/* 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::compartments::InCompartment;
use crate::dom::bindings::codegen::Bindings::GPUAdapterBinding::{
    self, GPUAdapterMethods, GPUDeviceDescriptor,
};
use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
use crate::dom::bindings::error::Error;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::str::DOMString;
use crate::dom::globalscope::GlobalScope;
use crate::dom::gpu::response_async;
use crate::dom::gpu::AsyncWGPUListener;
use crate::dom::gpudevice::GPUDevice;
use crate::dom::promise::Promise;
use crate::dom::window::Window;
use crate::script_runtime::JSContext as SafeJSContext;
use dom_struct::dom_struct;
use js::jsapi::{Heap, JSObject};
use std::ptr::NonNull;
use std::rc::Rc;
use webgpu::{wgpu, WebGPUAdapter, WebGPURequest, WebGPUResponse};

#[dom_struct]
pub struct GPUAdapter {
    reflector_: Reflector,
    name: DOMString,
    #[ignore_malloc_size_of = "mozjs"]
    extensions: Heap<*mut JSObject>,
    adapter: WebGPUAdapter,
}

impl GPUAdapter {
    pub fn new_inherited(
        name: DOMString,
        extensions: Heap<*mut JSObject>,
        adapter: WebGPUAdapter,
    ) -> GPUAdapter {
        GPUAdapter {
            reflector_: Reflector::new(),
            name,
            extensions,
            adapter,
        }
    }

    pub fn new(
        global: &GlobalScope,
        name: DOMString,
        extensions: Heap<*mut JSObject>,
        adapter: WebGPUAdapter,
    ) -> DomRoot<GPUAdapter> {
        reflect_dom_object(
            Box::new(GPUAdapter::new_inherited(name, extensions, adapter)),
            global,
            GPUAdapterBinding::Wrap,
        )
    }
}

impl GPUAdapterMethods for GPUAdapter {
    // https://gpuweb.github.io/gpuweb/#dom-gpuadapter-name
    fn Name(&self) -> DOMString {
        self.name.clone()
    }

    // https://gpuweb.github.io/gpuweb/#dom-gpuadapter-extensions
    fn Extensions(&self, _cx: SafeJSContext) -> NonNull<JSObject> {
        NonNull::new(self.extensions.get()).unwrap()
    }

    /// https://gpuweb.github.io/gpuweb/#dom-gpuadapter-requestdevice
    fn RequestDevice(&self, descriptor: &GPUDeviceDescriptor, comp: InCompartment) -> Rc<Promise> {
        let promise = Promise::new_in_current_compartment(&self.global(), comp);
        let sender = response_async(&promise, self);
        let desc = wgpu::instance::DeviceDescriptor {
            extensions: wgpu::instance::Extensions {
                anisotropic_filtering: descriptor.extensions.anisotropicFiltering,
            },
            limits: wgpu::instance::Limits {
                max_bind_groups: descriptor.limits.maxBindGroups,
            },
        };
        if let Some(window) = self.global().downcast::<Window>() {
            let id = window
                .Navigator()
                .create_device_id(self.adapter.0.backend());
            match window.webgpu_channel() {
                Some(thread) => thread
                    .0
                    .send(WebGPURequest::RequestDevice(sender, self.adapter, desc, id))
                    .unwrap(),
                None => promise.reject_error(Error::Type("No WebGPU thread...".to_owned())),
            }
        } else {
            promise.reject_error(Error::Type("No WebGPU thread...".to_owned()))
        };
        promise
    }
}

impl AsyncWGPUListener for GPUAdapter {
    fn handle_response(&self, response: WebGPUResponse, promise: &Rc<Promise>) {
        match response {
            WebGPUResponse::RequestDevice(device_id, _descriptor) => {
                let device = GPUDevice::new(
                    &self.global(),
                    &self,
                    Heap::default(),
                    Heap::default(),
                    device_id,
                );
                promise.resolve_native(&device);
            },
            _ => promise.reject_error(Error::Type(
                "Wrong response type from WebGPU thread...".to_owned(),
            )),
        }
    }
}