#!/usr/bin/env python
from __future__ import print_function
from __future__ import absolute_import
from contextlib import contextmanager
import logging
import os
import re
import sys
import optparse
import subprocess
import traceback

# check for the venv
from lib import sanity_check
sanity_check.check_venv(__file__)

import lister
from typing import cast, Any, Callable, Dict, Iterator, List, Optional, Tuple

# Exclude some directories and files from lint checking
EXCLUDED_FILES = [
    # Third-party code that doesn't match our style
    "api/integrations/perforce/git_p4.py",
    "puppet/apt/.forge-release",
    "puppet/apt/README.md",
    "static/third",
    # Transifex syncs translation.json files without trailing
    # newlines; there's nothing other than trailing newlines we'd be
    # checking for in these anyway.
    "static/locale",
]

@contextmanager
def bright_red_output():
    # type: () -> Iterator[None]
    # Make the lint output bright red
    sys.stdout.write('\x1B[1;31m')
    sys.stdout.flush()
    try:
        yield
    finally:
        # Restore normal terminal colors
        sys.stdout.write('\x1B[0m')


def check_pyflakes(options, by_lang):
    # type: (Any, Dict[str, List[str]]) -> bool
    if len(by_lang['py']) == 0:
        return False
    failed = False
    pyflakes = subprocess.Popen(['pyflakes'] + by_lang['py'],
                                stdout = subprocess.PIPE,
                                stderr = subprocess.PIPE,
                                universal_newlines = True)

    # pyflakes writes some output (like syntax errors) to stderr. :/
    for pipe in (pyflakes.stdout, pyflakes.stderr):
        assert(pipe is not None) # convince mypy that pipe cannot be None
        for ln in pipe:
            if options.full or not (
                    ('imported but unused' in ln or
                     'redefinition of unused' in ln or
                     # Our ipython startup pythonrc file intentionally imports *
                     ("scripts/lib/pythonrc.py" in ln and
                      " import *' used; unable to detect undefined names" in ln) or
                     # Special dev_settings.py import
                     "from .prod_settings_template import *" in ln or
                     ("settings.py" in ln and
                      ("settings import *' used; unable to detect undefined names" in ln or
                       "may be undefined, or defined from star imports" in ln)) or
                     ("zerver/tornado/ioloop_logging.py" in ln and
                      "redefinition of function 'instrument_tornado_ioloop'" in ln) or
                     ("zephyr_mirror_backend.py:" in ln and
                      "redefinition of unused 'simplejson' from line" in ln))):
                sys.stdout.write(ln)
                failed = True
    return failed


def check_pep8(files):
    # type: (List[str]) -> bool
    failed = False
    ignored_rules = [
        # Each of these rules are ignored for the explained reason.

        # "multiple spaces before operator"
        # There are several typos here, but also several instances that are
        # being used for alignment in dict keys/values using the `dict`
        # constructor. We could fix the alignment cases by switching to the `{}`
        # constructor, but it makes fixing this rule a little less
        # straightforward.
        'E221',

        # 'missing whitespace around arithmetic operator'
        # This should possibly be cleaned up, though changing some of
        # these may make the code less readable.
        'E226',

        # "unexpected spaces around keyword / parameter equals"
        # Many of these should be fixed, but many are also being used for
        # alignment/making the code easier to read.
        'E251',

        # 'at least two spaces before inline comment'
        # This we should probably clean up, but has 800+ instances in
        # conflict (many of them type comments), so fixing this will
        # be a lot of churn.
        'E261',

        # "block comment should start with '#'"
        # These serve to show which lines should be changed in files customized
        # by the user. We could probably resolve one of E265 or E266 by
        # standardizing on a single style for lines that the user might want to
        # change.
        'E265',

        # "too many leading '#' for block comment"
        # Most of these are there for valid reasons.
        'E266',

        # "expected 2 blank lines after class or function definition"
        # Zulip only uses 1 blank line after class/function
        # definitions; the PEP-8 recommendation results in super sparse code.
        'E302', 'E305',

        # "module level import not at top of file"
        # Most of these are there for valid reasons, though there might be a
        # few that could be eliminated.
        'E402',

        # "line too long"
        # Zulip is a bit less strict about line length, and has its
        # own check for this (see max_length)
        'E501',

