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/*
 * Copyright (c) godot-rust; Bromeon and contributors.
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

use crate::builtin::NodePath;
use crate::classes::{Node, PackedScene};
use crate::obj::{Gd, Inherits};

/// Manual extensions for the `Node` class.
impl Node {
    /// ⚠️ Retrieves the node at path `path`, panicking if not found or bad type.
    ///
    /// # Panics
    /// If the node is not found, or if it does not have type `T` or inherited.
    pub fn get_node_as<T>(&self, path: impl Into<NodePath>) -> Gd<T>
    where
        T: Inherits<Node>,
    {
        let path = path.into();
        let copy = path.clone(); // TODO avoid copy

        self.try_get_node_as(path).unwrap_or_else(|| {
            panic!(
                "There is no node of type {ty} at path `{copy}`",
                ty = T::class_name()
            )
        })
    }

    /// Retrieves the node at path `path` (fallible).
    ///
    /// If the node is not found, or if it does not have type `T` or inherited,
    /// `None` will be returned.
    pub fn try_get_node_as<T>(&self, path: impl Into<NodePath>) -> Option<Gd<T>>
    where
        T: Inherits<Node>,
    {
        let path = path.into();

        // TODO differentiate errors (not found, bad type) with Result
        self.get_node_or_null(path)
            .and_then(|node| node.try_cast::<T>().ok())
    }
}

// ----------------------------------------------------------------------------------------------------------------------------------------------

/// Manual extensions for the `PackedScene` class.
impl PackedScene {
    /// ⚠️ Instantiates the scene as type `T`, panicking if not found or bad type.
    ///
    /// # Panics
    /// If the scene is not type `T` or inherited.
    pub fn instantiate_as<T>(&self) -> Gd<T>
    where
        T: Inherits<Node>,
    {
        self.try_instantiate_as::<T>()
            .unwrap_or_else(|| panic!("Failed to instantiate {to}", to = T::class_name()))
    }

    /// Instantiates the scene as type `T` (fallible).
    ///
    /// If the scene is not type `T` or inherited.
    pub fn try_instantiate_as<T>(&self) -> Option<Gd<T>>
    where
        T: Inherits<Node>,
    {
        self.instantiate().and_then(|gd| gd.try_cast::<T>().ok())
    }
}