# -*- coding: utf-8 -
#
# This file is part of gunicorn released under the MIT license.
# See the NOTICE for more information.

import os
import sys
import traceback

from gunicorn import util
from gunicorn.arbiter import Arbiter
from gunicorn.config import Config, get_default_config_file
from gunicorn import debug
from gunicorn.six import execfile_

class BaseApplication(object):
    """
    An application interface for configuring and loading
    the various necessities for any given web framework.
    """
    def __init__(self, usage=None, prog=None):
        self.usage = usage
        self.cfg = None
        self.callable = None
        self.prog = prog
        self.logger = None
        self.do_load_config()

    def do_load_config(self):
        """
        Loads the configuration
        """
        try:
            self.load_default_config()
            self.load_config()
        except Exception as e:
            sys.stderr.write("\nError: %s\n" % str(e))
            sys.stderr.flush()
            sys.exit(1)

    def load_default_config(self):
        # init configuration
        self.cfg = Config(self.usage, prog=self.prog)

    def init(self, parser, opts, args):
        raise NotImplementedError

    def load(self):
        raise NotImplementedError

    def load_config(self):
        """
        This method is used to load the configuration from one or several input(s).
        Custom Command line, configuration file.
        You have to override this method in your class.
        """
        raise NotImplementedError

    def reload(self):
        self.do_load_config()
        if self.cfg.spew:
            debug.spew()

    def wsgi(self):
        if self.callable is None:
            self.callable = self.load()
        return self.callable

    def run(self):
        try:
            Arbiter(self).run()
        except RuntimeError as e:
            sys.stderr.write("\nError: %s\n\n" % e)
            sys.stderr.flush()
            sys.exit(1)

class Application(BaseApplication):
    def load_config_from_file(self, filename):
        """
        Loads the configuration file: the file is a python file, otherwise raise an RuntimeError
        Exception or stop the process if the configuration file contains a syntax error.
        """
        if not os.path.exists(filename):
            raise RuntimeError("%r doesn't exist" % filename)

        cfg = {
            "__builtins__": __builtins__,
            "__name__": "__config__",
            "__file__": filename,
            "__doc__": None,
            "__package__": None
        }
        try:
            execfile_(filename, cfg, cfg)
        except Exception:
            print("Failed to read config file: %s" % filename)
            traceback.print_exc()
            sys.exit(1)

        for k, v in cfg.items():
            # Ignore unknown names
            if k not in self.cfg.settings:
                continue
            try:
                self.cfg.set(k.lower(), v)
            except:
                sys.stderr.write("Invalid value for %s: %s\n\n" % (k, v))
                raise

        return cfg

    def load_config(self):
        # parse console args
        parser = self.cfg.parser()
        args = parser.parse_args()

        # optional settings from apps
        cfg = self.init(parser, args, args.args)

        # Load up the any app specific configuration
        if cfg and cfg is not None:
            for k, v in cfg.items():
                self.cfg.set(k.lower(), v)

        if args.config:
            self.load_config_from_file(args.config)
        else:
            default_config = get_default_config_file()
            if default_config is not None:
                self.load_config_from_file(default_config)

        # Lastly, update the configuration with any command line
        # settings.
        for k, v in args.__dict__.items():
            if v is None:
                continue
            if k == "args":
                continue
            self.cfg.set(k.lower(), v)

    def run(self):
        if self.cfg.check_config:
            try:
                self.load()
            except:
                sys.stderr.write("\nError while loading the application:\n\n")
                traceback.print_exc()
                sys.stderr.flush()
                sys.exit(1)
            sys.exit(0)

        if self.cfg.spew:
            debug.spew()

        if self.cfg.daemon:
            util.daemonize(self.cfg.enable_stdio_inheritance)

        # set python paths
        if self.cfg.pythonpath and self.cfg.pythonpath is not None:
            paths = self.cfg.pythonpath.split(",")
            for path in paths:
                pythonpath = os.path.abspath(path)
                if pythonpath not in sys.path:
                    sys.path.insert(0, pythonpath)

        super(Application, self).run()
