// ***************************************************************************
//
// Delphi MVC Framework
//
// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
//
// https://github.com/danieleteti/delphimvcframework
//
// ***************************************************************************
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// *************************************************************************** }

unit MVCFramework.RESTAdapter;

{$I dmvcframework.inc}

interface

uses
  System.Rtti, System.TypInfo, MVCFramework.RESTClient, MVCFramework.Commons,
  IdIOHandler, System.Classes, System.SysUtils;

const
  URL_SEPARATOR = '/';

type

  RESTResourceAttribute = class(TCustomAttribute)
  private
    FURL: string;
    FHTTPMethodType: TMVCHTTPMethodType;
    procedure SetURL(const Value: string);
    procedure SetHTTPMethodType(const Value: TMVCHTTPMethodType);
  public
    constructor Create(AMVCHTTPMethod: TMVCHTTPMethodType; AURL: string);
    property URL: string read FURL write SetURL;
    property HTTPMethodType: TMVCHTTPMethodType read FHTTPMethodType
      write SetHTTPMethodType;
  end;

  BodyAttribute = class(TCustomAttribute)
  private
    FOwnsObject: boolean;
    procedure SetOwnsObject(const Value: boolean);
  public
    constructor Create(AOwnsObject: boolean = true);
    property OwnsObject: boolean read FOwnsObject write SetOwnsObject;
  end;

  ParamAttribute = class(TCustomAttribute)
  private
    FParamType: string;
    FCustomFormat: string;
    FParamMatch: string;
    procedure SetCustomFormat(const Value: string);
    procedure SetParamType(const Value: string);
    procedure SetParamMatch(const Value: string);
  public
    constructor Create(AParamMatch: string; AParamType: string = '';
      ACustomFormat: string = '');
    property ParamMatch: string read FParamMatch write SetParamMatch;
    property ParamType: string read FParamType write SetParamType;
    property CustomFormat: string read FCustomFormat write SetCustomFormat;
    function FmtParamMatch: string;
  end;

  HeadersAttribute = class(TCustomAttribute)
  private
    FKey: string;
    FValue: string;
    procedure SetKey(const Value: string);
    procedure SetValue(const Value: string);
  public
    constructor Create(AKey: string; AValue: string);
    property Key: string read FKey write SetKey;
    property Value: string read FValue write SetValue;
  end;

  MappingAttribute = class(TCustomAttribute)
  private
    FClass: TClass;
  public
    constructor Create(AClass: TClass);
    function GetType: TRttiType;
  end;

  IRESTAdapter<T> = interface
    ['{AAA41F40-69DB-419B-9922-F59F990CBDB5}']
    function ResourcesService: T;
    procedure AddRequestHeaders(AObj: TRttiObject);
    procedure AddRequestHeader(AKey: string; AValue: string);
    procedure MapResult(AResp: IRESTResponse; AMethod: TRttiMethod;
      ARTTIType: TRttiType; out AResult: TValue);
  end;

  TRESTAdapter<T: IInvokable> = class(TVirtualInterface, IRESTAdapter<T>)
  private
    FRESTClient: TRESTClient;
    FRESTClientOwner: boolean;
    procedure SetRESTClient(const Value: TRESTClient);
    procedure SetRESTClientOwner(const Value: boolean);
  protected
    procedure DoInvoke(Method: TRttiMethod; const Args: TArray<TValue>;
      out Result: TValue);
    procedure AddRequestHeaders(AObj: TRttiObject);
    procedure AddRequestHeader(AKey: string; AValue: string);
    procedure MapResult(AResp: IRESTResponse; AMethod: TRttiMethod;
      ARTTIType: TRttiType; out AResult: TValue);
    function GetURL(AMethod: TRttiMethod; const Args: TArray<TValue>): string;
    function GetBodyAsString(AMethod: TRttiMethod;
      const Args: TArray<TValue>): string;
  public
    constructor Create;
    destructor Destroy; override;
    function Build(ARESTClient: TRESTClient; const ARESTClientOwner: boolean = false): T; overload;
    function Build(const AServerName: string; const AServerPort: Word = 80;
      AIOHandler: TIdIOHandler = nil): T; overload;

    function ResourcesService: T;
    property RESTClient: TRESTClient read FRESTClient write SetRESTClient;
    property RESTClientOwner: boolean read FRESTClientOwner write SetRESTClientOwner;
  end;