        # "do not assign a lambda expression, use a def"
        # Fixing these would probably reduce readability in most cases.
        'E731',
    ]
    if len(files) == 0:
        return False
    pep8 = subprocess.Popen(
        ['pycodestyle'] + files + ['--ignore={rules}'.format(rules=','.join(ignored_rules))],
        stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
    for pipe in (pep8.stdout, pep8.stderr):
        assert(pipe is not None) # convince mypy that pipe cannot be None
        for ln in pipe:
            sys.stdout.write(ln)
            failed = True
    return failed


def run_parallel(lint_functions):
    # type: (Dict[str, Callable[[], int]]) -> bool
    pids = []
    for name, func in lint_functions.items():
        pid = os.fork()
        if pid == 0:
            logging.info("start " + name)
            result = func()
            logging.info("finish " + name)
            sys.stdout.flush()
            sys.stderr.flush()
            os._exit(result)
        pids.append(pid)
    failed = False

    for pid in pids:
        (_, status) = os.waitpid(pid, 0)
        if status != 0:
            failed = True
    return failed

def build_custom_checkers(by_lang):
    # type: (Dict[str, List[str]]) -> Tuple[Callable[[], bool], Callable[[], bool]]
    RuleList = List[Dict[str, Any]]

    def custom_check_file(fn, rules, skip_rules=None, max_length=None):
        # type: (str, RuleList, Optional[Any], Optional[int]) -> bool
        failed = False
        lineFlag = False
        for i, line in enumerate(open(fn)):
            line_newline_stripped = line.strip('\n')
            line_fully_stripped = line_newline_stripped.strip()
            skip = False
            lineFlag = True
            for rule in skip_rules or []:
                if re.match(rule, line):
                    skip = True
            if skip:
                continue
            for rule in rules:
                exclude_list = rule.get('exclude', set())
                if fn in exclude_list or os.path.dirname(fn) in exclude_list:
                    continue
                exclude_list = rule.get('exclude_line', set())
                if (fn, line_fully_stripped) in exclude_list:
                    continue
                if rule.get("include_only"):
                    found = False
                    for item in rule.get("include_only", set()):
                        if item in fn:
                            found = True
                    if not found:
                        continue
                try:
                    line_to_check = line_fully_stripped
                    if rule.get('strip') is not None:
                        if rule['strip'] == '\n':
                            line_to_check = line_newline_stripped
                        else:
                            raise Exception("Invalid strip rule")
                    if re.search(rule['pattern'], line_to_check):
                        sys.stdout.write(rule['description'] + ' at %s line %s:\n' % (fn, i+1))
                        print(line)
                        failed = True
                except Exception:
                    print("Exception with %s at %s line %s" % (rule['pattern'], fn, i+1))
                    traceback.print_exc()
            if isinstance(line, bytes):
                line_length = len(line.decode("utf-8"))
            else:
                line_length = len(line)
            if (max_length is not None and line_length > max_length and
                '# type' not in line and 'test' not in fn and 'example' not in fn and
                not re.match("\[[ A-Za-z0-9_:,&()-]*\]: http.*", line) and
                    "#ignorelongline" not in line and 'migrations' not in fn):
                print("Line too long (%s) at %s line %s: %s" % (len(line), fn, i+1, line_newline_stripped))
                failed = True
            lastLine = line
        if lineFlag and '\n' not in lastLine:
            print("No newline at the end of file.  Fix with `sed -i '$a\\' %s`" % (fn,))
            failed = True
        return failed

