#! /usr/bin/env python

"""This script retrieves the value of a PARAMETER tag from either a MODEL or a
PLATFORM in one XML file.

Usage: 
       get_ece_config_param.py XML MODEL|PLATFORM PARAMETER

Example #1, retrieve the number of processor for IFS:

       get_ece_config_param.py config-run.xml IFS NUMPROC

Example #2, retrieve the 'run dir' on the 'bi' platform, defined in the config-run.xml: 
 
       get_ece_config_param.py config-run.xml bi RUN_DIR

If not found or error, returns nothing and exits with return code 1.
"""

from xml.etree import ElementTree, ElementInclude
import xml.sax
from io import StringIO
import sys
import os

if __name__ == "__main__":

    if len(sys.argv) != 4:
        sys.stderr.write( "Must pass THREE arguments! Usage:")
        sys.stderr.write( "    get_ece_config_param.py XMLFILE MODEL|PLATFORM PARAMETER")
        sys.exit(1)
        
    f = sys.argv[1]
    modelname = sys.argv[2]
    paramname = sys.argv[3]

    # -- PARSE FILE
    parser = xml.sax.make_parser()
    
    try:
        tree = ElementTree.parse(f)
    except IOError:
        sys.stderr.write( "Could not open file: %s\n" % f)
        sys.exit(1)
    except ElementTree.ParseError, v:
        row, column = v.position
        print "error on row", row, "column", column, ":", v
        sys.exit(1)
    except:
        sys.stderr.write( "Could not parse XML file: %s\n"+f)
        sys.exit(1)

    root = tree.getroot()
    ElementInclude.include(root)
    s = unicode(ElementTree.tostring(root))
    io = StringIO(s)
    parser.parse(io)

    # -- Get list of PARAMETER, first assuming it is a MODEL, if not it is a PLATFORM
    Params=[tag.findall('Parameter') for tag in root.findall('Model') if tag.get('name')==modelname]

    if not Params:
        Params=[tag.findall('Parameter') for tag in root.findall('Platform') if tag.get('name')==modelname]

    # -- Return value
    if Params:
        val=[k.find('Value').text for k in Params[0] if k.get('name') == paramname ]
    else:
        val=None
    
    if val:
        sys.stdout.write( val[0] )
    else:
        sys.stderr.write("Parameter '%s' or Model/Platform '%s' not found.\n" % (paramname,modelname))
        sys.exit(1)