"""An adapted copy of relevant site-packages functionality from Python stdlib.

This file contains some functions related to handling site-packages in Python
with jedi-specific modifications:

- the functions operate on sys_path argument rather than global sys.path

- in .pth files "import ..." lines that allow execution of arbitrary code are
  skipped to prevent code injection into jedi interpreter

"""

# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
# 2011, 2012, 2013, 2014, 2015 Python Software Foundation; All Rights Reserved

from __future__ import print_function

import sys
import os


def makepath(*paths):
    dir = os.path.join(*paths)
    try:
        dir = os.path.abspath(dir)
    except OSError:
        pass
    return dir, os.path.normcase(dir)


def _init_pathinfo(sys_path):
    """Return a set containing all existing directory entries from sys_path"""
    d = set()
    for dir in sys_path:
        try:
            if os.path.isdir(dir):
                dir, dircase = makepath(dir)
                d.add(dircase)
        except TypeError:
            continue
    return d


def addpackage(sys_path, sitedir, name, known_paths):
    """Process a .pth file within the site-packages directory:
       For each line in the file, either combine it with sitedir to a path
       and add that to known_paths, or execute it if it starts with 'import '.
    """
    if known_paths is None:
        known_paths = _init_pathinfo(sys_path)
        reset = 1
    else:
        reset = 0
    fullname = os.path.join(sitedir, name)
    try:
        f = open(fullname, "r")
    except OSError:
        return
    with f:
        for n, line in enumerate(f):
            if line.startswith("#"):
                continue
            try:
                if line.startswith(("import ", "import\t")):
                    # Change by immerrr: don't evaluate import lines to prevent
                    # code injection into jedi through pth files.
                    #
                    # exec(line)
                    continue
                line = line.rstrip()
                dir, dircase = makepath(sitedir, line)
                if not dircase in known_paths and os.path.exists(dir):
                    sys_path.append(dir)
                    known_paths.add(dircase)
            except Exception:
                print("Error processing line {:d} of {}:\n".format(n+1, fullname),
                      file=sys.stderr)
                import traceback
                for record in traceback.format_exception(*sys.exc_info()):
                    for line in record.splitlines():
                        print('  '+line, file=sys.stderr)
                print("\nRemainder of file ignored", file=sys.stderr)
                break
    if reset:
        known_paths = None
    return known_paths


def addsitedir(sys_path, sitedir, known_paths=None):
    """Add 'sitedir' argument to sys_path if missing and handle .pth files in
    'sitedir'"""
    if known_paths is None:
        known_paths = _init_pathinfo(sys_path)
        reset = 1
    else:
        reset = 0
    sitedir, sitedircase = makepath(sitedir)
    if not sitedircase in known_paths:
        sys_path.append(sitedir)        # Add path component
        known_paths.add(sitedircase)
    try:
        names = os.listdir(sitedir)
    except OSError:
        return
    names = [name for name in names if name.endswith(".pth")]
    for name in sorted(names):
        addpackage(sys_path, sitedir, name, known_paths)
    if reset:
        known_paths = None
    return known_paths