# -*- coding: utf-8 -*-
"""
 werkzeug.debug
 ~~~~~~~~~~~~~~

 WSGI application traceback debugger.

 :copyright: 2007 Pallets
 :license: BSD-3-Clause
"""
import getpass
import hashlib
import json
import mimetypes
import os
import pkgutil
import re
import sys
import time
import uuid
from itertools import chain
from os.path import basename
from os.path import join

from .._compat import text_type
from .._internal import _log
from ..http import parse_cookie
from ..security import gen_salt
from ..wrappers import BaseRequest as Request
from ..wrappers import BaseResponse as Response
from .console import Console
from .tbtools import get_current_traceback
from .tbtools import render_console_html

# A week
PIN_TIME = 60 * 60 * 24 * 7


def hash_pin(pin):
 if isinstance(pin, text_type):
 pin = pin.encode("utf-8", "replace")
 return hashlib.md5(pin + b"shittysalt").hexdigest()[:12]


_machine_id = None


def get_machine_id():
 global _machine_id

 if _machine_id is not None:
 return _machine_id

 def _generate():
 linux = b""

 # machine-id is stable across boots, boot_id is not.
 for filename in "/etc/machine-id", "/proc/sys/kernel/random/boot_id":
 try:
 with open(filename, "rb") as f:
 value = f.readline().strip()
 except IOError:
 continue

 if value:
 linux += value
 break

 # Containers share the same machine id, add some cgroup
 # information. This is used outside containers too but should be
 # relatively stable across boots.
 try:
 with open("/proc/self/cgroup", "rb") as f:
 linux += f.readline().strip().rpartition(b"/")[2]
 except IOError:
 pass

 if linux:
 return linux

 # On OS X, use ioreg to get the computer's serial number.
 try:
 # subprocess may not be available, e.g. Google App Engine
 # https://github.com/pallets/werkzeug/issues/925
 from subprocess import Popen, PIPE

 dump = Popen(
 ["ioreg", "-c", "IOPlatformExpertDevice", "-d", "2"], stdout=PIPE
 ).communicate()[0]
 match = re.search(b'"serial-number" = <([^>]+)', dump)

 if match is not None:
 return match.group(1)
 except (OSError, ImportError):
 pass

 # On Windows, use winreg to get the machine guid.
 try:
 import winreg as wr
 except ImportError:
 try:
 import _winreg as wr
 except ImportError:
 wr = None

 if wr is not None:
 try:
 with wr.OpenKey(
 wr.HKEY_LOCAL_MACHINE,
 "SOFTWARE\\Microsoft\\Cryptography",
 0,
 wr.KEY_READ | wr.KEY_WOW64_64KEY,
 ) as rk:
 guid, guid_type = wr.QueryValueEx(rk, "MachineGuid")

 if guid_type == wr.REG_SZ:
 return guid.encode("utf-8")

 return guid
 except WindowsError:
 pass

 _machine_id = _generate()
 return _machine_id


class _ConsoleFrame(object):
 """Helper class so that we can reuse the frame console code for the
 standalone console.
 """

 def __init__(self, namespace):
 self.console = Console(namespace)
 self.id = 0


def get_pin_and_cookie_name(app):
 """Given an application object this returns a semi-stable 9 digit pin
 code and a random key. The hope is that this is stable between
 restarts to not make debugging particularly frustrating. If the pin
 was forcefully disabled this returns `None`.

 Second item in the resulting tuple is the cookie name for remembering.
 """
 pin = os.environ.get("WERKZEUG_DEBUG_PIN")
 rv = None
 num = None

 # Pin was explicitly disabled
 if pin == "off":
 return None, None

 # Pin was provided explicitly
 if pin is not None and pin.replace("-", "").isdigit():
 # If there are separators in the pin, return it directly
 if "-" in pin:
 rv = pin
 else:
 num = pin

 modname = getattr(app, "__module__", app.__class__.__module__)

 try:
 # getuser imports the pwd module, which does not exist in Google
 # App Engine. It may also raise a KeyError if the UID does not
 # have a username, such as in Docker.
 username = getpass.getuser()
 except (ImportError, KeyError):
 username = None

 mod = sys.modules.get(modname)

 # This information only exists to make the cookie unique on the
 # computer, not as a security feature.
 probably_public_bits = [
 username,
 modname,
 getattr(app, "__name__", app.__class__.__name__),
 getattr(mod, "__file__", None),
 ]

