#!/usr/bin/env python
#
# Natural Language Toolkit: Deprecated Function & Class Finder
#
# Copyright (C) 2001-2024 NLTK Project
# Author: Edward Loper <edloper@gmail.com>
# URL: <https://www.nltk.org/>
# For license information, see LICENSE.TXT


"""
This command-line tool takes a list of python files or directories,
and searches them for calls to deprecated NLTK functions, or uses of
deprecated NLTK classes.  For each use of a deprecated object it
finds, it will print out a warning containing the offending line, as
well as its line number and containing file name.  If the terminal has
color support (and if epydoc is installed), then the offending
identifier will be highlighted in red.
"""

######################################################################
# Imports
######################################################################

import os
import re
import sys
import textwrap
import tokenize
from doctest import DocTestParser, register_optionflag

from cStringIO import StringIO

import nltk.corpus
from nltk import defaultdict

######################################################################
# Regexps
######################################################################

#: A little over-simplified, but it'll do.
STRING_PAT = (
    r"\s*[ur]{0,2}(?:"
    r'"""[\s\S]*?"""|'
    '"[^"\n]+?"|'
    r"'''[\s\S]*?'''|"
    "'[^'\n]+?'"
    r")\s*"
)
STRING_RE = re.compile(STRING_PAT)

STRINGS_PAT = f"{STRING_PAT}(?:[+]?{STRING_PAT})*"
STRINGS_RE = re.compile(STRINGS_PAT)

# Define a regexp to search for deprecated definitions.
DEPRECATED_DEF_PAT = (
    rf"^\s*@deprecated\s*\(\s*({STRINGS_PAT})\s*\)\s*\n+"
    + r"\s*def\s*(\w+).*"
    + r"|"
    + r"^\s*class\s+(\w+)\s*\(.*Deprecated.*\):\s*"
)
DEPRECATED_DEF_RE = re.compile(DEPRECATED_DEF_PAT, re.MULTILINE)

CORPUS_READ_METHOD_RE = re.compile(
    r"({})\.read\(".format("|".join(re.escape(n) for n in dir(nltk.corpus)))
)

CLASS_DEF_RE = re.compile(r"^\s*class\s+(\w+)\s*[:\(]")

######################################################################
# Globals
######################################################################
# Yes, it's bad programming practice, but this is a little hack
# script. :)  These get initialized by find_deprecated_defs.

deprecated_funcs = defaultdict(set)
deprecated_classes = defaultdict(set)
deprecated_methods = defaultdict(set)

try:
    from epydoc.cli import TerminalController
except ImportError:

    class TerminalController:
        def __getattr__(self, attr):
            return ""


term = TerminalController()

######################################################################
# Code
######################################################################


def strip_quotes(s):
    s = s.strip()
    while s and (s[0] in "ur") and (s[-1] in "'\""):
        s = s[1:]
    while s and (s[0] in "'\"" and (s[0] == s[-1])):
        s = s[1:-1]
    s = s.strip()
    return s


def find_class(s, index):
    lines = s[:index].split("\n")
    while lines:
        m = CLASS_DEF_RE.match(lines[-1])
        if m:
            return m.group(1) + "."
        lines.pop()
    return "?."


def find_deprecated_defs(pkg_dir):
    """
    Return a list of all functions marked with the @deprecated
    decorator, and classes with an immediate Deprecated base class, in
    all Python files in the given directory.
    """
    # Walk through the directory, finding python files.
    for root, dirs, files in os.walk(pkg_dir):
        for filename in files:
            if filename.endswith(".py"):
                # Search the file for any deprecated definitions.
                s = open(os.path.join(root, filename)).read()
                for m in DEPRECATED_DEF_RE.finditer(s):
                    if m.group(2):
                        name = m.group(2)
                        msg = " ".join(
                            strip_quotes(s) for s in STRING_RE.findall(m.group(1))
                        )
                        msg = " ".join(msg.split())
                        if m.group()[0] in " \t":
                            cls = find_class(s, m.start())
                            deprecated_methods[name].add((msg, cls, "()"))
                        else:
                            deprecated_funcs[name].add((msg, "", "()"))
                    else:
                        name = m.group(3)
                        m2 = STRING_RE.match(s, m.end())
                        if m2:
                            msg = strip_quotes(m2.group())
                        else:
                            msg = ""
                        msg = " ".join(msg.split())
                        deprecated_classes[name].add((msg, "", ""))


