#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Check for stylistic and formal issues in .rst and .py
# files included in the documentation.
#
# 01/2009, Georg Brandl

# TODO: - wrong versions in versionadded/changed
#       - wrong markup after versionchanged directive

import os
import re
import sys
import getopt
from string import ascii_letters
from os.path import join, splitext, abspath, exists
from collections import defaultdict

directives = [
    # standard docutils ones
    'admonition', 'attention', 'caution', 'class', 'compound', 'container',
    'contents', 'csv-table', 'danger', 'date', 'default-role', 'epigraph',
    'error', 'figure', 'footer', 'header', 'highlights', 'hint', 'image',
    'important', 'include', 'line-block', 'list-table', 'meta', 'note',
    'parsed-literal', 'pull-quote', 'raw', 'replace',
    'restructuredtext-test-directive', 'role', 'rubric', 'sectnum', 'sidebar',
    'table', 'target-notes', 'tip', 'title', 'topic', 'unicode', 'warning',
    # Sphinx and Python docs custom ones
    'acks', 'attribute', 'autoattribute', 'autoclass', 'autodata',
    'autoexception', 'autofunction', 'automethod', 'automodule',
    'availability', 'centered', 'cfunction', 'class', 'classmethod', 'cmacro',
    'cmdoption', 'cmember', 'code-block', 'confval', 'cssclass', 'ctype',
    'currentmodule', 'cvar', 'data', 'decorator', 'decoratormethod',
    'deprecated-removed', 'deprecated(?!-removed)', 'describe', 'directive',
    'doctest', 'envvar', 'event', 'exception', 'function', 'glossary',
    'highlight', 'highlightlang', 'impl-detail', 'index', 'literalinclude',
    'method', 'miscnews', 'module', 'moduleauthor', 'opcode', 'pdbcommand',
    'productionlist', 'program', 'role', 'sectionauthor', 'seealso',
    'sourcecode', 'staticmethod', 'tabularcolumns', 'testcode', 'testoutput',
    'testsetup', 'toctree', 'todo', 'todolist', 'versionadded',
    'versionchanged'
]

roles = [
    "(?<!py):class:",
    "(?<!:c|py):func:",
    "(?<!py):meth:",
    "(?<!:py):mod:",
    ":exc:",
    ":issue:",
    ":attr:",
    ":c:func:",
    ":ref:",
    ":const:",
    ":term:",
    "(?<!:c|py):data:",
    ":keyword:",
    ":file:",
    ":pep:",
    ":c:type:",
    ":c:member:",
    ":option:",
    ":rfc:",
    ":envvar:",
    ":c:data:",
    ":source:",
    ":mailheader:",
    ":program:",
    ":c:macro:",
    ":dfn:",
    ":kbd:",
    ":command:",
    ":mimetype:",
    ":opcode:",
    ":manpage:",
    ":py:data:",
    ":RFC:",
    ":pdbcmd:",
    ":abbr:",
    ":samp:",
    ":token:",
    ":PEP:",
    ":sup:",
    ":py:class:",
    ":menuselection:",
    ":doc:",
    ":sub:",
    ":py:meth:",
    ":newsgroup:",
    ":code:",
    ":py:func:",
    ":makevar:",
    ":guilabel:",
    ":title-reference:",
    ":py:mod:",
    ":download:",
    ":2to3fixer:",
]

all_directives = "(" + "|".join(directives) + ")"
all_roles = "(" + "|".join(roles) + ")"

# Find comments that looks like a directive, like:
# .. versionchanged 3.6
# or
# .. versionchanged: 3.6
# as it should be:
# .. versionchanged:: 3.6
seems_directive_re = re.compile(r"(?<!\.)\.\. %s([^a-z:]|:(?!:))" % all_directives)

# Find directive prefixed with three dots instead of two, like:
# ... versionchanged:: 3.6
# instead of:
# .. versionchanged:: 3.6
three_dot_directive_re = re.compile(r"\.\.\. %s::" % all_directives)

# Find role used with double backticks instead of simple backticks like:
# :const:``None``
# instead of:
# :const:`None`
double_backtick_role = re.compile(r"(?<!``)%s``" % all_roles)


