; docformat = 'rst'
;
; NAME: 
;    convertTaxoToColor
; PURPOSE:
;    Compute the expected color of a filter from a taxonomic class spectrum.
;
;+
; :Description:
;    Compute the expected color of a filter from a taxonomic class spectrum.
;
; :Categories:
;    Database, Asteroid, Colors
;    
; :Params:
;    taxo: in, required, type=structure
;        A structure of N reflectance spectra. Fields are::
;           .N: the number of classes
;           .wave: a vector of reference wavelength for each spectral bin (micron)
;           .class: an array of structure, with name, spec, and dev fields for each class
;    filter: in, required, type=structure
;        A structure defining the filter. Fields are::
;           .wave: a vector of reference wavelength for each spectral bin (micron)
;           .trans: the transmission curve 
;    reference: in, required, type=structure
;        A structure defining the reference filter. Fields are::
;           .wave: a vector of reference wavelength for each spectral bin (micron)
;           .trans: the transmission curve 
;
; :Keywords:
;    AB: in, optional, type=boolean, default=0
;      If set, returns the magnitude in the AB system [Oke, J.B. 1974, ApJS, 27, 21]
;    ST: in, optional, type=boolean, default=0
;      If set, returns the magnitude in the STMAG system [Stone, R.P.S. 1996, ApJS, 107, 423]
;    Vega: in, optional, type=boolean, default=1
;      If set, returns the magnitude in the Vega system [Bessel, M. S. 2005, ARA&A, 43, 293]
;
; :Returns: A structure with the 
;  
; :Examples:
;
; :Uses:
;    specToMag
;
; :Author:
;    B.Carry (OCA)
;
; :History:
;    Change History::
;      Written in December 2015, B. Carry (OCA)
;      2017 Aug. - B. Carry (OCA) - Outsource magnitude computation to specToMag code
;-
function convertTaxoToColor, taxo, filter, reference, AB=AB, ST=ST, Vega=Vega
  COMPILE_OPT hidden, idl2
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---    I -- Initialization And Input Verification              -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;

 ;--I.1-- Check Input Parameters  --------------------------------------------------------------
  if n_params() lt 3 then begin
    message, /ioError, 'syntax: color = convertTaxoToColor( taxo, filter, reference )'
    return, -1
  endif

 ;--I.2-- Check Validity of Input Spectra  -----------------------------------------------------
  requiredTag = ['N','wave','class']
  nbTag=n_elements(requiredTag)
  for kTag=0, nbTag-1 do begin
    if not tag_exist( taxo, requiredTag[kTag] ) then begin
      message, 'Field '+requiredTag[kTag]+' missing in taxo structure'
      return, -1
    endif
  endfor

 ;--I.3-- Check Validity of Input Filter  ------------------------------------------------------
  requiredTag = ['wave','trans']
  nbTag=n_elements(requiredTag)
  for kTag=0, nbTag-1 do begin
    if not tag_exist( filter, requiredTag[kTag] ) then begin
      message, 'Field '+requiredTag[kTag]+' missing in filter structure'
      return, -1
    endif
  endfor

 ;--I.4-- Check Validity of Input Filter  ------------------------------------------------------
  requiredTag = ['wave','trans']
  nbTag=n_elements(requiredTag)
  for kTag=0, nbTag-1 do begin
    if not tag_exist( reference, requiredTag[kTag] ) then begin
      message, 'Field '+requiredTag[kTag]+' missing in reference structure'
      return, -1
    endif
  endfor

 ;--I.5-- Define Output Structure  -------------------------------------------------------------
  empty={name:'',ref:0.,unc:0.}
  color=replicate(empty,taxo.N)
  



;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
;---  TAG ---   II -- Compute Color Indices                              -----------------------;
;-----------------------------------------------------------------------------------------------;
;-----------------------------------------------------------------------------------------------;
  for kTaxo=0, taxo.N-1 do begin

   ;--II.1-- Format Input Spectrum for specToMag Function  -------------------------------------;
    specIn = {wave: taxo.wave, flux:taxo.class[kTaxo].spec}
    specUp = {wave: taxo.wave, flux:taxo.class[kTaxo].dev}

   ;--II.2-- Reference Magnitude  --------------------------------------------------------------;
    refMag = specToMag( specIn, reference, /Vega )
    upRef = specToMag( specUp, reference, /Vega )
    refUnc = abs(refMag-upRef)

