage.Patients do
    for LStudyNode in LPatNode.Studies do
      if LStudyNode.DBID >= 0 then { TODO : DBID needs to be introduced }
        if LStudyIDSet = '' then
          LStudyIDSet := IntToStr(LStudyNode.DBID)
        else
          LStudyIDSet := LStudyIDSet + ',' + IntToStr(LStudyNode.DBID);

  // no patients to query?? bye bye
  if LStudyIDSet = '' then
    Exit(nil);

  // StudyID, StudyDate, StudyDescription, LastTransfer
  // - example query
  // Select std.id, std.dapatid, std.modality, std.studydescription,  std.lasttransfer from STUDY std where std.dapatid in (1,3,5) and std.deltag = 'f' order by std.dapatid asc, std.studydate desc
  Result := daOpenDataSet(GetdaserverThreadDB(), 'STUDY std', ['std.id', 'std.dapatid', 'std.kontoid', 'std.modality',
    'std.studydescription', 'std.studyinstanceuid', 'std.studydate', 'std.lasttransfer'],
    'std.id in (' + LStudyIDSet + ') and std.deltag = ''f'' order by std.dapatid asc, std.studydate desc');
  // fetch all results at once
  if Result <> nil then
    Result.FetchAll;
end;

end.