/*
 
* Java GPX Library (@__identifier__@).
 
* Copyright (c) @__year__@ Franz Wilhelmstötter
 
*
 
* 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.
 
*
 
* Author:
 
*
    
Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
 
*/
package io.jenetics.jpx;

import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
import static io.jenetics.jpx.Format.parseURI;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.net.URI;
import java.util.Objects;
import java.util.Optional;

/**
 
* Represents a link to an external resource (Web page, digital photo, video
 
* clip, etc) with additional information.
 
*
 
* @author<a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
 
* @version 1.2
 
* @since 1.0
 
*/

public final class Link implements Serializable {

	
private static final long serialVersionUID = 2L;

	
private final URI _href;
	
private final String _text;
	
private final String _type;

	
/**
	 
* Create a new {@code Link} object with the given parameters.
	 
*
	 
* @param href the hyperlink (mandatory)
	 
* @param text the text of the hyperlink (optional)
	 
* @param type the mime type of the content, e.g. {@code image/jpeg}
	 
*
        
(optional)
	 
* @throws NullPointerException if the given {@code href} is {@code null}
	 
*/

	
private Link(final URI href, final String text, final String type) {
		
_href = requireNonNull(href);
		
_text = text;
		
_type = type;
	
}

	
/**
	 
* Return the hyperlink.
	 
*
	 
* @return the hyperlink
	 
*/
	
public URI getHref() {
		
return _href;
	
}

	
/**
	 
* Return the hyperlink text.
	 
*
	 
* @return the hyperlink text
	 
*/

	
public Optional<String> getText() {
		
return Optional.ofNullable(_text);
	
}

	
/**
	 
* Return the mime type of the hyperlink
	 
*
	 
* @return the mime type
	 
*/
	
public Optional<String> getType() {
		
return Optional.ofNullable(_type);
	
}

	
@Override
	
public int hashCode() {
		
int hash = 37;
		
hash += 17*Objects.hashCode(_href) + 31;
		
hash += 17*Objects.hashCode(_text) + 31;
		
hash += 17*Objects.hashCode(_type) + 31;
		
return hash;
	
}

	
@Override
	
public boolean equals(final Object obj) {
		
return obj == this ||
			
obj instanceof Link &&
			
Objects.equals(((Link)obj)._href, _href) &&
			
Objects.equals(((Link)obj)._text, _text) &&
			
Objects.equals(((Link)obj)._type, _type);
	
}

	
@Override
	
public String toString() {
		
return format("Link[%s, text=%s, type=%s]", _href, _text, _type);
	
}


	
/* *************************************************************************
	 
*
  
Static object creation methods
	 
* ************************************************************************/


	
/**
	 
* Create a new {@code Link} object with the given parameters.
	 
*
	 
* @param href the hyperlink (mandatory)
	 
* @param text the text of the hyperlink (optional)
	 
* @param type the mime type of the content, e.g. {@code image/jpeg}
	 
*
        
(optional)
	 
* @return a new {@code Link} object with the given parameters
	 
* @throws NullPointerException if the given {@code href} is {@code null}
	 
*/

	
public static Link of(final URI href, final String text, final String type) {
		
return new Link(href, text, type);
	
}

	
/**
	 
* Create a new {@code Link} object with the given parameters.
	 
*
	 
* @param href the hyperlink (mandatory)
	 
* @param text the text of the hyperlink (optional)
	 
* @param type the mime type of the content, e.g. {@code image/jpeg}
	 
*
        
(optional)
	 
* @return a new {@code Link} object with the given parameters
	 
* @throws NullPointerException if the given {@code href} is {@code null}
	 
* @throws IllegalArgumentException if the given {@code href} is not a valid
	 
*
         
URL
	 
*/

	
public static Link of(final String href, final String text, final String type) {
		
return new Link(parseURI(requireNonNull(href)), text, type);
	
}

	
/**
	 
* Create a new {@code Link} object with the given {@code href}.
	 
*
	 
* @param href the hyperlink (mandatory)
	 
* @return a new {@code Link} object with the given {@code href}
	 
* @throws NullPointerException if the given {@code href} is {@code null}
	 
*/

	
public static Link of(final URI href) {
		
return new Link(href, null, null);
	
}

	
/**
	 
* Create a new {@code Link} object with the given {@code href}.
	 
*
	 
* @param href the hyperlink (mandatory)
	 
* @return a new {@code Link} object with the given {@code href}
	 
* @throws NullPointerException if the given {@code href} is {@code null}
	 
* @throws IllegalArgumentException if the given {@code href} is not a valid
	 
*
         
URL
	 
*/

	
public static Link of(final String href) {
		
return new Link(parseURI(requireNonNull(href)), null, null);
	
}

	
/* *************************************************************************
	 
*
  
Java object serialization
	 
* ************************************************************************/

	
private Object writeReplace() {
		
return new Serial(Serial.LINK, this);
	
}

	
private void readObject(final ObjectInputStream stream)
		
throws InvalidObjectException
	
{
		
throw new InvalidObjectException("Serialization proxy required.");
	
}

	
void write(final DataOutput out) throws IOException {
		
IO.writeString(_href.toString(), out);
		
IO.writeNullableString(_text, out);
		
IO.writeNullableString(_type, out);
	
}

	
static Link read(final DataInput in) throws IOException {
		
return new Link(
			
parseURI((IO.readString(in))),
			
IO.readNullableString(in),
			
IO.readNullableString(in)
		
);
	
}

	
/* *************************************************************************
	 
*
  
XML stream object serialization
	 
* ************************************************************************/


	
static final XMLWriter<Link> WRITER = XMLWriter.elem("link",
		
XMLWriter.attr("href").map(link -> link._href),
		
XMLWriter.elem("text").map(link -> link._text),
		
XMLWriter.elem("type").map(link -> link._type)
	
);

	
static final XMLReader<Link> READER = XMLReader.elem(
		
v -> Link.of((URI)v[0], (String)v[1], (String)v[2]),
		
"link",
		
XMLReader.attr("href").map(Format::parseURI),
		
XMLReader.elem("text"),
		
XMLReader.elem("type")
	
);

}