<?php

/**
 * Spyc -- A Simple PHP YAML Class
 *
 * This class can be used to read a YAML file and convert its contents
 * into a PHP array.  It currently supports a very limited subsection of
 * the YAML spec.
 *
 * @version 0.6.3 (Kirby fork for PHP 8.1+)
 * @author Vlad Andersen <vlad.andersen@gmail.com>
 * @author Chris Wanstrath <chris@ozmm.org>
 * @link https://github.com/mustangostang/spyc/
 * @copyright Copyright 2005-2006 Chris Wanstrath, 2006-2011 Vlad Andersen
 * @license http://www.opensource.org/licenses/mit-license.php MIT License
 * @package Spyc
 */
class Spyc
{
    // SETTINGS

    public const REMPTY = "\0\0\0\0\0";

    /**
     * Setting this to true will force YAMLDump to enclose any string value in
     * quotes.  False by default.
     *
     * @var bool
     */
    public $setting_dump_force_quotes = false;

    /**
     * Setting this to true will forse YAMLLoad to use syck_load function when
     * possible. False by default.
     * @var bool
     */
    public $setting_use_syck_is_possible = false;

    /**
     * Setting this to true will forse YAMLLoad to use syck_load function when
     * possible. False by default.
     * @var bool
     */
    public $setting_empty_hash_as_object = false;

    /**#@+
     * @access private
     * @var mixed
     */
    private $_dumpIndent;
    private $_dumpWordWrap;
    private $_containsGroupAnchor = false;
    private $_containsGroupAlias = false;
    private $path;
    private $result;
    private $LiteralPlaceHolder = '___YAML_Literal_Block___';
    private $SavedGroups = array();
    private $indent;
    /**
     * Path modifier that should be applied after adding current element.
     * @var array
     */
    private $delayedPath = array();

    /**#@+
     * @access public
     * @var mixed
     */
    public $_nodeId;

    /**
     * Load a valid YAML string to Spyc.
     * @param string $input
     * @return array
     */
    public function load($input)
    {
        return $this->_loadString($input);
    }

    /**
     * Load a valid YAML file to Spyc.
     * @param string $file
     * @return array
     */
    public function loadFile($file)
    {
        return $this->_load($file);
    }

    /**
     * Load YAML into a PHP array statically
     *
     * The load method, when supplied with a YAML stream (string or file),
     * will do its best to convert YAML in a file into a PHP array.  Pretty
     * simple.
     *  Usage:
     *  <code>
     *   $array = Spyc::YAMLLoad('lucky.yaml');
     *   print_r($array);
     *  </code>
     * @access public
     * @param string $input Path of YAML file or string containing YAML
     * @param array set options
     * @return array
     */
    public static function YAMLLoad($input, $options = [])
    {
        $Spyc = new Spyc();
        foreach ($options as $key => $value) {
            if (property_exists($Spyc, $key)) {
                $Spyc->$key = $value;
            }
        }
        return $Spyc->_load($input);
    }

    /**
     * Load a string of YAML into a PHP array statically
     *
     * The load method, when supplied with a YAML string, will do its best
     * to convert YAML in a string into a PHP array.  Pretty simple.
     *
     * Note: use this function if you don't want files from the file system
     * loaded and processed as YAML.  This is of interest to people concerned
     * about security whose input is from a string.
     *
     *  Usage:
     *  <code>
     *   $array = Spyc::YAMLLoadString("---\n0: hello world\n");
     *   print_r($array);
     *  </code>
     * @access public
     * @param string $input String containing YAML
     * @param array set options
     * @return array
     */
    public static function YAMLLoadString($input, $options = [])
    {
        $Spyc = new Spyc();
        foreach ($options as $key => $value) {
            if (property_exists($Spyc, $key)) {
                $Spyc->$key = $value;
            }
        }
        return $Spyc->_loadString($input);
    }

    /**
     * Dump YAML from PHP array statically
     *
     * The dump method, when supplied with an array, will do its best
     * to convert the array into friendly YAML.  Pretty simple.  Feel free to
     * save the returned string as nothing.yaml and pass it around.
     *
     * Oh, and you can decide how big the indent is and what the wordwrap
     * for folding is.  Pretty cool -- just pass in 'false' for either if
     * you want to use the default.
     *
     * Indent's default is 2 spaces, wordwrap's default is 40 characters.  And
     * you can turn off wordwrap by passing in 0.
     *
     * @access public
     * @param array|\stdClass $array PHP array
     * @param int $indent Pass in false to use the default, which is 2
     * @param int $wordwrap Pass in 0 for no wordwrap, false for default (40)
     * @param bool $no_opening_dashes Do not start YAML file with "---\n"
     * @return string
     */
    public static function YAMLDump($array, $indent = false, $wordwrap = false, $no_opening_dashes = false)
    {
        $spyc = new Spyc();
        return $spyc->dump($array, $indent, $wordwrap, $no_opening_dashes);
    }