    whitespace_rules = [
        # This linter should be first since bash_rules depends on it.
        {'pattern': '\s+$',
         'strip': '\n',
         'description': 'Fix trailing whitespace'},
        {'pattern': '\t',
         'strip': '\n',
         'exclude': set(['zerver/lib/bugdown/codehilite.py',
                         'tools/travis/success-http-headers.txt']),
         'description': 'Fix tab-based whitespace'},
    ]  # type: RuleList
    markdown_whitespace_rules = list([rule for rule in whitespace_rules if rule['pattern'] != '\s+$']) + [
        # Two spaces trailing a line with other content is okay--it's a markdown line break.
        # This rule finds one space trailing a non-space, three or more trailing spaces, and
        # spaces on an empty line.
        {'pattern': '((?<!\s)\s$)|(\s\s\s+$)|(^\s+$)',
         'strip': '\n',
         'description': 'Fix trailing whitespace'},
        {'pattern': '^#+[A-Za-z0-9]',
         'strip': '\n',
         'description': 'Missing space after # in heading'},
    ]  # type: RuleList
    js_rules = cast(RuleList, [
        {'pattern': '[^_]function\(',
         'description': 'The keyword "function" should be followed by a space'},
        {'pattern': '.*blueslip.warning\(.*',
         'description': 'The module blueslip has no function warning, try using blueslip.warn'},
        {'pattern': '[)]{$',
         'description': 'Missing space between ) and {'},
        {'pattern': '["\']json/',
         'description': 'Relative URL for JSON route not supported by i18n'},
        # This rule is constructed with + to avoid triggering on itself
        {'pattern': " =" + '[^ =>~"]',
         'description': 'Missing whitespace after "="'},
        {'pattern': '^[ ]*//[A-Za-z0-9]',
         'description': 'Missing space after // in comment'},
        {'pattern': 'if[(]',
         'description': 'Missing space between if and ('},
        {'pattern': 'else{$',
         'description': 'Missing space between else and {'},
        {'pattern': '^else {$',
         'description': 'Write JS else statements on same line as }'},
        {'pattern': '^else if',
         'description': 'Write JS else statements on same line as }'},
        {'pattern': 'console[.][a-z]',
         'exclude': set(['static/js/blueslip.js',
                         'frontend_tests/zjsunit',
                         'frontend_tests/casper_lib/common.js',
                         'frontend_tests/node_tests',
                         'static/js/debug.js']),
         'description': 'console.log and similar should not be used in webapp'},
        {'pattern': 'i18n[.]t',
         'include_only': set(['static/js/portico']),
         'description': 'i18n.t is not available in portico pages yet'},
        {'pattern': '[.]text\(["\'][a-zA-Z]',
         'description': 'Strings passed to $().text should be wrapped in i18n.t() for internationalization'},
        {'pattern': 'compose_error\(["\']',
         'exclude': set(['tools/lint']),
         'description': 'Argument to compose_error should be a literal string enclosed '
                        'by i18n.t()'},
        {'pattern': 'ui.report_success\(',
         'exclude': set(['tools/lint']),
         'description': 'Deprecated function, use ui_report.success.'},
        {'pattern': 'report.success\(["\']',
         'exclude': set(['tools/lint']),
         'description': 'Argument to report_success should be a literal string enclosed '
                        'by i18n.t()'},
        {'pattern': 'ui.report_error\(',
         'exclude': set(['tools/lint']),
         'description': 'Deprecated function, use ui_report.error.'},
        {'pattern': 'report.error\(["\']',
         'exclude': set(['tools/lint']),
         'description': 'Argument to report_error should be a literal string enclosed '
                        'by i18n.t()'},
    ]) + whitespace_rules
    python_rules = cast(RuleList, [
        {'pattern': '^(?!#)@login_required',
         'description': '@login_required is unsupported; use @zulip_login_required'},
        {'pattern': '".*"%\([a-z_].*\)?$',
         'description': 'Missing space around "%"'},
        {'pattern': "'.*'%\([a-z_].*\)?$",
         'exclude': set(['tools/lint',
                         'analytics/lib/counts.py',
                         'analytics/tests/test_counts.py',
                         ]),
         'exclude_line': set([
             ('zerver/views/users.py',
              "return json_error(_(\"Email '%(email)s' not allowed for realm '%(realm)s'\") %"),
             ('zproject/settings.py',
              "'format': '%(asctime)s %(levelname)-8s %(message)s'"),
         ]),
         'description': 'Missing space around "%"'},
        # This rule is constructed with + to avoid triggering on itself
        {'pattern': " =" + '[^ =>~"]',
         'description': 'Missing whitespace after "="'},
        {'pattern': '":\w[^"]*$',
         'description': 'Missing whitespace after ":"'},
        {'pattern': "':\w[^']*$",
         'description': 'Missing whitespace after ":"'},
        {'pattern': "^\s+[#]\w",
         'strip': '\n',
         'description': 'Missing whitespace after "#"'},
        {'pattern': "assertEquals[(]",
         'description': 'Use assertEqual, not assertEquals (which is deprecated).'},
        {'pattern': "== None",
         'exclude': 'tools/lint',
         'description': 'Use `is None` to check whether something is None'},
        {'pattern': "type:[(]",
         'description': 'Missing whitespace after ":" in type annotation'},
        {'pattern': "# type [(]",
         'description': 'Missing : after type in type annotation'},
        {'pattern': "#type",
         'exclude': 'tools/lint',
