#!/usr/bin/env python3

"""List all those Python files that require a coding directive

Usage: findnocoding.py dir1 [dir2...]
"""

__author__ = "Oleg Broytmann, Georg Brandl"

import sys, os, re, getopt

# our pysource module finds Python source files
try:
 import pysource
except ImportError:
 # emulate the module with a simple os.walk
 class pysource:
 has_python_ext = looks_like_python = can_be_compiled = None
 def walk_python_files(self, paths, *args, **kwargs):
 for path in paths:
 if os.path.isfile(path):
 yield path.endswith(".py")
 elif os.path.isdir(path):
 for root, dirs, files in os.walk(path):
 for filename in files:
 if filename.endswith(".py"):
 yield os.path.join(root, filename)
 pysource = pysource()


 print("The pysource module is not available; "
 "no sophisticated Python source file search will be done.", file=sys.stderr)


decl_re = re.compile(rb'^[ \t\f]*#.*?coding[:=][ \t]*([-\w.]+)')
blank_re = re.compile(rb'^[ \t\f]*(?:[#\r\n]|$)')

def get_declaration(line):
 match = decl_re.match(line)
 if match:
 return match.group(1)
 return b''

def has_correct_encoding(text, codec):
 try:
 str(text, codec)
 except UnicodeDecodeError:
 return False
 else:
 return True

def needs_declaration(fullpath):
 try:
 infile = open(fullpath, 'rb')
 except IOError: # Oops, the file was removed - ignore it
 return None

 with infile:
 line1 = infile.readline()
 line2 = infile.readline()

 if (get_declaration(line1) or
 blank_re.match(line1) and get_declaration(line2)):
 # the file does have an encoding declaration, so trust it
 return False

 # check the whole file for non utf-8 characters
 rest = infile.read()

 if has_correct_encoding(line1+line2+rest, "utf-8"):
 return False

 return True


usage = """Usage: %s [-cd] paths...
 -c: recognize Python source files trying to compile them
 -d: debug output""" % sys.argv[0]

if __name__ == '__main__':

 try:
 opts, args = getopt.getopt(sys.argv[1:], 'cd')
 except getopt.error as msg:
 print(msg, file=sys.stderr)
 print(usage, file=sys.stderr)
 sys.exit(1)

 is_python = pysource.looks_like_python
 debug = False

 for o, a in opts:
 if o == '-c':
 is_python = pysource.can_be_compiled
 elif o == '-d':
 debug = True

 if not args:
 print(usage, file=sys.stderr)
 sys.exit(1)

 for fullpath in pysource.walk_python_files(args, is_python):
 if debug:
 print("Testing for coding: %s" % fullpath)
 result = needs_declaration(fullpath)
 if result:
 print(fullpath)