{
    This file is part of the Free Pascal run time library.
    Copyright (c) 2019 by the Free Pascal development team

    extjs json

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    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.

 **********************************************************************}
unit extjsjson;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, httpdefs, fphttp, fpwebdata, fpextjs, fpjson, db, jsonparser;

type

  { TExtJSJSonWebdataInputAdaptor }

  TExtJSJSonWebdataInputAdaptor = CLass(TCustomWebdataInputAdaptor)
  private
    FRows : TJSONArray;
    FCurrentRow : TJSONObject;
    FRowIndex : integer;
    function CheckData: Boolean;
  Public
    procedure reset; override;
    Function GetNextBatch : Boolean; override;
    Function TryFieldValue(Const AFieldName : String; out AValue : String) : Boolean; override;
    Destructor destroy; override;
  end;

  { TExtJSJSONDataFormatter }
  TJSONObjectEvent = Procedure(Sender : TObject; AObject : TJSONObject) of Object;
  TJSONExceptionObjectEvent = Procedure(Sender : TObject; E : Exception; AResponse : TJSONObject) of Object;
  TJSONObjectAllowRowEvent = Procedure(Sender : TObject; Dataset : TDataset; Var Allow : Boolean) of Object;
  TJSONObjectAllowEvent = Procedure(Sender : TObject; AObject : TJSONObject; Var Allow : Boolean) of Object;

  TExtJSJSONDataFormatter = Class(TExtJSDataFormatter)
  private
    FAfterDataToJSON: TJSONObjectEvent;
    FAfterDelete: TJSONObjectEvent;
    FAfterInsert: TJSONObjectEvent;
    FAfterRowToJSON: TJSONObjectEvent;
    FAfterUpdate: TJSONObjectEvent;
    FBeforeDataToJSON: TJSONObjectEvent;
    FBeforeDelete: TNotifyEvent;
    FBeforeInsert: TNotifyEvent;
    FBeforeRowToJSON: TJSONObjectEvent;
    FBeforeUpdate: TNotifyEvent;
    FOnAllowRow: TJSONObjectAllowRowEvent;
    FOnErrorResponse: TJSONExceptionObjectEvent;
    FOnMetaDataToJSON: TJSONObjectEvent;
    FBatchResult : TJSONArray;
    Function AddIdToBatch : TJSONObject;
    procedure SendSuccess(ResponseContent: TStream; AddIDValue : Boolean = False);
  protected
    function AllowRow(ADataset : TDataset) : Boolean; virtual;
    Procedure StartBatch(ResponseContent : TStream); override;
    Procedure NextBatchItem(ResponseContent : TStream); override;
    Procedure EndBatch(ResponseContent : TStream); override;
    Function CreateAdaptor(ARequest : TRequest) : TCustomWebdataInputAdaptor; override;
    Function AddFieldToJSON(O: TJSONObject; const AFieldName: String; F: TField): TJSONData;
    function GetDataContentType: String; override;
    Function GetJSONMetaData: TJSONObject;
    function RowToJSON: TJSONObject;
    Procedure DoBeforeRow(ARow : TJSONObject); virtual;
    Procedure DoAfterRow(ARow : TJSONObject); virtual;
    Procedure DoBeforeData(AResponse : TJSONObject); virtual;
    Procedure DoAfterData(AResponse : TJSONObject); virtual;
    Procedure DoOnMetaData(AMetadata : TJSONObject); virtual;
    procedure DatasetToStream(Stream: TStream); override;
    Procedure DoExceptionToStream(E : Exception; ResponseContent : TStream); override;
    Procedure DoInsertRecord(ResponseContent : TStream); override;
    Procedure DoUpdateRecord(ResponseContent : TStream); override;
    Procedure DoDeleteRecord(ResponseContent : TStream); override;
  Public
    Destructor destroy; override;
  Published
    // Called before any fields are added to row object (passed to handler).
    Property AfterRowToJSON : TJSONObjectEvent Read FAfterRowToJSON Write FAfterRowToJSON;
    // Called After all fields are added to row object (passed to handler).
    Property BeforeRowToJSON : TJSONObjectEvent Read FBeforeRowToJSON Write FBeforeRowToJSON;
    // Called when metadata object has been created (passed to handler).
    Property OnMetaDataToJSON : TJSONObjectEvent Read FOnMetaDataToJSON Write FOnMetaDataToJSON;
    // Called when response object has been created, and has Rows property (response passed to handler).
    Property AfterDataToJSON : TJSONObjectEvent Read FAfterDataToJSON Write FAfterDataToJSON;
    // Called just before response object will be streamed (response passed to handler).
    Property BeforeDataToJSON : TJSONObjectEvent Read FBeforeDataToJSON Write FBeforeDataToJSON;
    // Called when an exception is caught and formatted.
    Property OnErrorResponse : TJSONExceptionObjectEvent Read FOnErrorResponse Write FOnErrorResponse;
    // Called to decide whether a record is sent to the client;
    Property OnAllowRow : TJSONObjectAllowRowEvent Read FOnAllowRow Write FOnAllowRow;
    // After a record was succesfully updated
    Property AfterUpdate : TJSONObjectEvent Read FAfterUpdate Write FAfterUpdate;
    // After a record was succesfully inserted.
    Property AfterInsert : TJSONObjectEvent Read FAfterInsert Write FAfterInsert;
    // After a record was succesfully inserted.
    Property AfterDelete : TJSONObjectEvent Read FAfterDelete Write FAfterDelete;
    // From TCustomHTTPDataContentProducer
    Property BeforeUpdate;
    Property BeforeInsert;
    Property BeforeDelete;
  end;