def print_deprecated_uses(paths):
    dep_names = set()
    dep_files = set()
    for path in sorted(paths):
        if os.path.isdir(path):
            dep_names.update(
                print_deprecated_uses([os.path.join(path, f) for f in os.listdir(path)])
            )
        elif path.endswith(".py"):
            print_deprecated_uses_in(open(path).readline, path, dep_files, dep_names, 0)
        elif path.endswith(".doctest") or path.endswith(".txt"):
            for example in DocTestParser().get_examples(open(path).read()):
                ex = StringIO(example.source)
                try:
                    print_deprecated_uses_in(
                        ex.readline, path, dep_files, dep_names, example.lineno
                    )
                except tokenize.TokenError:
                    print(
                        term.RED + "Caught TokenError -- "
                        "malformatted doctest?" + term.NORMAL
                    )
    return dep_names


def print_deprecated_uses_in(readline, path, dep_files, dep_names, lineno_offset):
    tokiter = tokenize.generate_tokens(readline)
    context = [""]
    for typ, tok, start, end, line in tokiter:
        # Remember the previous line -- it might contain
        # the @deprecated decorator.
        if line is not context[-1]:
            context.append(line)
            if len(context) > 10:
                del context[0]
        esctok = re.escape(tok)
        # Ignore all tokens except deprecated names.
        if not (
            tok in deprecated_classes
            or (tok in deprecated_funcs and re.search(rf"\b{esctok}\s*\(", line))
            or (
                tok in deprecated_methods
                and re.search(rf"(?!<\bself)[.]\s*{esctok}\s*\(", line)
            )
        ):
            continue
        # Hack: only complain about read if it's used after a corpus.
        if tok == "read" and not CORPUS_READ_METHOD_RE.search(line):
            continue
        # Ignore deprecated definitions:
        if DEPRECATED_DEF_RE.search("".join(context)):
            continue
        # Print a header for the first use in a file:
        if path not in dep_files:
            print("\n" + term.BOLD + path + term.NORMAL)
            print(f"  {term.YELLOW}linenum{term.NORMAL}")
            dep_files.add(path)
        # Mark the offending token.
        dep_names.add(tok)
        if term.RED:
            sub = term.RED + tok + term.NORMAL
        elif term.BOLD:
            sub = term.BOLD + tok + term.NORMAL
        else:
            sub = "<<" + tok + ">>"
        line = re.sub(rf"\b{esctok}\b", sub, line)
        # Print the offending line.
        print(
            "  {}[{:5d}]{} {}".format(
                term.YELLOW, start[0] + lineno_offset, term.NORMAL, line.rstrip()
            )
        )


def main():
    paths = sys.argv[1:] or ["."]

    print("Importing nltk...")
    try:
        import nltk
    except ImportError:
        print("Unable to import nltk -- check your PYTHONPATH.")
        sys.exit(-1)

    print("Finding definitions of deprecated functions & classes in nltk...")
    find_deprecated_defs(nltk.__path__[0])

    print("Looking for possible uses of deprecated funcs & classes...")
    dep_names = print_deprecated_uses(paths)

    if not dep_names:
        print("No deprecated funcs or classes found!")
    else:
        print("\n" + term.BOLD + "What you should use instead:" + term.NORMAL)
        for name in sorted(dep_names):
            msgs = (
                deprecated_funcs[name]
                .union(deprecated_classes[name])
                .union(deprecated_methods[name])
            )
            for msg, prefix, suffix in msgs:
                print(
                    textwrap.fill(
                        term.RED + prefix + name + suffix + term.NORMAL + ": " + msg,
                        width=75,
                        initial_indent=" " * 2,
                        subsequent_indent=" " * 6,
                    )
                )


if __name__ == "__main__":
    main()