# Find role used with no backticks instead of simple backticks like:
# :const:None
# instead of:
# :const:`None`
role_with_no_backticks = re.compile(r"%s[^` ]" % all_roles)

# Find role glued with another word like:
# the:c:func:`PyThreadState_LeaveTracing` function.
# instad of:
# the :c:func:`PyThreadState_LeaveTracing` function.
role_glued_with_word = re.compile(r"[a-zA-Z]%s" % all_roles)

default_role_re = re.compile(r"(^| )`\w([^`]*?\w)?`($| )")
leaked_markup_re = re.compile(r"[a-z]::\s|`|\.\.\s*\w+:")


checkers = {}

checker_props = {'severity': 1, 'falsepositives': False}


def checker(*suffixes, **kwds):
    """Decorator to register a function as a checker."""
    def deco(func):
        for suffix in suffixes:
            checkers.setdefault(suffix, []).append(func)
        for prop in checker_props:
            setattr(func, prop, kwds.get(prop, checker_props[prop]))
        return func
    return deco


@checker('.py', severity=4)
def check_syntax(fn, lines):
    """Check Python examples for valid syntax."""
    code = ''.join(lines)
    if '\r' in code:
        if os.name != 'nt':
            yield 0, '\\r in code file'
        code = code.replace('\r', '')
    try:
        compile(code, fn, 'exec')
    except SyntaxError as err:
        yield err.lineno, 'not compilable: %s' % err


@checker('.rst', severity=2)
def check_suspicious_constructs(fn, lines):
    """Check for suspicious reST constructs."""
    inprod = False
    for lno, line in enumerate(lines, start=1):
        if seems_directive_re.search(line):
            yield lno, "comment seems to be intended as a directive"
        if three_dot_directive_re.search(line):
            yield lno, "directive should start with two dots, not three."
        if double_backtick_role.search(line):
            yield lno, "role use a single backtick, double backtick found."
        if role_with_no_backticks.search(line):
            yield lno, "role use a single backtick, no backtick found."
        if role_glued_with_word.search(line):
            yield lno, "missing space before role"
        if ".. productionlist::" in line:
            inprod = True
        elif not inprod and default_role_re.search(line):
            yield lno, "default role used"
        elif inprod and not line.strip():
            inprod = False


@checker('.py', '.rst')
def check_whitespace(fn, lines):
    """Check for whitespace and line length issues."""
    for lno, line in enumerate(lines):
        if '\r' in line:
            yield lno+1, '\\r in line'
        if '\t' in line:
            yield lno+1, 'OMG TABS!!!1'
        if line[:-1].rstrip(' \t') != line[:-1]:
            yield lno+1, 'trailing whitespace'


@checker('.rst', severity=0)
def check_line_length(fn, lines):
    """Check for line length; this checker is not run by default."""
    for lno, line in enumerate(lines):
        if len(line) > 81:
            # don't complain about tables, links and function signatures
            if line.lstrip()[0] not in '+|' and \
               'http://' not in line and \
               not line.lstrip().startswith(('.. function',
                                             '.. method',
                                             '.. cfunction')):
                yield lno+1, "line too long"


@checker('.html', severity=2, falsepositives=True)
def check_leaked_markup(fn, lines):
    """Check HTML files for leaked reST markup; this only works if
    the HTML files have been built.
    """
    for lno, line in enumerate(lines):
        if leaked_markup_re.search(line):
            yield lno+1, 'possibly leaked markup: %r' % line


def hide_literal_blocks(lines):
    """Tool to remove literal blocks from given lines.

    It yields empty lines in place of blocks, so line numbers are
    still meaningful.
    """
    in_block = False
    for line in lines:
        if line.endswith("::\n"):
            in_block = True
        elif in_block:
            if line == "\n" or line.startswith(" "):
                line = "\n"
            else:
                in_block = False
        yield line


def type_of_explicit_markup(line):
    if re.match(fr'\.\. {all_directives}::', line):
        return 'directive'
    if re.match(r'\.\. \[[0-9]+\] ', line):
        return 'footnote'
    if re.match(r'\.\. \[[^\]]+\] ', line):
        return 'citation'
    if re.match(r'\.\. _.*[^_]: ', line):
        return 'target'
    if re.match(r'\.\. \|[^\|]*\| ', line):
        return 'substitution_definition'
    return 'comment'


def hide_comments(lines):
    """Tool to remove comments from given lines.

