<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Yaml;

use Symfony\Component\Yaml\Exception\ParseException;
use Symfony\Component\Yaml\Tag\TaggedValue;

/**
 * Parser parses YAML strings to convert them to PHP arrays.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 *
 * @final
 */
class Parser
{
    public const TAG_PATTERN = '(?P<tag>![\w!.\/:-]+)';
    public const BLOCK_SCALAR_HEADER_PATTERN = '(?P<separator>\||>)(?P<modifiers>\+|\-|\d+|\+\d+|\-\d+|\d+\+|\d+\-)?(?P<comments> +#.*)?';
    public const REFERENCE_PATTERN = '#^&(?P<ref>[^ ]++) *+(?P<value>.*)#u';

    private ?string $filename = null;
    private int $offset = 0;
    private int $numberOfParsedLines = 0;
    private ?int $totalNumberOfLines = null;
    private array $lines = [];
    private int $currentLineNb = -1;
    private string $currentLine = '';
    private array $refs = [];
    private array $skippedLineNumbers = [];
    private array $locallySkippedLineNumbers = [];
    private array $refsBeingParsed = [];

    /**
     * Parses a YAML file into a PHP value.
     *
     * @param string $filename The path to the YAML file to be parsed
     * @param int    $flags    A bit field of Yaml::PARSE_* constants to customize the YAML parser behavior
     *
     * @throws ParseException If the file could not be read or the YAML is not valid
     */
    public function parseFile(string $filename, int $flags = 0): mixed
    {
        if (!is_file($filename)) {
            throw new ParseException(sprintf('File "%s" does not exist.', $filename));
        }

        if (!is_readable($filename)) {
            throw new ParseException(sprintf('File "%s" cannot be read.', $filename));
        }

        $this->filename = $filename;

        try {
            return $this->parse(file_get_contents($filename), $flags);
        } finally {
            $this->filename = null;
        }
    }

    /**
     * Parses a YAML string to a PHP value.
     *
     * @param string $value A YAML string
     * @param int    $flags A bit field of Yaml::PARSE_* constants to customize the YAML parser behavior
     *
     * @throws ParseException If the YAML is not valid
     */
    public function parse(string $value, int $flags = 0): mixed
    {
        if (false === preg_match('//u', $value)) {
            throw new ParseException('The YAML value does not appear to be valid UTF-8.', -1, null, $this->filename);
        }

        $this->refs = [];

        try {
            $data = $this->doParse($value, $flags);
        } finally {
            $this->refsBeingParsed = [];
            $this->offset = 0;
            $this->lines = [];
            $this->currentLine = '';
            $this->numberOfParsedLines = 0;
            $this->refs = [];
            $this->skippedLineNumbers = [];
            $this->locallySkippedLineNumbers = [];
            $this->totalNumberOfLines = null;
        }

        return $data;
    }

    private function doParse(string $value, int $flags): mixed
    {
        $this->currentLineNb = -1;
        $this->currentLine = '';
        $value = $this->cleanup($value);
        $this->lines = explode("\n", $value);
        $this->numberOfParsedLines = \count($this->lines);
        $this->locallySkippedLineNumbers = [];
        $this->totalNumberOfLines ??= $this->numberOfParsedLines;

        if (!$this->moveToNextLine()) {
            return null;
        }

        $data = [];
        $context = null;
        $allowOverwrite = false;

        while ($this->isCurrentLineEmpty()) {
            if (!$this->moveToNextLine()) {
                return null;
            }
        }

        // Resolves the tag and returns if end of the document
        if (null !== ($tag = $this->getLineTag($this->currentLine, $flags, false)) && !$this->moveToNextLine()) {
            return new TaggedValue($tag, '');
        }

        do {
            if ($this->isCurrentLineEmpty()) {
                continue;
            }

            // tab?
            if ("\t" === $this->currentLine[0]) {
                throw new ParseException('A YAML file cannot contain tabs as indentation.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
            }

            Inline::initialize($flags, $this->getRealCurrentLineNb(), $this->filename);

            $isRef = $mergeNode = false;
            if ('-' === $this->currentLine[0] && self::preg_match('#^\-((?P<leadspaces>\s+)(?P<value>.+))?$#u', rtrim($this->currentLine), $values)) {
                if ($context && 'mapping' == $context) {
                    throw new ParseException('You cannot define a sequence item when in a mapping.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                }
                $context = 'sequence';

                if (isset($values['value']) && '&' === $values['value'][0] && self::preg_match(self::REFERENCE_PATTERN, $values['value'], $matches)) {
                    $isRef = $matches['ref'];
                    $this->refsBeingParsed[] = $isRef;
                    $values['value'] = $matches['value'];
                }

                if (isset($values['value'][1]) && '?' === $values['value'][0] && ' ' === $values['value'][1]) {
                    throw new ParseException('Complex mappings are not supported.', $this->getRealCurrentLineNb() + 1, $this->currentLine);
                }

                // array
                if (isset($values['value']) && str_starts_with(ltrim($values['value'], ' '), '-')) {
                    // Inline first child
                    $currentLineNumber = $this->getRealCurrentLineNb();

                    $sequenceIndentation = \strlen($values['leadspaces']) + 1;
                    $sequenceYaml = substr($this->currentLine, $sequenceIndentation);
                    $sequenceYaml .= "\n".$this->getNextEmbedBlock($sequenceIndentation, true);

