-- $Id: xss_01.lua,v 1.6 2008/07/24 20:42:25 dj Exp $

$debug

-- XSS source simulator
-- override must provide the following information:
--
-- xss : the name of the XSS source. It may be one of 
--       DCM, HIREFS, EIPS, or PIGS.
--
--  pitch, yaw: the source position in minutes of arc
--
--  for EIPS the following must be specified:
--
--     energy: the energy in keV
--     spot: The EIPS spot FITS file, relative to EIPS_ROOT
--		as defined below
--
--  for PIGS the following must be specified:
--
--     energy: the energy in keV
--
--  for DCM, the following must be specified
--  
--     crystal: either 'TAP', 'Ge', or 'Al'
--     energy:  the energy in keV
  

AXAF_ROOT = getenv( 'AXAF_ROOT' )
XSS_ROOT = AXAF_ROOT .. '/simul/databases/xss/'
EIPS_ROOT = XSS_ROOT .. 'eips-19980828/'
PIGS_IMAGE = XSS_ROOT .. 'pigs_spot_01.fits'

dofile( AXAF_ROOT .. '/simul/databases/xss/xss_distance_01.lua' )
dofile( AXAF_ROOT .. '/simul/lib/lua/AXAFCoords.lua' )
-- dofile( AXAF_ROOT .. '/simul/lib/lua/store.lua' )

$ifnot XSS_TEST
override( )
$end

------------------------------------------------------------------
------------------------------------------------------------------

-- these two functions (table_copy and table_union) are used to
-- generate the union of two tables.  they are used later on
-- to set up a new tagmethod for the "add" events for
-- tables.  this is just so that the code is cleaner later on,
-- lua doesn't know how to "add" tables

function table_copy( dest, src )

  local i, v = next(src, nil)  -- i is an index of t, v = t[i]

  while i do
    dest[i] = v
    i, v = next(src, i)        -- get next index
  end

  return new
end

function table_union( op1, op2 )
  new = {}
  table_copy( new, op1 )
  table_copy( new, op2 )
  return new
end

------------------------------------------------------------------
------------------------------------------------------------------

-- this is a helper function that will generate an error if the
-- passed global variables aren't defined

function checkglobal( pfx, ... )

  local i = 1

  while i <= arg.n do
    if nil == getglobal(arg[i]) then
      error( pfx .. "`" .. arg[i] .. "' isn't defined" )
    end
    i = i + 1
  end

end

------------------------------------------------------------------
------------------------------------------------------------------

-- this splits up a string on commas, and returns a table with
-- each of the substrings as indices, with their order in the
-- original string as the values

function optsplit( string )

  local fin
  local start = 1
  local toks = {}

  toks.n = 0

  fin = strfind( string, ',', start )
  while ( fin ) do
    toks.n = toks.n + 1
    toks[strsub( string, start, fin - 1 )] =  toks.n
    start = fin + 1
    fin = strfind( string, ',', start )
  end

  toks.n = toks.n + 1
  toks[strsub( string, start )] = toks.n

  return toks
end

------------------------------------------------------------------
------------------------------------------------------------------


function source( )

  local deg2rad = 3.14159265358979/180.0
  local arcsec2rad = deg2rad / 3600
  local arcmin2rad = deg2rad / 60

  local oldadd    = settagmethod( tag( {} ), "add", table_union )

  local pfx = 'xss: '

  checkglobal( pfx, 'xss', 'energy', 'pitch', 'yaw' )

  local theta, phi
  local el, az 

  el, az = pitchyaw_2_osac_elaz( pitch, yaw )
  theta, phi = osac_elaz_2_osac_polar( el, az )
  theta, phi = osac_polar_2_raygen_polar( theta, phi )

  -- split off possible options
  local src = optsplit( xss )

  local src_pos = { theta = theta, phi = phi, z = z }

  ----------------------------------------------------------------
  if ( src['EIPS'] ) then

    if ( nil == src_pos['z'] ) then	
      src_pos['z'] = - xss_distance( 'EIPS' )
    end
      
    begin_source( 'EIPS' )

      mono( "EIPS-mono", energy, 1 )

      if ( src['point'] ) then

        point( "EIPS-point", src_pos )

      else

	if ( nil == spot ) then
	    error( pfx .. "Must specify `spot' for EIPS source" )
	end

        local eips_image = EIPS_ROOT .. spot
        image( "EIPS-image", { file = eips_image } +  src_pos )

      end

    end_source( 'EIPS' )

  ----------------------------------------------------------------

  elseif ( src['HIREFS'] ) then

  -- don't have an image for this yet, so just do monochromatic point
  -- source
    if ( nil == src_pos['z'] ) then	
      src_pos['z'] = - xss_distance( 'HIREFS' )
    end
      
    begin_source( 'HIREFS' )
      mono( "HIREFS-mono", energy, 1 )
      point( "HIREFS-point", src_pos )
    end_source( 'HIREFS' )

  elseif ( src['DCM'] ) then

    checkglobal( pfx, 'crystal' )

    if ( nil == src_pos['z'] ) then	
      src_pos['z'] = - xss_distance( 'DCM', crystal, 'energy', energy )
    end
      
    -- don't have an image for this yet, so just do monochromatic point
    -- source

    begin_source( 'DCM' )
      mono( "DCM-mono", energy, 1 )
      point( "DCM-point", src_pos )
    end_source( 'DCM' )

  ----------------------------------------------------------------

  elseif ( src['PIGS'] ) then
    
    if ( nil == src_pos['z'] ) then	
      src_pos['z'] = - xss_distance( 'PIGS' )
    end

    begin_source( 'PIGS' )
      mono( "PIGS-mono", energy, 1 )

      if ( src['point'] ) then

        point( "PIGS-point", src_pos )

      else

        image( "PIGS-image", {file = PIGS_IMAGE} + src_pos)

      end
    end_source( 'PIGS' )

  ----------------------------------------------------------------
 
  else
    error( pfx .. "couldn't parse source string: " .. xss )

  end

end

$if XSS_TEST
source( )
$end