<?php

namespace BaoPham\TreeParser;

class TreeParser
{
	private $indentation = 2;

	/** @var string */
	private $tree;

	/** @var int */
	private $initialSpaces;

	/** @var array */
	private $structure;

	/** @var array */
	private $orderedNodes;


	/**
	 * TreeParser constructor.
	 * @param string $tree
	 *
	 * <<<TREE
	 *  Root
	 *    |- Level 1 - Order 1
	 *      |- Level 2 - Order 2
	 *        |- Level 3 - Order 3
	 *        |- Level 3 - Order 4
	 *      |- Level 2 - Order 5
	 *    |- Level 1 - Order 6
	 *      |- Level 2 - Order 7
	 *        |- Level 3 - Order 8
	 *          |- Level 4 - Order 9
	 * TREE;
	 */
	public function __construct($tree)
	{
		$this->tree = $tree;
	}


	public function parse()
	{
		$lines = explode(PHP_EOL, $this->tree);

		$this->setStructureAndOrderedNodes($lines);

		$root = $this->structure[TreeNode::ROOT_LEVEL][TreeNode::ROOT_ORDER];

		foreach ($this->orderedNodes as $node) {
		    if ($node->isRoot) {
		        continue;
		    }

		    $parent = $this->getParentForNode($node);

		    $parent->children[] = $node;

		    $node->parent = $parent;
		}

		return $root;
	}


	public function setTree($tree)
	{
		$this->tree = $tree;
	}


	public function getTree()
	{
		return $this->tree;
	}


	/**
	 * @return array
	 */
	public function getOrderedNodes()
	{
		return $this->orderedNodes;
	}


	/**
	 * @return array
	 */
	public function getStructure()
	{
		return $this->structure;
	}


	/**
	 * @param int $indentation
	 * @return TreeParser
	 */
	public function setIndentation($indentation)
	{
		$this->indentation = $indentation;
		return $this;
	}


	/**
	 * @param TreeNode $node
	 * @return TreeNode|null
	 */
	public function getParentForNode(TreeNode $node)
	{
		if ($node->level === TreeNode::ROOT_LEVEL) {
		    return null;
		}

		$parentLevel = $node->level - 1;

		$candidates = $this->structure[$parentLevel];

		$order = $node->order - 1;

		while ($order >= TreeNode::ROOT_ORDER) {
		    if (isset($candidates[$order])) {
		        return $candidates[$order];
		    }

		    --$order;
		}
	}


	/**
	 * @param $line
	 * @return int
	 */
	private function numberOfSpaces($line)
	{
		return strspn($line, ' ');
	}


	/**
	 * @param $numberOfSpaces
	 * @return int
	 * @throws InvalidNumberOfSpaces
	 */
	private function spacesToLevel($numberOfSpaces)
	{
		if ($numberOfSpaces === $this->initialSpaces) {
		    return 0;
		}

		if (($numberOfSpaces - $this->initialSpaces) % $this->indentation !== 0) {
		    throw new InvalidNumberOfSpaces(
		        "Make sure children's leading spaces being a multiple of {$this->indentation}"
		    );
		}

		return (int) ($numberOfSpaces - $this->initialSpaces) / $this->indentation;
	}


	private function lineToNode($line)
	{
		$line = trim($line);
		$line = ltrim($line, '|-');
		$line = trim($line);

		$node = new TreeNode();

		$node->name = $line;

		return $node;
	}


	private function setStructureAndOrderedNodes(array $lines)
	{
		$this->orderedNodes = [];

		$this->initialSpaces = null;

		$this->structure = [];

		foreach ($lines as $order => $line) {
		    $node = $this->lineToNode($line);

		    if ($this->initialSpaces === null) {
		        $this->initialSpaces = $this->numberOfSpaces($line);
		        $node->isRoot = true;
		    }

		    $node->order = (int) $order;

		    $node->level = $this->spacesToLevel($this->numberOfSpaces($line));

		    $this->structure[$node->level][$node->order] = $node;

		    $this->orderedNodes[] = $node;
		}
	}
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----NTIwNDgyMzQ5NDEzNjI0NyA0OTc0NTg3NDMwNjM2MzE5IDQ4MTk3NDAxOTE0NDY3NjY=