use std::cell::RefCell;
use std::io;
use std::rc::Rc;

use avril_core::serde_v8::{JsBuffer, from_v8};
use avril_core::{Extension, Op, WasmStreamingRegistry, v8};

pub fn init() -> Extension {
    Extension {
        name: "ext:wasmstreaming",
        dependencies: &["ext:http_types", "ext:webstreams"],
        ops: vec![
            Op::try_raw("op_wasm_streaming_register", |scope, args| {
                let callback = v8::Local::<v8::Function>::try_from(args.get(0))
                    .map_err(|_| io::Error::other("Expected a Wasm streaming callback"))?;
                let registry = scope
                    .get_slot::<Rc<RefCell<WasmStreamingRegistry>>>()
                    .ok_or_else(|| io::Error::other("Wasm streaming registry is unavailable"))?;
                registry
                    .borrow_mut()
                    .register(v8::Global::new(scope, callback))?;
                Ok::<_, io::Error>(v8::undefined(scope).into())
            }),
            Op::try_raw("op_wasm_streaming_write", |scope, args| {
                let id = from_v8(scope, args.get(0)).map_err(io::Error::other)?;
                let bytes: JsBuffer = from_v8(scope, args.get(1)).map_err(io::Error::other)?;
                let registry = scope
                    .get_slot::<Rc<RefCell<WasmStreamingRegistry>>>()
                    .ok_or_else(|| io::Error::other("Wasm streaming registry is unavailable"))?;
                registry
                    .borrow_mut()
                    .stream_mut(id)?
                    .on_bytes_received(bytes.as_ref());
                Ok::<_, io::Error>(v8::undefined(scope).into())
            }),
            Op::with_scope(
                "op_wasm_streaming_url",
                |scope, (id, url): (u64, String)| {
                    let registry = scope
                        .get_slot::<Rc<RefCell<WasmStreamingRegistry>>>()
                        .ok_or_else(|| {
                            io::Error::other("Wasm streaming registry is unavailable")
                        })?;
                    registry.borrow_mut().stream_mut(id)?.set_url(&url);
                    Ok::<_, io::Error>(())
                },
            ),
            Op::with_scope("op_wasm_streaming_finish", |scope, id: u64| {
                let registry = scope
                    .get_slot::<Rc<RefCell<WasmStreamingRegistry>>>()
                    .ok_or_else(|| io::Error::other("Wasm streaming registry is unavailable"))?;
                registry.borrow_mut().finish(id)
            }),
            Op::try_raw("op_wasm_streaming_abort", |scope, args| {
                let id = from_v8(scope, args.get(0)).map_err(io::Error::other)?;
                let registry = scope
                    .get_slot::<Rc<RefCell<WasmStreamingRegistry>>>()
                    .ok_or_else(|| io::Error::other("Wasm streaming registry is unavailable"))?;
                registry.borrow_mut().abort(id, args.get(1))?;
                Ok::<_, io::Error>(v8::undefined(scope).into())
            }),
        ],
        modules: &[(
            "ext:wasmstreaming/main.js",
            include_str!(concat!(env!("OUT_DIR"), "/main.js")),
        )],
        entry_point: Some("ext:wasmstreaming/main.js"),
    }
}