    /**
     * Dump PHP array to YAML
     *
     * The dump method, when supplied with an array, will do its best
     * to convert the array into friendly YAML.  Pretty simple.  Feel free to
     * save the returned string as tasteful.yaml and pass it around.
     *
     * Oh, and you can decide how big the indent is and what the wordwrap
     * for folding is.  Pretty cool -- just pass in 'false' for either if
     * you want to use the default.
     *
     * Indent's default is 2 spaces, wordwrap's default is 40 characters.  And
     * you can turn off wordwrap by passing in 0.
     *
     * @access public
     * @param array $array PHP array
     * @param int $indent Pass in false to use the default, which is 2
     * @param int $wordwrap Pass in 0 for no wordwrap, false for default (40)
     * @return string
     */
    public function dump($array, $indent = false, $wordwrap = false, $no_opening_dashes = false)
    {
        // Dumps to some very clean YAML.  We'll have to add some more features
        // and options soon.  And better support for folding.

        // New features and options.
        if ($indent === false or !is_numeric($indent)) {
            $this->_dumpIndent = 2;
        } else {
            $this->_dumpIndent = $indent;
        }

        if ($wordwrap === false or !is_numeric($wordwrap)) {
            $this->_dumpWordWrap = 40;
        } else {
            $this->_dumpWordWrap = $wordwrap;
        }

        // New YAML document
        $string = "";
        if (!$no_opening_dashes) $string = "---\n";

        // Start at the base of the array and move through it.
        if ($array) {
            $array = (array)$array;
            $previous_key = -1;
            foreach ($array as $key => $value) {
                if (!isset($first_key)) $first_key = $key;
                $string .= $this->_yamlize($key, $value, 0, $previous_key, $first_key, $array);
                $previous_key = $key;
            }
        }
        return $string;
    }

    /**
     * Attempts to convert a key / value array item to YAML
     * @access private
     * @param $key The name of the key
     * @param $value The value of the item
     * @param $indent The indent of the current node
     * @return string
     */
    private function _yamlize($key, $value, $indent, $previous_key = -1, $first_key = 0, $source_array = null)
    {
        if (is_object($value)) $value = (array)$value;
        if (is_array($value)) {
            if (empty ($value))
                return $this->_dumpNode($key, array(), $indent, $previous_key, $first_key, $source_array);
            // It has children.  What to do?
            // Make it the right kind of item
            $string = $this->_dumpNode($key, self::REMPTY, $indent, $previous_key, $first_key, $source_array);
            // Add the indent
            $indent += $this->_dumpIndent;
            // Yamlize the array
            $string .= $this->_yamlizeArray($value, $indent);
        } elseif (!is_array($value)) {
            // It doesn't have children.  Yip.
            $string = $this->_dumpNode($key, $value, $indent, $previous_key, $first_key, $source_array);
        }
        return $string;
    }

    /**
     * Attempts to convert an array to YAML
     * @access private
     * @param $array The array you want to convert
     * @param $indent The indent of the current level
     * @return string
     */
    private function _yamlizeArray($array, $indent)
    {
        if (is_array($array)) {
            $string = '';
            $previous_key = -1;
            foreach ($array as $key => $value) {
                if (!isset($first_key)) $first_key = $key;
                $string .= $this->_yamlize($key, $value, $indent, $previous_key, $first_key, $array);
                $previous_key = $key;
            }
            return $string;
        } else {
            return false;
        }
    }

    /**
     * Returns YAML from a key and a value
     * @access private
     * @param $key The name of the key
     * @param $value The value of the item
     * @param $indent The indent of the current node
     * @return string
     */
    private function _dumpNode($key, $value, $indent, $previous_key = -1, $first_key = 0, $source_array = null)
    {
        // do some folding here, for blocks
        if (
            is_string($value) &&
            (
                strpos($value, "\n") !== false ||
                strpos($value, ": ") !== false ||
                strpos($value, "- ") !== false ||
                strpos($value, "*") !== false ||
                strpos($value, "#") !== false ||
                strpos($value, "<") !== false ||
                strpos($value, ">") !== false ||
                strpos($value, '%') !== false ||
                strpos($value, '  ') !== false ||
                strpos($value, "[") !== false ||
                strpos($value, "]") !== false ||
                strpos($value, "{") !== false ||
                strpos($value, "}") !== false ||
                strpos($value, "&") !== false ||
                strpos($value, "'") !== false ||
                strpos($value, "!") === 0 ||
                substr($value, -1, 1) == ':'
            )
        ) {
            $value = $this->_doLiteralBlock($value, $indent);
        } else {
            $value = $this->_doFolding($value, $indent);
        }

