from secrets import token_hex
from json import JSONEncoder
from sqlalchemy.ext.associationproxy import association_proxy

from app import db
from app.models import PlayerFoundObjective, Role

class Objective(db.Model):
    """ !Always call set_hash after() creating new instance! """
    __tablename__ = 'objective'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64))
    game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
    hash = db.Column(db.String(32), unique=True, nullable=False)
    longitude = db.Column(db.Numeric(precision=15, scale=10, asdecimal=False, decimal_return_scale=None)) # maybe check asdecimal and decimal_return_scale later?
    latitude = db.Column(db.Numeric(precision=15, scale=10, asdecimal=False, decimal_return_scale=None))
    objective_found_by = db.relationship(
        'PlayerFoundObjective',
        back_populates='objective',
        cascade='save-update, merge, delete, delete-orphan')
    found_by = association_proxy('objective_found_by', 'game_player',
                                 creator=lambda game_player: PlayerFoundObjective(game_player=game_player))

    def set_hash(self):
        self.hash = token_hex(16)

    def owned_by(self, user):
        '''given user is an owner of a game object is part of'''
        return user in [gameplayer.user for gameplayer in self.game.game_players if gameplayer.role == Role.owner]

class ObjectiveMinimalEncoder(JSONEncoder):
    def default(self, objective):
        return {
            'name' : objective.name,
            'hash' : objective.hash,
            'longitude' : objective.longitude,
            'latitude' : objective.latitude
        }