<?php

namespace Dotenv;

use Dotenv\Exception\InvalidFileException;

class Parser
{
const INITIAL_STATE = 0;
const QUOTED_STATE = 1;
const ESCAPE_STATE = 2;
const WHITESPACE_STATE = 3;
const COMMENT_STATE = 4;

/**
* Parse the given variable name.
*
* @param string $name
*
* @return string
*/
public static function parseName($name)
{
return trim(str_replace(array('export ', '\'', '"'), '', $name));
}

/**
* Parse the given variable value.
*
* @param string $value
*
* @throws \Dotenv\Exception\InvalidFileException
*
* @return string
*/
public static function parseValue($value)
{
if ($value === '') {
return '';
} elseif ($value[0] === '"' || $value[0] === '\'') {
return Parser::parseQuotedValue($value);
} else {
return Parser::parseUnquotedValue($value);
}
}

/**
* Parse the given quoted value.
*
* @param string $value
*
* @throws \Dotenv\Exception\InvalidFileException
*
* @return string
*/
public static function parseQuotedValue($value)
{
$result = array_reduce(str_split($value), function ($data, $char) use ($value) {
switch ($data[1]) {
case Parser::INITIAL_STATE:
if ($char === '"' || $char === '\'') {
return array($data[0], Parser::QUOTED_STATE);
} else {
throw new InvalidFileException(
'Expected the value to start with a quote.'
);
}
case Parser::QUOTED_STATE:
if ($char === $value[0]) {
return array($data[0], Parser::WHITESPACE_STATE);
} elseif ($char === '\\') {
return array($data[0], Parser::ESCAPE_STATE);
} else {
return array($data[0].$char, Parser::QUOTED_STATE);
}
case Parser::ESCAPE_STATE:
if ($char === $value[0] || $char === '\\') {
return array($data[0].$char, Parser::QUOTED_STATE);
} else {
return array($data[0].'\\'.$char, Parser::QUOTED_STATE);
}
case Parser::WHITESPACE_STATE:
if ($char === '#') {
return array($data[0], Parser::COMMENT_STATE);
} elseif (!ctype_space($char)) {
throw new InvalidFileException(
'Dotenv values containing spaces must be surrounded by quotes.'
);
} else {
return array($data[0], Parser::WHITESPACE_STATE);
}
case Parser::COMMENT_STATE:
return array($data[0], Parser::COMMENT_STATE);
}
}, array('', Parser::INITIAL_STATE));

if ($result[1] === Parser::QUOTED_STATE || $result[1] === Parser::ESCAPE_STATE) {
throw new InvalidFileException(
'Dotenv values starting with a quote must finish with a closing quote.'
);
}

return trim($result[0]);
}

/**
* Parse the given unquoted value.
*
* @param string $value
*
* @throws \Dotenv\Exception\InvalidFileException
*
* @return string
*/
public static function parseUnquotedValue($value)
{
$parts = explode(' #', $value, 2);
$value = trim($parts[0]);

// Unquoted values cannot contain whitespace
if (preg_match('/\s+/', $value) > 0) {
// Check if value is a comment (usually triggered when empty value with comment)
if (preg_match('/^#/', $value) > 0) {
$value = '';
} else {
throw new InvalidFileException('Dotenv values containing spaces must be surrounded by quotes.');
}
}

return trim($value);
}
}