        if ($value === array()) $value = '[ ]';
        if ($value === "") $value = '""';
        if (self::isTranslationWord($value)) {
            $value = $this->_doLiteralBlock($value, $indent);
        }
        if (trim($value ?? '') != $value)
            $value = $this->_doLiteralBlock($value, $indent);

        if (is_bool($value)) {
            $value = $value ? "true" : "false";
        }

        if ($value === null) $value = 'null';
        if ($value === "'" . self::REMPTY . "'") $value = null;

        $spaces = str_repeat(' ', $indent);

        //if (is_int($key) && $key - 1 == $previous_key && $first_key===0) {
        if (is_array($source_array) && array_keys($source_array) === range(0, count($source_array) - 1)) {
            // It's a sequence
            $string = $spaces . '- ' . $value . "\n";
        } else {
            // if ($first_key===0)  throw new Exception('Keys are all screwy.  The first one was zero, now it\'s "'. $key .'"');
            // It's mapped
            if (strpos($key, ":") !== false || strpos($key, "#") !== false) {
                $key = '"' . $key . '"';
            }
            $string = rtrim($spaces . $key . ': ' . $value) . "\n";
        }
        return $string;
    }

    /**
     * Creates a literal block for dumping
     * @access private
     * @param $value
     * @param $indent int The value of the indent
     * @return string
     */
    private function _doLiteralBlock($value, $indent)
    {
        $value ??= '';

        if ($value === "\n") return '\n';
        if (strpos($value, "\n") === false && strpos($value, "'") === false) {
            return sprintf("'%s'", $value);
        }
        if (strpos($value, "\n") === false && strpos($value, '"') === false) {
            return sprintf('"%s"', $value);
        }
        $exploded = explode("\n", $value);
        $newValue = '|';
        if (isset($exploded[0]) && ($exploded[0] == "|" || $exploded[0] == "|-" || $exploded[0] == ">")) {
            $newValue = $exploded[0];
            unset($exploded[0]);
        }
        $indent += $this->_dumpIndent;
        $spaces = str_repeat(' ', $indent);
        foreach ($exploded as $line) {
            $line = trim($line);
            if (strpos($line, '"') === 0 && strrpos($line, '"') == (strlen($line) - 1) || strpos($line, "'") === 0 && strrpos($line, "'") == (strlen($line) - 1)) {
                $line = substr($line, 1, -1);
            }
            $newValue .= "\n" . $spaces . ($line);
        }
        return $newValue;
    }

    /**
     * Folds a string of text, if necessary
     * @access private
     * @param $value The string you wish to fold
     * @return string
     */
    private function _doFolding($value, $indent)
    {
        // Don't do anything if wordwrap is set to 0
        if ($this->_dumpWordWrap !== 0 && is_string($value) && strlen($value) > $this->_dumpWordWrap) {
            $indent += $this->_dumpIndent;
            $indent = str_repeat(' ', $indent);
            $wrapped = wordwrap($value, $this->_dumpWordWrap, "\n$indent");
            $value = ">\n" . $indent . $wrapped;
        } else {
            if ($this->setting_dump_force_quotes && is_string($value) && $value !== self::REMPTY)
                $value = '"' . $value . '"';
            if (is_numeric($value) && is_string($value))
                $value = '"' . $value . '"';
        }


        return $value;
    }

    private function isTrueWord($value)
    {
        $words = self::getTranslations(array('true', 'on', 'yes', 'y'));
        return in_array($value, $words, true);
    }

    private function isFalseWord($value)
    {
        $words = self::getTranslations(array('false', 'off', 'no', 'n'));
        return in_array($value, $words, true);
    }

    private function isNullWord($value)
    {
        $words = self::getTranslations(array('null', '~'));
        return in_array($value, $words, true);
    }

    private function isTranslationWord($value)
    {
        return (
            self::isTrueWord($value) ||
            self::isFalseWord($value) ||
            self::isNullWord($value)
        );
    }