implementation
{ $define wmdebug}
{$ifdef wmdebug}
uses dbugintf;
{$endif wmdebug}

Resourcestring
  SErrWrongDataFormat = 'Post ROWS data has wrong value type. Expected array or object, got : %s.';
  SerrNoExceptionMessage = 'No exception to take error message from.';

Const
  // Do not localize these strings
  SDefMetaDataProperty  = 'metaData';
  SDefFieldsProperty    = 'fields';
  SDefFieldProperty     = 'field';
  SDefFieldNameProperty = 'name';
  SDefDirectionProperty = 'direction';
  SDefSortInfoProperty  = 'sortInfo';
  SIdProperty           = 'idProperty';
  SSuccessProperty      = 'successProperty';
  SRootProperty         = 'root';
  STotalProperty        = 'totalProperty';
  SDefAscDesc : Array[Boolean] of string = ('ASC','DESC');

function TExtJSJSONDataFormatter.GetDataContentType: String;
begin
  Result:='text/html';
end;

function TExtJSJSONDataFormatter.CreateAdaptor(ARequest: TRequest
  ): TCustomWebdataInputAdaptor;
begin
  Result:=TExtJSJSonWebdataInputAdaptor.Create(Self);
  Result.Request:=ARequest;
end;

function TExtJSJSONDataFormatter.AddFieldToJSON(O : TJSONObject; const AFieldName : String; F : TField): TJSONData;

Var
  S : String;


begin
 if F.IsNull then
   Result:=O.Items[O.Add(AFieldName)]
 else
  Case F.DataType of
    ftSmallint,
    ftInteger,
    ftAutoInc,
    ftWord:
      Result:=O.Items[O.Add(AFieldName,F.AsInteger)];
    ftBoolean:
      Result:=O.Items[O.Add(AFieldName,F.AsBoolean)];
    ftLargeint:
      Result:=O.Items[O.Add(AFieldName,F.AsLargeInt)];
    ftDate:
      Result:=O.Items[O.Add(AFieldName,FormatDateTime('yyyy-mm-dd',F.AsDateTime))];
    ftDateTime:
      Result:=O.Items[O.Add(AFieldName,FormatDateTime('yyyy-mm-dd hh":"nn":"ss',F.AsDateTime))];
    ftTime:
      Result:=O.Items[O.Add(AFieldName,FormatDateTime('hh":"nn":"ss',F.AsDateTime))];
    ftMemo,
    ftFmtMemo,
    ftWideMemo,
    ftBlob :
      begin
      S:=F.AsString;
      If (OnTranscode<>Nil) then
        OnTranscode(Self,F,S,True);
      Result:=O.Items[O.Add(AFieldName,S)];
      end;
  else
    S:=F.DisplayText;
    If (OnTranscode<>Nil) then
      OnTranscode(Self,F,S,True);
    Result:=O.Items[O.Add(AFieldName,S)];
  end;
end;

function TExtJSJSONDataFormatter.RowToJSON: TJSONObject;

