# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:

# Copyright 2014-2016 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.

"""Loggers and utilities related to logging."""

import os
import sys
import html as pyhtml
import logging
import contextlib
import collections
import faulthandler
import traceback
import warnings
import json
import inspect

from PyQt5 import QtCore
# Optional imports
try:
    import colorama
except ImportError:
    colorama = None

_log_inited = False

COLORS = ['black', 'red', 'green', 'yellow', 'blue', 'purple', 'cyan', 'white']
COLOR_ESCAPES = {color: '\033[{}m'.format(i)
                 for i, color in enumerate(COLORS, start=30)}
RESET_ESCAPE = '\033[0m'


# Log formats to use.
SIMPLE_FMT = ('{green}{asctime:8}{reset} {log_color}{levelname}{reset}: '
              '{message}')
EXTENDED_FMT = ('{green}{asctime:8}{reset} '
                '{log_color}{levelname:8}{reset} '
                '{cyan}{name:10} {module}:{funcName}:{lineno}{reset} '
                '{log_color}{message}{reset}')
EXTENDED_FMT_HTML = (
    '<tr>'
    '<td><pre>%(green)s%(asctime)-8s%(reset)s</pre></td>'
    '<td><pre>%(log_color)s%(levelname)-8s%(reset)s</pre></td>'
    '<td></pre>%(cyan)s%(name)-10s</pre></td>'
    '<td><pre>%(cyan)s%(module)s:%(funcName)s:%(lineno)s%(reset)s</pre></td>'
    '<td><pre>%(log_color)s%(message)s%(reset)s</pre></td>'
    '</tr>'
)
DATEFMT = '%H:%M:%S'
LOG_COLORS = {
    'VDEBUG': 'white',
    'DEBUG': 'white',
    'INFO': 'green',
    'WARNING': 'yellow',
    'ERROR': 'red',
    'CRITICAL': 'red',
}

# We first monkey-patch logging to support our VDEBUG level before getting the
# loggers.  Based on http://stackoverflow.com/a/13638084
VDEBUG_LEVEL = 9
logging.addLevelName(VDEBUG_LEVEL, 'VDEBUG')
logging.VDEBUG = VDEBUG_LEVEL

LOG_LEVELS = {
    'VDEBUG': logging.VDEBUG,
    'DEBUG': logging.DEBUG,
    'INFO': logging.INFO,
    'WARNING': logging.WARNING,
    'ERROR': logging.ERROR,
    'CRITICAL': logging.CRITICAL,
}


def vdebug(self, msg, *args, **kwargs):
    """Log with a VDEBUG level.

    VDEBUG is used when a debug message is rather verbose, and probably of
    little use to the end user or for post-mortem debugging, i.e. the content
    probably won't change unless the code changes.
    """
    if self.isEnabledFor(VDEBUG_LEVEL):
        # pylint: disable=protected-access
        self._log(VDEBUG_LEVEL, msg, args, **kwargs)


logging.Logger.vdebug = vdebug


# The different loggers used.
statusbar = logging.getLogger('statusbar')
completion = logging.getLogger('completion')
destroy = logging.getLogger('destroy')
modes = logging.getLogger('modes')
webview = logging.getLogger('webview')
mouse = logging.getLogger('mouse')
misc = logging.getLogger('misc')
url = logging.getLogger('url')
procs = logging.getLogger('procs')
commands = logging.getLogger('commands')
init = logging.getLogger('init')
signals = logging.getLogger('signals')
hints = logging.getLogger('hints')
keyboard = logging.getLogger('keyboard')
downloads = logging.getLogger('downloads')
js = logging.getLogger('js')  # Javascript console messages
qt = logging.getLogger('qt')  # Warnings produced by Qt
rfc6266 = logging.getLogger('rfc6266')
ipc = logging.getLogger('ipc')
shlexer = logging.getLogger('shlexer')
save = logging.getLogger('save')
message = logging.getLogger('message')
config = logging.getLogger('config')
sessions = logging.getLogger('sessions')


ram_handler = None


def stub(suffix=''):
    """Show a STUB: message for the calling function."""
    function = inspect.stack()[1][3]
    text = "STUB: {}".format(function)
    if suffix:
        text = '{} ({})'.format(text, suffix)
    misc.warning(text)


class CriticalQtWarning(Exception):

    """Exception raised when there's a critical Qt warning."""


