from __future__ import print_function, division, absolute_import

from distutils.version import LooseVersion
import os
import warnings

import bokeh
from bokeh.server.server import Server
from tornado import web


if LooseVersion(bokeh.__version__) < LooseVersion('0.13.0'):
    warnings.warn("\nDask needs bokeh >= 0.13.0 for the dashboard."
                  "\nContinuing without the dashboard.")
    raise ImportError("Dask needs bokeh >= 0.13.0")


class BokehServer(object):
    server_kwargs = {}

    def listen(self, addr):
        if self.server:
            return
        if isinstance(addr, tuple):
            ip, port = addr
        else:
            port = addr
            ip = None
        for i in range(5):
            try:
                self.server = Server(self.apps,
                                     port=port, address=ip,
                                     check_unused_sessions_milliseconds=500,
                                     allow_websocket_origin=["*"],
                                     **self.server_kwargs)
                self.server.start()

                handlers = [(self.prefix + r'/statics/(.*)',
                             web.StaticFileHandler,
                             {'path': os.path.join(os.path.dirname(__file__), 'static')})]

                self.server._tornado.add_handlers(r'.*', handlers)

                return
            except (SystemExit, EnvironmentError) as exc:
                if port != 0:
                    if ("already in use" in str(exc) or  # Unix/Mac
                            "Only one usage of" in str(exc)):  # Windows
                        msg = ("Port %d is already in use. "
                               "\nPerhaps you already have a cluster running?"
                               "\nHosting the diagnostics dashboard on a random port instead."
                               % port)
                    else:
                        msg = "Failed to start diagnostics server on port %d. " % port + str(exc)
                    warnings.warn('\n' + msg)
                    port = 0
                if i == 4:
                    raise

    @property
    def port(self):
        return (self.server.port or
                list(self.server._http._sockets.values())[0].getsockname()[1])

    def stop(self):
        for context in self.server._tornado._applications.values():
            context.run_unload_hook()

        self.server._tornado._stats_job.stop()
        self.server._tornado._cleanup_job.stop()
        if self.server._tornado._ping_job is not None:
            self.server._tornado._ping_job.stop()

        # https://github.com/bokeh/bokeh/issues/5494
        if LooseVersion(bokeh.__version__) >= '0.12.4':
            self.server.stop()
