<?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;

/**

 * Parser parses YAML strings to convert them to PHP arrays.

 *

 * @author Fabien Potencier <fabien@symfony.com>

 */

class Parser

{

    private $offset         = 0;

    private $lines          = array();

    private $currentLineNb  = -1;

    private $currentLine    = '';

    private $refs           = array();

    /**

     * Constructor

     *

     * @param integer $offset The offset of YAML document (used for line numbers in error messages)

     */

    public function __construct($offset = 0)

    {

        $this->offset = $offset;

    }

    /**

     * Parses a YAML string to a PHP value.

     *

     * @param  string $value A YAML string

     *

     * @return mixed  A PHP value

     *

     * @throws ParseException If the YAML is not valid

     */

    public function parse($value)

    {

        $this->currentLineNb = -1;

        $this->currentLine = '';

        $this->lines = explode("\n", $this->cleanup($value));

        if (function_exists('mb_detect_encoding') && false === mb_detect_encoding($value, 'UTF-8', true)) {

            throw new ParseException('The YAML value does not appear to be valid UTF-8.');

        }

        if (function_exists('mb_internal_encoding') && ((int) ini_get('mbstring.func_overload')) & 2) {

            $mbEncoding = mb_internal_encoding();

            mb_internal_encoding('UTF-8');

        }

        $data = array();

        while ($this->moveToNextLine()) {

            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);

            }

            $isRef = $isInPlace = $isProcessed = false;

            if (preg_match('#^\-((?P<leadspaces>\s+)(?P<value>.+?))?\s*$#u', $this->currentLine, $values)) {

                if (isset($values['value']) && preg_match('#^&(?P<ref>[^ ]+) *(?P<value>.*)#u', $values['value'], $matches)) {

                    $isRef = $matches['ref'];

                    $values['value'] = $matches['value'];

                }

                // array

                if (!isset($values['value']) || '' == trim($values['value'], ' ') || 0 === strpos(ltrim($values['value'], ' '), '#')) {

                    $c = $this->getRealCurrentLineNb() + 1;

                    $parser = new Parser($c);

                    $parser->refs =& $this->refs;

                    $data[] = $parser->parse($this->getNextEmbedBlock());

                } else {

                    if (isset($values['leadspaces'])

                        && ' ' == $values['leadspaces']

                        && preg_match('#^(?P<key>'.Inline::REGEX_QUOTED_STRING.'|[^ \'"\{\[].*?) *\:(\s+(?P<value>.+?))?\s*$#u', $values['value'], $matches)

                    ) {

                        // this is a compact notation element, add to next block and parse

                        $c = $this->getRealCurrentLineNb();

                        $parser = new Parser($c);

                        $parser->refs =& $this->refs;

                        $block = $values['value'];

                        if (!$this->isNextLineIndented()) {

                            $block .= "\n".$this->getNextEmbedBlock($this->getCurrentLineIndentation() + 2);

                        }

                        $data[] = $parser->parse($block);

                    } else {

                        $data[] = $this->parseValue($values['value']);

                    }

                }

            } else if (preg_match('#^(?P<key>'.Inline::REGEX_QUOTED_STRING.'|[^ \'"\[\{].*?) *\:(\s+(?P<value>.+?))?\s*$#u', $this->currentLine, $values)) {

                try {

                    $key = Inline::parseScalar($values['key']);

                } catch (ParseException $e) {

                    $e->setParsedLine($this->getRealCurrentLineNb() + 1);

                    $e->setSnippet($this->currentLine);

                    throw $e;

                }

                if ('<<' === $key) {

                    if (isset($values['value']) && '*' === substr($values['value'], 0, 1)) {

                        $isInPlace = substr($values['value'], 1);

                        if (!array_key_exists($isInPlace, $this->refs)) {

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

                        }

                    } else {

                        if (isset($values['value']) && $values['value'] !== '') {

                            $value = $values['value'];

                        } else {

                            $value = $this->getNextEmbedBlock();

                        }

                        $c = $this->getRealCurrentLineNb() + 1;

                        $parser = new Parser($c);

