unit GameDiagnosticsExport;

{$mode objfpc}{$H+}

interface

type
  TDiagnosticExportOutcomeKind = (deokSuccess, deokCancel, deokError);

  TDiagnosticExportOutcome = record
    Kind: TDiagnosticExportOutcomeKind;
    ErrorMessage: string;
  end;

  TDiagnosticExportCallback = procedure(const AOutcome: TDiagnosticExportOutcome) of object;

procedure ExportDiagnosticReport(
  const AJsonSnapshot: string;
  const ACallback: TDiagnosticExportCallback
);

implementation

uses
  Classes, CastleMessaging, CastleStringUtils, SysUtils;

const
  ExportResultToken = 'diagnostic-report-export-result';

type
  TDiagnosticExportListener = class
  private
    FPending: Boolean;
    FCallback: TDiagnosticExportCallback;
    procedure Complete(const AKind: TDiagnosticExportOutcomeKind;
      const AErrorMessage: string);
    function MessageReceived(const Received: TCastleStringList;
      const ReceivedStream: TMemoryStream): Boolean;
  public
    constructor Create;
    destructor Destroy; override;
    procedure Export(const AJsonSnapshot: string;
      const ACallback: TDiagnosticExportCallback);
  end;

constructor TDiagnosticExportListener.Create;
begin
  inherited;
  Messaging.OnReceive.Add(@MessageReceived);
end;

destructor TDiagnosticExportListener.Destroy;
begin
  Messaging.OnReceive.Remove(@MessageReceived);
  inherited;
end;

procedure TDiagnosticExportListener.Complete(const AKind: TDiagnosticExportOutcomeKind;
  const AErrorMessage: string);
var
  Outcome: TDiagnosticExportOutcome;
  Callback: TDiagnosticExportCallback;
begin
  Callback := FCallback;
  FCallback := nil;
  FPending := False;
  Outcome.Kind := AKind;
  Outcome.ErrorMessage := AErrorMessage;
  if Assigned(Callback) then
    Callback(Outcome);
end;

function TDiagnosticExportListener.MessageReceived(
  const Received: TCastleStringList;
  const ReceivedStream: TMemoryStream): Boolean;
begin
  Result := (Received.Count > 0) and (Received[0] = ExportResultToken);
  if not Result or not FPending then
    Exit;

  if (Received.Count = 2) and (Received[1] = 'success') then
    Complete(deokSuccess, '')
  else
  if (Received.Count = 2) and (Received[1] = 'cancel') then
    Complete(deokCancel, '')
  else
  if (Received.Count = 3) and (Received[1] = 'error') then
    Complete(deokError, Received[2])
  else
    Complete(deokError, 'Malformed export-service response');
end;

procedure TDiagnosticExportListener.Export(const AJsonSnapshot: string;
  const ACallback: TDiagnosticExportCallback);
begin
  if FPending then
    raise Exception.Create('Diagnostic report export is already pending');
  FPending := True;
  FCallback := ACallback;
  Messaging.Send(['diagnostic-report-export', AJsonSnapshot]);
end;

var
  ExportListener: TDiagnosticExportListener;

procedure ExportDiagnosticReport(const AJsonSnapshot: string;
  const ACallback: TDiagnosticExportCallback);
begin
  ExportListener.Export(AJsonSnapshot, ACallback);
end;

initialization
  ExportListener := TDiagnosticExportListener.Create;
finalization
  FreeAndNil(ExportListener);
end.