def init_log(args):
    """Init loggers based on the argparse namespace passed."""
    level = args.loglevel.upper()
    try:
        numeric_level = getattr(logging, level)
    except AttributeError:
        raise ValueError("Invalid log level: {}".format(args.loglevel))

    if numeric_level > logging.DEBUG and args.debug:
        numeric_level = logging.DEBUG

    console, ram = _init_handlers(numeric_level, args.color, args.force_color,
                                  args.json_logging, args.loglines)
    root = logging.getLogger()
    if console is not None:
        if args.logfilter is not None:
            console.addFilter(LogFilter(args.logfilter.split(',')))
        root.addHandler(console)
    if ram is not None:
        root.addHandler(ram)
    root.setLevel(logging.NOTSET)
    logging.captureWarnings(True)
    _init_py_warnings()
    QtCore.qInstallMessageHandler(qt_message_handler)
    global _log_inited
    _log_inited = True


def _init_py_warnings():
    """Initialize Python warning handling."""
    warnings.simplefilter('default')
    warnings.filterwarnings('ignore', module='pdb', category=ResourceWarning)


@contextlib.contextmanager
def disable_qt_msghandler():
    """Contextmanager which temporarily disables the Qt message handler."""
    old_handler = QtCore.qInstallMessageHandler(None)
    try:
        yield
    finally:
        QtCore.qInstallMessageHandler(old_handler)


@contextlib.contextmanager
def ignore_py_warnings(**kwargs):
    """Contextmanager to temporarily disable certain Python warnings."""
    warnings.filterwarnings('ignore', **kwargs)
    yield
    if _log_inited:
        _init_py_warnings()


def _init_handlers(level, color, force_color, json_logging, ram_capacity):
    """Init log handlers.

    Args:
        level: The numeric logging level.
        color: Whether to use color if available.
        force_color: Force colored output.
        json_logging: Output log lines in JSON (this disables all colors).
    """
    global ram_handler
    console_fmt, ram_fmt, html_fmt, use_colorama = _init_formatters(
        level, color, force_color, json_logging)

    if sys.stderr is None:
        console_handler = None
    else:
        strip = False if force_color else None
        if use_colorama:
            stream = colorama.AnsiToWin32(sys.stderr, strip=strip)
        else:
            stream = sys.stderr
        console_handler = logging.StreamHandler(stream)
        console_handler.setLevel(level)
        console_handler.setFormatter(console_fmt)

    if ram_capacity == 0:
        ram_handler = None
    else:
        ram_handler = RAMHandler(capacity=ram_capacity)
        ram_handler.setLevel(logging.NOTSET)
        ram_handler.setFormatter(ram_fmt)
        ram_handler.html_formatter = html_fmt

    return console_handler, ram_handler


def _init_formatters(level, color, force_color, json_logging):
    """Init log formatters.

    Args:
        level: The numeric logging level.
        color: Whether to use color if available.
        force_color: Force colored output.
        json_logging: Format lines as JSON (disables all color).

    Return:
        A (console_formatter, ram_formatter, use_colorama) tuple.
        console_formatter/ram_formatter: logging.Formatter instances.
        use_colorama: Whether to use colorama.
    """
    console_fmt = EXTENDED_FMT if level <= logging.DEBUG else SIMPLE_FMT
    ram_formatter = ColoredFormatter(EXTENDED_FMT, DATEFMT, '{',
                                     use_colors=False)
    html_formatter = HTMLFormatter(EXTENDED_FMT_HTML, DATEFMT,
                                   log_colors=LOG_COLORS)
    if sys.stderr is None:
        return None, ram_formatter, html_formatter, False

    if json_logging:
        console_formatter = JSONFormatter()
        return console_formatter, ram_formatter, html_formatter, False

    use_colorama = False
    color_supported = os.name == 'posix' or colorama

    if color_supported and (sys.stderr.isatty() or force_color) and color:
        use_colors = True
        if colorama and os.name != 'posix':
            use_colorama = True
    else:
        use_colors = False

    console_formatter = ColoredFormatter(console_fmt, DATEFMT, '{',
                                         use_colors=use_colors)
    return console_formatter, ram_formatter, html_formatter, use_colorama


def qt_message_handler(msg_type, context, msg):
    """Qt message handler to redirect qWarning etc. to the logging system.

    Args:
        QtMsgType msg_type: The level of the message.
        QMessageLogContext context: The source code location of the message.
        msg: The message text.
    """
    # Mapping from Qt logging levels to the matching logging module levels.
    # Note we map critical to ERROR as it's actually "just" an error, and fatal
    # to critical.
    qt_to_logging = {
        QtCore.QtDebugMsg: logging.DEBUG,
        QtCore.QtWarningMsg: logging.WARNING,
        QtCore.QtCriticalMsg: logging.ERROR,
        QtCore.QtFatalMsg: logging.CRITICAL,
    }
    try:
        # pylint: disable=no-member,useless-suppression
        qt_to_logging[QtCore.QtInfoMsg] = logging.INFO
    except AttributeError:
        # Qt < 5.5
        pass