  IAsynchRequest = interface
    ['{3E720356-F2B7-4C32-8051-B7723263740F}']
    procedure SetAlwaysProc(const Value: TProc);
    procedure SetErrorProc(const Value: TProc<Exception>);
    procedure SetSuccessProc(const Value: TProc<TValue>);
    procedure SetSynchronized(const Value: boolean);

    function GetAlwaysProc: TProc;
    function GetErrorProc: TProc<Exception>;
    function GetSuccessProc: TProc<TValue>;
    function GetSynchronized: boolean;

    property SuccessProc: TProc<TValue> read GetSuccessProc
      write SetSuccessProc;
    property ErrorProc: TProc<Exception> read GetErrorProc write SetErrorProc;
    property AlwaysProc: TProc read GetAlwaysProc write SetAlwaysProc;
    property Synchronized: boolean read GetSynchronized write SetSynchronized;
  end;

  TAsynchRequest = class(TInterfacedObject, IAsynchRequest)
  private
    FSynchronized: boolean;
    FSuccessProc: TProc<TValue>;
    FErrorProc: TProc<Exception>;
    FAlwaysProc: TProc;
    procedure SetAlwaysProc(const Value: TProc);
    procedure SetErrorProc(const Value: TProc<Exception>);
    procedure SetSuccessProc(const Value: TProc<TValue>);
    procedure SetSynchronized(const Value: boolean);
    function GetAlwaysProc: TProc;
    function GetErrorProc: TProc<Exception>;
    function GetSuccessProc: TProc<TValue>;
    function GetSynchronized: boolean;
  public
    constructor Create(ASuccProc: TProc<TValue> = nil;
      AProcErr: TProc<Exception> = nil; AProcAlways: TProc = nil;
      ASynchronized: boolean = false);
    property SuccessProc: TProc<TValue> read GetSuccessProc
      write SetSuccessProc;
    property ErrorProc: TProc<Exception> read GetErrorProc write SetErrorProc;
    property AlwaysProc: TProc read GetAlwaysProc write SetAlwaysProc;
    property Synchronized: boolean read GetSynchronized write SetSynchronized;
  end;

implementation

uses
  ObjectsMappers,
{$IFDEF SYSTEMJSON}
  System.JSON,
{$ELSE}
  Data.DBXJSON,
  Data.SqlExpr,
  DBXCommon,
{$ENDIF}
  MVCFramework.RTTIUtils,
  MVCFramework.DuckTyping,
  Generics.Collections;

{ TRESTAdapter }

function TRESTAdapter<T>.Build(ARESTClient: TRESTClient;
  const ARESTClientOwner: boolean = false): T;
begin
  RESTClient := ARESTClient;
  RESTClientOwner := ARESTClientOwner;
  Result := ResourcesService;
end;

procedure TRESTAdapter<T>.AddRequestHeader(AKey, AValue: string);
begin
  if CompareText(AKey, 'ContentType') = 0 then
    FRESTClient.ContentType(AValue)
  else if CompareText(AKey, 'ContentEncoding') = 0 then
    FRESTClient.ContentEncoding(AValue)
  else if CompareText(AKey, 'Accept') = 0 then
    FRESTClient.Accept(AValue)
  else
    FRESTClient.RequestHeaders.Values[AKey] := AValue;
end;

procedure TRESTAdapter<T>.AddRequestHeaders(AObj: TRttiObject);
var
  _attr: TCustomAttribute;
begin
  for _attr in AObj.GetAttributes do
    if _attr is HeadersAttribute then
      AddRequestHeader(HeadersAttribute(_attr).Key,
        HeadersAttribute(_attr).Value);
end;

