#!/usr/bin/env python
# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright (c) 2012, Cloudscaling
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""nova HACKING file compliance testing

Built on top of pep8.py
"""

import imp
import inspect
import logging
import os
import re
import subprocess
import sys
import tokenize
import traceback

import pep8

# Don't need this for testing
logging.disable('LOG')

#N1xx comments
#N2xx except
#N3xx imports
#N4xx docstrings
#N5xx dictionaries/lists
#N6xx calling methods
#N7xx localization
#N8xx git commit messages
#N9xx other

IMPORT_EXCEPTIONS = ['sqlalchemy', 'migrate', 'nova.db.sqlalchemy.session',
                     'nova.db.sqlalchemy.migration.versioning_api']
# Paste is missing a __init__ in top level directory
START_DOCSTRING_TRIPLE = ['u"""', 'r"""', '"""', "u'''", "r'''", "'''"]
END_DOCSTRING_TRIPLE = ['"""', "'''"]
VERBOSE_MISSING_IMPORT = os.getenv('HACKING_VERBOSE_MISSING_IMPORT', 'False')

_missingImport = set([])


# Monkey patch broken excluded filter in pep8
# See https://github.com/jcrocholl/pep8/pull/111
def excluded(self, filename):
    """Check if options.exclude contains a pattern that matches filename."""
    basename = os.path.basename(filename)
    return any((pep8.filename_match(filename, self.options.exclude,
                                    default=False),
                pep8.filename_match(basename, self.options.exclude,
                                    default=False)))


def input_dir(self, dirname):
    """Check all files in this directory and all subdirectories."""
    dirname = dirname.rstrip('/')
    if self.excluded(dirname):
        return 0
    counters = self.options.report.counters
    verbose = self.options.verbose
    filepatterns = self.options.filename
    runner = self.runner
    for root, dirs, files in os.walk(dirname):
        if verbose:
            print('directory ' + root)
        counters['directories'] += 1
        for subdir in sorted(dirs):
            if self.excluded(os.path.join(root, subdir)):
                dirs.remove(subdir)
        for filename in sorted(files):
            # contain a pattern that matches?
            if ((pep8.filename_match(filename, filepatterns) and
                     not self.excluded(filename))):
                runner(os.path.join(root, filename))


def is_import_exception(mod):
    return (mod in IMPORT_EXCEPTIONS or
            any(mod.startswith(m + '.') for m in IMPORT_EXCEPTIONS))


def import_normalize(line):
    # convert "from x import y" to "import x.y"
    # handle "from x import y as z" to "import x.y as z"
    split_line = line.split()
    if ("import" in line and line.startswith("from ") and "," not in line and
                split_line[2] == "import" and split_line[3] != "*" and
                split_line[1] != "__future__" and
            (len(split_line) == 4 or
                 (len(split_line) == 6 and split_line[4] == "as"))):
        return "import %s.%s" % (split_line[1], split_line[3])
    else:
        return line


def nova_todo_format(physical_line, tokens):
    """Check for 'TODO()'.

    nova HACKING guide recommendation for TODO:
    Include your name with TODOs as in "#TODO(termie)"

    Okay: #TODO(sdague)
    N101: #TODO fail
    N101: #TODO (jogo) fail
    """
    # TODO(sdague): TODO check shouldn't fail inside of space
    pos = physical_line.find('TODO')
    pos1 = physical_line.find('TODO(')
    pos2 = physical_line.find('#')  # make sure it's a comment
    if (pos != pos1 and pos2 >= 0 and pos2 < pos and len(tokens) == 0):
        return pos, "N101: Use TODO(NAME)"


def nova_except_format(logical_line):
    r"""Check for 'except:'.

    nova HACKING guide recommends not using except:
    Do not write "except:", use "except Exception:" at the very least

    Okay: except Exception:
    N201: except:
    """
    if logical_line.startswith("except:"):
        yield 6, "N201: no 'except:' at least use 'except Exception:'"


def nova_except_format_assert(logical_line):
    r"""Check for 'assertRaises(Exception'.

    nova HACKING guide recommends not using assertRaises(Exception...):
    Do not use overly broad Exception type

    Okay: self.assertRaises(NovaException)
    N202: self.assertRaises(Exception)
    """
    if logical_line.startswith("self.assertRaises(Exception"):
        yield 1, "N202: assertRaises Exception too broad"


modules_cache = dict((mod, True) for mod in tuple(sys.modules.keys())
                                            + sys.builtin_module_names)

