/*
 * Copyright (c) Microsoft Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.microsoft.playwright.impl;

import com.google.gson.JsonObject;
import com.microsoft.playwright.*;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Base64;
import java.util.List;

class WebSocketImpl extends ChannelOwner implements WebSocket {
  private final ListenerCollection<EventType> listeners = new ListenerCollection<>();
  private final PageImpl page;
  private boolean isClosed;

  public WebSocketImpl(ChannelOwner parent, String type, String guid, JsonObject initializer) {
    super(parent, type, guid, initializer);
    page = (PageImpl) parent;
  }

  @Override
  public void addListener(EventType type, Listener<EventType> listener) {
    listeners.add(type, listener);
  }

  @Override
  public void removeListener(EventType type, Listener<EventType> listener) {
    listeners.remove(type, listener);
  }

  @Override
  public boolean isClosed() {
    return isClosed;
  }

  @Override
  public String url() {
    return initializer.get("url").getAsString();
  }

  private class WaitableWebSocketError<R> implements Waitable<R>, Listener<EventType> {
    private final List<EventType> subscribedEvents;
    private String errorMessage;

    WaitableWebSocketError() {
      subscribedEvents = Arrays.asList(EventType.CLOSE, EventType.SOCKETERROR);
      for (EventType e : subscribedEvents) {
        addListener(e, this);
      }
    }

    @Override
    public void handle(Event<EventType> event) {
      if (EventType.SOCKETERROR == event.type()) {
        errorMessage = "Socket error";
      } else if (EventType.CLOSE == event.type()) {
        errorMessage = "Socket closed";
      } else {
        return;
      }
      dispose();
    }

    @Override
    public boolean isDone() {
      return errorMessage != null;
    }

    @Override
    public R get() {
      throw new PlaywrightException(errorMessage);
    }

    @Override
    public void dispose() {
      for (EventType e : subscribedEvents) {
        removeListener(e, this);
      }
    }
  }

  @Override
  public Deferred<Event<EventType>> waitForEvent(EventType event, WaitForEventOptions options) {
    if (options == null) {
      options = new WaitForEventOptions();
    }
    List<Waitable<Event<EventType>>> waitables = new ArrayList<>();
    waitables.add(new WaitableEvent<>(listeners, event, options.predicate));
    waitables.add(new WaitableWebSocketError<>());
    waitables.add(page.createWaitForCloseHelper());
    waitables.add(page.createWaitableTimeout(options.timeout));
    return toDeferred(new WaitableRace<>(waitables));
  }

  private static class FrameDataImpl implements FrameData {
    private final byte[] bytes;

    FrameDataImpl(String payload, boolean isBase64) {
      if (isBase64) {
        bytes = Base64.getDecoder().decode(payload);
      } else {
        bytes = payload.getBytes();
      }
    }

    @Override
    public byte[] body() {
      return bytes;
    }

    @Override
    public String text() {
      return new String(bytes, StandardCharsets.UTF_8);
    }
  }

  @Override
  void handleEvent(String event, JsonObject parameters) {
    switch (event) {
      case "frameSent": {
        FrameDataImpl frameData = new FrameDataImpl(
          parameters.get("data").getAsString(), parameters.get("opcode").getAsInt() == 2);
        listeners.notify(EventType.FRAMESENT, frameData);
        break;
      }
      case "frameReceived": {
        FrameDataImpl frameData = new FrameDataImpl(
          parameters.get("data").getAsString(), parameters.get("opcode").getAsInt() == 2);
        listeners.notify(EventType.FRAMERECEIVED, frameData);
        break;
      }
      case "socketError": {
        String error = parameters.get("error").getAsString();
        listeners.notify(EventType.SOCKETERROR, error);
        break;
      }
      case "close": {
        isClosed = true;
        listeners.notify(EventType.CLOSE, null);
        break;
      }
      default: {
        throw new PlaywrightException("Unknown event: " + event);
      }
    }
  }
}