function TRESTAdapter<T>.Build(const AServerName: string;
  const AServerPort: Word; AIOHandler: TIdIOHandler): T;
var
  ARESTClient: TRESTClient;
begin
  ARESTClient := TRESTClient.Create(AServerName, AServerPort, AIOHandler);
  Result := Build(ARESTClient, true);
end;

constructor TRESTAdapter<T>.Create;
begin
  inherited Create(TypeInfo(T), DoInvoke);
end;

destructor TRESTAdapter<T>.Destroy;
begin
  // Ezequiel J. Müller (If it is created outside, it must be destroyed out)
  // d.spinetti added RESTClientOwner to manage desctruction of RESTClient and free its associated memory
  if RESTClientOwner and Assigned(FRESTClient) then
    FRESTClient.Free;
  inherited;
end;

procedure TRESTAdapter<T>.DoInvoke(Method: TRttiMethod;
  const Args: TArray<TValue>; out Result: TValue);
var
  Resp: IRESTResponse;
  _restresourceattr: RESTResourceAttribute;
  URL: string;
  Body: string;
  AsynchClass: IAsynchRequest;
  _mappingattr: MappingAttribute;
begin
  // Implementation of RESTClient DoGet DoPut ecc...
  if not TRTTIUtils.HasAttribute<RESTResourceAttribute>(Method,
    _restresourceattr) then
    raise Exception.CreateFmt('No REST Resource specified in method %s',
      [Method.Name]);

  // headers can be more than one
  // FRESTClient.RequestHeaders.Clear; //Ezequiel J. Müller (You can not clear the header, because I can use other.)
  // Interface
  AddRequestHeaders(TRTTIUtils.ctx.GetType(TypeInfo(T)));
  // Method
  AddRequestHeaders(Method);

  // URL and Body
  URL := GetURL(Method, Args);
  Body := GetBodyAsString(Method, Args);

  // Asynch way to do
  if Args[Length(Args) - 1].TryAsType<IAsynchRequest>(AsynchClass) then
  begin
    FRESTClient.Asynch(
      procedure(ARESTResponse: IRESTResponse)
      var
        ResValue: TValue;
      begin
        if TRTTIUtils.HasAttribute<MappingAttribute>(Method, _mappingattr) then
          MapResult(ARESTResponse, Method, _mappingattr.GetType, ResValue)
        else
          ResValue := TValue.From(ARESTResponse);
        if Assigned(AsynchClass.SuccessProc) then
          AsynchClass.SuccessProc(ResValue);
      end, AsynchClass.ErrorProc, AsynchClass.AlwaysProc,
      AsynchClass.Synchronized);
  end;

  case _restresourceattr.HTTPMethodType of
    httpGET:
      Resp := FRESTClient.doGET(URL, []);
    httpPUT:
      Resp := FRESTClient.doPUT(URL, [], Body);
    httpPOST:
      Resp := FRESTClient.doPOST(URL, [], Body);
  end;

  // if the response code is > 400 raise exception
  // if Resp.ResponseCode >= 400 then
  // raise Exception.CreateFmt
  // ('Error on execute request ''%s''. Message: %d %s ',
  // [URL, Resp.ResponseCode, Resp.BodyAsString]);

  // if is a procedure no need a return type
  if Assigned(Method.ReturnType) then
    MapResult(Resp, Method, Method.ReturnType, Result);

end;

function TRESTAdapter<T>.GetBodyAsString(AMethod: TRttiMethod;
const Args: TArray<TValue>): string;
var
  _parameters: TArray<TRttiParameter>;
  I: Integer;
  _parameter: TRttiParameter;
  _param: BodyAttribute;
  _attrlistof: MapperListOf;
  Arg: TValue;
begin
  _parameters := AMethod.GetParameters;
  for I := 0 to Length(_parameters) - 1 do
  begin
    _parameter := _parameters[I];
    // ARG := ARGS[I+1] because
    // Args	RTTI for the arguments of the interface method that has been called. The first argument (located at index 0) represents the interface instance itself.
    Arg := Args[I + 1];
    if TRTTIUtils.HasAttribute<BodyAttribute>(_parameter, _param) then
      try
        if Arg.IsObject then
        begin
          if TRTTIUtils.HasAttribute<MapperListOf>(AMethod, _attrlistof) then
            Exit(Mapper.ObjectListToJSONArrayString(WrapAsList(Arg.AsObject), true))
          else
            Exit(Mapper.ObjectToJSONObjectString(Arg.AsObject));
        end
        else
          Exit(TRTTIUtils.TValueAsString(Arg, '', ''));
      finally
        if _param.OwnsObject and Arg.IsObject then
        begin
{$HINTS OFF}
          Arg.AsObject.Free;
{$HINTS ON}
        end;
      end;
  end;
end;