    /**
     * Coerce a string into a native type
     * Reference: http://yaml.org/type/bool.html
     * TODO: Use only words from the YAML spec.
     * @access private
     * @param $value The value to coerce
     */
    private function coerceValue(&$value)
    {
        if (self::isTrueWord($value)) {
            $value = true;
        } elseif (self::isFalseWord($value)) {
            $value = false;
        } elseif (self::isNullWord($value)) {
            $value = null;
        }
    }

    /**
     * Given a set of words, perform the appropriate translations on them to
     * match the YAML 1.1 specification for type coercing.
     * @param $words The words to translate
     * @access private
     */
    private static function getTranslations(array $words)
    {
        $result = array();
        foreach ($words as $i) {
            $result = array_merge($result, array(ucfirst($i), strtoupper($i), strtolower($i)));
        }
        return $result;
    }

    // LOADING FUNCTIONS

    private function _load($input)
    {
        $Source = $this->loadFromSource($input);
        return $this->loadWithSource($Source);
    }

    private function _loadString($input)
    {
        $Source = $this->loadFromString($input);
        return $this->loadWithSource($Source);
    }

    private function loadWithSource($Source)
    {
        if (empty ($Source)) return array();
        if ($this->setting_use_syck_is_possible && function_exists('syck_load')) {
            $array = syck_load(implode("\n", $Source));
            return is_array($array) ? $array : array();
        }

        $this->path = array();
        $this->result = array();

        $cnt = count($Source);
        for ($i = 0; $i < $cnt; $i++) {
            $line = $Source[$i];

            $this->indent = strlen($line) - strlen(ltrim($line));
            $tempPath = $this->getParentPathByIndent($this->indent);
            $line = self::stripIndent($line, $this->indent);
            if (self::isComment($line)) continue;
            if (self::isEmpty($line)) continue;
            $this->path = $tempPath;

            $literalBlockStyle = self::startsLiteralBlock($line);
            if ($literalBlockStyle) {
                $line = rtrim($line, $literalBlockStyle . " \n");
                $literalBlock = '';
                $line .= ' ' . $this->LiteralPlaceHolder;
                $literal_block_indent = strlen($Source[$i + 1]) - strlen(ltrim($Source[$i + 1]));
                while (++$i < $cnt && $this->literalBlockContinues($Source[$i], $this->indent)) {
                    $literalBlock = $this->addLiteralLine($literalBlock, $Source[$i], $literalBlockStyle, $literal_block_indent);
                }
                $i--;
            }

            // Strip out comments
            if (strpos($line, '#')) {
                $line = preg_replace('/\s*#([^"\']+)$/', '', $line);
            }

            while (++$i < $cnt && self::greedilyNeedNextLine($line)) {
                $line = rtrim($line, " \n\t\r") . ' ' . ltrim($Source[$i], " \t");
            }
            $i--;

            $lineArray = $this->_parseLine($line);

            if ($literalBlockStyle)
                $lineArray = $this->revertLiteralPlaceHolder($lineArray, $literalBlock);

            $this->addArray($lineArray, $this->indent);

            foreach ($this->delayedPath as $indent => $delayedPath)
                $this->path[$indent] = $delayedPath;

            $this->delayedPath = array();

        }
        return $this->result;
    }

    private function loadFromSource($input)
    {
        if (!empty($input) && strpos($input, "\n") === false && file_exists($input))
            $input = file_get_contents($input);

        return $this->loadFromString($input);
    }

    private function loadFromString($input)
    {
        $lines = explode("\n", $input);
        foreach ($lines as $k => $_) {
            $lines[$k] = rtrim($_, "\r");
        }
        return $lines;
    }

    /**
     * Parses YAML code and returns an array for a node
     * @access private
     * @param string $line A line from the YAML file
     * @return array
     */
    private function _parseLine($line)
    {
        if (!$line) return array();
        $line = trim($line);
        if (!$line) return array();

        $group = $this->nodeContainsGroup($line);
        if ($group) {
            $this->addGroup($line, $group);
            $line = $this->stripGroup($line, $group);
        }

        if ($this->startsMappedSequence($line)) {
            return $this->returnMappedSequence($line);
        }

        if ($this->startsMappedValue($line)) {
            return $this->returnMappedValue($line);
        }

        if ($this->isArrayElement($line))
            return $this->returnArrayElement($line);

        if ($this->isPlainArray($line))
            return $this->returnPlainArray($line);

        return $this->returnKeyValuePair($line);
    }

    /**
     * Finds the type of the passed value, returns the value as the new type.
     * @access private
     * @param string $value
     * @return mixed
     */
    private function _toType($value)
    {
        if ($value === '') return "";

        if ($this->setting_empty_hash_as_object && $value === '{}') {
            return new stdClass();
        }