Var
  F : TField;
  I : Integer;


begin
  Result:=TJSONObject.Create();
  try
    DobeforeRow(Result);
    For I:=0 to Dataset.Fields.Count-1 do
      begin
      F:=Dataset.Fields[I];
      AddFieldToJSON(Result,F.FieldName,F);
      end;
    DoAfterRow(Result);
  except
    Result.Free;
    Raise;
  end;
end;

procedure TExtJSJSONDataFormatter.DoBeforeRow(ARow: TJSONObject);
begin
  If Assigned(FBeforeRowToJSON) then
    FBeforeRowToJSON(Self,ARow);
end;

procedure TExtJSJSONDataFormatter.DoAfterRow(ARow: TJSONObject);
begin
  If Assigned(FAfterRowToJSON) then
    FAfterRowToJSON(Self,ARow);
end;

procedure TExtJSJSONDataFormatter.DoBeforeData(AResponse: TJSONObject);
begin
  If Assigned(FBeforeDataToJSON) then
    FBeforeDataToJSON(Self,AResponse);
end;

procedure TExtJSJSONDataFormatter.DoAfterData(AResponse: TJSONObject);
begin
  If Assigned(FAfterDataToJSON) then
    FAfterDataToJSON(Self,AResponse);
end;

procedure TExtJSJSONDataFormatter.DoOnMetaData(AMetadata: TJSONObject);
begin
  If Assigned(FOnMetaDataToJSON) then
    FOnMetaDataToJSON(Self,AMetaData);
end;

Function TExtJSJSONDataFormatter.GetJSONMetaData: TJSONObject;

Var
  F : TJSONArray;
  Fi : TField;
  I : Integer;
  O : TJSONObject;
  SF,FT : String;

begin
  If (SortField='') then
    SF:=Dataset.Fields[0].FieldName
  else
    SF:=SortField;
  Result:=TJSonObject.Create;
  try
    F:=TJSONArray.Create;
    Result.add(SDefFieldsProperty,F);
    For I:=0 to Dataset.Fields.Count-1 do
      begin
      Fi:=Dataset.Fields[i];
      O:=TJSONObject.Create();
      O.Add(SDefFieldNameProperty,Fi.FieldName);
      Ft:='';
      Case Fi.DataType of
        ftInteger,
        ftSmallint,
        ftWord,
        ftLargeInt : FT:='int';
        ftCurrency,
        ftFloat,
        ftBCD : FT:='float';
        ftBoolean : ft:='boolean';
        ftDate,
        ftDateTime,
        ftTimeStamp,
        ftTime : ft:='date';
        ftString,
        ftMemo,
        ftFmtMemo,
        ftFixedChar,
        ftWideString,
        ftWideMemo : ft:='string'
      end;
      if (FT<>'') then
        begin
        O.Add('type',FT);
        if (FT='date') then
          // Needs improving
          Case Fi.DataType of
            ftDate : O.Add('dateFormat','Y-m-d');
            ftTime : O.Add('dateFormat','H:i:s');
            ftDateTime,
            ftTimeStamp : O.Add('dateFormat','Y-m-d H:i:s');
          end;
        end;
      F.Add(O);
      end;
    O:=TJSONObject.Create();
    O.Add(SDefFieldProperty,SF);
    O.Add(SDefDirectionProperty,SDefAscDesc[SortDescending]);
    Result.Add(SDefSortInfoProperty,O);
 {$ifdef wmdebug}senddebug('ID property: '+Provider.IDFieldName);{$endif}
    Result.Add(SIdProperty,Provider.IDFieldName);
    Result.Add(SSuccessProperty, SuccessProperty);
    Result.Add(SRootProperty, RowsProperty);
    Result.Add(STotalProperty, totalProperty);
    DoOnMetaData(Result);
  except
    Result.free;
    Raise;
  end;
end;

procedure TExtJSJSONDataFormatter.DatasetToStream(Stream: TStream);

