-- $Id: mono-point_02.lua,v 1.4 1999/02/01 20:16:21 tibbetts Exp dj $
--
-- raygen specification for multiple monochromatic point sources
-- at different energies.
-- the override function must set the following global variable:
--
--    energy -> one of the following options:
--
--              -  single energy, e.g. energy=1.49. flux is set to the 
--		   default value (see below).
--
--              -  lua table of energies, e.g. energy={1.49,4.51}. fluxes
--		   are set to the default value (see below)
--
--              -  lua table of tables of energies and photon fluxes,
--                  e.g. energy={{1.49,0.5},{4.51,1.25}}
--
--		-  a filename of an rdb table containing energies and,
--                 optionally, fluxes.  the column containing energies
--                 defaults to 'energy'.  it can be specified with the
--                 energy_colname variable.  if fluxes are specified in
--                 the rdb table, the flux_colname variable should be set
--                 to the name of the column.  otherwise, fluxes are
--                 set to the default value (see below).
--                 
--
-- The following global variables are optional; 
-- optional global variables are applied to each point source;
-- defaults are set by raygen:
--
--    flux  -> the user specified default flux.  this will be used if
--             fluxes are not specified with energies.  if flux is not
--             specified the default default flux is 1. 
--    z     -> the position of the source. 0 is at CAP datum A,
--             z increases from the source to the focal plane
--    theta -> the radial position of the source in the sky, in
--             minutes of arc
--    phi   -> the azimuthal angle of the source, in degrees
$debug
AXAF_ROOT = getenv( 'AXAF_ROOT' )

dofile( AXAF_ROOT .. '/simul/lib/lua/RDB.lua' )


override( )

function mono_point( )

  local pfx = 'mono-point_02.lua: '
  local local_flux = 1
  local attrs = {}

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

  if ( "nil" == type( energy ) ) then
    error( pfx .. "energy not specified" )
  end

  -- if user didn't define flux, set it to the default
  if ( nil == flux ) then
    flux = local_flux
  end

  if ( nil ~= z ) then
    attrs['z'] = z
  end

  if ( nil ~= theta ) then
    attrs['theta'] = theta * arcmin2rad
  end

  if ( nil ~= phi ) then
    attrs['phi'] = phi * deg2rad
  end

  if ( "table" == type( energy ) ) then
    local i = nil
    local e = nil

    -- loop through the table putting index in i and value in e
    i, e = next( energy, i )
    while ( nil ~= i ) do

      -- if value is a table then look for a flux 
      if ( "table" == type( e ) ) then
        e = energy[i][1]

        -- if flux is not defined in table, default to flux
        if ( nil == energy[i][2] ) then
          local_flux = flux

	-- else use the flux given
	else
          local_flux = energy[i][2]
        end

      -- else default to flux
      else
        local_flux = flux
      end 

      begin_source( "s"..e )
        mono( "mono", e, local_flux )

        point( "source", attrs )
      end_source( "s"..e )

      i, e = next( energy, i )
    end

  -- elseif energy is just a number, use default flux
  elseif ( "number" == type( energy ) ) then

    begin_source( "s" .. tostring( energy ) )
        mono( "mono", energy, flux )

        point( "source", attrs )
    end_source( "s" .. tostring( energy ) )
 
  -- elseif energy is a string, it's the name of an rdb file
  elseif ( "string" == type( energy ) ) then

    -- open rdb file
    rdb, msg = RDB:new( energy )    
    if ( nil == rdb ) then
      error( pfx .. energy .. ': ' .. msg )
    end
    
    -- see if energy column name was specified via override()
    if ( nil == energy_colname ) then
      energy_colname = 'energy'
    end

    -- check that the energy column exists
    if ( nil == rdb:pos( energy_colname ) ) then
      error( pfx .. "column `" .. energy_colname .. 
	     "' doesn\'t exist in rdb file " .. energy )
    end

    -- if flux column is specified, then check that
    if ( nil ~= flux_colname and nil == rdb:pos( flux_colname ) ) then
      error( pfx .. "column `" .. flux_colname .. 
	     "' doesn\'t exist in rdb file " .. energy )
    end

    -- now, loop through rdb table and create the sources
    local data
    data = rdb:read( )
    while data do
      energy = data[energy_colname]
      if ( nil ~= flux_colname ) then
        flux = data[flux_colname]
      end

      begin_source( "s" .. tostring( energy ) )
        mono( "mono", energy, flux )
        point( "source", attrs )
      end_source( "s" .. tostring( energy ) )

      data = rdb:read( )
    end

  -- else energy is an unexpected type
  else
    error( pfx .. "unexpected type: energy = `" .. energy .. "'" )
  end


end

function source( )
  mono_point( )
end