RE_RELATIVE_IMPORT = re.compile('^from\s*[.]')


def nova_import_rules(logical_line):
    r"""Check for imports.

    nova HACKING guide recommends one import per line:
    Do not import more than one module per line

    Examples:
    Okay: from nova.compute import api
    N301: from nova.compute import api, utils


    Imports should usually be on separate lines.

    nova HACKING guide recommends importing only modules:
    Do not import objects, only modules

    Examples:
    Okay: from os import path
    Okay: from os import path as p
    Okay: from os import (path as p)
    Okay: import os.path
    Okay: from nova.compute import rpcapi
    N302: from os.path import dirname as dirname2
    N302: from os.path import (dirname as dirname2)
    N303: from os.path import *
    N304: from .compute import rpcapi
    """
    #NOTE(afazekas): An old style relative import example will not be able to
    # pass the doctest, since the relativity depends on the file's locality

    def is_module_for_sure(mod, search_path=sys.path):
        mod = mod.replace('(', '')  # Ignore parentheses
        try:
            mod_name = mod
            while '.' in mod_name:
                pack_name, _sep, mod_name = mod.partition('.')
                f, p, d = imp.find_module(pack_name, search_path)
                search_path = [p]
            imp.find_module(mod_name, search_path)
        except ImportError:
            try:
                # NOTE(vish): handle namespace modules
                module = __import__(mod)
            except ImportError, exc:
                # NOTE(vish): the import error might be due
                #             to a missing dependency
                missing = str(exc).split()[-1]
                if (missing != mod.split('.')[-1] or
                            "cannot import" in str(exc)):
                    _missingImport.add(missing)
                    return True
                return False
            except Exception, exc:
                # NOTE(jogo) don't stack trace if unexpected import error,
                # log and continue.
                traceback.print_exc()
                return False
        return True

    def is_module(mod):
        """Checks for non module imports."""
        if mod in modules_cache:
            return modules_cache[mod]
        res = is_module_for_sure(mod)
        modules_cache[mod] = res
        return res

    current_path = os.path.dirname(pep8.current_file)
    current_mod = os.path.basename(pep8.current_file)
    if current_mod[-3:] == ".py":
        current_mod = current_mod[:-3]

    split_line = logical_line.split()
    split_line_len = len(split_line)
    if (split_line[0] in ('import', 'from') and split_line_len > 1 and
            not is_import_exception(split_line[1])):
        pos = logical_line.find(',')
        if pos != -1:
            if split_line[0] == 'from':
                yield pos, "N301: one import per line"
            return  # ',' is not supported by the N302 checker yet
        pos = logical_line.find('*')
        if pos != -1:
            yield pos, "N303: No wildcard (*) import."
            return

        if split_line_len in (2, 4, 6) and split_line[1] != "__future__":
            if 'from' == split_line[0] and split_line_len > 3:
                mod = '.'.join((split_line[1], split_line[3]))
                if is_import_exception(mod):
                    return
                if RE_RELATIVE_IMPORT.search(logical_line):
                    yield logical_line.find('.'), ("N304: No "
                                                   "relative imports. '%s' is a relative import"
                                                   % logical_line)
                    return

                if not is_module(mod):
                    yield 0, ("N302: import only modules."
                              "'%s' does not import a module" % logical_line)
                return

        #NOTE(afazekas): import searches first in the package
        # The import keyword just imports modules
        # The guestfs module now imports guestfs
        mod = split_line[1]
        if (current_mod != mod and
                not is_module(mod) and
                is_module_for_sure(mod, [current_path])):
            yield 0, ("N304: No relative imports."
                      " '%s' is a relative import"
                      % logical_line)


#TODO(jogo): import template: N305


def nova_import_alphabetical(logical_line, blank_lines, previous_logical,
                             indent_level, previous_indent_level):
    r"""Check for imports in alphabetical order.

    nova HACKING guide recommendation for imports:
    imports in human alphabetical order

    Okay: import os\nimport sys\n\nimport nova\nfrom nova import test
    N306: import sys\nimport os
    """
    # handle import x
    # use .lower since capitalization shouldn't dictate order
    split_line = import_normalize(logical_line.strip()).lower().split()
    split_previous = import_normalize(previous_logical.strip()).lower().split()

    if blank_lines < 1 and indent_level == previous_indent_level:
        length = [2, 4]
        if (len(split_line) in length and len(split_previous) in length and
                    split_line[0] == "import" and split_previous[0] == "import"):
            if split_line[1] < split_previous[1]:
                yield (0, "N306: imports not in alphabetical order (%s, %s)"
                          % (split_previous[1], split_line[1]))


def nova_import_no_db_in_virt(logical_line, filename):
    """Check for db calls from nova/virt

    As of grizzly-2 all the database calls have been removed from
    nova/virt, and we want to keep it that way.