                    $data[] = $this->parseBlock($currentLineNumber, rtrim($sequenceYaml), $flags);
                } elseif (!isset($values['value']) || '' == trim($values['value'], ' ') || str_starts_with(ltrim($values['value'], ' '), '#')) {
                    $data[] = $this->parseBlock($this->getRealCurrentLineNb() + 1, $this->getNextEmbedBlock(null, true) ?? '', $flags);
                } elseif (null !== $subTag = $this->getLineTag(ltrim($values['value'], ' '), $flags)) {
                    $data[] = new TaggedValue(
                        $subTag,
                        $this->parseBlock($this->getRealCurrentLineNb() + 1, $this->getNextEmbedBlock(null, true), $flags)
                    );
                } else {
                    if (
                        isset($values['leadspaces'])
                        && (
                            '!' === $values['value'][0]
                            || self::preg_match('#^(?P<key>'.Inline::REGEX_QUOTED_STRING.'|[^ \'"\{\[].*?) *\:(\s+(?P<value>.+?))?\s*$#u', $this->trimTag($values['value']), $matches)
                        )
                    ) {
                        $block = $values['value'];
                        if ($this->isNextLineIndented() || isset($matches['value']) && '>-' === $matches['value']) {
                            $block .= "\n".$this->getNextEmbedBlock($this->getCurrentLineIndentation() + \strlen($values['leadspaces']) + 1);
                        }

                        $data[] = $this->parseBlock($this->getRealCurrentLineNb(), $block, $flags);
                    } else {
                        $data[] = $this->parseValue($values['value'], $flags, $context);
                    }
                }
                if ($isRef) {
                    $this->refs[$isRef] = end($data);
                    array_pop($this->refsBeingParsed);
                }
            } elseif (
                self::preg_match('#^(?P<key>(?:![^\s]++\s++)?(?:'.Inline::REGEX_QUOTED_STRING.'|[^ \'"\[\{!].*?)) *\:(( |\t)++(?P<value>.+))?$#u', rtrim($this->currentLine), $values)
                && (!str_contains($values['key'], ' #') || \in_array($values['key'][0], ['"', "'"]))
            ) {
                if ($context && 'sequence' == $context) {
                    throw new ParseException('You cannot define a mapping item when in a sequence.', $this->currentLineNb + 1, $this->currentLine, $this->filename);
                }
                $context = 'mapping';

                try {
                    $key = Inline::parseScalar($values['key']);
                } catch (ParseException $e) {
                    $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                    $e->setSnippet($this->currentLine);

                    throw $e;
                }

                if (!\is_string($key) && !\is_int($key)) {
                    throw new ParseException((is_numeric($key) ? 'Numeric' : 'Non-string').' keys are not supported. Quote your evaluable mapping keys instead.', $this->getRealCurrentLineNb() + 1, $this->currentLine);
                }

                // Convert float keys to strings, to avoid being converted to integers by PHP
                if (\is_float($key)) {
                    $key = (string) $key;
                }

                if ('<<' === $key && (!isset($values['value']) || '&' !== $values['value'][0] || !self::preg_match('#^&(?P<ref>[^ ]+)#u', $values['value'], $refMatches))) {
                    $mergeNode = true;
                    $allowOverwrite = true;
                    if (isset($values['value'][0]) && '*' === $values['value'][0]) {
                        $refName = substr(rtrim($values['value']), 1);
                        if (!\array_key_exists($refName, $this->refs)) {
                            if (false !== $pos = array_search($refName, $this->refsBeingParsed, true)) {
                                throw new ParseException(sprintf('Circular reference [%s] detected for reference "%s".', implode(', ', array_merge(\array_slice($this->refsBeingParsed, $pos), [$refName])), $refName), $this->currentLineNb + 1, $this->currentLine, $this->filename);
                            }

                            throw new ParseException(sprintf('Reference "%s" does not exist.', $refName), $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }

                        $refValue = $this->refs[$refName];

                        if (Yaml::PARSE_OBJECT_FOR_MAP & $flags && $refValue instanceof \stdClass) {
                            $refValue = (array) $refValue;
                        }

                        if (!\is_array($refValue)) {
                            throw new ParseException('YAML merge keys used with a scalar value instead of an array.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }

                        $data += $refValue; // array union
                    } else {
                        if (isset($values['value']) && '' !== $values['value']) {
                            $value = $values['value'];
                        } else {
                            $value = $this->getNextEmbedBlock();
                        }
                        $parsed = $this->parseBlock($this->getRealCurrentLineNb() + 1, $value, $flags);

                        if (Yaml::PARSE_OBJECT_FOR_MAP & $flags && $parsed instanceof \stdClass) {
                            $parsed = (array) $parsed;
                        }

                        if (!\is_array($parsed)) {
                            throw new ParseException('YAML merge keys used with a scalar value instead of an array.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }

                        if (isset($parsed[0])) {
                            // If the value associated with the merge key is a sequence, then this sequence is expected to contain mapping nodes
                            // and each of these nodes is merged in turn according to its order in the sequence. Keys in mapping nodes earlier
                            // in the sequence override keys specified in later mapping nodes.
                            foreach ($parsed as $parsedItem) {
                                if (Yaml::PARSE_OBJECT_FOR_MAP & $flags && $parsedItem instanceof \stdClass) {
                                    $parsedItem = (array) $parsedItem;
                                }