function TRESTAdapter<T>.GetURL(AMethod: TRttiMethod;
const Args: TArray<TValue>): string;
var
  _restresourceattr: RESTResourceAttribute;
  IURL: string;
  SplitUrl: TArray<string>;
  URLDict: TDictionary<string, string>;
  Split: string;
  _parameters: TArray<TRttiParameter>;
  I: Integer;
  _parameter: TRttiParameter;
  _param: ParamAttribute;
  Arg: TValue;
begin
  _restresourceattr := TRTTIUtils.GetAttribute<RESTResourceAttribute>(AMethod);
  IURL := _restresourceattr.URL;
  SplitUrl := IURL.Split([URL_SEPARATOR]);
  URLDict := TDictionary<string, string>.Create;
  try
    for Split in SplitUrl do
      if not Split.IsEmpty then
        URLDict.Add(Split, Split);
    _parameters := AMethod.GetParameters;
    // ARG := ARGS[I+1] because
    // Args	RTTI for the arguments of the interface method that has been called. The first argument (located at index 0) represents the interface instance itself.
    for I := 0 to Length(_parameters) - 1 do
    begin
      _parameter := _parameters[I];
      Arg := Args[I + 1];
      if TRTTIUtils.HasAttribute<ParamAttribute>(_parameter, _param) then
        URLDict[_param.FmtParamMatch] := TRTTIUtils.TValueAsString(Arg,
          _param.ParamType, _param.CustomFormat);
    end;

    for Split in SplitUrl do
      if not Split.IsEmpty then
        Result := Result + URL_SEPARATOR + URLDict[Split];

    if IURL.EndsWith(URL_SEPARATOR) and not(Result.EndsWith(URL_SEPARATOR)) then
      Result := Result + URL_SEPARATOR;

  finally
    URLDict.Free;
  end;
end;

procedure TRESTAdapter<T>.MapResult(AResp: IRESTResponse; AMethod: TRttiMethod;
ARTTIType: TRttiType; out AResult: TValue);
var
  _attrlistof: MapperListOf;
begin
  if ARTTIType.TypeKind = tkClass then
  begin
    // ListOf
    if TRTTIUtils.HasAttribute<MapperListOf>(AMethod, _attrlistof) then
    begin
      AResult := TRTTIUtils.CreateObject(ARTTIType.QualifiedName);
      Mapper.JSONArrayToObjectList(WrapAsList(AResult.AsObject),
        _attrlistof.Value, AResp.BodyAsJsonValue as TJSONArray, false);
    end
    // JSONValue
    else if ARTTIType.AsInstance.MetaclassType.InheritsFrom(TJSONValue) then
      AResult := TJSONObject.ParseJSONValue(AResp.BodyAsString)
      // Object
    else
      AResult := Mapper.JSONObjectToObject(ARTTIType.QualifiedName,
        AResp.BodyAsJsonObject)
  end
  else
    // IRESTResponse
    if ARTTIType.QualifiedName = TRTTIUtils.ctx.GetType(TypeInfo(IRESTResponse))
      .QualifiedName then
      AResult := AResult.From(AResp)
    else // else a simple BodyAsString
      AResult := AResp.BodyAsString
end;

function TRESTAdapter<T>.ResourcesService: T;
var
  pInfo: PTypeInfo;
begin
  pInfo := TypeInfo(T);
  if QueryInterface(GetTypeData(pInfo).Guid, Result) <> 0 then
  begin
    raise Exception.Create('RESTAdapter is unable to cast to its interface');
  end;
end;

procedure TRESTAdapter<T>.SetRESTClient(const Value: TRESTClient);
begin
  FRESTClient := Value;
end;

procedure TRESTAdapter<T>.SetRESTClientOwner(const Value: boolean);
begin
  FRESTClientOwner := Value;
end;

