<?php

namespace Composer\DependencyResolver;

/**
 * Wrapper around a Rule which keeps track of the two literals it watches
 *
 * Used by RuleWatchGraph to store rules in two RuleWatchChains.
 *
 * @author Nils Adermann <naderman@naderman.de>
 */
class RuleWatchNode
{
	/** @var int */
	public $watch1;

	/** @var int */
	public $watch2;

	/** @var Rule */
	protected $rule;


	/**
	 * Creates a new node watching the first and second literals of the rule.
	 *
	 * @param Rule $rule The rule to wrap
	 */
	public function __construct(Rule $rule)
	{
		$this->rule = $rule;

		$literals = $rule->getLiterals();

		$literalCount = \count($literals);
		$this->watch1 = $literalCount > 0 ? $literals[0] : 0;
		$this->watch2 = $literalCount > 1 ? $literals[1] : 0;
	}


	/**
	 * Places the second watch on the rule's literal, decided at the highest level
	 *
	 * Useful for learned rules where the literal for the highest rule is most
	 * likely to quickly lead to further decisions.
	 *
	 * @param Decisions $decisions The decisions made so far by the solver
	 */
	public function watch2OnHighest(Decisions $decisions): void
	{
		$literals = $this->rule->getLiterals();

		// if there are only 2 elements, both are being watched anyway
		if (\count($literals) < 3 || $this->rule instanceof MultiConflictRule) {
		    return;
		}

		$watchLevel = 0;

		foreach ($literals as $literal) {
		    $level = $decisions->decisionLevel($literal);

		    if ($level > $watchLevel) {
		        $this->watch2 = $literal;
		        $watchLevel = $level;
		    }
		}
	}


	/**
	 * Returns the rule this node wraps
	 */
	public function getRule(): Rule
	{
		return $this->rule;
	}


	/**
	 * Given one watched literal, this method returns the other watched literal
	 *
	 * @param  int $literal The watched literal that should not be returned
	 * @return int A literal
	 */
	public function getOtherWatch(int $literal): int
	{
		if ($this->watch1 === $literal) {
		    return $this->watch2;
		}

		return $this->watch1;
	}


	/**
	 * Moves a watch from one literal to another
	 *
	 * @param int $from The previously watched literal
	 * @param int $to   The literal to be watched now
	 */
	public function moveWatch(int $from, int $to): void
	{
		if ($this->watch1 === $from) {
		    $this->watch1 = $to;
		} else {
		    $this->watch2 = $to;
		}
	}
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----ODI3MjMwMzEwMDI3NTA4MSA4NjEzMjg3MDIyNjY3OTEgNTc1MTk2MzIyNjg2MzIwMA==