                                if (!\is_array($parsedItem)) {
                                    throw new ParseException('Merge items must be arrays.', $this->getRealCurrentLineNb() + 1, $parsedItem, $this->filename);
                                }

                                $data += $parsedItem; // array union
                            }
                        } else {
                            // If the value associated with the key is a single mapping node, each of its key/value pairs is inserted into the
                            // current mapping, unless the key already exists in it.
                            $data += $parsed; // array union
                        }
                    }
                } elseif ('<<' !== $key && isset($values['value']) && '&' === $values['value'][0] && self::preg_match(self::REFERENCE_PATTERN, $values['value'], $matches)) {
                    $isRef = $matches['ref'];
                    $this->refsBeingParsed[] = $isRef;
                    $values['value'] = $matches['value'];
                }

                $subTag = null;
                if ($mergeNode) {
                    // Merge keys
                } elseif (!isset($values['value']) || '' === $values['value'] || str_starts_with($values['value'], '#') || (null !== $subTag = $this->getLineTag($values['value'], $flags)) || '<<' === $key) {
                    // hash
                    // if next line is less indented or equal, then it means that the current value is null
                    if (!$this->isNextLineIndented() && !$this->isNextLineUnIndentedCollection()) {
                        // Spec: Keys MUST be unique; first one wins.
                        // But overwriting is allowed when a merge node is used in current block.
                        if ($allowOverwrite || !isset($data[$key])) {
                            if (null !== $subTag) {
                                $data[$key] = new TaggedValue($subTag, '');
                            } else {
                                $data[$key] = null;
                            }
                        } else {
                            throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), $this->getRealCurrentLineNb() + 1, $this->currentLine);
                        }
                    } else {
                        // remember the parsed line number here in case we need it to provide some contexts in error messages below
                        $realCurrentLineNbKey = $this->getRealCurrentLineNb();
                        $value = $this->parseBlock($this->getRealCurrentLineNb() + 1, $this->getNextEmbedBlock(), $flags);
                        if ('<<' === $key) {
                            $this->refs[$refMatches['ref']] = $value;

                            if (Yaml::PARSE_OBJECT_FOR_MAP & $flags && $value instanceof \stdClass) {
                                $value = (array) $value;
                            }

                            $data += $value;
                        } elseif ($allowOverwrite || !isset($data[$key])) {
                            // Spec: Keys MUST be unique; first one wins.
                            // But overwriting is allowed when a merge node is used in current block.
                            if (null !== $subTag) {
                                $data[$key] = new TaggedValue($subTag, $value);
                            } else {
                                $data[$key] = $value;
                            }
                        } else {
                            throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), $realCurrentLineNbKey + 1, $this->currentLine);
                        }
                    }
                } else {
                    $value = $this->parseValue(rtrim($values['value']), $flags, $context);
                    // Spec: Keys MUST be unique; first one wins.
                    // But overwriting is allowed when a merge node is used in current block.
                    if ($allowOverwrite || !isset($data[$key])) {
                        $data[$key] = $value;
                    } else {
                        throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), $this->getRealCurrentLineNb() + 1, $this->currentLine);
                    }
                }
                if ($isRef) {
                    $this->refs[$isRef] = $data[$key];
                    array_pop($this->refsBeingParsed);
                }
            } elseif ('"' === $this->currentLine[0] || "'" === $this->currentLine[0]) {
                if (null !== $context) {
                    throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                }

                try {
                    return Inline::parse($this->lexInlineQuotedString(), $flags, $this->refs);
                } catch (ParseException $e) {
                    $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                    $e->setSnippet($this->currentLine);

                    throw $e;
                }
            } elseif ('{' === $this->currentLine[0]) {
                if (null !== $context) {
                    throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                }

                try {
                    $parsedMapping = Inline::parse($this->lexInlineMapping(), $flags, $this->refs);

                    while ($this->moveToNextLine()) {
                        if (!$this->isCurrentLineEmpty()) {
                            throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }
                    }

                    return $parsedMapping;
                } catch (ParseException $e) {
                    $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                    $e->setSnippet($this->currentLine);

                    throw $e;
                }
            } elseif ('[' === $this->currentLine[0]) {
                if (null !== $context) {
                    throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                }

                try {
                    $parsedSequence = Inline::parse($this->lexInlineSequence(), $flags, $this->refs);

                    while ($this->moveToNextLine()) {
                        if (!$this->isCurrentLineEmpty()) {
                            throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }
                    }

                    return $parsedSequence;
                } catch (ParseException $e) {
                    $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                    $e->setSnippet($this->currentLine);

                    throw $e;
                }
            } else {
                // multiple documents are not supported
                if ('---' === $this->currentLine) {
                    throw new ParseException('Multiple documents are not supported.', $this->currentLineNb + 1, $this->currentLine, $this->filename);
                }

                if (isset($this->currentLine[1]) && '?' === $this->currentLine[0] && ' ' === $this->currentLine[1]) {
                    throw new ParseException('Complex mappings are not supported.', $this->getRealCurrentLineNb() + 1, $this->currentLine);
                }