         'description': 'Missing whitespace after "#" in type annotation'},
        {'pattern': 'if[(]',
         'description': 'Missing space between if and ('},
        {'pattern': ", [)]",
         'description': 'Unnecessary whitespace between "," and ")"'},
        {'pattern': "%  [(]",
         'description': 'Unnecessary whitespace between "%" and "("'},
        # This next check could have false positives, but it seems pretty
        # rare; if we find any, they can be added to the exclude list for
        # this rule.
        {'pattern': ' % [a-zA-Z0-9_.]*\)?$',
         'exclude_line': set([
             ('tools/tests/test_template_parser.py', '{% foo'),
         ]),
         'description': 'Used % comprehension without a tuple'},
        {'pattern': '.*%s.* % \([a-zA-Z0-9_.]*\)$',
         'description': 'Used % comprehension without a tuple'},
        {'pattern': 'django.utils.translation',
         'include_only': set(['test']),
         'description': 'Test strings should not be tagged for translationx'},
        {'pattern': 'json_success\({}\)',
         'description': 'Use json_success() to return nothing'},
        # To avoid json_error(_variable) and json_error(_(variable))
        {'pattern': '\Wjson_error\(_\(?\w+\)',
         'exclude': set(['tools/lint', 'zerver/tests']),
         'description': 'Argument to json_error should be a literal string enclosed by _()'},
        {'pattern': '\Wjson_error\([\'"].+[),]$',
         'exclude': set(['tools/lint', 'zerver/tests']),
         'exclude_line': set([
             # We don't want this string tagged for translation.
             ('zerver/views/compatibility.py', 'return json_error("Client is too old")'),
         ]),
         'description': 'Argument to json_error should a literal string enclosed by _()'},
        # To avoid JsonableError(_variable) and JsonableError(_(variable))
        {'pattern': '\WJsonableError\(_\(?\w.+\)',
         'exclude': set(['tools/lint', 'zerver/tests']),
         'description': 'Argument to JsonableError should be a literal string enclosed by _()'},
        {'pattern': '\WJsonableError\(["\'].+\)',
         'exclude': set(['tools/lint', 'zerver/tests']),
         'description': 'Argument to JsonableError should be a literal string enclosed by _()'},
        {'pattern': '([a-zA-Z0-9_]+)=REQ\([\'"]\\1[\'"]',
         'description': 'REQ\'s first argument already defaults to parameter name'},
        {'pattern': 'self\.client\.(get|post|patch|put|delete)',
         'exclude': set(['zilencer/tests.py']),
         'description': \
         '''Do not call self.client directly for put/patch/post/get.
    See WRAPPER_COMMENT in test_helpers.py for details.
    '''},
        # Directly fetching Message objects in e.g. views code is often a security bug.
        {'pattern': '[^r][M]essage.objects.get',
         'exclude': set(["zerver/tests", "zerver/worker/queue_processors.py"]),
         'description': 'Please use access_message() to fetch Message objects',
         },
        {'pattern': '[S]tream.objects.get',
         'include_only': set(["zerver/views/"]),
         'description': 'Please use access_stream_by_*() to fetch Stream objects',
         },
        {'pattern': 'get_stream[(]',
         'include_only': set(["zerver/views/", "zerver/lib/actions.py"]),
         # messages.py needs to support accessing invite-only streams
         # that you are no longer subscribed to, so need get_stream.
         'exclude': set(['zerver/views/messages.py']),
         'exclude_line': set([
             # This is a check for whether a stream rename is invalid because it already exists
             ('zerver/lib/actions.py', 'get_stream(new_name, stream.realm)'),
             # This one in check_message is kinda terrible, since it's
             # how most instances are written, but better to exclude something than nothing
             ('zerver/lib/actions.py', 'stream = get_stream(stream_name, realm)'),
             ('zerver/lib/actions.py', 'get_stream(signups_stream, admin_realm)'),
         ]),
         'description': 'Please use access_stream_by_*() to fetch Stream objects',
         },
        {'pattern': '[S]tream.objects.filter',
         'include_only': set(["zerver/views/"]),
         'description': 'Please use access_stream_by_*() to fetch Stream objects',
         },
        {'pattern': '^from (zerver|analytics|confirmation)',
         'include_only': set(["/migrations/"]),
         'exclude': set(['zerver/migrations/0032_verify_all_medium_avatar_images.py',
                         'zerver/migrations/0041_create_attachments_for_old_messages.py',
                         'zerver/migrations/0060_move_avatars_to_be_uid_based.py']),
         'description': "Don't import models or other code in migrations; see docs/schema-migrations.md",
         },
        {'pattern': 'datetime[.](now|utcnow)',
         'include_only': set(["zerver/", "analytics/"]),
         'description': "Don't use datetime in backend code.\n"
         "See https://zulip.readthedocs.io/en/latest/code-style.html#naive-datetime-objects",
         },
        {'pattern': 'render_to_response\(',
         'description': "Use render() instead of render_to_response().",
         'exclude': set(['tools/lint']),
         },
        # This rule might give false positives in virtualenv setup files which should be excluded,
        # and comments which should be rewritten to avoid use of "python2", "python3", etc.
        {'pattern': 'python[23]',
         'exclude': set(['tools/lib/provision.py',
                         'tools/setup/setup_venvs.py',
                         'scripts/lib/setup_venv.py',
                         'tools/lint']),