                        $parser->refs =& $this->refs;

                        $parsed = $parser->parse($value);

                        $merged = array();

                        if (!is_array($parsed)) {

                            throw new ParseException('YAML merge keys used with a scalar value instead of an array.', $this->getRealCurrentLineNb() + 1, $this->currentLine);

                        } else if (isset($parsed[0])) {

                            // Numeric array, merge individual elements

                            foreach (array_reverse($parsed) as $parsedItem) {

                                if (!is_array($parsedItem)) {

                                    throw new ParseException('Merge items must be arrays.', $this->getRealCurrentLineNb() + 1, $parsedItem);

                                }

                                $merged = array_merge($parsedItem, $merged);

                            }

                        } else {

                            // Associative array, merge

                            $merged = array_merge($merged, $parsed);

                        }

                        $isProcessed = $merged;

                    }

                } else if (isset($values['value']) && preg_match('#^&(?P<ref>[^ ]+) *(?P<value>.*)#u', $values['value'], $matches)) {

                    $isRef = $matches['ref'];

                    $values['value'] = $matches['value'];

                }

                if ($isProcessed) {

                    // Merge keys

                    $data = $isProcessed;

                // hash

                } else if (!isset($values['value']) || '' == trim($values['value'], ' ') || 0 === strpos(ltrim($values['value'], ' '), '#')) {

                    // if next line is less indented or equal, then it means that the current value is null

                    if ($this->isNextLineIndented()) {

                        $data[$key] = null;

                    } else {

                        $c = $this->getRealCurrentLineNb() + 1;

                        $parser = new Parser($c);

                        $parser->refs =& $this->refs;

                        $data[$key] = $parser->parse($this->getNextEmbedBlock());

                    }

                } else {

                    if ($isInPlace) {

                        $data = $this->refs[$isInPlace];

                    } else {

                        $data[$key] = $this->parseValue($values['value']);

                    }

                }

            } else {

                // 1-liner followed by newline

                if (2 == count($this->lines) && empty($this->lines[1])) {

                    try {

                        $value = Inline::parse($this->lines[0]);

                    } catch (ParseException $e) {

                        $e->setParsedLine($this->getRealCurrentLineNb() + 1);

                        $e->setSnippet($this->currentLine);

                        throw $e;

                    }

                    if (is_array($value)) {

                        $first = reset($value);

                        if (is_string($first) && '*' === substr($first, 0, 1)) {

                            $data = array();

                            foreach ($value as $alias) {

                                $data[] = $this->refs[substr($alias, 1)];

                            }

                            $value = $data;

                        }

                    }

                    if (isset($mbEncoding)) {

                        mb_internal_encoding($mbEncoding);

                    }

                    return $value;

                }

                switch (preg_last_error()) {

                    case PREG_INTERNAL_ERROR:

                        $error = 'Internal PCRE error.';

                        break;

                    case PREG_BACKTRACK_LIMIT_ERROR:

                        $error = 'pcre.backtrack_limit reached.';

                        break;

                    case PREG_RECURSION_LIMIT_ERROR:

                        $error = 'pcre.recursion_limit reached.';

                        break;

                    case PREG_BAD_UTF8_ERROR:

                        $error = 'Malformed UTF-8 data.';

                        break;

                    case PREG_BAD_UTF8_OFFSET_ERROR:

                        $error = 'Offset doesn\'t correspond to the begin of a valid UTF-8 code point.';

                        break;

                    default:

                        $error = 'Unable to parse.';

                }

                throw new ParseException($error, $this->getRealCurrentLineNb() + 1, $this->currentLine);

            }

            if ($isRef) {

                $this->refs[$isRef] = end($data);

            }

        }

        if (isset($mbEncoding)) {

            mb_internal_encoding($mbEncoding);

        }

        return empty($data) ? null : $data;

    }

    /**

     * Returns the current line number (takes the offset into account).

     *

     * @return integer The current line number

     */

    private function getRealCurrentLineNb()

    {

        return $this->currentLineNb + $this->offset;

    }

    /**

     * Returns the current line indentation.

