/**
  @file mv_tokenauth.sas
  @brief Get initial Refresh and Access Tokens
  @details Before a Refresh Token can be obtained, the client must be
    registered by an administrator.  This can be done using the
    `mv_registerclient` macro, after which the user must visit a URL to get an
    additional code (if using oauth).

    That code (or username / password) is used here to get the Refresh Token
    (and an initial Access Token).  THIS MACRO CAN ONLY BE USED ONCE - further
    access tokens can be obtained using the `mv_gettokenrefresh` macro.

    Access tokens expire frequently (every 10 hours or so) whilst refresh tokens
    expire periodically (every month or so).  This is all configurable.

  Usage:

      filename mc url
        "https://raw.githubusercontent.com/sasjs/core/main/all.sas";
      %inc mc;


      %mv_registerclient(outds=clientinfo)

      %mv_tokenauth(inds=clientinfo,code=LD39EpalOf)

    A great article for explaining all these steps is available here:

    https://blogs.sas.com/content/sgf/2019/01/25/authentication-to-sas-viya/

  @param inds= A dataset containing client_id, client_secret, and auth_code
  @param outds= A dataset containing access_token and refresh_token
  @param client_id= The client name
  @param client_secret= client secret
  @param grant_type= valid values are "password" or "authorization_code"
    (unquoted). The default is authorization_code.
  @param code= If grant_type=authorization_code then provide the necessary code
    here
  @param user= If grant_type=password then provide the username here
  @param pass= If grant_type=password then provide the password here
  @param access_token_var= The global macro variable to contain the access token
  @param refresh_token_var= The global macro variable to contain the refresh
    token
  @param base_uri= The Viya API server location

  @version VIYA V.03.04
  @author Allan Bowe, source: https://github.com/sasjs/core

  <h4> SAS Macros </h4>
  @li mp_abort.sas
  @li mf_getplatform.sas
  @li mf_getuniquefileref.sas
  @li mf_getuniquelibref.sas
  @li mf_existds.sas

**/

%macro mv_tokenauth(inds=mv_registerclient
    ,outds=mv_tokenauth
    ,client_id=someclient
    ,client_secret=somesecret
    ,grant_type=authorization_code
    ,code=
    ,user=
    ,pass=
    ,access_token_var=ACCESS_TOKEN
    ,refresh_token_var=REFRESH_TOKEN
    ,base_uri=#NOTSET#
  );
%global &access_token_var &refresh_token_var;

%local fref1 fref2 libref;

/* test the validity of inputs */
%mp_abort(iftrue=(&grant_type ne authorization_code and &grant_type ne password)
  ,mac=&sysmacroname
  ,msg=%str(Invalid value for grant_type: &grant_type)
)

%if %mf_existds(&inds) %then %do;
  data _null_;
    set &inds;
    call symputx('client_id',client_id,'l');
    call symputx('client_secret',client_secret,'l');
    if not missing(auth_code) then call symputx('code',auth_code,'l');
  run;
%end;

%mp_abort(iftrue=(&grant_type=authorization_code and %str(&code)=%str())
  ,mac=&sysmacroname
  ,msg=%str(Authorization code required)
)

%mp_abort(iftrue=(
  &grant_type=password and (%str(&user)=%str() or %str(&pass)=%str()))
  ,mac=&sysmacroname
  ,msg=%str(username / password required)
)

/* prepare appropriate grant type */
%let fref1=%mf_getuniquefileref();

data _null_;
  file &fref1;
  if "&grant_type"='authorization_code' then string=cats(
    'grant_type=authorization_code&code=',symget('code'));
  else string=cats('grant_type=password&username=',symget('user')
    ,'&password=',symget(pass));
  call symputx('grantstring',cats("'",string,"'"));
run;
/*data _null_;infile &fref1;input;put _infile_;run;*/

/**
  * Request access token
  */
%if &base_uri=#NOTSET# %then %let base_uri=%mf_getplatform(VIYARESTAPI);

%let fref2=%mf_getuniquefileref();
proc http method='POST' in=&grantstring out=&fref2
  url="&base_uri/SASLogon/oauth/token"
  WEBUSERNAME="&client_id"
  WEBPASSWORD="&client_secret"
  AUTH_BASIC;
  headers "Accept"="application/json"
          "Content-Type"="application/x-www-form-urlencoded";
run;
/*data _null_;infile &fref2;input;put _infile_;run;*/

/**
  * Extract access / refresh tokens
  */

%let libref=%mf_getuniquelibref();
libname &libref JSON fileref=&fref2;

/* extract the tokens */
data &outds;
  set &libref..root;
  call symputx("&access_token_var",access_token);
  call symputx("&refresh_token_var",refresh_token);
run;


libname &libref clear;
filename &fref1 clear;
filename &fref2 clear;

%mend mv_tokenauth;