import copy
from citext import CIText
from flask import g

from sqlalchemy.dialects.postgresql import UUID
from ereuse_devicehub.db import db
from ereuse_devicehub.resources.user.models import User
from sortedcontainers import SortedSet
from ereuse_devicehub.resources.models import Thing

from sqlalchemy import BigInteger, Column, Sequence
from sqlalchemy.orm import backref
from teal.db import CASCADE_OWN, URL

from ereuse_devicehub.resources.enums import Severity


_sorted_documents = {
    'order_by': lambda: TradeDocument.created,
    'collection_class': SortedSet
}

class TradeDocument(Thing):
    """This represent a document involved in a trade action.
    Every document is added to a lot.
    When this lot is converted in one trade, the action trade is added to the document
    and the action trade need to be confirmed for the both users of the trade.
    This confirmation can be revoked and this revoked need to be ConfirmRevoke for have
    some efect.

    This documents can be invoices or list of devices or certificates of erasure of
    one disk.

    Like a Devices one document have actions and is possible add or delete of one lot
    if this lot don't have a trade

    The document is saved in the database

    """

    id = Column(BigInteger, Sequence('device_seq'), primary_key=True)
    id.comment = """The identifier of the device for this database. Used only
    internally for software; users should not use this.
    """
    # type = Column(Unicode(STR_SM_SIZE), nullable=False)
    date = Column(db.DateTime)
    date.comment = """The date of document, some documents need to have one date
    """
    id_document = Column(CIText())
    id_document.comment = """The id of one document like invoice so they can be linked."""
    description = Column(db.CIText())
    description.comment = """A description of document."""
    owner_id = db.Column(UUID(as_uuid=True),
                         db.ForeignKey(User.id),
                         nullable=False,
                         default=lambda: g.user.id)
    owner = db.relationship(User, primaryjoin=owner_id == User.id)
    lot_id = db.Column(UUID(as_uuid=True),
                         db.ForeignKey('lot.id'),
                         nullable=False)
    lot = db.relationship('Lot',
                          backref=backref('documents',
                                          lazy=True,
                                          cascade=CASCADE_OWN,
                                          **_sorted_documents),
                            primaryjoin='TradeDocument.lot_id == Lot.id')
    lot.comment = """Lot to which the document is associated"""
    file_name = Column(db.CIText())
    file_name.comment = """This is the name of the file when user up the document."""
    file_hash = Column(db.CIText())
    file_hash.comment = """This is the hash of the file produced from frontend."""
    url = db.Column(URL())
    url.comment = """This is the url where resides the document."""

    __table_args__ = (
        db.Index('document_id', id, postgresql_using='hash'),
        # db.Index('type_doc', type, postgresql_using='hash')
    )

    @property
    def actions(self) -> list:
        """All the actions where the device participated, including:

        1. Actions performed directly to the device.
        2. Actions performed to a component.
        3. Actions performed to a parent device.

        Actions are returned by descending ``created`` time.
        """
        return sorted(self.actions_multiple_docs, key=lambda x: x.created)

    @property
    def trading(self):
        """The trading state, or None if no Trade action has
        ever been performed to this device. This extract the posibilities for to do"""

        confirm = 'Confirm'
        to_confirm = 'ToConfirm'
        revoke = 'Revoke'

        if not self.actions:
            return

        actions = copy.copy(self.actions)
        actions = list(reversed(actions))
        ac = actions[0]

        if ac.type == confirm:
            return confirm

        if ac.type == revoke:
            return revoke

        if ac.type == confirm:
            if ac.user == self.owner:
                return confirm
            return to_confirm

    def last_action_of(self, *types):
        """Gets the last action of the given types.

        :raise LookupError: Device has not an action of the given type.
        """
        try:
            # noinspection PyTypeHints
            actions = self.actions
            actions.sort(key=lambda x: x.created)
            return next(e for e in reversed(actions) if isinstance(e, types))
        except StopIteration:
            raise LookupError('{!r} does not contain actions of types {}.'.format(self, types))

    def _warning_actions(self, actions):
        return sorted(ev for ev in actions if ev.severity >= Severity.Warning)


    def __lt__(self, other):
        return self.id < other.id

    def __str__(self) -> str:
        return '{0.file_name}'.format(self)