#!/usr/bin/env python3
# -*- coding: utf-8 -*-


import sys
import os
import argparse
import socket
import errno
import subprocess

import mathics
from mathics_django import server_version_string, license_string
from mathics_django import settings as mathics_settings  # Prevents UnboundLocalError
from mathics_django.version import __version__ as django_frontend_version


def check_database():
    # Check for the database
    database_file = mathics_settings.DATABASES["default"]["NAME"]

    if not os.path.exists(database_file):
        print("warning: database file %s not found\n" % database_file)
        if not os.path.exists(mathics_settings.DATA_DIR):
            print("Creating data directory %s" % mathics_settings.DATA_DIR)
            os.makedirs(mathics_settings.DATA_DIR)

    print("Migrating database %s" % database_file)
    manage_file = os.path.join(os.path.dirname(os.path.realpath(__file__)), "manage.py")
    try:
        subprocess.check_call([sys.executable, manage_file, "migrate", "--noinput"])
        print("\ndatabase initialized sucessfully")
    except subprocess.CalledProcessError:
        print("error: failed to create database")
        sys.exit(1)


def parse_args():
    argparser = argparse.ArgumentParser(
        prog="mathicsserver",
        usage="%(prog)s [options]",
        add_help=False,
        description="""Mathics server for the graphical user interface in a
            web browser. It is not intended for production use on a public Web
            server!""",
        epilog="""Please feel encouraged to contribute to Mathics! Create
            your own fork, make the desired changes, commit, and make a pull
            request.""",
    )

    argparser.add_argument(
        "--help", "-h", help="show this help message and exit", action="help"
    )
    argparser.add_argument(
        "--quiet", "-q", help="don't print message at startup", action="store_true"
    )
    argparser.add_argument(
        "--version",
        "-v",
        action="version",
        version="Mathics: %s;, mathicsserver: %s."
        % (mathics.__version__, django_frontend_version),
    )
    argparser.add_argument(
        "--port",
        "-p",
        dest="port",
        metavar="PORT",
        default=8000,
        type=int,
        help="use PORT as server port",
    )
    argparser.add_argument(
        "--external",
        "-e",
        dest="external",
        action="store_true",
        help="allow external access to server",
    )

    return argparser.parse_args()


def launch_app(args):
    quit_command = "CTRL-BREAK" if sys.platform == "win32" else "CONTROL-C"
    port = args.port

    if not args.quiet:
        print()
        print("Django front end version %s" % django_frontend_version)
        print(server_version_string)
        print()
        print(license_string)
        print()
        print("Quit by pressing %s\n" % quit_command)
        print(
            """Open the graphical user interface at
http://localhost:%d\nin Firefox, Chrome, or Safari to use Mathics\n"""
            % port
        )

    if args.external:
        addr = "0.0.0.0"
    else:
        addr = "127.0.0.1"

    try:
        from django.core.servers.basehttp import run, get_internal_wsgi_application

        handler = get_internal_wsgi_application()
        run(addr, port, handler)
    except socket.error as e:
        # Use helpful error messages instead of ugly tracebacks.
        ERRORS = {
            errno.EACCES: "You don't have permission to access that port.",
            errno.EADDRINUSE: "That port is already in use.",
            errno.EADDRNOTAVAIL: "That IP address can't be assigned to.",
        }
        try:
            error_text = ERRORS[e.errno]
        except KeyError:
            error_text = str(e)
        sys.stderr.write("Error: %s" % error_text + "\n")
        # Need to use an OS exit because sys.exit doesn't work in a thread
        os._exit(1)
    except KeyboardInterrupt:
        print("\nGoodbye!\n")
        sys.exit(0)


def main():
    os.environ["DJANGO_SETTINGS_MODULE"] = "mathics_django.settings"
    check_database()
    args = parse_args()
    launch_app(args)


if __name__ == "__main__":
    main()
