<?php

/*
* This file is part of Composer.
*
* (c) Nils Adermann <naderman@naderman.de>
* Jordi Boggiano <j.boggiano@seld.be>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/

namespace Composer\Package;

use Composer\Semver\Constraint\ConstraintInterface;

/**
* Represents a link between two packages, represented by their names
*
* @author Nils Adermann <naderman@naderman.de>
*/
class Link
{
/**
* @var string
*/
protected $source;

/**
* @var string
*/
protected $target;

/**
* @var ConstraintInterface|null
*/
protected $constraint;

/**
* @var string
*/
protected $description;

/**
* @var string|null
*/
protected $prettyConstraint;

/**
* Creates a new package link.
*
* @param string $source
* @param string $target
* @param ConstraintInterface|null $constraint Constraint applying to the target of this link
* @param string $description Used to create a descriptive string representation
* @param string|null $prettyConstraint
*/
public function __construct($source, $target, ConstraintInterface $constraint = null, $description = 'relates to', $prettyConstraint = null)
{
$this->source = strtolower($source);
$this->target = strtolower($target);
$this->constraint = $constraint;
$this->description = $description;
$this->prettyConstraint = $prettyConstraint;
}

/**
* @return string
*/
public function getDescription()
{
return $this->description;
}

/**
* @return string
*/
public function getSource()
{
return $this->source;
}

/**
* @return string
*/
public function getTarget()
{
return $this->target;
}

/**
* @return ConstraintInterface|null
*/
public function getConstraint()
{
return $this->constraint;
}

/**
* @throws \UnexpectedValueException If no pretty constraint was provided
* @return string
*/
public function getPrettyConstraint()
{
if (null === $this->prettyConstraint) {
throw new \UnexpectedValueException(sprintf('Link %s has been misconfigured and had no prettyConstraint given.', $this));
}

return $this->prettyConstraint;
}

/**
* @return string
*/
public function __toString()
{
return $this->source.' '.$this->description.' '.$this->target.' ('.$this->constraint.')';
}

/**
* @param PackageInterface $sourcePackage
* @return string
*/
public function getPrettyString(PackageInterface $sourcePackage)
{
return $sourcePackage->getPrettyString().' '.$this->description.' '.$this->target.' '.$this->constraint->getPrettyString().'';
}
}