     *

     * @return integer The current line indentation

     */

    private function getCurrentLineIndentation()

    {

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

    }

    /**

     * Returns the next embed block of YAML.

     *

     * @param integer $indentation The indent level at which the block is to be read, or null for default

     *

     * @return string A YAML string

     *

     * @throws ParseException When indentation problem are detected

     */

    private function getNextEmbedBlock($indentation = null)

    {

        $this->moveToNextLine();

        if (null === $indentation) {

            $newIndent = $this->getCurrentLineIndentation();

            if (!$this->isCurrentLineEmpty() && 0 == $newIndent) {

                throw new ParseException('Indentation problem.', $this->getRealCurrentLineNb() + 1, $this->currentLine);

            }

        } else {

            $newIndent = $indentation;

        }

        $data = array(substr($this->currentLine, $newIndent));

        while ($this->moveToNextLine()) {

            if ($this->isCurrentLineEmpty()) {

                if ($this->isCurrentLineBlank()) {

                    $data[] = substr($this->currentLine, $newIndent);

                }

                continue;

            }

            $indent = $this->getCurrentLineIndentation();

            if (preg_match('#^(?P<text> *)$#', $this->currentLine, $match)) {

                // empty line

                $data[] = $match['text'];

            } else if ($indent >= $newIndent) {

                $data[] = substr($this->currentLine, $newIndent);

            } else if (0 == $indent) {

                $this->moveToPreviousLine();

                break;

            } else {

                throw new ParseException('Indentation problem.', $this->getRealCurrentLineNb() + 1, $this->currentLine);

            }

        }

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

    }

    /**

     * Moves the parser to the next line.

     *

     * @return Boolean

     */

    private function moveToNextLine()

    {

        if ($this->currentLineNb >= count($this->lines) - 1) {

            return false;

        }

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

        return true;

    }

    /**

     * Moves the parser to the previous line.

     */

    private function moveToPreviousLine()

    {

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

    }

    /**

     * Parses a YAML value.

     *

     * @param  string $value A YAML value

     *

     * @return mixed  A PHP value

     *

     * @throws ParseException When reference does not exist

     */

    private function parseValue($value)

    {

        if ('*' === substr($value, 0, 1)) {

            if (false !== $pos = strpos($value, '#')) {

                $value = substr($value, 1, $pos - 2);

            } else {

                $value = substr($value, 1);

            }

            if (!array_key_exists($value, $this->refs)) {

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

            }

            return $this->refs[$value];

        }

        if (preg_match('/^(?P<separator>\||>)(?P<modifiers>\+|\-|\d+|\+\d+|\-\d+|\d+\+|\d+\-)?(?P<comments> +#.*)?$/', $value, $matches)) {

            $modifiers = isset($matches['modifiers']) ? $matches['modifiers'] : '';

            return $this->parseFoldedScalar($matches['separator'], preg_replace('#\d+#', '', $modifiers), intval(abs($modifiers)));

        }

        try {

            return Inline::parse($value);

        } catch (ParseException $e) {

            $e->setParsedLine($this->getRealCurrentLineNb() + 1);

            $e->setSnippet($this->currentLine);

            throw $e;

        }

    }

    /**

     * Parses a folded scalar.

     *

     * @param  string  $separator   The separator that was used to begin this folded scalar (| or >)

     * @param  string  $indicator   The indicator that was used to begin this folded scalar (+ or -)

     * @param  integer $indentation The indentation that was used to begin this folded scalar

     *

     * @return string  The text value

     */

    private function parseFoldedScalar($separator, $indicator = '', $indentation = 0)

    {

        $separator = '|' == $separator ? "\n" : ' ';

        $text = '';

        $notEOF = $this->moveToNextLine();

        while ($notEOF && $this->isCurrentLineBlank()) {

            $text .= "\n";

            $notEOF = $this->moveToNextLine();

        }

        if (!$notEOF) {

            return '';

        }

        if (!preg_match('#^(?P<indent>'.($indentation ? str_repeat(' ', $indentation) : ' +').')(?P<text>.*)$#u', $this->currentLine, $matches)) {