// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

((window) => {
  const core = window.Deno.core;
  const { requiredArguments } = window.__bootstrap.webUtil;
  const CONNECTING = 0;
  const OPEN = 1;
  const CLOSING = 2;
  const CLOSED = 3;

  class WebSocket extends EventTarget {
    #readyState = CONNECTING;

    constructor(url, protocols = []) {
      super();
      requiredArguments("WebSocket", arguments.length, 1);

      const wsURL = new URL(url);

      if (wsURL.protocol !== "ws:" && wsURL.protocol !== "wss:") {
        throw new DOMException(
          "Only ws & wss schemes are allowed in a WebSocket URL.",
          "SyntaxError",
        );
      }

      if (wsURL.hash !== "" || wsURL.href.endsWith("#")) {
        throw new DOMException(
          "Fragments are not allowed in a WebSocket URL.",
          "SyntaxError",
        );
      }

      this.#url = wsURL.href;

      if (protocols && typeof protocols === "string") {
        protocols = [protocols];
      }

      if (
        protocols.some((x) => protocols.indexOf(x) !== protocols.lastIndexOf(x))
      ) {
        throw new DOMException(
          "Can't supply multiple times the same protocol.",
          "SyntaxError",
        );
      }

      core.jsonOpAsync("op_ws_create", {
        url: wsURL.href,
        protocols: protocols.join(", "),
      }).then((create) => {
        if (create.success) {
          this.#rid = create.rid;
          this.#extensions = create.extensions;
          this.#protocol = create.protocol;

          if (this.#readyState === CLOSING) {
            core.jsonOpAsync("op_ws_close", {
              rid: this.#rid,
            }).then(() => {
              this.#readyState = CLOSED;

              const errEvent = new Event("error");
              errEvent.target = this;
              this.onerror?.(errEvent);
              this.dispatchEvent(errEvent);

              const event = new CloseEvent("close");
              event.target = this;
              this.onclose?.(event);
              this.dispatchEvent(event);
              core.close(this.#rid);
            });
          } else {
            this.#readyState = OPEN;
            const event = new Event("open");
            event.target = this;
            this.onopen?.(event);
            this.dispatchEvent(event);

            this.#eventLoop();
          }
        } else {
          this.#readyState = CLOSED;

          const errEvent = new Event("error");
          errEvent.target = this;
          this.onerror?.(errEvent);
          this.dispatchEvent(errEvent);

          const closeEvent = new CloseEvent("close");
          closeEvent.target = this;
          this.onclose?.(closeEvent);
          this.dispatchEvent(closeEvent);
        }
      }).catch((err) => {
        this.#readyState = CLOSED;

        const errorEv = new ErrorEvent(
          "error",
          { error: err, message: err.toString() },
        );
        errorEv.target = this;
        this.onerror?.(errorEv);
        this.dispatchEvent(errorEv);

        const closeEv = new CloseEvent("close");
        closeEv.target = this;
        this.onclose?.(closeEv);
        this.dispatchEvent(closeEv);
      });
    }

    get CONNECTING() {
      return CONNECTING;
    }
    get OPEN() {
      return OPEN;
    }
    get CLOSING() {
      return CLOSING;
    }
    get CLOSED() {
      return CLOSED;
    }

    get readyState() {
      return this.#readyState;
    }

    #extensions = "";
    #protocol = "";
    #url = "";
    #rid;

    get extensions() {
      return this.#extensions;
    }
    get protocol() {
      return this.#protocol;
    }