Var
  Rows : TJSONArray;
  Meta,Resp : TJSONObject;
  L : String;
  DS : TDataset;
  i,RCount,ACount : Integer;

begin
  Rows:=Nil;
  Resp:=TJSONObject.Create;
  try
    Rows:=TJSONArray.Create();
    Resp.Add(RowsProperty,Rows);
    DoBeforeData(Resp);
    DS:=Dataset;
    DS.First;
    RCount:=0;
    If MetaData then
      begin
      Meta:=GetJSONMetaData;
      Resp.Add(SDefMetaDataProperty,Meta);
      end;
    // Go to start
    ACount:=PageStart;
    While (Not DS.EOF) and (ACount>0) do
      begin
      DS.Next;
      Dec(ACount);
      Inc(RCount);
      end;
    ACount:=PageSize;
    While (not DS.EOF) and ((PageSize=0) or (ACount>0)) do
      begin
      If AllowRow(DS) then
        begin
        Inc(RCount);
        Dec(ACount);
        Rows.Add(RowToJSON);
        end;
      DS.Next;
      end;
    If (PageSize>0) then
      While (not DS.EOF) do
        begin
        Inc(RCount);
        DS.Next;
        end;
    Resp.Add(SuccessProperty,True);
    If (PageSize>0) then
       Resp.Add(TotalProperty,RCount);
    DoAfterData(Resp);
    L:=Resp.AsJSON;
    Stream.WriteBuffer(L[1],Length(L));
  finally
    Resp.Free;
  end;
end;

procedure TExtJSJSONDataFormatter.DoExceptionToStream(E: Exception;
  ResponseContent: TStream);

Var
   Resp : TJSonObject;
   L : String;

begin
  Resp:=tjsonObject.Create();
  try
    Resp.Add(SuccessProperty,False);
    If Assigned(E) then
      Resp.Add(MessageProperty,E.Message)
    else
      Resp.Add(MessageProperty,SerrNoExceptionMessage);
    L:=Resp.AsJSON;
    If Length(L)>0 then
      ResponseContent.WriteBuffer(L[1],Length(L));
    Resp.Add('root',RowsProperty);
    Resp.Add(RowsProperty,TJSONArray.Create());
    If Assigned(FOnErrorResponse) then
      FOnErrorResponse(Self,E,Resp);
  finally
    Resp.Free;
  end;
end;

procedure TExtJSJSONDataFormatter.SendSuccess(ResponseContent: TStream; AddIDValue : Boolean = False);

Var
   Resp : TJSonObject;
   L : String;

begin
  try
    Resp:=TJsonObject.Create;
    Resp.Add(SuccessProperty,True);
    Resp.Add('root',Self.RowsProperty);
    If Assigned(FBatchResult) and (FBatchResult.Count>0) then
      begin
      Resp.Add(Self.RowsProperty,FBatchResult);
      FBatchResult:=Nil;
      end
    else
      Resp.Add(Self.RowsProperty,TJSONNull.Create());
    L:=Resp.AsJSON;
    ResponseContent.WriteBuffer(L[1],Length(L));
  finally
    Resp.Free;
  end;
end;

function TExtJSJSONDataFormatter.AllowRow(ADataset: TDataset): Boolean;
begin
  Result:=True;
  If Assigned(FOnAllowRow) then
    FOnAllowRow(Self,Dataset,Result);
end;

procedure TExtJSJSONDataFormatter.StartBatch(ResponseContent: TStream);
begin
  If Assigned(FBatchResult) then
    FBatchResult.Clear
  else
    FBatchResult:=TJSONArray.Create();
end;

procedure TExtJSJSONDataFormatter.NextBatchItem(ResponseContent: TStream);
begin
end;

procedure TExtJSJSONDataFormatter.EndBatch(ResponseContent: TStream);
begin
  SendSuccess(Responsecontent,True);
end;

Function TExtJSJSONDataFormatter.AddIdToBatch : TJSONObject;

begin
  Result:=TJSONObject.Create([Provider.IDFieldName,Provider.IDFieldValue]);
  FBatchResult.Add(Result);
end;

procedure TExtJSJSONDataFormatter.DoInsertRecord(ResponseContent: TStream);