 # This information is here to make it harder for an attacker to
 # guess the cookie name. They are unlikely to be contained anywhere
 # within the unauthenticated debug page.
 private_bits = [str(uuid.getnode()), get_machine_id()]

 h = hashlib.md5()
 for bit in chain(probably_public_bits, private_bits):
 if not bit:
 continue
 if isinstance(bit, text_type):
 bit = bit.encode("utf-8")
 h.update(bit)
 h.update(b"cookiesalt")

 cookie_name = "__wzd" + h.hexdigest()[:20]

 # If we need to generate a pin we salt it a bit more so that we don't
 # end up with the same value and generate out 9 digits
 if num is None:
 h.update(b"pinsalt")
 num = ("%09d" % int(h.hexdigest(), 16))[:9]

 # Format the pincode in groups of digits for easier remembering if
 # we don't have a result yet.
 if rv is None:
 for group_size in 5, 4, 3:
 if len(num) % group_size == 0:
 rv = "-".join(
 num[x : x + group_size].rjust(group_size, "0")
 for x in range(0, len(num), group_size)
 )
 break
 else:
 rv = num

 return rv, cookie_name


class DebuggedApplication(object):
 """Enables debugging support for a given application::

 from werkzeug.debug import DebuggedApplication
 from myapp import app
 app = DebuggedApplication(app, evalex=True)

 The `evalex` keyword argument allows evaluating expressions in a
 traceback's frame context.

 :param app: the WSGI application to run debugged.
 :param evalex: enable exception evaluation feature (interactive
 debugging). This requires a non-forking server.
 :param request_key: The key that points to the request object in ths
 environment. This parameter is ignored in current
 versions.
 :param console_path: the URL for a general purpose console.
 :param console_init_func: the function that is executed before starting
 the general purpose console. The return value
 is used as initial namespace.
 :param show_hidden_frames: by default hidden traceback frames are skipped.
 You can show them by setting this parameter
 to `True`.
 :param pin_security: can be used to disable the pin based security system.
 :param pin_logging: enables the logging of the pin system.
 """

 def __init__(
 self,
 app,
 evalex=False,
 request_key="werkzeug.request",
 console_path="/console",
 console_init_func=None,
 show_hidden_frames=False,
 pin_security=True,
 pin_logging=True,
 ):
 if not console_init_func:
 console_init_func = None
 self.app = app
 self.evalex = evalex
 self.frames = {}
 self.tracebacks = {}
 self.request_key = request_key
 self.console_path = console_path
 self.console_init_func = console_init_func
 self.show_hidden_frames = show_hidden_frames
 self.secret = gen_salt(20)
 self._failed_pin_auth = 0

 self.pin_logging = pin_logging
 if pin_security:
 # Print out the pin for the debugger on standard out.
 if os.environ.get("WERKZEUG_RUN_MAIN") == "true" and pin_logging:
 _log("warning", " * Debugger is active!")
 if self.pin is None:
 _log("warning", " * Debugger PIN disabled. DEBUGGER UNSECURED!")
 else:
 _log("info", " * Debugger PIN: %s" % self.pin)
 else:
 self.pin = None

 @property
 def pin(self):
 if not hasattr(self, "_pin"):
 self._pin, self._pin_cookie = get_pin_and_cookie_name(self.app)
 return self._pin

 @pin.setter
 def pin(self, value):
 self._pin = value

 @property
 def pin_cookie_name(self):
 """The name of the pin cookie."""
 if not hasattr(self, "_pin_cookie"):
 self._pin, self._pin_cookie = get_pin_and_cookie_name(self.app)
 return self._pin_cookie

 def debug_application(self, environ, start_response):
 """Run the application and conserve the traceback frames."""
 app_iter = None
 try:
 app_iter = self.app(environ, start_response)
 for item in app_iter:
 yield item
 if hasattr(app_iter, "close"):
 app_iter.close()
 except Exception:
 if hasattr(app_iter, "close"):
 app_iter.close()
 traceback = get_current_traceback(
 skip=1,
 show_hidden_frames=self.show_hidden_frames,
 ignore_system_exceptions=True,
 )
 for frame in traceback.frames:
 self.frames[frame.id] = frame
 self.tracebacks[traceback.id] = traceback

 try:
 start_response(
 "500 INTERNAL SERVER ERROR",
 [
 ("Content-Type", "text/html; charset=utf-8"),
 # Disable Chrome's XSS protection, the debug
 # output can cause false-positives.
 ("X-XSS-Protection", "0"),
 ],
 )
 except Exception:
 # if we end up here there has been output but an error
 # occurred. in that situation we can do nothing fancy any
 # more, better log something into the error log and fall
 # back gracefully.
 environ["wsgi.errors"].write(
 "Debugging middleware caught exception in streamed "
 "response at a point where response headers were already "
 "sent.\n"
 )
 else:
 is_trusted = bool(self.check_pin_trust(environ))
 yield traceback.render_full(
 evalex=self.evalex, evalex_trusted=is_trusted, secret=self.secret
 ).encode("utf-8", "replace")

 traceback.log(environ["wsgi.errors"])

 def execute_command(self, request, command, frame):
 """Execute a command in a console."""