;    print, refMag, upRef, refUnc

   ;--II.3-- Current Filter Magnitude  ---------------------------------------------------------;
    curMag = specToMag( specIn, filter, /Vega )
    upMag = specToMag( specUp, filter, /Vega )
    curUnc = abs(curMag-upMag)

;    print, curMag, upMag, curUnc


    cgPlot, specIn.wave, specIn.flux, /xLog, xRange=[0.1, 10], /yLog
    cgPlot, /OverPlot, specIn.wave, specUp.flux, color='gray'

    cgPlot, /OverPlot, reference.wave, reference.trans, color='blue'
    cgPlot, /OverPlot, filter.wave, filter.trans, color='orange'

   ;--II.4-- Store Photometry in Structure  ----------------------------------------------------;
    color[kTaxo].name = taxo.class[kTaxo].name
    color[kTaxo].ref = (refMag-curMag)
    color[kTaxo].unc = refUnc + curUnc

  endfor

  return, color

end


;-------------------old and rong code!!!
;;---
;;---;-----------------------------------------------------------------------------------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---;---  TAG ---   II -- Spectral Normalization                             -----------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---
;;---   ;--II.1-- Interpolate over Reference  -------------------------------------------------------
;;---    spec4ref = interpol( taxo.class[kTaxo].spec, taxo.wave, reference.wave )
;;---
;;---   ;--II.2-- Normalize spectra  ----------------------------------------------------------------
;;---    refColor = total( spec4ref * reference.trans ) / total(reference.trans) 
;;---    norma = taxo.class[kTaxo]
;;---    norma.spec /= refColor
;;---    norma.dev  /= refColor
;;---
;;---
;;---;    cgPlot, taxo.wave, taxo.class[kTaxo].spec, thick=1, xr=[0.1,3]
;;---;    cgPlot, /OverPlot, reference.wave, spec4ref, color='red', thick=4
;;---;stop
;;---;    cgPlot, taxo.wave, norma.spec, thick=1, xr=[0.1,3]
;;---;    cgPlot, /OverPlot, reference.wave, spec4ref, color='red', thick=4
;;---;
;;---;    cgPlot, /OverPlot, reference.wave, reference.trans, color='gray'
;;---;    cgPlot, /OverPlot, filter.wave, filter.trans, color='dark gray'
;;---;    print, total(  norma.spec * reference.trans) / total(reference.trans)
;;---;stop
;;---
;;---;-----------------------------------------------------------------------------------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---;---  TAG ---  III -- Convert Spectra to Color                           -----------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---;-----------------------------------------------------------------------------------------------;
;;---
;;---   ;--II.1-- Interpolate Spectrum over Filter  -------------------------------------------------
;;---    spec4filter = interpol( taxo.class[kTaxo].spec, taxo.wave, filter.wave )
;;---    dev4filter = interpol(  taxo.class[kTaxo].dev, taxo.wave, filter.wave )
;;---;---good?    spec4filter = interpol( norma.spec, taxo.wave, filter.wave )
;;---;---good?    dev4filter = interpol( norma.dev, taxo.wave, filter.wave )
;;---
;;---;    cgPlot, /over, filter.wave, spec4filter, color='green'      , thick=2
;;---;    cgPlot, /over, reference.wave, reference.trans, color='navy', thick=2
;;---;    cgPlot, /over, filter.wave, filter.trans, color='navy'      , thick=2
;;---
;;---   ;--II.2-- Convert Spectrum to Photometry  ---------------------------------------------------
;;---    flux = total( spec4filter*filter.trans ) / total(filter.trans)
;;---    unc  = total( dev4filter*filter.trans ) / total(filter.trans)
;;---
;;---   ;--II.3-- Store Photometry in Structure  ----------------------------------------------------
;;---    color[kTaxo].name = taxo.class[kTaxo].name
;;---    color[kTaxo].ref = flux / refColor
;;---    color[kTaxo].unc = unc  / refColor
;;---;    color[kTaxo].ref = flux
;;---;    color[kTaxo].unc = unc
;;---
;;---    
;;---;    gC = where(filter.trans gt 0.02 )
;;---;    centC = median( filter.wave[gC] )
;;---;    cgPlot, /over, centC, flux, psym=4
;;---;stop
;;---  endfor
;;---
;;---  return, color
;;---
;;---end
;;---