/**

* Jooby https://jooby.io

* Apache License Version 2.0 https://jooby.io/LICENSE.txt

* Copyright 2014 Edgar Espina

*/

package io.jooby;

import javax.annotation.Nonnull;

import javax.annotation.Nullable;

import java.io.ByteArrayOutputStream;

import java.util.Arrays;

import static java.nio.charset.StandardCharsets.UTF_8;

/**

* Server-Sent message.

*

* @author edgar

* @since 2.5.0

*/

public class ServerSentMessage {

private static final byte SEPARATOR = '\n';

private static final byte[] ID = "id:".getBytes(UTF_8);

private static final byte[] EVENT = "event:".getBytes(UTF_8);

private static final byte[] RETRY = "retry:".getBytes(UTF_8);

private static final byte[] DATA = "data:".getBytes(UTF_8);

private Object id;

private String event;

private final Object data;

private Long retry;

/**

* Creates a new message.

*

* @param data Data. Must not be <code>null</code>.

*/

public ServerSentMessage(@Nonnull Object data) {

this.data = data;

}

/**

* The event ID to set the EventSource object's last event ID value.

*

* @return The event ID to set the EventSource object's last event ID value.

*/

public @Nullable Object getId() {

return id;

}

/**

* Set The event ID to set the EventSource object's last event ID value.

*

* @param id Event ID. Converted to String.

* @return This message.

*/

public @Nonnull ServerSentMessage setId(@Nullable Object id) {

this.id = id == null ? null : id.toString();

return this;

}

/**

* A string identifying the type of event described. If this is specified, an event will be

* dispatched on the browser to the listener for the specified event name; the website source

* code should use addEventListener() to listen for named events. The onmessage handler is

* called if no event name is specified for a message.

*

* @return Event type.

*/

public @Nullable String getEvent() {

return event;

}

/**

* Set event type.

*

* @param event Event type.

* @return This message.

*/

public @Nonnull ServerSentMessage setEvent(@Nullable String event) {

this.event = event;

return this;

}

/**

* The data field for the message. When the EventSource receives multiple consecutive lines that

* begin with data:, it will concatenate them, inserting a newline character between each one.

* Trailing newlines are removed.

*

* @return Data.

*/

public @Nonnull Object getData() {

return data;

}

/**

* The reconnection time to use when attempting to send the event. This must be an integer,

* specifying the reconnection time in milliseconds. If a non-integer value is specified,

* the field is ignored.

*

* @return Retry option.

*/

public @Nullable Long getRetry() {

return retry;

}

/**

* Set retry option.

*

* @param retry Retry option.

* @return This message.

*/

public @Nonnull ServerSentMessage setRetry(@Nullable Long retry) {

this.retry = retry;

return this;

}

/**

* Encode message as event source stream format.

*

* @param ctx Web context. To encode complex objects.

* @return Encoded data.

*/

public @Nonnull byte[] toByteArray(@Nonnull Context ctx) {

try {

Route route = ctx.getRoute();

MessageEncoder encoder = route.getEncoder();

byte[] bytes = encoder.encode(ctx, data);

ByteArrayOutputStream buffer = new ByteArrayOutputStream(bytes.length);

if (id != null) {

buffer.write(ID);

buffer.write(id.toString().getBytes(UTF_8));

buffer.write(SEPARATOR);

}

if (event != null) {

buffer.write(EVENT);

buffer.write(event.getBytes(UTF_8));

buffer.write(SEPARATOR);

}

if (retry != null) {

buffer.write(RETRY);

buffer.write(retry.toString().getBytes(UTF_8));

buffer.write(SEPARATOR);

}

/** do multi-line processing: */

buffer.write(DATA);

int offset = 0;

for (int i = 0; i < bytes.length; i++) {

byte ch = bytes[i];

if (ch == '\n') {

buffer.write(Arrays.copyOfRange(bytes, offset, offset + i));

buffer.write(SEPARATOR);

if (i + 1 < bytes.length) {

buffer.write(DATA);

}

offset = i + 1;

}

}

if (offset == 0) {

buffer.write(bytes);

} else if (offset < bytes.length) {

buffer.write(Arrays.copyOfRange(bytes, offset, bytes.length));

}

buffer.write(SEPARATOR);

buffer.write(SEPARATOR);

return buffer.toByteArray();

} catch (Exception x) {

throw SneakyThrows.propagate(x);

}

}

}