    # Change levels of some well-known messages to debug so they don't get
    # shown to the user.
    #
    # If a message starts with any text in suppressed_msgs, it's not logged as
    # error.
    suppressed_msgs = [
        # PNGs in Qt with broken color profile
        # https://bugreports.qt.io/browse/QTBUG-39788
        'libpng warning: iCCP: Not recognizing known sRGB profile that has '
            'been edited',  # flake8: disable=E131
        'libpng warning: iCCP: known incorrect sRGB profile',
        # Hopefully harmless warning
        'OpenType support missing for script ',
        # Error if a QNetworkReply gets two different errors set. Harmless Qt
        # bug on some pages.
        # https://bugreports.qt.io/browse/QTBUG-30298
        'QNetworkReplyImplPrivate::error: Internal problem, this method must '
            'only be called once.',
        # Sometimes indicates missing text, but most of the time harmless
        'load glyph failed ',
        # Harmless, see https://bugreports.qt.io/browse/QTBUG-42479
        'content-type missing in HTTP POST, defaulting to '
            'application/x-www-form-urlencoded. '
            'Use QNetworkRequest::setHeader() to fix this problem.',
        # https://bugreports.qt.io/browse/QTBUG-43118
        'Using blocking call!',
        # Hopefully harmless
        '"Method "GetAll" with signature "s" on interface '
            '"org.freedesktop.DBus.Properties" doesn\'t exist',
        '"Method \\"GetAll\\" with signature \\"s\\" on interface '
            '\\"org.freedesktop.DBus.Properties\\" doesn\'t exist\\n"',
        'WOFF support requires QtWebKit to be built with zlib support.',
        # Weird Enlightment/GTK X extensions
        'QXcbWindow: Unhandled client message: "_E_',
        'QXcbWindow: Unhandled client message: "_ECORE_',
        'QXcbWindow: Unhandled client message: "_GTK_',
        # Happens on AppVeyor CI
        'SetProcessDpiAwareness failed:',
        # https://bugreports.qt.io/browse/QTBUG-49174
        'QObject::connect: Cannot connect (null)::stateChanged('
            'QNetworkSession::State) to '
            'QNetworkReplyHttpImpl::_q_networkSessionStateChanged('
            'QNetworkSession::State)',
        # https://bugreports.qt.io/browse/QTBUG-53989
        "Image of format '' blocked because it is not considered safe. If you "
            "are sure it is safe to do so, you can white-list the format by "
            "setting the environment variable QTWEBKIT_IMAGEFORMAT_WHITELIST=",
        # Installing Qt from the installer may cause it looking for SSL3 which
        # may not be available on the system
        "QSslSocket: cannot resolve SSLv3_client_method",
        "QSslSocket: cannot resolve SSLv3_server_method",
    ]
    if sys.platform == 'darwin':
        suppressed_msgs += [
            'libpng warning: iCCP: known incorrect sRGB profile',
            # https://bugreports.qt.io/browse/QTBUG-47154
            'virtual void QSslSocketBackendPrivate::transmit() SSLRead failed '
                'with: -9805',  # flake8: disable=E131
        ]

    # Messages which will trigger an exception immediately
    critical_msgs = [
        'Could not parse stylesheet of object',
    ]

    if any(msg.strip().startswith(pattern) for pattern in critical_msgs):
        # For some reason, the stack gets lost when raising here...
        logger = logging.getLogger('misc')
        logger.error("Got critical Qt warning!", stack_info=True)
        raise CriticalQtWarning(msg)
    elif any(msg.strip().startswith(pattern) for pattern in suppressed_msgs):
        level = logging.DEBUG
    else:
        level = qt_to_logging[msg_type]

    if context.function is None:
        func = 'none'
    elif ':' in context.function:
        func = '"{}"'.format(context.function)
    else:
        func = context.function

    if context.category is None or context.category == 'default':
        name = 'qt'
    else:
        name = 'qt-' + context.category
    if msg.splitlines()[0] == ('This application failed to start because it '
                               'could not find or load the Qt platform plugin '
                               '"xcb".'):
        # Handle this message specially.
        msg += ("\n\nOn Archlinux, this should fix the problem:\n"
                "    pacman -S libxkbcommon-x11")
        faulthandler.disable()
    stack = ''.join(traceback.format_stack())
    record = qt.makeRecord(name, level, context.file, context.line, msg, None,
                           None, func, sinfo=stack)
    qt.handle(record)


@contextlib.contextmanager
def hide_qt_warning(pattern, logger='qt'):
    """Hide Qt warnings matching the given regex."""
    log_filter = QtWarningFilter(pattern)
    logger_obj = logging.getLogger(logger)
    logger_obj.addFilter(log_filter)
    try:
        yield
    finally:
        logger_obj.removeFilter(log_filter)


class QtWarningFilter(logging.Filter):

    """Filter to filter Qt warnings.

