#*******************************************************************************
# ALMA - Atacama Large Millimeter Array
# Copyright (c) UKATC - UK Astronomy Technology Centre, Science and Technology Facilities Council, 2011
# (in the framework of the ALMA collaboration).
# All rights reserved.
# 
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# 
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
# 
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
#*******************************************************************************
## Check ALMA Python scripts
##
## A M Chavan, ESO, 14-Jan-2005
##
## $Id: ScriptValidator.py,v 1.3 2005/02/02 12:23:33 amchavan Exp $

import sys
## from pyclbr         import readmodule   ### NOT SUPPORTED BY JYTHON
## from posix          import getcwd

__all__ = [ 'ScriptValidator' ]

class ScriptValidator:

    pathname = ""		# Pathname of the script to check
    text = ""			# Text of the script to check
    ignore = []			# List of names to be ignored
    report = ""			# Verification report: if empty, all is OK
    superclass = "ControlScript" # name of script superclass
    
    ## Constructor
    ## Define a verifier for a Python script
    ## Args:
    ##    pathname Pathname of the file containing the input script;
    ##             relative pathnames are resolved from the current
    ##             working directory.
    def __init__( self, pathname ):

        self.pathname = pathname
        
        try:
            f = open( pathname )
            self.text = f.read()
            f.close()
        except IOError, e:
            self.report = self.formatIOError( e, pathname )

        #print ">>>" + self.text + "<<<"
        

    ## Verify if the input script is valid.
    ## Verification steps include:
    ##     Script is not empty
    ##     Python syntax is correct
    ##     The script is a valid ALMA script (TODO: see
    ##     the verifyalma() method)
    ##
    ## Return: if all is well, an empty string is returned;
    ## otherwise, an error report is generated and returned.
    ##
    def verify( self ):

        # Report any errors reported by the
        # constructor
        #----------------------------------------
        if len( self.report ) != 0:
            return self.report
        
        # Check script length
        #----------------------------------------
        if self.text == None or len( self.text ) == 0:
            return "Script is empty"

        # Check if the given script is a valid
        # Python script
        #----------------------------------------
        try:
            compile( self.text, "???", "exec" )
        except SyntaxError, info:
            self.report = self.formatSyntaxError( info )
            return self.report
        except Exception, info:
            self.report = info
            return self.report

        self.report = self.verifyalma()
        return self.report
    

    ## Analyze the given script and see if it contains
    ## a valid ALMA script.
    ## We assume that the script is a syntactically valid
    ## Python script. We also assume that the script pathame
    ## ends with the ".py" extension.
    ##
    ## TODO: define "what" exactly constitutes a valid
    ##       ALMA Python script
    ##
    ## Return: if all is well, an empty string is returned;
    ## otherwise, an error report is generated and returned.
    ##
    def verifyalma( self ):

        l = len( self.pathname)			# retrieve module name
        module = self.pathname[0:l-3]
        numsc = 0				# we found 0 script classes
        
        ## NOTE: following line requires the 'pyclbr' package, which 
        ##       is NOT SUPPORTED BY JYTHON 
        ## mdesc = readmodule( module )		# parse the script
        mdesc = {}
        ret = ""				# we return this error report
        
        for cname in mdesc.keys():		# foreach classname...
            if cname == 'ControlScript':	# ignore this
                continue

            cdesc = mdesc[cname]
            super = cdesc.super			# list of superclasses

            ## TODO
            ## Find out if a class is defined, and if
            ## that is a subclass of ControlScript
# KEEP THE FOLLOWING LINES for future extension
#============================================================
#            print cdesc.module
#            print cdesc.name
#            print cdesc.super
#            print cdesc.methods
#            print cdesc.file
#            print cdesc.lineno

        return ret

    
    ## Utility function: format a SyntaxError exception nicely
    ## for display to user
    ##
    def formatSyntaxError( self, e ):
        ret = "SyntaxError: " + str( e ) + ":\n" + 			\
              e.text + "\n" + "^".rjust( e.offset )
        return ret
    
    ## Utility function: format an IOError exception nicely
    ## for display to user
    ##
    def formatIOError( self, e, info="" ):
        msg = e.args[0]
        ret = "IOError: %s: %s" % (info, msg )
        return ret