                // 1-liner optionally followed by newline(s)
                if (\is_string($value) && $this->lines[0] === trim($value)) {
                    try {
                        $value = Inline::parse($this->lines[0], $flags, $this->refs);
                    } catch (ParseException $e) {
                        $e->setParsedLine($this->getRealCurrentLineNb() + 1);
                        $e->setSnippet($this->currentLine);

                        throw $e;
                    }

                    return $value;
                }

                // try to parse the value as a multi-line string as a last resort
                if (0 === $this->currentLineNb) {
                    $previousLineWasNewline = false;
                    $previousLineWasTerminatedWithBackslash = false;
                    $value = '';

                    foreach ($this->lines as $line) {
                        $trimmedLine = trim($line);
                        if ('#' === ($trimmedLine[0] ?? '')) {
                            continue;
                        }
                        // If the indentation is not consistent at offset 0, it is to be considered as a ParseError
                        if (0 === $this->offset && isset($line[0]) && ' ' === $line[0]) {
                            throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }

                        if (str_contains($line, ': ')) {
                            throw new ParseException('Mapping values are not allowed in multi-line blocks.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
                        }

                        if ('' === $trimmedLine) {
                            $value .= "\n";
                        } elseif (!$previousLineWasNewline && !$previousLineWasTerminatedWithBackslash) {
                            $value .= ' ';
                        }

                        if ('' !== $trimmedLine && str_ends_with($line, '\\')) {
                            $value .= ltrim(substr($line, 0, -1));
                        } elseif ('' !== $trimmedLine) {
                            $value .= $trimmedLine;
                        }

                        if ('' === $trimmedLine) {
                            $previousLineWasNewline = true;
                            $previousLineWasTerminatedWithBackslash = false;
                        } elseif (str_ends_with($line, '\\')) {
                            $previousLineWasNewline = false;
                            $previousLineWasTerminatedWithBackslash = true;
                        } else {
                            $previousLineWasNewline = false;
                            $previousLineWasTerminatedWithBackslash = false;
                        }
                    }

                    try {
                        return Inline::parse(trim($value));
                    } catch (ParseException) {
                        // fall-through to the ParseException thrown below
                    }
                }

                throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
            }
        } while ($this->moveToNextLine());

        if (null !== $tag) {
            $data = new TaggedValue($tag, $data);
        }

        if (Yaml::PARSE_OBJECT_FOR_MAP & $flags && 'mapping' === $context && !\is_object($data)) {
            $object = new \stdClass();

            foreach ($data as $key => $value) {
                $object->$key = $value;
            }

            $data = $object;
        }

        return $data ?: null;
    }

    private function parseBlock(int $offset, string $yaml, int $flags): mixed
    {
        $skippedLineNumbers = $this->skippedLineNumbers;

        foreach ($this->locallySkippedLineNumbers as $lineNumber) {
            if ($lineNumber < $offset) {
                continue;
            }

            $skippedLineNumbers[] = $lineNumber;
        }

        $parser = new self();
        $parser->offset = $offset;
        $parser->totalNumberOfLines = $this->totalNumberOfLines;
        $parser->skippedLineNumbers = $skippedLineNumbers;
        $parser->refs = &$this->refs;
        $parser->refsBeingParsed = $this->refsBeingParsed;

        return $parser->doParse($yaml, $flags);
    }

    /**
     * Returns the current line number (takes the offset into account).
     *
     * @internal
     */
    public function getRealCurrentLineNb(): int
    {
        $realCurrentLineNumber = $this->currentLineNb + $this->offset;

        foreach ($this->skippedLineNumbers as $skippedLineNumber) {
            if ($skippedLineNumber > $realCurrentLineNumber) {
                break;
            }

            ++$realCurrentLineNumber;
        }

        return $realCurrentLineNumber;
    }

    private function getCurrentLineIndentation(): int
    {
        if (' ' !== ($this->currentLine[0] ?? '')) {
            return 0;
        }

        return \strlen($this->currentLine) - \strlen(ltrim($this->currentLine, ' '));
    }

    /**
     * Returns the next embed block of YAML.
     *
     * @param int|null $indentation The indent level at which the block is to be read, or null for default
     * @param bool     $inSequence  True if the enclosing data structure is a sequence
     *
     * @throws ParseException When indentation problem are detected
     */
    private function getNextEmbedBlock(?int $indentation = null, bool $inSequence = false): string
    {
        $oldLineIndentation = $this->getCurrentLineIndentation();

        if (!$this->moveToNextLine()) {
            return '';
        }

        if (null === $indentation) {
            $newIndent = null;
            $movements = 0;

            do {
                $EOF = false;

                // empty and comment-like lines do not influence the indentation depth
                if ($this->isCurrentLineEmpty() || $this->isCurrentLineComment()) {
                    $EOF = !$this->moveToNextLine();

                    if (!$EOF) {
                        ++$movements;
                    }
                } else {
                    $newIndent = $this->getCurrentLineIndentation();
                }
            } while (!$EOF && null === $newIndent);

            for ($i = 0; $i < $movements; ++$i) {
                $this->moveToPreviousLine();
            }