    N307
    """
    if "nova/virt" in filename and not filename.endswith("fake.py"):
        if logical_line.startswith("from nova import db"):
            yield (0, "N307: nova.db import not allowed in nova/virt/*")


def is_docstring(physical_line, previous_logical):
    """Return True if found docstring
    'A docstring is a string literal that occurs as the first statement in a
    module, function, class,'
    http://www.python.org/dev/peps/pep-0257/#what-is-a-docstring
    """
    line = physical_line.lstrip()
    start = max([line.find(i) for i in START_DOCSTRING_TRIPLE])
    end = max([line[-4:-1] == i for i in END_DOCSTRING_TRIPLE])
    if (previous_logical.startswith("def ") or
            previous_logical.startswith("class ")):
        if start is 0:
            return True
        else:
            # Handle multi line comments
            return end and start in (-1, len(line) - 4)


def nova_docstring_start_space(physical_line, previous_logical):
    r"""Check for docstring not start with space.

    nova HACKING guide recommendation for docstring:
    Docstring should not start with space

    Okay: def foo():\n    '''This is good.'''
    Okay: def foo():\n    a = ''' This is not a docstring.'''
    Okay: def foo():\n    pass\n    ''' This is not.'''
    N401: def foo():\n    ''' This is not.'''
    """
    # short circuit so that we don't fail on our own fail test
    # when running under external pep8
    if physical_line.find("N401: def foo()") != -1:
        return

    # it's important that we determine this is actually a docstring,
    # and not a doc block used somewhere after the first line of a
    # function def
    if is_docstring(physical_line, previous_logical):
        pos = max([physical_line.find(i) for i in START_DOCSTRING_TRIPLE])
        if physical_line[pos + 3] == ' ':
            return (pos, "N401: docstring should not start with"
                         " a space")


def nova_docstring_one_line(physical_line, previous_logical):
    r"""Check one line docstring end.

    nova HACKING guide recommendation for one line docstring:
    A one line docstring looks like this and ends in punctuation.

    Okay: def foo():\n    '''This is good.'''
    Okay: def foo():\n    '''This is good too!'''
    Okay: def foo():\n    '''How about this?'''
    Okay: def foo():\n    a = '''This is not a docstring'''
    Okay: def foo():\n    pass\n    '''This is not a docstring'''
    Okay: class Foo:\n    pass\n    '''This is not a docstring'''
    N402: def foo():\n    '''This is not'''
    N402: def foo():\n    '''Bad punctuation,'''
    N402: class Foo:\n    '''Bad punctuation,'''
    """
    #TODO(jogo) make this apply to multi line docstrings as well
    line = physical_line.lstrip()
    if is_docstring(physical_line, previous_logical):
        pos = max([line.find(i) for i in START_DOCSTRING_TRIPLE])  # start
        end = max([line[-4:-1] == i for i in END_DOCSTRING_TRIPLE])  # end

        if pos != -1 and end and len(line) > pos + 4:
            if line[-5] not in ['.', '?', '!']:
                return pos, "N402: one line docstring needs punctuation."


def nova_docstring_multiline_end(physical_line, previous_logical, tokens):
    r"""Check multi line docstring end.

    nova HACKING guide recommendation for docstring:
    Docstring should end on a new line

    Okay: '''foobar\nfoo\nbar\n'''
    Okay: def foo():\n    '''foobar\nfoo\nbar\n'''
    Okay: class Foo:\n    '''foobar\nfoo\nbar\n'''
    Okay: def foo():\n    a = '''not\na\ndocstring'''
    Okay: def foo():\n    pass\n'''foobar\nfoo\nbar\n   d'''
    N403: def foo():\n    '''foobar\nfoo\nbar\ndocstring'''
    N403: class Foo:\n    '''foobar\nfoo\nbar\ndocstring'''\n\n
    """
    # if find OP tokens, not a docstring
    ops = [t for t, _, _, _, _ in tokens if t == tokenize.OP]
    if (is_docstring(physical_line, previous_logical) and len(tokens) > 0 and
                len(ops) == 0):
        pos = max(physical_line.find(i) for i in END_DOCSTRING_TRIPLE)
        if physical_line.strip() not in START_DOCSTRING_TRIPLE:
            return (pos, "N403: multi line docstring end on new line")


def nova_docstring_multiline_start(physical_line, previous_logical, tokens):
    r"""Check multi line docstring start with summary.