         'description': 'Explicit python invocations should not include a version'}
    ]) + whitespace_rules
    bash_rules = [
        {'pattern': '#!.*sh [-xe]',
         'description': 'Fix shebang line with proper call to /usr/bin/env for Bash path, change -x|-e switches'
                        ' to set -x|set -e'},
    ] + whitespace_rules[0:1]  # type: RuleList
    css_rules = cast(RuleList, [
        {'pattern': '^[^:]*:\S[^:]*;$',
         'description': "Missing whitespace after : in CSS"},
        {'pattern': '[a-z]{',
         'description': "Missing whitespace before '{' in CSS."},
        {'pattern': 'https://',
         'description': "Zulip CSS should have no dependencies on external resources"},
        {'pattern': '^[ ][ ][a-zA-Z0-9]',
         'description': "Incorrect 2-space indentation in CSS",
         'exclude': set(['static/third/thirdparty-fonts.css']),
         'strip': '\n'},
        {'pattern': '{\w',
         'description': "Missing whitespace after '{' in CSS (should be newline)."},
        {'pattern': ' thin[; ]',
         'description': "thin CSS attribute is under-specified, please use 1px."},
        {'pattern': ' medium[; ]',
         'description': "medium CSS attribute is under-specified, please use pixels."},
        {'pattern': ' thick[; ]',
         'description': "thick CSS attribute is under-specified, please use pixels."},
    ]) + whitespace_rules  # type: RuleList
    prose_style_rules = [
        {'pattern': '[^\/\#\-\"]([jJ]avascript)',  # exclude usage in hrefs/divs
         'description': "javascript should be spelled JavaScript"},
        {'pattern': '[^\/\-\.\"\'\_\=\>]([gG]ithub)[^\.\-\_\"\<]',  # exclude usage in hrefs/divs
         'description': "github should be spelled GitHub"},
        {'pattern': '[oO]rganisation',  # exclude usage in hrefs/divs
         'description': "Organization is spelled with a z"},
        {'pattern': '!!! warning',
         'description': "!!! warning is invalid; it's spelled '!!! warn'"},
    ]  # type: RuleList
    html_rules = whitespace_rules + prose_style_rules + [
        {'pattern': 'placeholder="[^{]',
         'description': "`placeholder` value should be translatable.",
         'exclude_line': [('templates/zerver/register.html', 'placeholder="acme"'),
                          ('templates/zerver/register.html', 'placeholder="Acme"'),
                          ('static/templates/settings/realm-domains-modal.handlebars',
                           '<td><input type="text" class="new-realm-domain" placeholder="acme.com"></input></td>')],
         'exclude': set(["static/templates/settings/emoji-settings-admin.handlebars",
                         "static/templates/settings/realm-filter-settings-admin.handlebars",
                         "static/templates/settings/bot-settings.handlebars"])},
        {'pattern': "placeholder='[^{]",
         'description': "`placeholder` value should be translatable."},
        {'pattern': 'script src="http',
         'description': "Don't directly load dependencies from CDNs.  See docs/front-end-build-process.md"},
        {'pattern': "title='[^{]",
         'description': "`title` value should be translatable."},
        {'pattern': 'title="[^{\:]',
         'exclude_line': set([
             ('templates/zerver/markdown_help.html',
              '<td><img alt=":heart:" class="emoji" src="/static/generated/emoji/images/emoji/heart.png" title=":heart:" /></td>')
         ]),
         'exclude': set(["templates/zerver/emails"]),
         'description': "`title` value should be translatable."},
        {'pattern': '\Walt=["\'][^{"\']',
         'description': "alt argument should be enclosed by _() or it should be an empty string.",
         'exclude': set(['tools/lint',
                         'static/templates/settings/display-settings.handlebars',
                         'templates/zerver/keyboard_shortcuts.html',
                         'templates/zerver/markdown_help.html']),
         },
        {'pattern': '\Walt=["\']{{ ?["\']',
         'description': "alt argument should be enclosed by _().",
         'exclude': set(['tools/lint']),
         },
    ]  # type: RuleList
    handlebars_rules = html_rules + [
        {'pattern': "[<]script",
         'description': "Do not use inline <script> tags here; put JavaScript in static/js instead."},
        {'pattern': "{{t '.*' }}[\.\?!]",
         'description': "Period should be part of the translatable string."},
        {'pattern': '{{t ".*" }}[\.\?!]',
         'description': "Period should be part of the translatable string."},
        {'pattern': "{{/tr}}[\.\?!]",
         'description': "Period should be part of the translatable string."},
    ]
    jinja2_rules = html_rules + [
        {'pattern': "{% endtrans %}[\.\?!]",
         'description': "Period should be part of the translatable string."},
        {'pattern': "{{ _(.+) }}[\.\?!]",
         'description': "Period should be part of the translatable string."},
    ]
    json_rules = []  # type: RuleList # fix newlines at ends of files
    # It is okay that json_rules is empty, because the empty list
    # ensures we'll still check JSON files for whitespace.
    markdown_rules = markdown_whitespace_rules + prose_style_rules + [
        {'pattern': '\[(?P<url>[^\]]+)\]\((?P=url)\)',
         'description': 'Linkified markdown URLs should use cleaner <http://example.com> syntax.'}
    ]
    help_markdown_rules = markdown_rules + [
        {'pattern': '[a-z][.][A-Z]',
         'description': "Likely missing space after end of sentence"},
        {'pattern': '[rR]ealm',
         'description': "Realms are referred to as Organizations in user-facing docs."},
    ]
    txt_rules = whitespace_rules