            $unindentedEmbedBlock = $this->isStringUnIndentedCollectionItem();

            if (!$this->isCurrentLineEmpty() && 0 === $newIndent && !$unindentedEmbedBlock) {
                throw new ParseException('Indentation problem.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
            }
        } else {
            $newIndent = $indentation;
        }

        $data = [];

        if ($this->getCurrentLineIndentation() >= $newIndent) {
            $data[] = substr($this->currentLine, $newIndent ?? 0);
        } elseif ($this->isCurrentLineEmpty() || $this->isCurrentLineComment()) {
            $data[] = $this->currentLine;
        } else {
            $this->moveToPreviousLine();

            return '';
        }

        if ($inSequence && $oldLineIndentation === $newIndent && isset($data[0][0]) && '-' === $data[0][0]) {
            // the previous line contained a dash but no item content, this line is a sequence item with the same indentation
            // and therefore no nested list or mapping
            $this->moveToPreviousLine();

            return '';
        }

        $isItUnindentedCollection = $this->isStringUnIndentedCollectionItem();
        $isItComment = $this->isCurrentLineComment();

        while ($this->moveToNextLine()) {
            if ($isItComment && !$isItUnindentedCollection) {
                $isItUnindentedCollection = $this->isStringUnIndentedCollectionItem();
                $isItComment = $this->isCurrentLineComment();
            }

            $indent = $this->getCurrentLineIndentation();

            if ($isItUnindentedCollection && !$this->isCurrentLineEmpty() && !$this->isStringUnIndentedCollectionItem() && $newIndent === $indent) {
                $this->moveToPreviousLine();
                break;
            }

            if ($this->isCurrentLineBlank()) {
                $data[] = substr($this->currentLine, $newIndent ?? 0);
                continue;
            }

            if ($indent >= $newIndent) {
                $data[] = substr($this->currentLine, $newIndent ?? 0);
            } elseif ($this->isCurrentLineComment()) {
                $data[] = $this->currentLine;
            } elseif (0 == $indent) {
                $this->moveToPreviousLine();

                break;
            } else {
                throw new ParseException('Indentation problem.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
            }
        }

        return implode("\n", $data);
    }

    private function hasMoreLines(): bool
    {
        return (\count($this->lines) - 1) > $this->currentLineNb;
    }

    /**
     * Moves the parser to the next line.
     */
    private function moveToNextLine(): bool
    {
        if ($this->currentLineNb >= $this->numberOfParsedLines - 1) {
            return false;
        }

        $this->currentLine = $this->lines[++$this->currentLineNb];

        return true;
    }

    /**
     * Moves the parser to the previous line.
     */
    private function moveToPreviousLine(): bool
    {
        if ($this->currentLineNb < 1) {
            return false;
        }

        $this->currentLine = $this->lines[--$this->currentLineNb];

        return true;
    }

    /**
     * Parses a YAML value.
     *
     * @param string $value   A YAML value
     * @param int    $flags   A bit field of Yaml::PARSE_* constants to customize the YAML parser behavior
     * @param string $context The parser context (either sequence or mapping)
     *
     * @throws ParseException When reference does not exist
     */
    private function parseValue(string $value, int $flags, string $context): mixed
    {
        if (str_starts_with($value, '*')) {
            if (false !== $pos = strpos($value, '#')) {
                $value = substr($value, 1, $pos - 2);
            } else {
                $value = substr($value, 1);
            }

            if (!\array_key_exists($value, $this->refs)) {
                if (false !== $pos = array_search($value, $this->refsBeingParsed, true)) {
                    throw new ParseException(sprintf('Circular reference [%s] detected for reference "%s".', implode(', ', array_merge(\array_slice($this->refsBeingParsed, $pos), [$value])), $value), $this->currentLineNb + 1, $this->currentLine, $this->filename);
                }

                throw new ParseException(sprintf('Reference "%s" does not exist.', $value), $this->currentLineNb + 1, $this->currentLine, $this->filename);
            }

            return $this->refs[$value];
        }

        if (\in_array($value[0], ['!', '|', '>'], true) && self::preg_match('/^(?:'.self::TAG_PATTERN.' +)?'.self::BLOCK_SCALAR_HEADER_PATTERN.'$/', $value, $matches)) {
            $modifiers = $matches['modifiers'] ?? '';

            $data = $this->parseBlockScalar($matches['separator'], preg_replace('#\d+#', '', $modifiers), abs((int) $modifiers));

            if ('' !== $matches['tag'] && '!' !== $matches['tag']) {
                if ('!!binary' === $matches['tag']) {
                    return Inline::evaluateBinaryScalar($data);
                }

                return new TaggedValue(substr($matches['tag'], 1), $data);
            }

            return $data;
        }

        try {
            if ('' !== $value && '{' === $value[0]) {
                $cursor = \strlen(rtrim($this->currentLine)) - \strlen(rtrim($value));

                return Inline::parse($this->lexInlineMapping($cursor), $flags, $this->refs);
            } elseif ('' !== $value && '[' === $value[0]) {
                $cursor = \strlen(rtrim($this->currentLine)) - \strlen(rtrim($value));

                return Inline::parse($this->lexInlineSequence($cursor), $flags, $this->refs);
            }

            switch ($value[0] ?? '') {
                case '"':
                case "'":
                    $cursor = \strlen(rtrim($this->currentLine)) - \strlen(rtrim($value));
                    $parsedValue = Inline::parse($this->lexInlineQuotedString($cursor), $flags, $this->refs);

                    if (isset($this->currentLine[$cursor]) && preg_replace('/\s*(#.*)?$/A', '', substr($this->currentLine, $cursor))) {
                        throw new ParseException(sprintf('Unexpected characters near "%s".', substr($this->currentLine, $cursor)));
                    }

                    return $parsedValue;
                default:
                    $lines = [];

                    while ($this->moveToNextLine()) {
                        // unquoted strings end before the first unindented line
                        if (0 === $this->getCurrentLineIndentation()) {
                            $this->moveToPreviousLine();