        $first_character = $value[0];
        $last_character = substr($value, -1, 1);

        $is_quoted = false;
        do {
            if (!$value) break;
            if ($first_character != '"' && $first_character != "'") break;
            if ($last_character != '"' && $last_character != "'") break;
            $is_quoted = true;
        } while (0);

        if ($is_quoted) {
            $value = str_replace('\n', "\n", $value);
            if ($first_character == "'")
                return strtr(substr($value, 1, -1), array('\'\'' => '\'', '\\\'' => '\''));
            return strtr(substr($value, 1, -1), array('\\"' => '"', '\\\'' => '\''));
        }

        if (strpos($value, ' #') !== false && !$is_quoted)
            $value = preg_replace('/\s+#(.+)$/', '', $value);

        if ($first_character == '[' && $last_character == ']') {
            // Take out strings sequences and mappings
            $innerValue = trim(substr($value, 1, -1));
            if ($innerValue === '') return array();
            $explode = $this->_inlineEscape($innerValue);
            // Propagate value array
            $value = array();
            foreach ($explode as $v) {
                $value[] = $this->_toType($v);
            }
            return $value;
        }

        if (strpos($value, ': ') !== false && $first_character != '{') {
            $array = explode(': ', $value);
            $key = trim($array[0]);
            array_shift($array);
            $value = trim(implode(': ', $array));
            $value = $this->_toType($value);
            return array($key => $value);
        }

        if ($first_character == '{' && $last_character == '}') {
            $innerValue = trim(substr($value, 1, -1));
            if ($innerValue === '') return array();
            // Inline Mapping
            // Take out strings sequences and mappings
            $explode = $this->_inlineEscape($innerValue);
            // Propagate value array
            $array = array();
            foreach ($explode as $v) {
                $SubArr = $this->_toType($v);
                if (empty($SubArr)) continue;
                if (is_array($SubArr)) {
                    $array[key($SubArr)] = $SubArr[key($SubArr)];
                    continue;
                }
                $array[] = $SubArr;
            }
            return $array;
        }

        if ($value == 'null' || $value == 'NULL' || $value == 'Null' || $value == '' || $value == '~') {
            return null;
        }

        if (is_numeric($value) && preg_match('/^(-|)[1-9]+[0-9]*$/', $value)) {
            $intvalue = (int)$value;
            if ($intvalue != PHP_INT_MAX && $intvalue != ~PHP_INT_MAX)
                $value = $intvalue;
            return $value;
        }

        if (is_string($value) && preg_match('/^0[xX][0-9a-fA-F]+$/', $value)) {
            // Hexadecimal value.
            return hexdec($value);
        }

        $this->coerceValue($value);

        if (is_numeric($value)) {
            if ($value === '0') return 0;
            if (rtrim($value, 0) === $value)
                $value = (float)$value;
            return $value;
        }

        return $value;
    }

    /**
     * Used in inlines to check for more inlines or quoted strings
     * @access private
     * @return array
     */
    private function _inlineEscape($inline)
    {
        // There's gotta be a cleaner way to do this...
        // While pure sequences seem to be nesting just fine,
        // pure mappings and mappings with sequences inside can't go very
        // deep.  This needs to be fixed.

        $seqs = array();
        $maps = array();
        $saved_strings = array();
        $saved_empties = array();

        // Check for empty strings
        $regex = '/("")|(\'\')/';
        if (preg_match_all($regex, $inline, $strings)) {
            $saved_empties = $strings[0];
            $inline = preg_replace($regex, 'YAMLEmpty', $inline);
        }
        unset($regex);

        // Check for strings
        $regex = '/(?:(")|(?:\'))((?(1)[^"]+|[^\']+))(?(1)"|\')/';
        if (preg_match_all($regex, $inline, $strings)) {
            $saved_strings = $strings[0];
            $inline = preg_replace($regex, 'YAMLString', $inline);
        }
        unset($regex);

        $i = 0;
        do {

            // Check for sequences
            while (preg_match('/\[([^{}\[\]]+)\]/U', $inline, $matchseqs)) {
                $seqs[] = $matchseqs[0];
                $inline = preg_replace('/\[([^{}\[\]]+)\]/U', ('YAMLSeq' . (count($seqs) - 1) . 's'), $inline, 1);
            }

