FUNCTION dustem_plugin_mbbdy_isrf, key=key,val=val,scope=scope,paramtag=paramtag,help=help

;+
; NAME:
;    dustem_plugin_mbbdy_isrf
;
; PURPOSE:
;    DUSTEM plugin to compute modified black-body emission
;
; CATEGORY:
;    DUSTEM Wrapper, Plugins, Lowlevel
;
; CALLING SEQUENCE:
;    output=dustem_plugin_mbbdy([,key=][,val=])
;
; INPUTS:
;    None
;
; OPTIONAL INPUT PARAMETERS:
;    key  = input parameter number
;    val  = input parameter value
;
; OUTPUTS:
;    output = MBB spectrum (on dustem wavelengths) (output[*,0] is Stokes I, output[*,1] Stokes Q and output[*,2] Stokes U)
;
; OPTIONAL OUTPUT PARAMETERS:
;    None
;
; ACCEPTED KEY-WORDS:
;    help                  = if set, print this help
;
; COMMON BLOCKS:
;    None
;
; SIDE EFFECTS:
;    None
;
; RESTRICTIONS:
;    The DustEM fortran code must be installed
;    The DustEMWrap idl code must be installed
;
; PROCEDURE:
;    This is a dustem plugin
;
; EXAMPLES:
;
; MODIFICATION HISTORY:
;    Written by JPB 
;    Evolution details on the DustEMWrap gitlab.
;    See http://dustemwrap.irap.omp.eu/ for FAQ and help.  
;-

IF keyword_set(help) THEN BEGIN
  doc_library,'dustem_plugin_mbbdy_isrf'
  output=0.
  goto,the_end
ENDIF

;default values of input parameters
amp = 0.5 ; Amplitude of the modified black-body emission  
temp = 40 ; Temperature of the dust species
beta = 1.8 ; Emissivity index

lambref = 250 ;microns

;default polarization values  
smallp=0.
psi=0.

paramtag=['Amp','beta (Plaw_index)','p','Psi (deg)']
IF keyword_set(key) THEN BEGIN 
  
  ind1=where(key EQ 1,count1) ; reading amp
  ind2=where(key EQ 2,count2) ; reading beta
  
  ;In the case this plugin is used in polarization 
  ind3=where(key EQ 3,count3) ; reading smallp
  ind4=where(key EQ 4,count4) ; reading psi  
  
      
  IF count1 NE 0 then amp=val[ind1[0]] ;else default value
  IF count2 NE 0 then beta=val[ind2[0]] ; // //
  IF count3 NE 0 then smallp=val[ind3[0]] ; // //
  IF count4 NE 0 then psi=val[ind4[0]] ; // //
   
ENDIF


;********YOU NEEED TO MAKE SURE THAT LAMBIR AND MA_ISRF.LAMBISRF ARE THE SAME******** 
;************************************************************************************


;integrating the mathis isrf
ma_isrf_dat=!dustem_soft_dir+'data/ISRF_MATHIS.DAT'
ma_isrf=dustem_read_isrf(ma_isrf_dat)
un=uniq(ma_isrf.isrf)

int_mathis=INT_TABULATED((ma_isrf.lambisrf)[un],(ma_isrf.isrf)[un])


;integrating the composite isrf
int_isrf=INT_TABULATED((ma_isrf.lambisrf)[un],((*(*!dustem_plugin).stellar_population))[un])

;lambir=dustem_get_wavelengths()
lambir=dustem_get_wavelengths()
Nwavs=n_elements(lambir)
tau_o_nh = 1.00E-25*(*!dustem_HCD)*(lambir/lambref)^(-1.*beta)

;fact = 1.e4*(*!dustem_HCD)/(4.*!pi)/(3.e8/1.e-6/ma_isrf.lambisrf)*1.e20/1.e7
tempref=19.00 ;K

temp=tempref*(int_isrf/int_mathis)^(1./(4+beta)) 
;stop
spec=amp*tau_o_nh*dustem_planck_function(temp,lambir)

;stop
output=fltarr(Nwavs,3)
output[*,0]=spec

;polarization this actually need to 
polar_ippsi2iqu,output[*,0],Q,U,replicate(smallp,Nwavs),replicate(psi,Nwavs)

output[*,1]=Q
output[*,2]=U


scope='ADD_SED+ADD_POLSED'


the_end:
RETURN,output
  
END