"""

Provides a 'pyramid' command as a replacement to the 'start' command.

The reloading strategy is heavily inspired by (and partially copied from)

the pyramid script 'pserve'.

"""

from __future__ import print_function

import atexit

import errno

import os

import signal

import sys

import tempfile

import time

import threading

import subprocess

from cubicweb import BadCommandUsage, ExecutionError

from cubicweb.__pkginfo__ import numversion as cwversion

from cubicweb.cwconfig import CubicWebConfiguration as cwcfg

from cubicweb.cwctl import CWCTL, InstanceCommand, init_cmdline_log_threshold

from cubicweb.pyramid import wsgi_application_from_cwconfig

from cubicweb.server import set_debug

import waitress

MAXFD = 1024

DBG_FLAGS = ('RQL', 'SQL', 'REPO', 'HOOKS', 'OPS', 'SEC', 'MORE')

LOG_LEVELS = ('debug', 'info', 'warning', 'error')

class PyramidStartHandler(InstanceCommand):

    """Start an interactive pyramid server.

    This command requires http://hg.logilab.org/review/pyramid_cubicweb/

    <instance>

      identifier of the instance to configure.

    """

    name = 'pyramid'

    options = (

        ('no-daemon',

         {'action': 'store_true',

          'help': 'Run the server in the foreground.'}),

        ('debug-mode',

         {'action': 'store_true',

          'help': 'Activate the repository debug mode ('

                  'logs in the console and the debug toolbar).'

                  ' Implies --no-daemon'}),

        ('debug',

         {'short': 'D', 'action': 'store_true',

          'help': 'Equals to "--debug-mode --no-daemon --reload"'}),

        ('reload',

         {'action': 'store_true',

          'help': 'Restart the server if any source file is changed'}),

        ('reload-interval',

         {'type': 'int', 'default': 1,

          'help': 'Interval, in seconds, between file modifications checks'}),

        ('loglevel',

         {'short': 'l', 'type': 'choice', 'metavar': '<log level>',

          'default': None, 'choices': LOG_LEVELS,

          'help': 'debug if -D is set, error otherwise; '

                  'one of %s' % (LOG_LEVELS,),

          }),

        ('dbglevel',

         {'type': 'multiple_choice', 'metavar': '<dbg level>',

          'default': None,

          'choices': DBG_FLAGS,

          'help': ('Set the server debugging flags; you may choose several '

                   'values in %s; imply "debug" loglevel' % (DBG_FLAGS,)),

          }),

        ('profile',

         {'action': 'store_true',

          'default': False,

          'help': 'Enable profiling'}),

        ('profile-output',

         {'type': 'string',

          'default': None,

          'help': 'Profiling output file (default: "program.prof")'}),

        ('profile-dump-every',

         {'type': 'int',

          'default': None,

          'metavar': 'N',

          'help': 'Dump profile stats to ouput every N requests '

                  '(default: 100)'}),

    )

    if cwversion >= (3, 21, 0):

        options = options + (

            ('param',

             {'short': 'p',

              'type': 'named',

              'metavar': 'key1:value1,key2:value2',

              'default': {},

              'help': 'override <key> configuration file option with <value>.',

              }),

        )

    _reloader_environ_key = 'CW_RELOADER_SHOULD_RUN'

    _reloader_filelist_environ_key = 'CW_RELOADER_FILELIST'

    def debug(self, msg):

        print('DEBUG - %s' % msg)

    def info(self, msg):

        print('INFO - %s' % msg)

    def ordered_instances(self):

        instances = super(PyramidStartHandler, self).ordered_instances()

        if (self['debug-mode'] or self['debug'] or self['reload']) \

                and len(instances) > 1:

            raise BadCommandUsage(

                '--debug-mode, --debug and --reload can be used on a single '

                'instance only')

        return instances

    def quote_first_command_arg(self, arg):

        """

        There's a bug in Windows when running an executable that's

        located inside a path with a space in it.  This method handles

        that case, or on non-Windows systems or an executable with no

        spaces, it just leaves well enough alone.