    Attributes:
        _pattern: The start of the message.
    """

    def __init__(self, pattern):
        super().__init__()
        self._pattern = pattern

    def filter(self, record):
        """Determine if the specified record is to be logged."""
        do_log = not record.msg.strip().startswith(self._pattern)
        return do_log


class LogFilter(logging.Filter):

    """Filter to filter log records based on the commandline argument.

    The default Filter only supports one name to show - we support a
    comma-separated list instead.

    Attributes:
        _names: A list of names that should be logged.
    """

    def __init__(self, names):
        super().__init__()
        self._names = names

    def filter(self, record):
        """Determine if the specified record is to be logged."""
        if self._names is None:
            return True
        if record.levelno > logging.DEBUG:
            # More important than DEBUG, so we won't filter at all
            return True
        for name in self._names:
            if record.name == name:
                return True
            elif not record.name.startswith(name):
                continue
            elif record.name[len(name)] == '.':
                return True
        return False


class RAMHandler(logging.Handler):

    """Logging handler which keeps the messages in a deque in RAM.

    Loosely based on logging.BufferingHandler which is unsuitable because it
    uses a simple list rather than a deque.

    Attributes:
        _data: A deque containing the logging records.
    """

    def __init__(self, capacity):
        super().__init__()
        self.html_formatter = None
        if capacity != -1:
            self._data = collections.deque(maxlen=capacity)
        else:
            self._data = collections.deque()

    def emit(self, record):
        if record.levelno >= logging.DEBUG:
            # We don't log VDEBUG to RAM.
            self._data.append(record)

    def dump_log(self, html=False, level='vdebug'):
        """Dump the complete formatted log data as string.

        FIXME: We should do all the HTML formatter via jinja2.
        (probably obsolete when moving to a widget for logging,
        https://github.com/The-Compiler/qutebrowser/issues/34
        """
        minlevel = LOG_LEVELS.get(level.upper(), VDEBUG_LEVEL)
        lines = []
        fmt = self.html_formatter.format if html else self.format
        self.acquire()
        try:
            records = list(self._data)
        finally:
            self.release()
        for record in records:
            if record.levelno >= minlevel:
                lines.append(fmt(record))
        return '\n'.join(lines)


class ColoredFormatter(logging.Formatter):

    """Logging formatter to output colored logs.

    Attributes:
        use_colors: Whether to do colored logging or not.
    """

    def __init__(self, fmt, datefmt, style, *, use_colors):
        super().__init__(fmt, datefmt, style)
        self._use_colors = use_colors

    def format(self, record):
        if self._use_colors:
            color_dict = dict(COLOR_ESCAPES)
            color_dict['reset'] = RESET_ESCAPE
            log_color = LOG_COLORS[record.levelname]
            color_dict['log_color'] = COLOR_ESCAPES[log_color]
        else:
            color_dict = {color: '' for color in COLOR_ESCAPES}
            color_dict['reset'] = ''
            color_dict['log_color'] = ''
        record.__dict__.update(color_dict)
        return super().format(record)


class HTMLFormatter(logging.Formatter):

    """Formatter for HTML-colored log messages.

    Attributes:
        _log_colors: The colors to use for logging levels.
        _colordict: The colordict passed to the logger.
    """

    def __init__(self, fmt, datefmt, log_colors):
        """Constructor.

        Args:
            fmt: The format string to use.
            datefmt: The date format to use.
            log_colors: The colors to use for logging levels.
        """
        super().__init__(fmt, datefmt)
        self._log_colors = log_colors
        self._colordict = {}
        # We could solve this nicer by using CSS, but for this simple case this
        # works.
        for color in COLORS:
            self._colordict[color] = '<font color="{}">'.format(color)
        self._colordict['reset'] = '</font>'

    def format(self, record):
        record.__dict__.update(self._colordict)
        if record.levelname in self._log_colors:
            color = self._log_colors[record.levelname]
            record.log_color = self._colordict[color]
        else:
            record.log_color = ''
        for field in ['msg', 'filename', 'funcName', 'levelname', 'module',
                      'name', 'pathname', 'processName', 'threadName']:
            data = str(getattr(record, field))
            setattr(record, field, pyhtml.escape(data))
        msg = super().format(record)
        if not msg.endswith(self._colordict['reset']):
            msg += self._colordict['reset']
        return msg

    def formatTime(self, record, datefmt=None):
        out = super().formatTime(record, datefmt)
        return pyhtml.escape(out)


class JSONFormatter(logging.Formatter):

    """Formatter for JSON-encoded log messages."""

    def format(self, record):
        obj = {}
        for field in ['created', 'levelname', 'name', 'module', 'funcName',
                      'lineno', 'levelno']:
            obj[field] = getattr(record, field)
        obj['message'] = record.getMessage()
        if record.exc_info is not None:
            obj['traceback'] = super().formatException(record.exc_info)
        return json.dumps(obj)
