# loggingutil.py - utility for logging events

#

# Copyright 2010 Nicolas Dumazet

# Copyright 2013 Facebook, Inc.

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

import errno

from . import (

    encoding,

)

from .utils import (

    dateutil,

    procutil,

    stringutil,

)

def openlogfile(ui, vfs, name, maxfiles=0, maxsize=0):

    """Open log file in append mode, with optional rotation

    If maxsize > 0, the log file will be rotated up to maxfiles.

    """

    def rotate(oldpath, newpath):

        try:

            vfs.unlink(newpath)

        except OSError as err:

            if err.errno != errno.ENOENT:

                ui.debug(

                    b"warning: cannot remove '%s': %s\n"

                    % (newpath, encoding.strtolocal(err.strerror))

                )

        try:

            if newpath:

                vfs.rename(oldpath, newpath)

        except OSError as err:

            if err.errno != errno.ENOENT:

                ui.debug(

                    b"warning: cannot rename '%s' to '%s': %s\n"

                    % (newpath, oldpath, encoding.strtolocal(err.strerror))

                )

    if maxsize > 0:

        try:

            st = vfs.stat(name)

        except OSError:

            pass

        else:

            if st.st_size >= maxsize:

                path = vfs.join(name)

                for i in range(maxfiles - 1, 1, -1):

                    rotate(

                        oldpath=b'%s.%d' % (path, i - 1),

                        newpath=b'%s.%d' % (path, i),

                    )

                rotate(oldpath=path, newpath=maxfiles > 0 and path + b'.1')

    return vfs(name, b'a', makeparentdirs=False)

def _formatlogline(msg):

    date = dateutil.datestr(format=b'%Y/%m/%d %H:%M:%S')

    pid = procutil.getpid()

    return b'%s (%d)> %s' % (date, pid, msg)

def _matchevent(event, tracked):

    return b'*' in tracked or event in tracked

class filelogger:

    """Basic logger backed by physical file with optional rotation"""

    def __init__(self, vfs, name, tracked, maxfiles=0, maxsize=0):

        self._vfs = vfs

        self._name = name

        self._trackedevents = set(tracked)

        self._maxfiles = maxfiles

        self._maxsize = maxsize

    def tracked(self, event):

        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):

        line = _formatlogline(msg)

        try:

            with openlogfile(

                ui,

                self._vfs,

                self._name,

                maxfiles=self._maxfiles,

                maxsize=self._maxsize,

            ) as fp:

                fp.write(line)

        except IOError as err:

            ui.debug(

                b'cannot write to %s: %s\n'

                % (self._name, stringutil.forcebytestr(err))

            )

class fileobjectlogger:

    """Basic logger backed by file-like object"""

    def __init__(self, fp, tracked):

        self._fp = fp

        self._trackedevents = set(tracked)

    def tracked(self, event):

        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):

        line = _formatlogline(msg)

        try:

            self._fp.write(line)

            self._fp.flush()

        except IOError as err:

            ui.debug(

                b'cannot write to %s: %s\n'

                % (

                    stringutil.forcebytestr(self._fp.name),

                    stringutil.forcebytestr(err),

                )

            )

class proxylogger:

    """Forward log events to another logger to be set later"""

    def __init__(self):

        self.logger = None

    def tracked(self, event):

        return self.logger is not None and self.logger.tracked(event)

    def log(self, ui, event, msg, opts):

        assert self.logger is not None

        self.logger.log(ui, event, msg, opts)