 return Response(frame.console.eval(command), mimetype="text/html")

 def display_console(self, request):
 """Display a standalone shell."""
 if 0 not in self.frames:
 if self.console_init_func is None:
 ns = {}
 else:
 ns = dict(self.console_init_func())
 ns.setdefault("app", self.app)
 self.frames[0] = _ConsoleFrame(ns)
 is_trusted = bool(self.check_pin_trust(request.environ))
 return Response(
 render_console_html(secret=self.secret, evalex_trusted=is_trusted),
 mimetype="text/html",
 )

 def paste_traceback(self, request, traceback):
 """Paste the traceback and return a JSON response."""
 rv = traceback.paste()
 return Response(json.dumps(rv), mimetype="application/json")

 def get_resource(self, request, filename):
 """Return a static resource from the shared folder."""
 filename = join("shared", basename(filename))
 try:
 data = pkgutil.get_data(__package__, filename)
 except OSError:
 data = None
 if data is not None:
 mimetype = mimetypes.guess_type(filename)[0] or "application/octet-stream"
 return Response(data, mimetype=mimetype)
 return Response("Not Found", status=404)

 def check_pin_trust(self, environ):
 """Checks if the request passed the pin test. This returns `True` if the
 request is trusted on a pin/cookie basis and returns `False` if not.
 Additionally if the cookie's stored pin hash is wrong it will return
 `None` so that appropriate action can be taken.
 """
 if self.pin is None:
 return True
 val = parse_cookie(environ).get(self.pin_cookie_name)
 if not val or "|" not in val:
 return False
 ts, pin_hash = val.split("|", 1)
 if not ts.isdigit():
 return False
 if pin_hash != hash_pin(self.pin):
 return None
 return (time.time() - PIN_TIME) < int(ts)

 def _fail_pin_auth(self):
 time.sleep(5.0 if self._failed_pin_auth > 5 else 0.5)
 self._failed_pin_auth += 1

 def pin_auth(self, request):
 """Authenticates with the pin."""
 exhausted = False
 auth = False
 trust = self.check_pin_trust(request.environ)

 # If the trust return value is `None` it means that the cookie is
 # set but the stored pin hash value is bad. This means that the
 # pin was changed. In this case we count a bad auth and unset the
 # cookie. This way it becomes harder to guess the cookie name
 # instead of the pin as we still count up failures.
 bad_cookie = False
 if trust is None:
 self._fail_pin_auth()
 bad_cookie = True

 # If we're trusted, we're authenticated.
 elif trust:
 auth = True

 # If we failed too many times, then we're locked out.
 elif self._failed_pin_auth > 10:
 exhausted = True

 # Otherwise go through pin based authentication
 else:
 entered_pin = request.args.get("pin")
 if entered_pin.strip().replace("-", "") == self.pin.replace("-", ""):
 self._failed_pin_auth = 0
 auth = True
 else:
 self._fail_pin_auth()

 rv = Response(
 json.dumps({"auth": auth, "exhausted": exhausted}),
 mimetype="application/json",
 )
 if auth:
 rv.set_cookie(
 self.pin_cookie_name,
 "%s|%s" % (int(time.time()), hash_pin(self.pin)),
 httponly=True,
 )
 elif bad_cookie:
 rv.delete_cookie(self.pin_cookie_name)
 return rv

 def log_pin_request(self):
 """Log the pin if needed."""
 if self.pin_logging and self.pin is not None:
 _log(
 "info", " * To enable the debugger you need to enter the security pin:"
 )
 _log("info", " * Debugger pin code: %s" % self.pin)
 return Response("")

 def __call__(self, environ, start_response):
 """Dispatch the requests."""
 # important: don't ever access a function here that reads the incoming
 # form data! Otherwise the application won't have access to that data
 # any more!
 request = Request(environ)
 response = self.debug_application
 if request.args.get("__debugger__") == "yes":
 cmd = request.args.get("cmd")
 arg = request.args.get("f")
 secret = request.args.get("s")
 traceback = self.tracebacks.get(request.args.get("tb", type=int))
 frame = self.frames.get(request.args.get("frm", type=int))
 if cmd == "resource" and arg:
 response = self.get_resource(request, arg)
 elif cmd == "paste" and traceback is not None and secret == self.secret:
 response = self.paste_traceback(request, traceback)
 elif cmd == "pinauth" and secret == self.secret:
 response = self.pin_auth(request)
 elif cmd == "printpin" and secret == self.secret:
 response = self.log_pin_request()
 elif (
 self.evalex
 and cmd is not None
 and frame is not None
 and self.secret == secret
 and self.check_pin_trust(environ)
 ):
 response = self.execute_command(request, cmd, frame)
 elif (
 self.evalex
 and self.console_path is not None
 and request.path == self.console_path
 ):
 response = self.display_console(request)
 return response(environ, start_response)