"""Handle the management of resources."""
import json
from uuid import UUID, uuid4
from typing import Any, Dict, Sequence, NamedTuple

from pymonad.maybe import Just, Maybe, Nothing

from gn3.auth import db
from gn3.auth.dictify import dictify
from gn3.auth.authentication.users import User

from ..checks import authorised_p
from ..errors import AuthorisationError
from ..groups.models import Group, user_group, is_group_leader

class MissingGroupError(AuthorisationError):
    """Raised for any resource operation without a group."""

class ResourceCategory(NamedTuple):
    """Class representing a resource category."""
    resource_category_id: UUID
    resource_category_key: str
    resource_category_description: str

    def dictify(self) -> dict[str, Any]:
        """Return a dict representation of `ResourceCategory` objects."""
        return {
            "resource_category_id": self.resource_category_id,
            "resource_category_key": self.resource_category_key,
            "resource_category_description": self.resource_category_description
        }

class Resource(NamedTuple):
    """Class representing a resource."""
    group: Group
    resource_id: UUID
    resource_name: str
    resource_category: ResourceCategory
    public: bool

    def dictify(self) -> dict[str, Any]:
        """Return a dict representation of `Resource` objects."""
        return {
            "group": dictify(self.group), "resource_id": self.resource_id,
            "resource_name": self.resource_name,
            "resource_category": dictify(self.resource_category),
            "public": self.public
        }

@authorised_p(("group:resource:create-resource",),
              error_description="Insufficient privileges to create a resource",
              oauth2_scope="profile resource")
def create_resource(
        conn: db.DbConnection, resource_name: str,
        resource_category: ResourceCategory, user: User) -> Resource:
    """Create a resource item."""
    with db.cursor(conn) as cursor:
        group = user_group(cursor, user).maybe(
            False, lambda grp: grp)# type: ignore[misc, arg-type]
        if not group:
            raise MissingGroupError(
                "User with no group cannot create a resource.")
        resource = Resource(group, uuid4(), resource_name, resource_category, False)
        cursor.execute(
            "INSERT INTO resources VALUES (?, ?, ?, ?, ?)",
            (str(resource.group.group_id), str(resource.resource_id),
             resource_name,
             str(resource.resource_category.resource_category_id),
             1 if resource.public else 0))
        # assign_resource_owner_role(conn, resource, user)

    return resource

def resource_category_by_id(
        conn: db.DbConnection, category_id: UUID) -> Maybe[ResourceCategory]:
    """Retrieve a resource category by its ID."""
    with db.cursor(conn) as cursor:
        cursor.execute(
            "SELECT * FROM resource_categories WHERE "
            "resource_category_id=?",
            (str(category_id),))
        results = cursor.fetchone()
        if results:
            return Just(ResourceCategory(
                UUID(results["resource_category_id"]),
                results["resource_category_key"],
                results["resource_category_description"]))

    return Nothing

def resource_categories(conn: db.DbConnection) -> Sequence[ResourceCategory]:
    """Retrieve all available resource categories"""
    with db.cursor(conn) as cursor:
        cursor.execute("SELECT * FROM resource_categories")
        return tuple(
            ResourceCategory(UUID(row[0]), row[1], row[2])
            for row in cursor.fetchall())
    return tuple()

def public_resources(conn: db.DbConnection) -> Sequence[Resource]:
    """List all resources marked as public"""
    categories = {
        str(cat.resource_category_id): cat for cat in resource_categories(conn)
    }
    with db.cursor(conn) as cursor:
        cursor.execute("SELECT * FROM resources WHERE public=1")
        results = cursor.fetchall()
        group_uuids = tuple(row[0] for row in results)
        query = ("SELECT * FROM groups WHERE group_id IN "
                 f"({', '.join(['?'] * len(group_uuids))})")
        cursor.execute(query, group_uuids)
        groups = {
            row[0]: Group(
                UUID(row[0]), row[1], json.loads(row[2] or "{}"))
            for row in cursor.fetchall()
        }
        return tuple(
            Resource(groups[row[0]], UUID(row[1]), row[2], categories[row[3]],
                     bool(row[4]))
            for row in results)

def group_leader_resources(
        cursor: db.DbCursor, user: User, group: Group,
        res_categories: Dict[UUID, ResourceCategory]) -> Sequence[Resource]:
    """Return all the resources available to the group leader"""
    if is_group_leader(cursor, user, group):
        cursor.execute("SELECT * FROM resources WHERE group_id=?",
                       (str(group.group_id),))
        return tuple(
            Resource(group, UUID(row[1]), row[2], res_categories[UUID(row[3])],
                     bool(row[4]))
            for row in cursor.fetchall())
    return tuple()

def user_resources(conn: db.DbConnection, user: User) -> Sequence[Resource]:
    """List the resources available to the user"""
    categories = { # Repeated in `public_resources` function
        cat.resource_category_id: cat for cat in resource_categories(conn)
    }
    with db.cursor(conn) as cursor:
        def __all_resources__(group) -> Sequence[Resource]:
            gl_resources = group_leader_resources(cursor, user, group, categories)

            cursor.execute(
                ("SELECT resources.* FROM group_user_roles_on_resources "
                 "LEFT JOIN resources "
                 "ON group_user_roles_on_resources.resource_id=resources.resource_id "
                 "WHERE group_user_roles_on_resources.group_id = ? "
                 "AND group_user_roles_on_resources.user_id = ?"),
                (str(group.group_id), str(user.user_id)))
            private_res = tuple(
                Resource(group, UUID(row[1]), row[2], categories[UUID(row[3])],
                         bool(row[4]))
                for row in cursor.fetchall())
            return tuple({
                res.resource_id: res
                for res in
                (private_res + gl_resources + public_resources(conn))# type: ignore[operator]
            }.values())

        # Fix the typing here
        return user_group(cursor, user).map(__all_resources__).maybe(# type: ignore[arg-type,misc]
            public_resources(conn), lambda res: res)# type: ignore[arg-type,return-value]