        """

        if (sys.platform != 'win32' or ' ' not in arg):

            # Problem does not apply:

            return arg

        try:

            import win32api

        except ImportError:

            raise ValueError(

                "The executable %r contains a space, and in order to "

                "handle this issue you must have the win32api module "

                "installed" % arg)

        arg = win32api.GetShortPathName(arg)

        return arg

    def _remove_pid_file(self, written_pid, filename):

        current_pid = os.getpid()

        if written_pid != current_pid:

            # A forked process must be exiting, not the process that

            # wrote the PID file

            return

        if not os.path.exists(filename):

            return

        with open(filename) as f:

            content = f.read().strip()

        try:

            pid_in_file = int(content)

        except ValueError:

            pass

        else:

            if pid_in_file != current_pid:

                msg = "PID file %s contains %s, not expected PID %s"

                self.out(msg % (filename, pid_in_file, current_pid))

                return

        self.info("Removing PID file %s" % filename)

        try:

            os.unlink(filename)

            return

        except OSError as e:

            # Record, but don't give traceback

            self.out("Cannot remove PID file: (%s)" % e)

        # well, at least lets not leave the invalid PID around...

        try:

            with open(filename, 'w') as f:

                f.write('')

        except OSError as e:

            self.out('Stale PID left in file: %s (%s)' % (filename, e))

        else:

            self.out('Stale PID removed')

    def record_pid(self, pid_file):

        pid = os.getpid()

        self.debug('Writing PID %s to %s' % (pid, pid_file))

        with open(pid_file, 'w') as f:

            f.write(str(pid))

        atexit.register(

            self._remove_pid_file, pid, pid_file)

    def daemonize(self, pid_file):

        pid = live_pidfile(pid_file)

        if pid:

            raise ExecutionError(

                "Daemon is already running (PID: %s from PID file %s)"

                % (pid, pid_file))

        self.debug('Entering daemon mode')

        pid = os.fork()

        if pid:

            # The forked process also has a handle on resources, so we

            # *don't* want proper termination of the process, we just

            # want to exit quick (which os._exit() does)

            os._exit(0)

        # Make this the session leader

        os.setsid()

        # Fork again for good measure!

        pid = os.fork()

        if pid:

            os._exit(0)

        # @@: Should we set the umask and cwd now?

        import resource  # Resource usage information.

        maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]

        if (maxfd == resource.RLIM_INFINITY):

            maxfd = MAXFD

        # Iterate through and close all file descriptors.

        for fd in range(0, maxfd):

            try:

                os.close(fd)

            except OSError:  # ERROR, fd wasn't open to begin with (ignored)

                pass

        if (hasattr(os, "devnull")):

            REDIRECT_TO = os.devnull

        else:

            REDIRECT_TO = "/dev/null"

        os.open(REDIRECT_TO, os.O_RDWR)  # standard input (0)

        # Duplicate standard input to standard output and standard error.

        os.dup2(0, 1)  # standard output (1)

        os.dup2(0, 2)  # standard error (2)

    def restart_with_reloader(self):

        self.debug('Starting subprocess with file monitor')

        with tempfile.NamedTemporaryFile(delete=False) as f:

            filelist_path = f.name

        while True:

            args = [self.quote_first_command_arg(sys.executable)] + sys.argv

            new_environ = os.environ.copy()

            new_environ[self._reloader_environ_key] = 'true'

            new_environ[self._reloader_filelist_environ_key] = filelist_path

            proc = None

            try:

                try:

                    proc = subprocess.Popen(args, env=new_environ)

                    exit_code = proc.wait()

                    proc = None

                    print("Process exited with", exit_code)

                except KeyboardInterrupt:

                    self.info('^C caught in monitor process')

                    return 1

            finally:

                if proc is not None:

                    proc.terminate()

                    self.info(

                        'Waiting for the server to stop. Hit CTRL-C to exit')

                    exit_code = proc.wait()

            if exit_code != 3:

                with open(filelist_path) as f:

                    filelist = [line.strip() for line in f]

                if filelist:

                    self.info("Reloading failed. Waiting for a file to change")

                    mon = Monitor(extra_files=filelist, nomodules=True)

                    while mon.check_reload():