                            break;
                        }

                        $lines[] = trim($this->currentLine);
                    }

                    for ($i = 0, $linesCount = \count($lines), $previousLineBlank = false; $i < $linesCount; ++$i) {
                        if ('' === $lines[$i]) {
                            $value .= "\n";
                            $previousLineBlank = true;
                        } elseif ($previousLineBlank) {
                            $value .= $lines[$i];
                            $previousLineBlank = false;
                        } else {
                            $value .= ' '.$lines[$i];
                            $previousLineBlank = false;
                        }
                    }

                    Inline::$parsedLineNumber = $this->getRealCurrentLineNb();

                    $parsedValue = Inline::parse($value, $flags, $this->refs);

                    if ('mapping' === $context && \is_string($parsedValue) && '"' !== $value[0] && "'" !== $value[0] && '[' !== $value[0] && '{' !== $value[0] && '!' !== $value[0] && str_contains($parsedValue, ': ')) {
                        throw new ParseException('A colon cannot be used in an unquoted mapping value.', $this->getRealCurrentLineNb() + 1, $value, $this->filename);
                    }

                    return $parsedValue;
            }
        } catch (ParseException $e) {
            $e->setParsedLine($this->getRealCurrentLineNb() + 1);
            $e->setSnippet($this->currentLine);

            throw $e;
        }
    }

    /**
     * Parses a block scalar.
     *
     * @param string $style       The style indicator that was used to begin this block scalar (| or >)
     * @param string $chomping    The chomping indicator that was used to begin this block scalar (+ or -)
     * @param int    $indentation The indentation indicator that was used to begin this block scalar
     */
    private function parseBlockScalar(string $style, string $chomping = '', int $indentation = 0): string
    {
        $notEOF = $this->moveToNextLine();
        if (!$notEOF) {
            return '';
        }

        $isCurrentLineBlank = $this->isCurrentLineBlank();
        $blockLines = [];

        // leading blank lines are consumed before determining indentation
        while ($notEOF && $isCurrentLineBlank) {
            // newline only if not EOF
            if ($notEOF = $this->moveToNextLine()) {
                $blockLines[] = '';
                $isCurrentLineBlank = $this->isCurrentLineBlank();
            }
        }

        // determine indentation if not specified
        if (0 === $indentation) {
            $currentLineLength = \strlen($this->currentLine);

            for ($i = 0; $i < $currentLineLength && ' ' === $this->currentLine[$i]; ++$i) {
                ++$indentation;
            }
        }

        if ($indentation > 0) {
            $pattern = sprintf('/^ {%d}(.*)$/', $indentation);

            while (
                $notEOF && (
                    $isCurrentLineBlank
                    || self::preg_match($pattern, $this->currentLine, $matches)
                )
            ) {
                if ($isCurrentLineBlank && \strlen($this->currentLine) > $indentation) {
                    $blockLines[] = substr($this->currentLine, $indentation);
                } elseif ($isCurrentLineBlank) {
                    $blockLines[] = '';
                } else {
                    $blockLines[] = $matches[1];
                }

                // newline only if not EOF
                if ($notEOF = $this->moveToNextLine()) {
                    $isCurrentLineBlank = $this->isCurrentLineBlank();
                }
            }
        } elseif ($notEOF) {
            $blockLines[] = '';
        }

        if ($notEOF) {
            $blockLines[] = '';
            $this->moveToPreviousLine();
        } elseif (!$notEOF && !$this->isCurrentLineLastLineInDocument()) {
            $blockLines[] = '';
        }

        // folded style
        if ('>' === $style) {
            $text = '';
            $previousLineIndented = false;
            $previousLineBlank = false;

            for ($i = 0, $blockLinesCount = \count($blockLines); $i < $blockLinesCount; ++$i) {
                if ('' === $blockLines[$i]) {
                    $text .= "\n";
                    $previousLineIndented = false;
                    $previousLineBlank = true;
                } elseif (' ' === $blockLines[$i][0]) {
                    $text .= "\n".$blockLines[$i];
                    $previousLineIndented = true;
                    $previousLineBlank = false;
                } elseif ($previousLineIndented) {
                    $text .= "\n".$blockLines[$i];
                    $previousLineIndented = false;
                    $previousLineBlank = false;
                } elseif ($previousLineBlank || 0 === $i) {
                    $text .= $blockLines[$i];
                    $previousLineIndented = false;
                    $previousLineBlank = false;
                } else {
                    $text .= ' '.$blockLines[$i];
                    $previousLineIndented = false;
                    $previousLineBlank = false;
                }
            }
        } else {
            $text = implode("\n", $blockLines);
        }