            // Check for mappings
            while (preg_match('/{([^\[\]{}]+)}/U', $inline, $matchmaps)) {
                $maps[] = $matchmaps[0];
                $inline = preg_replace('/{([^\[\]{}]+)}/U', ('YAMLMap' . (count($maps) - 1) . 's'), $inline, 1);
            }

            if ($i++ >= 10) break;

        } while (strpos($inline, '[') !== false || strpos($inline, '{') !== false);

        $explode = explode(',', $inline);
        $explode = array_map('trim', $explode);
        $stringi = 0;
        $i = 0;

        while (1) {

            // Re-add the sequences
            if (!empty($seqs)) {
                foreach ($explode as $key => $value) {
                    if (strpos($value, 'YAMLSeq') !== false) {
                        foreach ($seqs as $seqk => $seq) {
                            $explode[$key] = str_replace(('YAMLSeq' . $seqk . 's'), $seq, $value);
                            $value = $explode[$key];
                        }
                    }
                }
            }

            // Re-add the mappings
            if (!empty($maps)) {
                foreach ($explode as $key => $value) {
                    if (strpos($value, 'YAMLMap') !== false) {
                        foreach ($maps as $mapk => $map) {
                            $explode[$key] = str_replace(('YAMLMap' . $mapk . 's'), $map, $value);
                            $value = $explode[$key];
                        }
                    }
                }
            }

            // Re-add the strings
            if (!empty($saved_strings)) {
                foreach ($explode as $key => $value) {
                    while (strpos($value, 'YAMLString') !== false) {
                        $explode[$key] = preg_replace('/YAMLString/', $saved_strings[$stringi], $value, 1);
                        unset($saved_strings[$stringi]);
                        ++$stringi;
                        $value = $explode[$key];
                    }
                }
            }


            // Re-add the empties
            if (!empty($saved_empties)) {
                foreach ($explode as $key => $value) {
                    while (strpos($value, 'YAMLEmpty') !== false) {
                        $explode[$key] = preg_replace('/YAMLEmpty/', '', $value, 1);
                        $value = $explode[$key];
                    }
                }
            }

            $finished = true;
            foreach ($explode as $key => $value) {
                if (strpos($value, 'YAMLSeq') !== false) {
                    $finished = false;
                    break;
                }
                if (strpos($value, 'YAMLMap') !== false) {
                    $finished = false;
                    break;
                }
                if (strpos($value, 'YAMLString') !== false) {
                    $finished = false;
                    break;
                }
                if (strpos($value, 'YAMLEmpty') !== false) {
                    $finished = false;
                    break;
                }
            }
            if ($finished) break;

            $i++;
            if ($i > 10)
                break; // Prevent infinite loops.
        }

        return $explode;
    }

    private function literalBlockContinues($line, $lineIndent)
    {
        if (!trim($line ?? '')) return true;
        if (strlen($line) - strlen(ltrim($line)) > $lineIndent) return true;
        return false;
    }

    private function referenceContentsByAlias($alias)
    {
        do {
            if (!isset($this->SavedGroups[$alias])) {
                echo "Bad group name: $alias.";
                break;
            }
            $groupPath = $this->SavedGroups[$alias];
            $value = $this->result;
            foreach ($groupPath as $k) {
                $value = $value[$k];
            }
        } while (false);
        return $value;
    }

    private function addArrayInline($array, $indent)
    {
        $CommonGroupPath = $this->path;
        if (empty ($array)) return false;

        foreach ($array as $k => $_) {
            $this->addArray(array($k => $_), $indent);
            $this->path = $CommonGroupPath;
        }
        return true;
    }

    private function addArray($incoming_data, $incoming_indent)
    {
        if (count($incoming_data) > 1)
            return $this->addArrayInline($incoming_data, $incoming_indent);

        $key = key($incoming_data);
        $value = isset($incoming_data[$key]) ? $incoming_data[$key] : null;
        if ($key === '__!YAMLZero') $key = '0';

        if ($incoming_indent == 0 && !$this->_containsGroupAlias && !$this->_containsGroupAnchor) { // Shortcut for root-level values.
            if ($key || $key === '' || $key === '0') {
                $this->result[$key] = $value;
            } else {
                $this->result[] = $value;
                end($this->result);
                $key = key($this->result);
            }
            $this->path[$incoming_indent] = $key;
            return;
        }

        $history = array();
        // Unfolding inner array tree.
        $history[] = $_arr = $this->result;
        foreach ($this->path as $k) {
            $history[] = $_arr = $_arr[$k];
        }

        if ($this->_containsGroupAlias) {
            $value = $this->referenceContentsByAlias($this->_containsGroupAlias);
            $this->_containsGroupAlias = false;
        }