                        time.sleep(1)

                else:

                    return exit_code

            self.info('%s %s %s' % ('-' * 20, 'Restarting', '-' * 20))

    def set_needreload(self):

        self._needreload = True

    def install_reloader(self, poll_interval, extra_files, filelist_path):

        mon = Monitor(

            poll_interval=poll_interval, extra_files=extra_files,

            atexit=self.set_needreload, filelist_path=filelist_path)

        mon_thread = threading.Thread(target=mon.periodic_reload)

        mon_thread.daemon = True

        mon_thread.start()

    def configfiles(self, cwconfig):

        """Generate instance configuration filenames"""

        yield cwconfig.main_config_file()

        for f in (

                'sources', 'logging.conf', 'pyramid.ini', 'pyramid-debug.ini'):

            f = os.path.join(cwconfig.apphome, f)

            if os.path.exists(f):

                yield f

    def i18nfiles(self, cwconfig):

        """Generate instance i18n files"""

        i18ndir = os.path.join(cwconfig.apphome, 'i18n')

        if os.path.exists(i18ndir):

            for lang in cwconfig.available_languages():

                f = os.path.join(i18ndir, lang, 'LC_MESSAGES', 'cubicweb.mo')

                if os.path.exists(f):

                    yield f

    def pyramid_instance(self, appid):

        self._needreload = False

        debugmode = self['debug-mode'] or self['debug']

        autoreload = self['reload'] or self['debug']

        daemonize = not (self['no-daemon'] or debugmode or autoreload)

        if autoreload and not os.environ.get(self._reloader_environ_key):

            return self.restart_with_reloader()

        cwconfig = cwcfg.config_for(appid, debugmode=debugmode)

        if cwversion >= (3, 21, 0):

            cwconfig.cmdline_options = self.config.param

        if autoreload:

            _turn_sigterm_into_systemexit()

            self.debug('Running reloading file monitor')

            extra_files = [sys.argv[0]]

            extra_files.extend(self.configfiles(cwconfig))

            extra_files.extend(self.i18nfiles(cwconfig))

            self.install_reloader(

                self['reload-interval'], extra_files,

                filelist_path=os.environ.get(

                    self._reloader_filelist_environ_key))

        if daemonize:

            self.daemonize(cwconfig['pid-file'])

            self.record_pid(cwconfig['pid-file'])

        if self['dbglevel']:

            self['loglevel'] = 'debug'

            set_debug('|'.join('DBG_' + x.upper() for x in self['dbglevel']))

        init_cmdline_log_threshold(cwconfig, self['loglevel'])

        app = wsgi_application_from_cwconfig(

            cwconfig, profile=self['profile'],

            profile_output=self['profile-output'],

            profile_dump_every=self['profile-dump-every']

        )

        host = cwconfig['interface']

        port = cwconfig['port'] or 8080

        repo = app.application.registry['cubicweb.repository']

        try:

            repo.start_looping_tasks()

            waitress.serve(app, host=host, port=port)

        finally:

            repo.shutdown()

        if self._needreload:

            return 3

        return 0

CWCTL.register(PyramidStartHandler)

def live_pidfile(pidfile):  # pragma: no cover

    """(pidfile:str) -> int | None

    Returns an int found in the named file, if there is one,

    and if there is a running process with that process id.

    Return None if no such process exists.

    """

    pid = read_pidfile(pidfile)

    if pid:

        try:

            os.kill(int(pid), 0)

            return pid

        except OSError as e:

            if e.errno == errno.EPERM:

                return pid

    return None

def read_pidfile(filename):

    if os.path.exists(filename):

        try:

            with open(filename) as f:

                content = f.read()

            return int(content.strip())

        except (ValueError, IOError):

            return None

    else:

        return None

def _turn_sigterm_into_systemexit():

    """Attempts to turn a SIGTERM exception into a SystemExit exception."""

    try:

        import signal

    except ImportError:

        return