        // deal with trailing newlines
        if ('' === $chomping) {
            $text = preg_replace('/\n+$/', "\n", $text);
        } elseif ('-' === $chomping) {
            $text = preg_replace('/\n+$/', '', $text);
        }

        return $text;
    }

    /**
     * Returns true if the next line is indented.
     */
    private function isNextLineIndented(): bool
    {
        $currentIndentation = $this->getCurrentLineIndentation();
        $movements = 0;

        do {
            $EOF = !$this->moveToNextLine();

            if (!$EOF) {
                ++$movements;
            }
        } while (!$EOF && ($this->isCurrentLineEmpty() || $this->isCurrentLineComment()));

        if ($EOF) {
            for ($i = 0; $i < $movements; ++$i) {
                $this->moveToPreviousLine();
            }

            return false;
        }

        $ret = $this->getCurrentLineIndentation() > $currentIndentation;

        for ($i = 0; $i < $movements; ++$i) {
            $this->moveToPreviousLine();
        }

        return $ret;
    }

    private function isCurrentLineEmpty(): bool
    {
        return $this->isCurrentLineBlank() || $this->isCurrentLineComment();
    }

    private function isCurrentLineBlank(): bool
    {
        return '' === $this->currentLine || '' === trim($this->currentLine, ' ');
    }

    private function isCurrentLineComment(): bool
    {
        // checking explicitly the first char of the trim is faster than loops or strpos
        $ltrimmedLine = '' !== $this->currentLine && ' ' === $this->currentLine[0] ? ltrim($this->currentLine, ' ') : $this->currentLine;

        return '' !== $ltrimmedLine && '#' === $ltrimmedLine[0];
    }

    private function isCurrentLineLastLineInDocument(): bool
    {
        return ($this->offset + $this->currentLineNb) >= ($this->totalNumberOfLines - 1);
    }

    private function cleanup(string $value): string
    {
        $value = str_replace(["\r\n", "\r"], "\n", $value);

        // strip YAML header
        $count = 0;
        $value = preg_replace('#^\%YAML[: ][\d\.]+.*\n#u', '', $value, -1, $count);
        $this->offset += $count;

        // remove leading comments
        $trimmedValue = preg_replace('#^(\#.*?\n)+#s', '', $value, -1, $count);
        if (1 === $count) {
            // items have been removed, update the offset
            $this->offset += substr_count($value, "\n") - substr_count($trimmedValue, "\n");
            $value = $trimmedValue;
        }

        // remove start of the document marker (---)
        $trimmedValue = preg_replace('#^\-\-\-.*?\n#s', '', $value, -1, $count);
        if (1 === $count) {
            // items have been removed, update the offset
            $this->offset += substr_count($value, "\n") - substr_count($trimmedValue, "\n");
            $value = $trimmedValue;

            // remove end of the document marker (...)
            $value = preg_replace('#\.\.\.\s*$#', '', $value);
        }

        return $value;
    }

    private function isNextLineUnIndentedCollection(): bool
    {
        $currentIndentation = $this->getCurrentLineIndentation();
        $movements = 0;

        do {
            $EOF = !$this->moveToNextLine();

            if (!$EOF) {
                ++$movements;
            }
        } while (!$EOF && ($this->isCurrentLineEmpty() || $this->isCurrentLineComment()));

        if ($EOF) {
            return false;
        }

        $ret = $this->getCurrentLineIndentation() === $currentIndentation && $this->isStringUnIndentedCollectionItem();

        for ($i = 0; $i < $movements; ++$i) {
            $this->moveToPreviousLine();
        }

        return $ret;
    }

    private function isStringUnIndentedCollectionItem(): bool
    {
        return '-' === rtrim($this->currentLine) || str_starts_with($this->currentLine, '- ');
    }

    /**
     * A local wrapper for "preg_match" which will throw a ParseException if there
     * is an internal error in the PCRE engine.
     *
     * This avoids us needing to check for "false" every time PCRE is used
     * in the YAML engine
     *
     * @throws ParseException on a PCRE internal error
     *
     * @internal
     */
    public static function preg_match(string $pattern, string $subject, ?array &$matches = null, int $flags = 0, int $offset = 0): int
    {
        if (false === $ret = preg_match($pattern, $subject, $matches, $flags, $offset)) {
            throw new ParseException(preg_last_error_msg());
        }

        return $ret;
    }

    /**
     * Trim the tag on top of the value.
     *
     * Prevent values such as "!foo {quz: bar}" to be considered as
     * a mapping block.
     */
    private function trimTag(string $value): string
    {
        if ('!' === $value[0]) {
            return ltrim(substr($value, 1, strcspn($value, " \r\n", 1)), ' ');
        }

        return $value;
    }

    private function getLineTag(string $value, int $flags, bool $nextLineCheck = true): ?string
    {
        if ('' === $value || '!' !== $value[0] || 1 !== self::preg_match('/^'.self::TAG_PATTERN.' *( +#.*)?$/', $value, $matches)) {
            return null;
        }

        if ($nextLineCheck && !$this->isNextLineIndented()) {
            return null;
        }

        $tag = substr($matches['tag'], 1);