        // Adding string or numeric key to the innermost level or $this->arr.
        if (is_string($key) && $key == '<<') {
            if (!is_array($_arr)) {
                $_arr = array();
            }

            $_arr = array_merge($_arr, $value);
        } elseif ($key || $key === '' || $key === '0') {
            if (!is_array($_arr))
                $_arr = array($key => $value);
            else
                $_arr[$key] = $value;
        } elseif (!is_array($_arr)) {
            $_arr = array($value);
            $key = 0;
        } else {
            $_arr[] = $value;
            end($_arr);
            $key = key($_arr);
        }

        $reverse_path = array_reverse($this->path);
        $reverse_history = array_reverse($history);
        $reverse_history[0] = $_arr;
        $cnt = count($reverse_history) - 1;
        for ($i = 0; $i < $cnt; $i++) {
            $reverse_history[$i + 1][$reverse_path[$i]] = $reverse_history[$i];
        }
        $this->result = $reverse_history[$cnt];

        $this->path[$incoming_indent] = $key;

        if ($this->_containsGroupAnchor) {
            $this->SavedGroups[$this->_containsGroupAnchor] = $this->path;
            if (is_array($value)) {
                $k = key($value);
                if (!is_int($k)) {
                    $this->SavedGroups[$this->_containsGroupAnchor][$incoming_indent + 2] = $k;
                }
            }
            $this->_containsGroupAnchor = false;
        }

    }

    private static function startsLiteralBlock($line)
    {
        $lastChar = substr(trim($line ?? ''), -1);
        if ($lastChar != '>' && $lastChar != '|') return false;
        if ($lastChar == '|') return $lastChar;
        // HTML tags should not be counted as literal blocks.
        if (preg_match('#<.*?>$#', $line)) return false;
        return $lastChar;
    }

    private static function greedilyNeedNextLine($line)
    {
        $line = trim($line ?? '');
        if (!strlen($line)) return false;
        if (substr($line, -1, 1) == ']') return false;
        if ($line[0] == '[') return true;
        if (preg_match('#^[^:]+?:\s*\[#', $line)) return true;
        return false;
    }

    private function addLiteralLine($literalBlock, $line, $literalBlockStyle, $indent = -1)
    {
        $line = self::stripIndent($line, $indent);
        if ($literalBlockStyle !== '|') {
            $line = self::stripIndent($line);
        }
        $line = rtrim($line, "\r\n\t ") . "\n";
        if ($literalBlockStyle == '|') {
            return $literalBlock . $line;
        }
        if (strlen($line) == 0)
            return rtrim($literalBlock, ' ') . "\n";
        if ($line == "\n" && $literalBlockStyle == '>') {
            return rtrim($literalBlock, " \t") . "\n";
        }
        if ($line != "\n")
            $line = trim($line, "\r\n ") . " ";
        return $literalBlock . $line;
    }

    public function revertLiteralPlaceHolder($lineArray, $literalBlock)
    {
        foreach ($lineArray as $k => $_) {
            if (is_array($_))
                $lineArray[$k] = $this->revertLiteralPlaceHolder($_, $literalBlock);
            elseif (substr($_, -1 * strlen($this->LiteralPlaceHolder)) == $this->LiteralPlaceHolder)
                $lineArray[$k] = rtrim($literalBlock, " \r\n");
        }
        return $lineArray;
    }

    private static function stripIndent($line, $indent = -1)
    {
        $line ??= '';

        if ($indent == -1) $indent = strlen($line) - strlen(ltrim($line));
        return substr($line, $indent);
    }

    private function getParentPathByIndent($indent)
    {
        if ($indent == 0) return array();
        $linePath = $this->path;
        do {
            end($linePath);
            $lastIndentInParentPath = key($linePath);
            if ($indent <= $lastIndentInParentPath) array_pop($linePath);
        } while ($indent <= $lastIndentInParentPath);
        return $linePath;
    }

    private function clearBiggerPathValues($indent)
    {
        if ($indent == 0) $this->path = array();
        if (empty ($this->path)) return true;

        foreach ($this->path as $k => $_) {
            if ($k > $indent) unset ($this->path[$k]);
        }

        return true;
    }

    private static function isComment($line)
    {
        if (!$line) return false;
        if ($line[0] == '#') return true;
        if (trim($line, " \r\n\t") == '---') return true;
        return false;
    }

    private static function isEmpty($line)
    {
        return (trim($line ?? '') === '');
    }

