from jinja2 import Environment, FileSystemLoader
from sys import argv
from textwrap import dedent
from re import search # regular expressions

def pretty(line,indent):
    line = dedent(line)
    if search('^#', line): # check if line is a preprocessor directive
       print line
    else:
       print (3*indent)*' ' + line
    	
env=Environment(loader=FileSystemLoader('.'))
tpl=env.get_template(argv[1])
source = tpl.render()
source = [line for line in source.split('\n') if line.strip() != '']

# regular expressions matching Fortran keywords
# \b detects word boundaries
# $ and ( must be escaped : \$, \(
# THIS|THAT means THIS or THAT
# raw Python strings r'blabla' avoid doubling '\'
noop      = r'!\$OMP'
increase  = r'\bTHEN\b|\bDO\b|\bSELECT CASE\b'
inter     = r'\bELSE\b|\bCASE\(|\bCASE DEFAULT\b'
decrease  = r'\bEND IF\b|\bENDIF\b|\bEND DO\b|\bENDDO\b|\bEND SELECT\b' 

indent=1

for line in source :
    if search(noop, line) :
        pretty(line,indent)
    elif search(decrease, line) :
        indent = indent-1
        pretty(line,indent)
    elif search(increase,line):
        pretty(line,indent)
        indent = indent+1
    elif search(inter,line):
        pretty(line,indent-1)
    else:
        pretty(line,indent)