"""
Exits

Exits are connectors between Rooms. An exit always has a destination property
set and has a single command defined on itself with the same name as its key,
for allowing Characters to traverse the exit to its destination.

"""

from evennia.objects.objects import DefaultExit
from evennia.commands.cmdset import CmdSet
from evennia.commands.command import Command
from evennia.utils import utils

from .objects import ObjectParent
from utils.word_list import choices

MOVE_DELAY = {"stroll": 6, "walk": 4, "run": 2, "sprint": 1}

SPEED_DESCS = {"stroll": "strolling", "walk": "walking", "run": "running", "sprint": "sprinting"}


class Exit(ObjectParent, DefaultExit):
    """
    Exits are connectors between rooms. Exits are normal Objects except
    they defines the `destination` property and overrides some hooks
    and methods to represent the exits.

    See mygame/typeclasses/objects.py for a list of
    properties and methods available on all Objects child classes like this.
    """

    def at_traverse(self, traveler, destination):
        """
        Implements the actual traversal, using utils.delay to delay the move_to.
        """
        # if the traverser has an Attribute move_speed, use that,
        # otherwise default to "walk" speed
        move_speed = traveler.db.move_speed or "walk"
        move_delay = MOVE_DELAY.get(move_speed, 4)
        pre_check = traveler.at_pre_move(destination)

        def move_callback():
            "This callback will be called by utils.delay after move_delay seconds."
            source_location = traveler.location
            if traveler.move_to(destination, move_type="traverse"):
                self.at_post_traverse(traveler, source_location)
            else:
                if self.db.err_traverse:
                    # if exit has a better error message, let's use it.
                    self.caller.msg(self.db.err_traverse)
                else:
                    # No shorthand error message. Call hook.
                    self.at_failed_traverse(traveler)

        if pre_check:
            moving = SPEED_DESCS[move_speed]
            if self.db.traverse_msg:
                msg = choices(f"\n{self.db.traverse_msg}\n", move_speed, moving)
            else:
                if self.key in ['north', 'south', 'east', 'west']:
                    msg = f"You start {moving} {self.key}."
                else:
                    msg = f"You start {moving} on {self.key}."

            traveler.msg(msg)
        else:
            if self.db.err_traverse:
                # if exit has a better error message, let's use it.
                self.caller.msg(self.db.err_traverse)
            return False

        # create a delayed movement
        t = utils.delay(move_delay, move_callback)

        # we store the deferred on the character, this will allow us
        # to abort the movement. We must use an ndb here since
        # deferreds cannot be pickled.
        traveler.ndb.currently_moving = t


class Opener():
    """
    A mixin that can open or close an exit.
    Done by moving an Exit to/from None and a Room.
    """
    def do_open(self, room_obj=None, exit_obj=None):
        """
        Move a stored exit into a room.
        """
        if not room_obj:
            room_obj = self.db.room
        if not exit_obj:
            exit_obj = self.db.exit
        # Do the move:
        if exit_obj and room_obj:
            exit_obj.location = room_obj

    def do_close(self, exit_obj=None):
        """
        Remove an exit.
        """
        if not exit_obj:
            exit_obj = self.db.exit
        # Do the move:
        if exit_obj:
            exit_obj.location = None

#
# set speed - command
#

class CmdSetSpeed(Command):
    """
    set your movement speed

    Usage:
      setspeed stroll|walk|run|sprint

    This will set your movement speed, determining how long time
    it takes to traverse exits. If no speed is set, 'walk' speed
    is assumed.
    """

    key = "setspeed"

    def func(self):
        """
        Simply sets an Attribute used by the SlowExit above.
        """
        speed = self.args.lower().strip()
        if speed not in SPEED_DESCS:
            self.caller.msg("Usage: setspeed stroll||walk||run||sprint")
        elif self.caller.db.move_speed == speed:
            self.caller.msg("You are already %s." % SPEED_DESCS[speed])
        else:
            self.caller.db.move_speed = speed
            self.caller.msg("You are now %s." % SPEED_DESCS[speed])


#
# stop moving - command
#


class CmdStop(Command):
    """
    stop moving

    Usage:
      stop

    Stops the current movement, if any.
    """

    key = "stop"

    def func(self):
        """
        This is a very simple command, using the
        stored deferred from the exit traversal above.
        """
        currently_moving = self.caller.ndb.currently_moving
        if currently_moving and not currently_moving.called:
            currently_moving.cancel()
            self.caller.msg("You stop moving.")
            for observer in self.caller.location.contents_get(self.caller):
                observer.msg("%s stops." % self.caller.get_display_name(observer))
        else:
            self.caller.msg("You are not moving.")


class SlowExitCmdSet(CmdSet):
    def at_cmdset_creation(self):
        self.add(CmdSetSpeed())
        self.add(CmdStop())