    def check_custom_checks_py():
        # type: () -> bool
        failed = False

        for fn in by_lang['py']:
            if custom_check_file(fn, python_rules, max_length=140):
                failed = True
        return failed

    def check_custom_checks_nonpy():
        # type: () -> bool
        failed = False

        for fn in by_lang['js']:
            if custom_check_file(fn, js_rules):
                failed = True

        for fn in by_lang['sh']:
            if custom_check_file(fn, bash_rules):
                failed = True

        for fn in by_lang['css']:
            if custom_check_file(fn, css_rules):
                failed = True

        for fn in by_lang['handlebars']:
            if custom_check_file(fn, handlebars_rules):
                failed = True

        for fn in by_lang['html']:
            if custom_check_file(fn, jinja2_rules):
                failed = True

        for fn in by_lang['json']:
            if custom_check_file(fn, json_rules):
                failed = True

        markdown_docs_length_exclude = {
            "api/bots/converter/readme.md",
            "docs/bots-guide.md",
            "docs/dev-env-first-time-contributors.md",
            "docs/webhook-walkthrough.md",
            "docs/life-of-a-request.md",
            "docs/logging.md",
            "docs/migration-renumbering.md",
            "docs/readme-symlink.md",
            "README.md",
            "zerver/webhooks/helloworld/doc.md",
            "zerver/webhooks/solano/doc.md",
            "zerver/webhooks/trello/doc.md",
            "zerver/webhooks/papertrail/doc.md",
        }
        for fn in by_lang['md']:
            max_length = None
            if fn not in markdown_docs_length_exclude:
                max_length = 120
            rules = markdown_rules
            if fn.startswith("templates/zerver/help"):
                rules = help_markdown_rules
            if custom_check_file(fn, rules, max_length=max_length):
                failed = True