    nova HACKING guide recommendation for docstring:
    Docstring should start with A multi line docstring has a one-line summary

    Okay: '''foobar\nfoo\nbar\n'''
    Okay: def foo():\n    a = '''\nnot\na docstring\n'''
    N404: def foo():\n'''\nfoo\nbar\n'''\n\n
    """
    if is_docstring(physical_line, previous_logical):
        pos = max([physical_line.find(i) for i in START_DOCSTRING_TRIPLE])
        # start of docstring when len(tokens)==0
        if len(tokens) == 0 and pos != -1 and len(physical_line) == pos + 4:
            if physical_line.strip() in START_DOCSTRING_TRIPLE:
                return (pos, "N404: multi line docstring "
                             "should start with a summary")


def nova_no_cr(physical_line):
    r"""Check that we only use newlines not carriage returns.

    Okay: import os\nimport sys
    # pep8 doesn't yet replace \r in strings, will work on an
    # upstream fix
    N901 import os\r\nimport sys
    """
    pos = physical_line.find('\r')
    if pos != -1 and pos == (len(physical_line) - 2):
        return (pos, "N901: Windows style line endings not allowed in code")


FORMAT_RE = re.compile("%(?:"
                       "%|"           # Ignore plain percents
                       "(\(\w+\))?"   # mapping key
                       "([#0 +-]?"    # flag
                       "(?:\d+|\*)?"  # width
                       "(?:\.\d+)?"   # precision
                       "[hlL]?"       # length mod
                       "\w))")        # type


class LocalizationError(Exception):
    pass


def check_i18n():
    """Generator that checks token stream for localization errors.

    Expects tokens to be ``send``ed one by one.
    Raises LocalizationError if some error is found.
    """
    while True:
        try:
            token_type, text, _, _, line = yield
        except GeneratorExit:
            return

        if (token_type == tokenize.NAME and text == "_" and
                not line.startswith('def _(msg):')):

            while True:
                token_type, text, start, _, _ = yield
                if token_type != tokenize.NL:
                    break
            if token_type != tokenize.OP or text != "(":
                continue  # not a localization call

            format_string = ''
            while True:
                token_type, text, start, _, _ = yield
                if token_type == tokenize.STRING:
                    format_string += eval(text)
                elif token_type == tokenize.NL:
                    pass
                else:
                    break

            if not format_string:
                raise LocalizationError(start,
                                        "N701: Empty localization string")
            if token_type != tokenize.OP:
                raise LocalizationError(start,
                                        "N701: Invalid localization call")
            if text != ")":
                if text == "%":
                    raise LocalizationError(start,
                                            "N702: Formatting operation should be outside"
                                            " of localization method call")
                elif text == "+":
                    raise LocalizationError(start,
                                            "N702: Use bare string concatenation instead"
                                            " of +")
                else:
                    raise LocalizationError(start,
                                            "N702: Argument to _ must be just a string")

            format_specs = FORMAT_RE.findall(format_string)
            positional_specs = [(key, spec) for key, spec in format_specs
                                if not key and spec]
            # not spec means %%, key means %(smth)s
            if len(positional_specs) > 1:
                raise LocalizationError(start,
                                        "N703: Multiple positional placeholders")


def nova_localization_strings(logical_line, tokens):
    r"""Check localization in line.

    Okay: _("This is fine")
    Okay: _("This is also fine %s")
    N701: _('')
    N702: _("Bob" + " foo")
    N702: _("Bob %s" % foo)
    # N703 check is not quite right, disabled by removing colon
    N703 _("%s %s" % (foo, bar))
    """
    # TODO(sdague) actually get these tests working
    gen = check_i18n()
    next(gen)
    try:
        map(gen.send, tokens)
        gen.close()
    except LocalizationError as e:
        yield e.args

#TODO(jogo) Dict and list objects


def nova_is_not(logical_line):
    r"""Check localization in line.

