# main.py
"""
Parse and execute statements either in stdin or in file
"""

import sys
import os

from antlr4 import *
from fspowLexer import fspowLexer
from fspowParser import fspowParser
# from fspowListener import fspowListener
# from antlr4.tree.Trees import Trees
from TreesUser import TreesUser
from fspowVisitorUser import fspowVisitorUser


def main(argv):
    # argv[1] s/be name of source file
    # if missing, use stdin
    if len(argv) == 1:
        # StdinStream is a standard ANTLR class read by the lexer
        # (It is not a file descriptor)        
        inpstream = StdinStream()
    else:
        inpname = argv[1]
        # FileStream is a standard ANTLR class read by the lexer
        # (It is not a file descriptor)        
        inpstream = FileStream(inpname)

    

    # The lexer analyses the characters on inpstream and produces tokens 
    lexer = fspowLexer(inpstream)
    # .. on the token stream (belonging to a standard ANTLR class)
    tokstream = CommonTokenStream(lexer)

    # The parser produces an abstract syntax tree
    parser = fspowParser(tokstream)
    # When we execute the parse, we need to give it the starting rule of our grammar,
    # which in our case is 'start' (as defined in fspow.g4),
    # so here we invoke the method named after this rule: start()
    tree = parser.prog()
    
    # print the parse tree
    #print(TreesUser.toStringTree(tree, None, parser))
    print(TreesUser.PrettyPrint(tree, None, parser))

    visitor = fspowVisitorUser()
    visitor.visit(tree)
    
    # The listener defines the actions to take upon entering an exiting nodes for 
    # specific tokens on the AST
    # listener = fspowListener()
    
    # A ParseTreeWalker is annother standard ANTLR class, that performs a walk on the AST
    # walker = ParseTreeWalker()

    # Get the tree walker to perform a walk on the AST, getting the listener to perform
    # the appropriate actions
    # walker.walk~(listener, tree)


if __name__ == '__main__':
    main(sys.argv)