    private function isArrayElement($line)
    {
        if (!$line || !is_scalar($line)) return false;
        if (substr($line, 0, 2) != '- ') return false;
        if (strlen($line) > 3)
            if (substr($line, 0, 3) == '---') return false;

        return true;
    }

    private function isHashElement($line)
    {
        return strpos($line, ':');
    }

    private function isLiteral($line)
    {
        if ($this->isArrayElement($line)) return false;
        if ($this->isHashElement($line)) return false;
        return true;
    }


    private static function unquote($value)
    {
        if (!$value) return $value;
        if (!is_string($value)) return $value;
        if ($value[0] == '\'') return trim($value, '\'');
        if ($value[0] == '"') return trim($value, '"');
        return $value;
    }

    private function startsMappedSequence($line)
    {
        return (substr($line ?? '', 0, 2) == '- ' && substr($line ?? '', -1, 1) == ':');
    }

    private function returnMappedSequence($line)
    {
        $array = array();
        $key = self::unquote(trim(substr($line ?? '', 1, -1)));
        $array[$key] = array();
        $this->delayedPath = array(strpos($line ?? '', $key) + $this->indent => $key);
        return array($array);
    }

    private function checkKeysInValue($value)
    {
        if (strchr('[{"\'', $value[0] ?? '') === false) {
            if (strchr($value ?? '', ': ') !== false) {
                throw new Exception('Too many keys: ' . $value);
            }
        }
    }

    private function returnMappedValue($line)
    {
        $this->checkKeysInValue($line);
        $array = array();
        $key = self::unquote(trim(substr($line ?? '', 0, -1)));
        $array[$key] = '';
        return $array;
    }

    private function startsMappedValue($line)
    {
        return (substr($line, -1, 1) == ':');
    }

    private function isPlainArray($line)
    {
        return ($line[0] == '[' && substr($line, -1, 1) == ']');
    }

    private function returnPlainArray($line)
    {
        return $this->_toType($line);
    }

    private function returnKeyValuePair($line)
    {
        $array = array();
        $key = '';
        if (strpos($line ?? '', ': ')) {
            // It's a key/value pair most likely
            // If the key is in double quotes pull it out
            if (($line[0] == '"' || $line[0] == "'") && preg_match('/^(["\'](.*)["\'](\s)*:)/', $line, $matches)) {
                $value = trim(str_replace($matches[1], '', $line));
                $key = $matches[2];
            } else {
                // Do some guesswork as to the key and the value
                $explode = explode(': ', $line);
                $key = trim(array_shift($explode));
                $value = trim(implode(': ', $explode));
                $this->checkKeysInValue($value);
            }
            // Set the type of the value.  Int, string, etc
            $value = $this->_toType($value);

            if ($key === '0') $key = '__!YAMLZero';
            $array[$key] = $value;
        } else {
            $array = array($line);
        }
        return $array;

    }


    private function returnArrayElement($line)
    {
        if (strlen($line ?? '') <= 1) return array(array()); // Weird %)
        $array = array();
        $value = trim(substr($line, 1));
        $value = $this->_toType($value);
        if ($this->isArrayElement($value)) {
            $value = $this->returnArrayElement($value);
        }
        $array[] = $value;
        return $array;
    }


    private function nodeContainsGroup($line)
    {
        $symbolsForReference = 'A-z0-9_\-';
        if (strpos($line, '&') === false && strpos($line, '*') === false) return false; // Please die fast ;-)
        if ($line[0] == '&' && preg_match('/^(&[' . $symbolsForReference . ']+)/', $line, $matches)) return $matches[1];
        if ($line[0] == '*' && preg_match('/^(\*[' . $symbolsForReference . ']+)/', $line, $matches)) return $matches[1];
        if (preg_match('/(&[' . $symbolsForReference . ']+)$/', $line, $matches)) return $matches[1];
        if (preg_match('/(\*[' . $symbolsForReference . ']+$)/', $line, $matches)) return $matches[1];
        if (preg_match('#^\s*<<\s*:\s*(\*[^\s]+).*$#', $line, $matches)) return $matches[1];
        return false;

    }

    private function addGroup($line, $group)
    {
        if ($group[0] == '&') $this->_containsGroupAnchor = substr($group ?? '', 1);
        if ($group[0] == '*') $this->_containsGroupAlias = substr($group ?? '', 1);
    }

    private function stripGroup($line, $group)
    {
        $line = trim(str_replace($group ?? '', '', $line));
        return $line;
    }
}