#!/usr/bin/env python2
import os
import subprocess
import sys
import tempfile

NOT_PEP8_COMPLIANT_MESSAGE_PRE = \
    "Your code is not fully pep8 compliant and contains"\
    " the following coding style issues:\n\n"

NOT_PEP8_COMPLIANT_MESSAGE_POST = \
    "Please fix these errors and commit again, you can do so "\
    "from the root directory automatically like this, assuming the whole "\
    "file is to be commited:"

NO_PEP8_MESSAGE = \
    "You should install the pep8 style checker to be able"\
    " to commit in this repo.\nIt allows us to garantee that "\
    "anything that is commited respects the pep8 coding style "\
    "standard.\nYou can install it:\n"\
    "  * on ubuntu, debian: $sudo apt-get install pep8 \n"\
    "  * on fedora: #yum install python-pep8 \n"\
    "  * on arch: #pacman -S pep8-python3 \n"\
    "  * or add the official pep8 from http://www.python.org/dev/peps/pep-0008/"\
    " in your $PATH"


def system(*args, **kwargs):
    kwargs.setdefault('stdout', subprocess.PIPE)
    proc = subprocess.Popen(args, **kwargs)
    out, err = proc.communicate()
    if type(out) == bytes:
        out = out.decode()
    return out


def copy_files_to_tmp_dir(files):
    tempdir = tempfile.mkdtemp()
    for name in files:
        filename = os.path.join(tempdir, name)
        filepath = os.path.dirname(filename)
        if not os.path.exists(filepath):
            os.makedirs(filepath)
        with open(filename, 'w') as f:
            system('git', 'show', ':' + name, stdout=f)

    return tempdir


def main():
    modified_files = system('git', 'diff-index', '--cached',
                            '--name-only', 'HEAD', '--diff-filter=ACMR').split("\n")[:-1]
    non_compliant_files = []
    output_message = None

    for modified_file in modified_files:
        try:
            if not modified_file.endswith(".py"):
                continue
            pep8_errors = system('pep8', '--repeat', '--ignore', 'E501,E128', modified_file)
            if pep8_errors:
                if output_message is None:
                    output_message = NOT_PEP8_COMPLIANT_MESSAGE_PRE
                output_message += pep8_errors
                non_compliant_files.append(modified_file)
        except OSError:
            output_message = NO_PEP8_MESSAGE
            break

    if output_message:
        print output_message
        if non_compliant_files:
            print NOT_PEP8_COMPLIANT_MESSAGE_POST
            for non_compliant_file in non_compliant_files:
                print "autopep8 -i ", non_compliant_file, "; git add ", \
                    non_compliant_file
            print "git commit"
        sys.exit(1)


if __name__ == '__main__':
    main()