    #binaryType = "blob";
    get binaryType() {
      return this.#binaryType;
    }
    set binaryType(value) {
      if (value === "blob" || value === "arraybuffer") {
        this.#binaryType = value;
      }
    }
    #bufferedAmount = 0;
    get bufferedAmount() {
      return this.#bufferedAmount;
    }

    get url() {
      return this.#url;
    }

    onopen = () => {};
    onerror = () => {};
    onclose = () => {};
    onmessage = () => {};

    send(data) {
      requiredArguments("WebSocket.send", arguments.length, 1);

      if (this.#readyState != OPEN) {
        throw Error("readyState not OPEN");
      }

      const sendTypedArray = (ta) => {
        this.#bufferedAmount += ta.size;
        core.jsonOpAsync("op_ws_send", {
          rid: this.#rid,
        }, ta).then(() => {
          this.#bufferedAmount -= ta.size;
        });
      };

      if (data instanceof Blob) {
        data.slice().arrayBuffer().then((ab) =>
          sendTypedArray(new DataView(ab))
        );
      } else if (
        data instanceof Int8Array || data instanceof Int16Array ||
        data instanceof Int32Array || data instanceof Uint8Array ||
        data instanceof Uint16Array || data instanceof Uint32Array ||
        data instanceof Uint8ClampedArray || data instanceof Float32Array ||
        data instanceof Float64Array || data instanceof DataView
      ) {
        sendTypedArray(data);
      } else if (data instanceof ArrayBuffer) {
        sendTypedArray(new DataView(data));
      } else {
        const string = String(data);
        const encoder = new TextEncoder();
        const d = encoder.encode(string);
        this.#bufferedAmount += d.size;
        core.jsonOpAsync("op_ws_send", {
          rid: this.#rid,
          text: string,
        }).then(() => {
          this.#bufferedAmount -= d.size;
        });
      }
    }

    close(code, reason) {
      if (code && (code !== 1000 && !(3000 <= code > 5000))) {
        throw new DOMException(
          "The close code must be either 1000 or in the range of 3000 to 4999.",
          "NotSupportedError",
        );
      }

      const encoder = new TextEncoder();
      if (reason && encoder.encode(reason).byteLength > 123) {
        throw new DOMException(
          "The close reason may not be longer than 123 bytes.",
          "SyntaxError",
        );
      }

      if (this.#readyState === CONNECTING) {
        this.#readyState = CLOSING;
      } else if (this.#readyState === OPEN) {
        this.#readyState = CLOSING;

        core.jsonOpAsync("op_ws_close", {
          rid: this.#rid,
          code,
          reason,
        }).then(() => {
          this.#readyState = CLOSED;
          const event = new CloseEvent("close", {
            wasClean: true,
            code,
            reason,
          });
          event.target = this;
          this.onclose?.(event);
          this.dispatchEvent(event);
          core.close(this.#rid);
        });
      }
    }

    async #eventLoop() {
      if (this.#readyState === OPEN) {
        const message = await core.jsonOpAsync(
          "op_ws_next_event",
          { rid: this.#rid },
        );
        if (message.type === "string" || message.type === "binary") {
          let data;

          if (message.type === "string") {
            data = message.data;
          } else {
            if (this.binaryType === "blob") {
              data = new Blob([new Uint8Array(message.data)]);
            } else {
              data = new Uint8Array(message.data).buffer;
            }
          }

          const event = new MessageEvent("message", {
            data,
            origin: this.#url,
          });
          event.target = this;
          this.onmessage?.(event);
          this.dispatchEvent(event);

          this.#eventLoop();
        } else if (message.type === "close") {
          this.#readyState = CLOSED;
          const event = new CloseEvent("close", {
            wasClean: true,
            code: message.code,
            reason: message.reason,
          });
          event.target = this;
          this.onclose?.(event);
          this.dispatchEvent(event);
        } else if (message.type === "error") {
          this.#readyState = CLOSED;

          const errorEv = new Event("error");
          errorEv.target = this;
          this.onerror?.(errorEv);
          this.dispatchEvent(errorEv);

          this.#readyState = CLOSED;
          const closeEv = new CloseEvent("close");
          closeEv.target = this;
          this.onclose?.(closeEv);
          this.dispatchEvent(closeEv);
        }
      }
    }
  }

  Object.defineProperties(WebSocket, {
    CONNECTING: {
      value: 0,
    },
    OPEN: {
      value: 1,
    },
    CLOSING: {
      value: 2,
    },
    CLOSED: {
      value: 3,
    },
  });

  window.__bootstrap.webSocket = {
    WebSocket,
  };
})(this);