Var
  D : TJSONObject;

begin
  Inherited;
  D:=AddIDToBatch;
  If Assigned(FAfterInsert) then
    FAfterInsert(Self,D);
end;

procedure TExtJSJSONDataFormatter.DoUpdateRecord(ResponseContent: TStream);

Var
  D : TJSONObject;

begin
  inherited DoUpdateRecord(ResponseContent);
  D:=AddIDToBatch;
  If Assigned(FAfterUpdate) then
    FAfterUpdate(Self,D);
end;

procedure TExtJSJSONDataFormatter.DoDeleteRecord(ResponseContent: TStream);
begin
  inherited DoDeleteRecord(ResponseContent);
  If Assigned(FAfterDelete) then
    FAfterDelete(Self,Nil);
end;

destructor TExtJSJSONDataFormatter.destroy;
begin
  FreeAndNil(FBatchResult);
  inherited destroy;
end;

{ TExtJSJSonWebdataInputAdaptor }

function TExtJSJSonWebdataInputAdaptor.CheckData : Boolean;

Var
  D : TJSONData;
  P : TJSONParser;
  S : String;

begin
  Result:=Assigned(FCurrentRow);
  If Not (Result) and TryParamValue('rows',S) then
    begin
    {$ifdef wmdebug}senddebug('Check data: '+GetParamValue('rows'));{$endif}
    P:=TJSONParser.Create(S);
    try
      D:=P.Parse;
      {$ifdef wmdebug}senddebug('Classname : '+D.ClassName);{$endif}
      If D is TJSONArray then
        begin
        FRows:=TJSONArray(D);
        FRowIndex:=0;
        FCurrentRow:=FRows.Items[0] as TJSONObject;
        end
      else If D is TJSONObject then
        begin
        FRows:=Nil;
        FCurrentRow:=TJSONObject(D);
        end
      else if D is TJSONInt64Number then
        begin
        FRows:=nil;
        FCurrentRow:=TJSONObject.Create(['ID',D]);
        end
      else
        begin
        FreeAndNil(D);
        Raise EFPHTTPError.CreateFmt(SErrWrongDataFormat,[D.ClassName]);
        end;
      Result:=True;
    finally
      P.Free;
    end;
    end;
end;

procedure TExtJSJSonWebdataInputAdaptor.reset;
begin
  If (FRows=Nil) then
    FreeAndNil(FCurrentRow)
  else
    FreeAndNil(FRows);
  FRowIndex:=0;
  inherited reset;
end;

function TExtJSJSonWebdataInputAdaptor.GetNextBatch: Boolean;
begin
  If (FRows=Nil) then
    Result:=inherited GetNextBatch
  else
    begin
    Result:=FRowindex<FRows.Count-1;
    Inc(FRowIndex);
    If Result then
      FCurrentRow:=FRows.Items[FRowIndex] as TJSONObject
    else
      FCurrentRow:=Nil;
    end;
end;

function TExtJSJSonWebdataInputAdaptor.TryFieldValue(const AFieldName: String;
  out AValue: String): Boolean;

Var
  I : Integer;

begin
  Result:=False;
  if CheckData then
    begin
    I:=FCurrentRow.IndexOfName(AFieldName);
    Result:=I<>-1;
    if result and (FCurrentRow.Items[I].JSONType<>jtNull) then
      AValue:=FCurrentRow.Items[I].AsString;
    end;
end;

destructor TExtJSJSonWebdataInputAdaptor.destroy;
begin
  If Assigned(FRows) then
    FreeAndNil(FRows)
  else if assigned(FCurrentRow) then
    FreeAndNil(FCurrentRow);
  inherited destroy;
end;

initialization
  WebDataProviderManager.RegisterInputAdaptor('ExtJS - JSON',TExtJSJSONWebdataInputAdaptor);
  WebDataProviderManager.RegisterDataProducer('ExtJS - JSON',TExtJSJSONDataFormatter);

finalization
  WebDataProviderManager.UnRegisterInputAdaptor('ExtJS - JSON');
  WebDataProviderManager.UnRegisterDataProducer('ExtJS - JSON')
end.