"""
Uses the pyflakes library to find lint in all modules.

From the pyflakes_ project page:

    Pyflakes is a simple program which checks Python source files for
    errors. It is similar to PyChecker in scope, but differs in that it
    does not execute the modules to check them. This is both safer and
    faster, although it does not perform as many checks. Unlike PyLint,
    Pyflakes checks only for logical errors in programs; it does not
    perform any checks on style.

.. _pyflakes: http://divmod.org/projects/pyflakes

"""

from distutils import log
from buildutils.cmd import Command

class flakes(Command):
    description = "check source files for errors and inefficiencies"
    
    # list of (long name, short name, description) tuples
    user_options = []
    
    def initialize_options(self):
        pass
    
    def finalize_options(self):
        pass

    def check(self, module, file):
        import compiler, sys, traceback
        import pyflakes
        log.debug('checking file %r', file)
        code = open(file, 'r').read()
        try:
            tree = compiler.parse(code)
        except (SyntaxError, IndentationError):
            print >> sys.stderr, 'could not compile %r. Traceback:' % (file,)
            traceback.print_exc(0, sys.stderr)
        else:
            w = pyflakes.Checker(tree, file)
            w.messages.sort(lambda a, b: cmp(a.lineno, b.lineno))
            for warning in w.messages:
                self.warn(warning)
        
    def run(self):
        self.require('pyflakes')
        base = self.get_finalized_command('build_py')
        for (package, module, file) in base.find_all_modules():
            self.check(module, file)