        for fn in by_lang['txt'] + by_lang['text']:
            if custom_check_file(fn, txt_rules):
                failed = True

        for fn in by_lang['yaml']:
            if custom_check_file(fn, txt_rules):
                failed = True

        return failed

    return (check_custom_checks_py, check_custom_checks_nonpy)

def run():
    # type: () -> None
    parser = optparse.OptionParser()
    parser.add_option('--force', default=False,
                      action="store_true",
                      help='Run tests despite possible problems.')
    parser.add_option('--full',
                      action='store_true',
                      help='Check some things we typically ignore')
    parser.add_option('--pep8',
                      action='store_true',
                      help='Run the pep8 checker')
    parser.add_option('--no-gitlint',
                      action='store_true',
                      help='Disable gitlint')
    parser.add_option('--modified', '-m',
                      action='store_true',
                      help='Only check modified files')
    parser.add_option('--verbose', '-v',
                      action='store_true',
                      help='Print verbose timing output')
    (options, args) = parser.parse_args()

    tools_dir = os.path.dirname(os.path.abspath(__file__))
    root_dir = os.path.dirname(tools_dir)
    sys.path.insert(0, root_dir)

    from tools.lib.test_script import (
        get_provisioning_status,
    )

    os.chdir(root_dir)

    if not options.force:
        ok, msg = get_provisioning_status()
        if not ok:
            print(msg)
            print('If you really know what you are doing, use --force to run anyway.')
            sys.exit(1)

    by_lang = cast(Dict[str, List[str]],
                   lister.list_files(args, modified_only=options.modified,
                                     ftypes=['py', 'sh', 'js', 'pp', 'css', 'handlebars',
                                             'html', 'json', 'md', 'txt', 'text', 'yaml'],
                                     use_shebang=True, group_by_ftype=True, exclude=EXCLUDED_FILES))

    # Invoke the appropriate lint checker for each language,
    # and also check files for extra whitespace.

    logging.basicConfig(format="%(asctime)s %(message)s")
    logger = logging.getLogger()
    if options.verbose:
        logger.setLevel(logging.INFO)
    else:
        logger.setLevel(logging.WARNING)

    check_custom_checks_py, check_custom_checks_nonpy = build_custom_checkers(by_lang)

    lint_functions = {}  # type: Dict[str, Callable[[], int]]

    def lint(func):
        # type: (Callable[[], int]) -> Callable[[], int]
        lint_functions[func.__name__] = func
        return func

    def external_linter(name, command, target_langs=[]):
        # type: (str, List[str], List[str]) -> None
        def run_linter():
            # type: () -> int
            if len(target_langs) == 0:
                return subprocess.call(command)
            targets = [target for lang in target_langs for target in by_lang[lang]]
            if len(targets) == 0:
                return 0
            return subprocess.call(command + targets)
        lint_functions[name] = run_linter

    with bright_red_output():
        external_linter('add_class', ['tools/find-add-class'])
        external_linter('css', ['tools/check-css'], ['css'])
        external_linter('eslint', ['node', 'node_modules/.bin/eslint', '--quiet'], ['js'])
        external_linter('tslint', ['node', 'node_modules/.bin/tslint', '-c',
                                   'static/ts/tslint.json'], ['ts'])
        external_linter('puppet', ['puppet', 'parser', 'validate'], ['pp'])
        external_linter('templates', ['tools/check-templates'], ['handlebars', 'html'])
        external_linter('urls', ['tools/check-urls'])

        # gitlint disabled until we can stabilize it more
#        if not options.no_gitlint:
#            external_linter('commit_messages', ['tools/commit-message-lint'])

        @lint
        def custom_py():
            # type: () -> int
            failed = check_custom_checks_py()
            return 1 if failed else 0

        @lint
        def custom_nonpy():
            # type: () -> int
            failed = check_custom_checks_nonpy()
            return 1 if failed else 0

        @lint
        def pyflakes():
            # type: () -> int
            failed = check_pyflakes(options, by_lang)
            return 1 if failed else 0

        if options.pep8:
            @lint
            def pep8():
                # type: () -> int
                failed = check_pep8(by_lang['py'])
                return 1 if failed else 0

        failed = run_parallel(lint_functions)

    sys.exit(1 if failed else 0)

if __name__ == '__main__':
    run()