<?php


namespace Seld\PharUtils;

class Timestamps
{
    private $contents;

    
    public function __construct($file)
    {
        $this->contents = file_get_contents($file);
    }

    
    public function updateTimestamps($timestamp = null)
    {
        if ($timestamp instanceof \DateTime || $timestamp instanceof \DateTimeInterface) {
            $timestamp = $timestamp->getTimestamp();
        } elseif (is_string($timestamp)) {
            $timestamp = strtotime($timestamp);
        } elseif (!is_int($timestamp)) {
            $timestamp = strtotime('1984-12-24T00:00:00Z');
        }

        
        if (!preg_match('{__HALT_COMPILER\(\);(?: +\?>)?\r?\n}', $this->contents, $match, PREG_OFFSET_CAPTURE)) {
            throw new \RuntimeException('Could not detect the stub\'s end in the phar');
        }

        
        $pos = $match[0][1] + strlen($match[0][0]);
        $stubEnd = $pos + $this->readUint($pos, 4);
        $pos += 4;

        $numFiles = $this->readUint($pos, 4);
        $pos += 4;

        
        $pos += 2;

        
        $pos += 4;

        $aliasLength = $this->readUint($pos, 4);
        $pos += 4 + $aliasLength;

        $metadataLength = $this->readUint($pos, 4);
        $pos += 4 + $metadataLength;

        while ($pos < $stubEnd) {
            $filenameLength = $this->readUint($pos, 4);
            $pos += 4 + $filenameLength;

            
            $pos += 4;

            
            $timeStampBytes = pack('L', $timestamp);
            $this->contents[$pos + 0] = $timeStampBytes[0];
            $this->contents[$pos + 1] = $timeStampBytes[1];
            $this->contents[$pos + 2] = $timeStampBytes[2];
            $this->contents[$pos + 3] = $timeStampBytes[3];

            
            $pos += 4*4;

            $metadataLength = $this->readUint($pos, 4);
            $pos += 4 + $metadataLength;

            $numFiles--;
        }

        if ($numFiles !== 0) {
            throw new \LogicException('All files were not processed, something must have gone wrong');
        }
    }

    
    public function save($path, $signatureAlgo)
    {
        $pos = $this->determineSignatureBegin();

        $algos = array(
            \Phar::MD5 => 'md5',
            \Phar::SHA1 => 'sha1',
            \Phar::SHA256 => 'sha256',
            \Phar::SHA512 => 'sha512',
        );

        if (!isset($algos[$signatureAlgo])) {
            throw new \UnexpectedValueException('Invalid hash algorithm given: '.$signatureAlgo.' expected one of Phar::MD5, Phar::SHA1, Phar::SHA256 or Phar::SHA512');
        }
        $algo = $algos[$signatureAlgo];

        
        $signature = hash($algo, substr($this->contents, 0, $pos), true)
            
            . pack('L', $signatureAlgo)
            
            . 'GBMB';

        $this->contents = substr($this->contents, 0, $pos) . $signature;

        return file_put_contents($path, $this->contents);
    }

    private function readUint($pos, $bytes)
    {
        $res = unpack('V', substr($this->contents, $pos, $bytes));

        return $res[1];
    }

    
    private function determineSignatureBegin()
    {
        
        if (!preg_match('{__HALT_COMPILER\(\);(?: +\?>)?\r?\n}', $this->contents, $match, PREG_OFFSET_CAPTURE)) {
            throw new \RuntimeException('Could not detect the stub\'s end in the phar');
        }

        
        $pos = $match[0][1] + strlen($match[0][0]);
        $manifestEnd = $pos + 4 + $this->readUint($pos, 4);

        $pos += 4;
        $numFiles = $this->readUint($pos, 4);

        $pos += 4;

        
        $pos += 2;

        
        $pos += 4;

        $aliasLength = $this->readUint($pos, 4);
        $pos += 4 + $aliasLength;

        $metadataLength = $this->readUint($pos, 4);
        $pos += 4 + $metadataLength;

        $compressedSizes = 0;
        while (($numFiles > 0) && ($pos < $manifestEnd - 24)) {
            $filenameLength = $this->readUint($pos, 4);
            $pos += 4 + $filenameLength;

            
            $pos += 2*4;

            $compressedSizes += $this->readUint($pos, 4);
            
            $pos += 3*4;

            $metadataLength = $this->readUint($pos, 4);
            $pos += 4 + $metadataLength;

            $numFiles--;
        }

        if ($numFiles !== 0) {
            throw new \LogicException('All files were not processed, something must have gone wrong');
        }

        return $manifestEnd + $compressedSizes;
    }
}