#!/usr/bin/env python
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###
### Modifies or add an element in an XML file
###
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##
##  Warning, to install, configure, run, use any of Olivier Marti's
##  software or to read the associated documentation you'll need at least
##  one (1) brain in a reasonably working order. Lack of this implement
##  will void any warranties (either express or implied).
##  O. Marti assumes no responsability for errors, omissions,
##  data loss, or any other consequences caused directly or indirectly by
##  the usage of his software by incorrectly or partially configured
##  personal.
##
## SVN information
__Author__   = "$Author$"
__Date__     = "$Date$"
__Revision__ = "$Revision$"
__Id__       = "$Id$"
__HeadURL    = "$HeadURL$"

# python update_xml.py -i ~/Unix/TOOLS/MOSAIX/iodef_atm_to_oce.xml -o essai.xml -n 'context[@id="interpol_read"]/file_definition/file[@id="file_src"]/field[@id="mask_src"]' -k name=Bidon
# python update_xml.py -i ~/Unix/TOOLS/MOSAIX/iodef_atm_to_oce.xml -d -o essai.xml -n 'context[@id="interpol_run"]/file_definition/file[@id="dia"]/variable[@name="title"]' -t "SRC mask interpolated to DST"
# python update_xml.py -i ~/Unix/TOOLS/MOSAIX/iodef_atm_to_oce.xml -o essai.xml -c InFile.txt

# Tested with python/2.7.12 and python/3.6.4
#
import xml.etree.ElementTree
import argparse, sys, textwrap, shlex
    
# Check version of Python
Version = sys.version_info
if Version < (2,7,0) :
  sys.stderr.write ( "You need python 2.7 or later to run this script\n" )
  sys.stderr.write ( "Present version is: " + str(Version[0]) + "." + str(Version[1]) + "." + str(Version[2]) + "\n" )
  sys.exit (1)

## ============================================================================
## Needed functions

def simplify_string_list (list_str) :
    '''Concatenate some elements of the list of strings when needed'''
    zlist = list_str.copy () ; list_new = []
    while ( len (zlist) > 0 ) :
        arg = zlist.pop (0)    
        if arg[0] == '"' :
            for arg2 in zlist.copy () :
                arg = arg + " " + arg2
                zlist.pop (0)
                if arg2[-1] == '"' : break
        arg = arg.strip('"').strip("'")
        list_new.append (arg)
    return list_new
  
def UpdateNode (iodef, Node, Text=None, Key=None) :
    '''Update an xml node'''
    # Remove whitespaces at both ends
    Node = Node.rstrip().lstrip()

    ## Find node
    nodeList = iodef.findall (Node)

    ## Check that one and only one node is found
    if len (nodeList) == 0 :
        print ( "Error : node not found" )
        print ( "Node  : ", Node )
        sys.exit (1)
    
    if len (nodeList) > 1 :
        print ( "Error : " + len (nodeList)+" occurences of node found in file" )
        print ( "Node  : ", Node )
        sys.exit (2)

    ## Update element
    elem = nodeList[0]

    if Text != None :
        if Verbose : print ( 'Node:', Node, ' -- Text:', Text  )
        if Debug :
            print ( 'Attributes of node: ' + str (elem.attrib) )
            print ( 'Text              : ' + str (elem.text)   )
        elem.text = Text

    if Key != None :
      
        # Check the syntax
        if not '=' in Key :
            print ( 'Key syntax error. Correct syntax is -k Key=Value' )
            sys.exit (-1)
        else :
            KeyName, Value = Key.split ('=')
            if Verbose : print ( 'Node:', Node, ' -- Key:', Key )
            # To do : check that KeyName exist (it is added if not : do we want that ?)
            if Debug :
                print ( 'Attributes of node: ' + str (elem.attrib) )
            elem.attrib.update ( { KeyName:Value } )

    return iodef

## ============================================================================
## Main code

# Creating a parser to read the command line arguments
# The first step in using the argparse is creating an ArgumentParser object:
parser = argparse.ArgumentParser (description = """
Examples with the modification on the command line : 
     python %(prog)s -i iodef.xml -n 'context[@id="interpol_run"]/file_definition/file[@id="file_src"]/field[@id="mask_source"]' -k name -v maskutil_T
     python %(prog)s -i iodef.xml -n 'context[@id="interpol_run"]/file_definition/file[@id="dia"]/variable[@name="dest_grid"]'   -t dstDomainType