        // Built-in tags
        if ($tag && '!' === $tag[0]) {
            throw new ParseException(sprintf('The built-in tag "!%s" is not implemented.', $tag), $this->getRealCurrentLineNb() + 1, $value, $this->filename);
        }

        if (Yaml::PARSE_CUSTOM_TAGS & $flags) {
            return $tag;
        }

        throw new ParseException(sprintf('Tags support is not enabled. You must use the flag "Yaml::PARSE_CUSTOM_TAGS" to use "%s".', $matches['tag']), $this->getRealCurrentLineNb() + 1, $value, $this->filename);
    }

    private function lexInlineQuotedString(int &$cursor = 0): string
    {
        $quotation = $this->currentLine[$cursor];
        $value = $quotation;
        ++$cursor;

        $previousLineWasNewline = true;
        $previousLineWasTerminatedWithBackslash = false;
        $lineNumber = 0;

        do {
            if (++$lineNumber > 1) {
                $cursor += strspn($this->currentLine, ' ', $cursor);
            }

            if ($this->isCurrentLineBlank()) {
                $value .= "\n";
            } elseif (!$previousLineWasNewline && !$previousLineWasTerminatedWithBackslash) {
                $value .= ' ';
            }

            for (; \strlen($this->currentLine) > $cursor; ++$cursor) {
                switch ($this->currentLine[$cursor]) {
                    case '\\':
                        if ("'" === $quotation) {
                            $value .= '\\';
                        } elseif (isset($this->currentLine[++$cursor])) {
                            $value .= '\\'.$this->currentLine[$cursor];
                        }

                        break;
                    case $quotation:
                        ++$cursor;

                        if ("'" === $quotation && isset($this->currentLine[$cursor]) && "'" === $this->currentLine[$cursor]) {
                            $value .= "''";
                            break;
                        }

                        return $value.$quotation;
                    default:
                        $value .= $this->currentLine[$cursor];
                }
            }

            if ($this->isCurrentLineBlank()) {
                $previousLineWasNewline = true;
                $previousLineWasTerminatedWithBackslash = false;
            } elseif ('\\' === $this->currentLine[-1]) {
                $previousLineWasNewline = false;
                $previousLineWasTerminatedWithBackslash = true;
            } else {
                $previousLineWasNewline = false;
                $previousLineWasTerminatedWithBackslash = false;
            }

            if ($this->hasMoreLines()) {
                $cursor = 0;
            }
        } while ($this->moveToNextLine());

        throw new ParseException('Malformed inline YAML string.');
    }

    private function lexUnquotedString(int &$cursor): string
    {
        $offset = $cursor;
        $cursor += strcspn($this->currentLine, '[]{},: ', $cursor);

        if ($cursor === $offset) {
            throw new ParseException('Malformed unquoted YAML string.');
        }

        return substr($this->currentLine, $offset, $cursor - $offset);
    }

    private function lexInlineMapping(int &$cursor = 0): string
    {
        return $this->lexInlineStructure($cursor, '}');
    }

    private function lexInlineSequence(int &$cursor = 0): string
    {
        return $this->lexInlineStructure($cursor, ']');
    }

    private function lexInlineStructure(int &$cursor, string $closingTag): string
    {
        $value = $this->currentLine[$cursor];
        ++$cursor;

        do {
            $this->consumeWhitespaces($cursor);

            while (isset($this->currentLine[$cursor])) {
                switch ($this->currentLine[$cursor]) {
                    case '"':
                    case "'":
                        $value .= $this->lexInlineQuotedString($cursor);
                        break;
                    case ':':
                    case ',':
                        $value .= $this->currentLine[$cursor];
                        ++$cursor;
                        break;
                    case '{':
                        $value .= $this->lexInlineMapping($cursor);
                        break;
                    case '[':
                        $value .= $this->lexInlineSequence($cursor);
                        break;
                    case $closingTag:
                        $value .= $this->currentLine[$cursor];
                        ++$cursor;

                        return $value;
                    case '#':
                        break 2;
                    default:
                        $value .= $this->lexUnquotedString($cursor);
                }

                if ($this->consumeWhitespaces($cursor)) {
                    $value .= ' ';
                }
            }

            if ($this->hasMoreLines()) {
                $cursor = 0;
            }
        } while ($this->moveToNextLine());

        throw new ParseException('Malformed inline YAML string.');
    }

    private function consumeWhitespaces(int &$cursor): bool
    {
        $whitespacesConsumed = 0;

        do {
            $whitespaceOnlyTokenLength = strspn($this->currentLine, ' ', $cursor);
            $whitespacesConsumed += $whitespaceOnlyTokenLength;
            $cursor += $whitespaceOnlyTokenLength;

            if (isset($this->currentLine[$cursor])) {
                return 0 < $whitespacesConsumed;
            }

            if ($this->hasMoreLines()) {
                $cursor = 0;
            }
        } while ($this->moveToNextLine());

        return 0 < $whitespacesConsumed;
    }
}

.NET Framework

Project Request

ProjectC

Vehicle Maintenance

Movie Navigator

Customers Exchange

ATM

.NET Core

Mail Daemon

Custom

Buns of code

PHP

Mediabox

Loan Castle

Content Management

Laravel

Phone Check

Frontend

Forex Wall

Business projects

Certification Center

Amerikas Auto

Pet projects

Geolocation Assistant

Web Dynamics

Blackball

Good old times

DOS Clock

BrainOut

Airport Administrator

Atomizer

Mediabox