    It yields empty lines in place of comments, so line numbers are
    still meaningful.
    """
    in_multiline_comment = False
    for line in lines:
        if line == "..\n":
            in_multiline_comment = True
        elif in_multiline_comment:
            if line == "\n" or line.startswith(" "):
                line = "\n"
            else:
                in_multiline_comment = False
        if line.startswith(".. ") and type_of_explicit_markup(line) == 'comment':
            line = "\n"
        yield line



@checker(".rst", severity=2)
def check_missing_surrogate_space_on_plural(fn, lines):
    r"""Check for missing 'backslash-space' between a code sample a letter.

    Good: ``Point``\ s
    Bad: ``Point``s
    """
    in_code_sample = False
    check_next_one = False
    for lno, line in enumerate(hide_comments(hide_literal_blocks(lines))):
        tokens = line.split("``")
        for token_no, token in enumerate(tokens):
            if check_next_one:
                if token[0] in ascii_letters:
                    yield lno + 1, f"Missing backslash-space between code sample and {token!r}."
                check_next_one = False
            if token_no == len(tokens) - 1:
                continue
            if in_code_sample:
                check_next_one = True
            in_code_sample = not in_code_sample

def main(argv):
    usage = '''\
Usage: %s [-v] [-f] [-s sev] [-i path]* [path]

Options:  -v       verbose (print all checked file names)
          -f       enable checkers that yield many false positives
          -s sev   only show problems with severity >= sev
          -i path  ignore subdir or file path
''' % argv[0]
    try:
        gopts, args = getopt.getopt(argv[1:], 'vfs:i:')
    except getopt.GetoptError:
        print(usage)
        return 2

    verbose = False
    severity = 1
    ignore = []
    falsepos = False
    for opt, val in gopts:
        if opt == '-v':
            verbose = True
        elif opt == '-f':
            falsepos = True
        elif opt == '-s':
            severity = int(val)
        elif opt == '-i':
            ignore.append(abspath(val))

    if len(args) == 0:
        path = '.'
    elif len(args) == 1:
        path = args[0]
    else:
        print(usage)
        return 2

    if not exists(path):
        print('Error: path %s does not exist' % path)
        return 2

    count = defaultdict(int)

    for root, dirs, files in os.walk(path):
        # ignore subdirs in ignore list
        if abspath(root) in ignore:
            del dirs[:]
            continue

        for fn in files:
            fn = join(root, fn)
            if fn[:2] == './':
                fn = fn[2:]

            # ignore files in ignore list
            if abspath(fn) in ignore:
                continue

            ext = splitext(fn)[1]
            checkerlist = checkers.get(ext, None)
            if not checkerlist:
                continue

            if verbose:
                print('Checking %s...' % fn)

            try:
                with open(fn, 'r', encoding='utf-8') as f:
                    lines = list(f)
            except (IOError, OSError) as err:
                print('%s: cannot open: %s' % (fn, err))
                count[4] += 1
                continue

            for checker in checkerlist:
                if checker.falsepositives and not falsepos:
                    continue
                csev = checker.severity
                if csev >= severity:
                    for lno, msg in checker(fn, lines):
                        print('[%d] %s:%d: %s' % (csev, fn, lno, msg))
                        count[csev] += 1
    if verbose:
        print()
    if not count:
        if severity > 1:
            print('No problems with severity >= %d found.' % severity)
        else:
            print('No problems found.')
    else:
        for severity in sorted(count):
            number = count[severity]
            print('%d problem%s with severity %d found.' %
                  (number, number > 1 and 's' or '', severity))
    return int(bool(count))


if __name__ == '__main__':
    sys.exit(main(sys.argv))