Usage with a command file : 
     python %(prog)s -i iodef.xml -c commands.txt
   
Syntax in the command file : removes the quote around the node description : 
-n context[@id="interpol_run"]/file_definition/file[@id="dia"]/variable[@name="dest_grid"]   -t dstDomainType

   """ + "SVN : " + __Revision__, formatter_class=argparse.RawDescriptionHelpFormatter, epilog='-------- This is the end of the help message --------')

# Adding arguments
group1 = parser.add_mutually_exclusive_group (required=False)

parser.add_argument ( '-i', '--input'  , help="XML input file"          , default='iodef.xml', type=str, metavar='<input_file>'  )
parser.add_argument ( '-o', '--output' , help="XML output file"         , default=None       , type=str, metavar='<output_file>' )
parser.add_argument ( '-n', '--node'   , help="XML node in Xpath syntax", default=None, type=str, metavar='<xml_node>')
group1.add_argument ( '-k', '--key'    , help="XML key to update and new value (-k <name>=<value>)", default=None, type=str, metavar='<xml_key>' )
group1.add_argument ( '-t', '--text'   , help="Will replace the 'text' part of the Xpath by <text>", default=None, type=str, metavar='<text>' )
parser.add_argument ( '-d', '--debug'  , help="Extensive debug prints", action="store_true", default=False )
parser.add_argument ( '-v', '--verbose', help="Some verbosity"        , action="store_true", default=False )
parser.add_argument ( '-c', '--commandfile', help="file with list of command", default=None, type=str )

# Parse command line
myargs  = parser.parse_args ()
Verbose = myargs.verbose
Debug   = myargs.debug

if Debug : print ( "Command line arguments : ", myargs )

FileCommand = myargs.commandfile
FileIn      = myargs.input
FileOut     = myargs.output
Node        = myargs.node
Key         = myargs.key
Text        = myargs.text
    
if FileCommand != None : 
    if ( Node != None or Key != None or Text != None ) :
        print ('Error : when a command file is specified, options -k|--key, -n|--node are unused' )
        exit (-2)
    
if FileOut == None : FileOut = FileIn
    
## Get XML tree from input file
iodef = xml.etree.ElementTree.parse ( FileIn )

if FileCommand == None :
    ## Only one node to modify
    iodef = UpdateNode (iodef, Node, Key, Text)

else :
    ## Read a list of modification commands in a command file
    fic = open (FileCommand, 'r')
    lignes = fic.readlines()

    for nn, ligne in enumerate (lignes) :
        ligne = ligne.strip ().split ('#')[0] # Remove leading and trailing blanks, and trailing comments
        if Debug : print (nn+1, ':', type (ligne) , ':', len (ligne) , ':', ligne, ':')
        if ligne == '' or ligne == None or len(ligne) == 0 or ligne[0] == '#' :
            if Debug : print ('Skips blank or comment line')
        else : 
            list_args = shlex.split (ligne)
        
            if Debug :
                print ( '{:3d} : '.format(nn+1), end='')
                print ( list_args )
            # Parse args line
            myargs_ligne = parser.parse_args (list_args)

            Node     = myargs_ligne.node
            Key      = myargs_ligne.key
            Text     = myargs_ligne.text

            UpdateNode (iodef, Node, Text, Key)
    
## Writes XML tree to file
iodef.write ( FileOut )

## This is the end
if Debug : print ('This is the end')
#sys.exit (0)
    
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###
###                               That's all folk's !!!
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