# -*- coding: UTF-8 -*

"""Users and Roles models for ScoDoc
"""

import base64
from datetime import datetime, timedelta
from hashlib import md5
import json
import os
from time import time

from flask import current_app, url_for
from flask_login import UserMixin, AnonymousUserMixin
from werkzeug.security import generate_password_hash, check_password_hash

import jwt

from app import db, login

from app.scodoc.sco_permissions import Permission
from app.scodoc.sco_roles_default import SCO_ROLES_DEFAULTS


class User(UserMixin, db.Model):
    """ScoDoc users, handled by Flask / SQLAlchemy"""

    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), index=True, unique=True)
    email = db.Column(db.String(120), index=True, unique=True)
    password_hash = db.Column(db.String(128))
    about_me = db.Column(db.String(140))
    last_seen = db.Column(db.DateTime, default=datetime.utcnow)
    token = db.Column(db.String(32), index=True, unique=True)
    token_expiration = db.Column(db.DateTime)
    roles = db.relationship("Role", secondary="user_role", viewonly=True)
    Permission = Permission

    def __init__(self, **kwargs):
        self.roles = []
        super(User, self).__init__(**kwargs)
        if (
            not self.roles
            and self.email
            and self.email == current_app.config["SCODOC_ADMIN_MAIL"]
        ):
            # super-admin
            admin_role = Role.query.filter_by(name="Admin").first()
            assert admin_role
            self.add_role(admin_role, None)
            db.session.commit()
        current_app.logger.info("creating user with roles={}".format(self.roles))

    def __repr__(self):
        return "<User {}>".format(self.username)

    def __str__(self):
        return self.username

    def set_password(self, password):
        "Set password"
        if password:
            self.password_hash = generate_password_hash(password)
        else:
            self.password_hash = None

    def check_password(self, password):
        """Check given password vs current one.
        Returns `True` if the password matched, `False` otherwise.
        """
        if not self.password_hash:  # user without password can't login
            return False
        return check_password_hash(self.password_hash, password)

    def get_reset_password_token(self, expires_in=600):
        return jwt.encode(
            {"reset_password": self.id, "exp": time() + expires_in},
            current_app.config["SECRET_KEY"],
            algorithm="HS256",
        ).decode("utf-8")

    @staticmethod
    def verify_reset_password_token(token):
        try:
            id = jwt.decode(
                token, current_app.config["SECRET_KEY"], algorithms=["HS256"]
            )["reset_password"]
        except:
            return
        return User.query.get(id)

    def to_dict(self, include_email=False):
        data = {
            "id": self.id,
            "username": self.username,
            "last_seen": self.last_seen.isoformat() + "Z",
            "about_me": self.about_me,
        }
        if include_email:
            data["email"] = self.email
        return data

    def from_dict(self, data, new_user=False):
        for field in ["username", "email", "about_me"]:
            if field in data:
                setattr(self, field, data[field])
        if new_user and "password" in data:
            self.set_password(data["password"])

    def get_token(self, expires_in=3600):
        now = datetime.utcnow()
        if self.token and self.token_expiration > now + timedelta(seconds=60):
            return self.token
        self.token = base64.b64encode(os.urandom(24)).decode("utf-8")
        self.token_expiration = now + timedelta(seconds=expires_in)
        db.session.add(self)
        return self.token

    def revoke_token(self):
        self.token_expiration = datetime.utcnow() - timedelta(seconds=1)

    @staticmethod
    def check_token(token):
        user = User.query.filter_by(token=token).first()
        if user is None or user.token_expiration < datetime.utcnow():
            return None
        return user

    # Permissions management:
    def has_permission(self, perm, dept):
        """Check if user has permission `perm` in given `dept`.
        Emulate Zope `has_permission``

        Args:
            perm: integer, one of the value defined in Permission class.
            context:
        """
        # les role liés à ce département, et les roles avec dept=None (super-admin)
        roles_in_dept = (
            UserRole.query.filter_by(user_id=self.id)
            .filter((UserRole.dept == dept) | (UserRole.dept == None))
            .all()
        )
        for user_role in roles_in_dept:
            if user_role.role.has_permission(perm):
                return True
        return False

    # Role management
    def add_role(self, role, dept):
        """Add a role to this user.
        :param role: Role to add.
        """
        self.user_roles.append(UserRole(user=self, role=role, dept=dept))

    def add_roles(self, roles, dept):
        """Add roles to this user.
        :param roles: Roles to add.
        """
        for role in roles:
            self.add_role(role, dept)

    def set_roles(self, roles, dept):
        self.user_roles = [UserRole(user=self, role=r, dept=dept) for r in roles]

    def get_roles(self):
        for role in self.roles:
            yield role

    def is_administrator(self):
        return self.has_permission(Permission.ScoSuperAdmin, None)


class AnonymousUser(AnonymousUserMixin):
    def has_permission(self, perm, dept=None):
        return False

    def is_administrator(self):
        return False


login.anonymous_user = AnonymousUser


class Role(db.Model):
    """Roles for ScoDoc"""

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64), unique=True)
    default = db.Column(db.Boolean, default=False, index=True)
    permissions = db.Column(db.BigInteger)  # 64 bits
    users = db.relationship("User", secondary="user_role", viewonly=True)
    # __table_args__ = (db.UniqueConstraint("name", "dept", name="_rolename_dept_uc"),)

    def __init__(self, **kwargs):
        super(Role, self).__init__(**kwargs)
        if self.permissions is None:
            self.permissions = 0

    def __repr__(self):
        return "<Role {} perm={:0{w}b}>".format(
            self.name,
            self.permissions & ((1 << Permission.NBITS) - 1),
            w=Permission.NBITS,
        )

    def add_permission(self, perm):
        self.permissions |= perm

    def remove_permission(self, perm):
        self.permissions = self.permissions & ~perm

    def reset_permissions(self):
        self.permissions = 0

    def has_permission(self, perm):
        return self.permissions & perm == perm

    @staticmethod
    def insert_roles():
        """Create default roles"""
        default_role = "Observateur"
        for r, permissions in SCO_ROLES_DEFAULTS.items():
            role = Role.query.filter_by(name=r).first()
            if role is None:
                role = Role(name=r)
            role.reset_permissions()
            for perm in permissions:
                role.add_permission(perm)
            role.default = role.name == default_role
            db.session.add(role)
        db.session.commit()

    @staticmethod
    def get_named_role(name):
        """Returns existing role with given name, or None."""
        return Role.query.filter_by(name=name).first()


class UserRole(db.Model):
    """Associate user to role, in a dept.
    If dept is None, the role applies to all departments (eg super admin).
    """

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    role_id = db.Column(db.Integer, db.ForeignKey("role.id"))
    dept = db.Column(db.String(64))
    user = db.relationship(
        User, backref=db.backref("user_roles", cascade="all, delete-orphan")
    )
    role = db.relationship(
        Role, backref=db.backref("user_roles", cascade="all, delete-orphan")
    )

    def __repr__(self):
        return "<UserRole u={} r={} dept={}>".format(self.user, self.role, self.dept)


@login.user_loader
def load_user(id):
    return User.query.get(int(id))