    Okay: if x is not y
    N901: if not X is Y
    N901: if not X.B is Y
    """
    split_line = logical_line.split()
    if (len(split_line) == 5 and split_line[0] == 'if' and
                split_line[1] == 'not' and split_line[3] == 'is'):
        yield (logical_line.find('not'), "N901: Use the 'is not' "
                                         "operator for when testing for unequal identities")


def nova_not_in(logical_line):
    r"""Check localization in line.

    Okay: if x not in y
    Okay: if not (X in Y or X is Z)
    Okay: if not (X in Y)
    N902: if not X in Y
    N902: if not X.B in Y
    """
    split_line = logical_line.split()
    if (len(split_line) == 5 and split_line[0] == 'if' and
                split_line[1] == 'not' and split_line[3] == 'in' and not
    split_line[2].startswith('(')):
        yield (logical_line.find('not'), "N902: Use the 'not in' "
                                         "operator for collection membership evaluation")

current_file = ""


def readlines(filename):
    """Record the current file being tested."""
    pep8.current_file = filename
    return open(filename).readlines()


def add_nova():
    """Monkey patch in nova guidelines.

    Look for functions that start with nova_  and have arguments
    and add them to pep8 module
    Assumes you know how to write pep8.py checks
    """
    for name, function in globals().items():
        if not inspect.isfunction(function):
            continue
        args = inspect.getargspec(function)[0]
        if args and name.startswith("nova"):
            exec("pep8.%s = %s" % (name, name))


def once_git_check_commit_title():
    """Check git commit messages.

    nova HACKING recommends not referencing a bug or blueprint in first line,
    it should provide an accurate description of the change
    N801
    N802 Title limited to 72 chars
    """
    #Get title of most recent commit

    subp = subprocess.Popen(['git', 'log', '--no-merges', '--pretty=%s', '-1'],
                            stdout=subprocess.PIPE)
    title = subp.communicate()[0]
    if subp.returncode:
        raise Exception("git log failed with code %s" % subp.returncode)

    #From https://github.com/openstack/openstack-ci-puppet
    #       /blob/master/modules/gerrit/manifests/init.pp#L74
    #Changeid|bug|blueprint
    git_keywords = (r'(I[0-9a-f]{8,40})|'
                    '([Bb]ug|[Ll][Pp])[\s\#:]*(\d+)|'
                    '([Bb]lue[Pp]rint|[Bb][Pp])[\s\#:]*([A-Za-z0-9\\-]+)')
    GIT_REGEX = re.compile(git_keywords)

    error = False
    #NOTE(jogo) if match regex but over 3 words, acceptable title
    if GIT_REGEX.search(title) is not None and len(title.split()) <= 3:
        print ("N801: git commit title ('%s') should provide an accurate "
               "description of the change, not just a reference to a bug "
               "or blueprint" % title.strip())
        error = True
        # HACKING.rst recommends commit titles 50 chars or less, but enforces
    # a 72 character limit
    if len(title.decode('utf-8')) > 72:
        print ("N802: git commit title ('%s') should be under 50 chars"
               % title.strip())
        error = True
    return error

imports_on_separate_lines_N301_compliant = r"""
    Imports should usually be on separate lines.

    Okay: import os\nimport sys
    E401: import sys, os

    N301: from subprocess import Popen, PIPE
    Okay: from myclas import MyClass
    Okay: from foo.bar.yourclass import YourClass
    Okay: import myclass
    Okay: import foo.bar.yourclass
    """

if __name__ == "__main__":
    #include nova path
    sys.path.append(os.getcwd())
    #Run once tests (not per line)
    once_error = once_git_check_commit_title()
    #NOVA error codes start with an N
    pep8.SELFTEST_REGEX = re.compile(r'(Okay|[EWN]\d{3}):\s(.*)')
    pep8.ERRORCODE_REGEX = re.compile(r'[EWN]\d{3}')
    add_nova()
    pep8.current_file = current_file
    pep8.readlines = readlines
    pep8.StyleGuide.excluded = excluded
    pep8.StyleGuide.input_dir = input_dir
    # we need to kill this doctring otherwise the self tests fail
    pep8.imports_on_separate_lines.__doc__ = \
        imports_on_separate_lines_N301_compliant

    try:
        pep8._main()
        sys.exit(once_error)
    finally:
        if len(_missingImport) > 0:
            print >> sys.stderr, ("%i imports missing in this test environment"
                                  % len(_missingImport))