{ RESTResourceAttribute }

constructor RESTResourceAttribute.Create(AMVCHTTPMethod: TMVCHTTPMethodType;
AURL: string);
begin
  FURL := AURL;
  FHTTPMethodType := AMVCHTTPMethod;
end;

procedure RESTResourceAttribute.SetHTTPMethodType
  (const Value: TMVCHTTPMethodType);
begin
  FHTTPMethodType := Value;
end;

procedure RESTResourceAttribute.SetURL(const Value: string);
begin
  FURL := Value;
end;

{ BodyAttribute }

constructor BodyAttribute.Create(AOwnsObject: boolean);
begin
  inherited Create;
  FOwnsObject := AOwnsObject;
end;

procedure BodyAttribute.SetOwnsObject(const Value: boolean);
begin
  FOwnsObject := Value;
end;

{ ParamAttribute }

constructor ParamAttribute.Create(AParamMatch: string;
AParamType, ACustomFormat: string);
begin
  inherited Create;
  FParamMatch := AParamMatch;
  FParamType := AParamType;
  FCustomFormat := ACustomFormat;
end;

function ParamAttribute.FmtParamMatch: string;
begin
  Result := '{' + ParamMatch + '}';
end;

procedure ParamAttribute.SetCustomFormat(const Value: string);
begin
  FCustomFormat := Value;
end;

procedure ParamAttribute.SetParamMatch(const Value: string);
begin
  FParamMatch := Value;
end;

procedure ParamAttribute.SetParamType(const Value: string);
begin
  FParamType := Value;
end;

{ HeadersAttribute }

constructor HeadersAttribute.Create(AKey: string; AValue: string);
begin
  FKey := AKey;
  FValue := AValue;
end;

procedure HeadersAttribute.SetKey(const Value: string);
begin
  FKey := Value;
end;

procedure HeadersAttribute.SetValue(const Value: string);
begin
  FValue := Value;
end;

{ TAsynchRequest }

constructor TAsynchRequest.Create(ASuccProc: TProc<TValue> = nil;
AProcErr: TProc<Exception> = nil; AProcAlways: TProc = nil;
ASynchronized: boolean = false);
begin
  inherited Create;
  FSuccessProc := ASuccProc;
  FErrorProc := AProcErr;
  FAlwaysProc := AProcAlways;
  FSynchronized := ASynchronized;
end;

function TAsynchRequest.GetAlwaysProc: TProc;
begin
  Result := FAlwaysProc;
end;

function TAsynchRequest.GetErrorProc: TProc<Exception>;
begin
  Result := FErrorProc;
end;

function TAsynchRequest.GetSuccessProc: TProc<TValue>;
begin
  Result := FSuccessProc;
end;

function TAsynchRequest.GetSynchronized: boolean;
begin
  Result := FSynchronized;
end;

procedure TAsynchRequest.SetAlwaysProc(const Value: TProc);
begin
  FAlwaysProc := Value;
end;

procedure TAsynchRequest.SetErrorProc(const Value: TProc<Exception>);
begin
  FErrorProc := Value;
end;

procedure TAsynchRequest.SetSuccessProc(const Value: TProc<TValue>);
begin
  FSuccessProc := Value;
end;

procedure TAsynchRequest.SetSynchronized(const Value: boolean);
begin
  FSynchronized := Value;
end;

{ MappingAttribute }

constructor MappingAttribute.Create(AClass: TClass);
begin
  FClass := AClass;
end;

function MappingAttribute.GetType: TRttiType;
begin
  Result := TRTTIUtils.ctx.GetType(FClass);
end;

end.