"""
Python representation of `user` table.
"""

from __future__ import annotations

from typing import Any, Sequence

from pydantic import root_validator
from sqlalchemy.exc import IntegrityError
from sqlmodel import Field, Relationship, SQLModel

from ..config import Config
from .connection import Connection
from .device import Device
from .tag import Tag, TagValue


class UserBase(SQLModel):
    """
    Common to all representations of users
    """

    name: str = Field(primary_key=True)
    email: str | None = Field(default=None)

    country: str | None = Field(default=None)
    state: str | None = Field(default=None)
    city: str | None = Field(default=None)
    organization: str | None = Field(default=None)
    organizational_unit: str | None = Field(default=None)


class UserCreate(UserBase):
    """
    Representation of a newly created user
    """

    password: str | None = Field(default=None)
    password_clear: str | None = Field(default=None)

    @root_validator
    @classmethod
    def hash_password(cls, values: dict[str, Any]) -> dict[str, Any]:
        """
        Ensure the `password` value of this user gets set.
        """

        if (values.get("password")) is not None:
            # password is set
            return values

        if (password_clear := values.get("password_clear")) is None:
            raise ValueError("No password to hash")

        if (current_config := Config._) is None:
            raise ValueError("Not configured")

        values["password"] = current_config.crypto.crypt_context.hash(
            password_clear)

        return values


class UserRead(UserBase):
    """
    Representation of a user read via the API
    """

    pass


class User(UserBase, table=True):
    """
    Representation of `user` table
    """

    password: str

    tags: list[Tag] = Relationship(
        back_populates="user",
        sa_relationship_kwargs={
            "lazy": "joined",
            "cascade": "all, delete-orphan",
        },
    )

    devices: list[Device] = Relationship(
        back_populates="owner",
    )

    @classmethod
    def create(
        cls,
        *,
        user: UserCreate,
    ) -> User | None:
        """
        Create a new user in the database.
        """

        try:
            with Connection.session as db:
                new_user = cls.from_orm(user)

                db.add(new_user)
                db.commit()
                db.refresh(new_user)

                return new_user

        except IntegrityError:
            # user already existed
            return None

    @classmethod
    def get(cls, name: str) -> User | None:
        """
        Load user from database by name.
        """

        with Connection.session as db:
            return db.get(cls, name)

    @classmethod
    def authenticate(
        cls,
        name: str,
        password: str,
    ) -> User | None:
        """
        Authenticate with name/password against users in database.
        """

        crypt_context = Config._.crypto.crypt_context

        if (user := cls.get(name)) is None:
            # nonexistent user, fake doing password verification
            crypt_context.dummy_verify()
            return None

        if not crypt_context.verify(password, user.password):
            # password hash mismatch
            return None

        return user

    def update(self) -> None:
        """
        Update this user in the database.
        """

        with Connection.session as db:
            db.add(self)
            db.commit()
            db.refresh(self)

    def delete(self) -> None:
        """
        Delete this user from the database.
        """

        with Connection.session as db:
            db.delete(self)
            db.commit()

    def get_tags(self) -> set[TagValue]:
        """
        Return the tags of this user.
        """

        return set(
            tag._
            for tag in self.tags
        )

    def set_tags(
        self,
        tags: Sequence[TagValue],
    ) -> None:
        """
        Change the tags of this user.
        """

        self.tags = [
            Tag(
                user_name=self.name,
                tag_value=tag.value,
            ) for tag in tags
        ]

    def _can(
        self,
        tag: TagValue,
    ) -> bool:
        """
        Check if this user has a tag.
        """

        return (
            tag in self.get_tags()
            # admin can do everything
            or TagValue.admin in self.get_tags()
        )

    def can_edit(
        self,
        user: User,
    ) -> bool:
        """
        Check if this user can edit another user.
        """

        return (
            user.name == self.name
            # admin can edit everything
            or self._can(TagValue.admin)
        )

    def is_admin(
        self,
    ) -> bool:
        """
        Check if this user is an admin.
        """

        # is admin with "admin" tag
        return self._can(TagValue.admin)

    def can_login(
        self,
    ) -> bool:
        """
        Check if this user can log in.
        """

        return (
            # can login with "login" tag
            self._can(TagValue.login)
            # admins can always login
            or self.is_admin()
        )

    def can_be_edited_by(
        self,
        user: User,
    ) -> bool:
        """
        Check if this user can be edited by another user.
        """

        return (
            # user can edit itself
            self.name == user.name
            # admin can edit every user
            or user._can(TagValue.admin)
        )

    def can_be_deleted_by(
        self,
        user: User,
    ) -> bool:
        """
        Check if this user can be deleted by another user.
        """

        return (
            # only admin can delete users
            user._can(TagValue.admin)
            # even admin cannot delete itself
            and self.name != user.name
        )

    def owns(
        self,
        device: Device,
    ) -> bool:
        """
        Check if this user owns a device.
        """

        return (
            device.owner_name == self.name
            # admin owns everything
            or self._can(TagValue.admin)
        )