<?php

namespace App\PdfExport;

use Closure;
use Exception;
use Qs_Db_Table;
use Qs_Options;
use Qs_String;
use Zend_Db_Expr;
use Zend_Db_Select;

/**
 * PDF Export Tool for:
 *  - creating separate pdf files using Zend_Db_Select if the are not exists or expired
 *  - creating zip archive with pdf files
 *  - downloading zip file
 * @package App\PdfExport
 */
class Tool
{
    const RESULT_ZIP = 'zip';
    const RESULT_PDF = 'pdf';

    /** @var  Zend_Db_Select */
    protected $select;
    /**
     * @var Qs_Db_Table
     */
    protected $table;
    protected $targetDir;
    protected $itemFileName;
    protected $resultType = self::RESULT_ZIP;

    /** @var  Closure */
    protected $pdfFactoryCallback;

    public function __construct(array $options)
    {
        Qs_Options::setOptions($this, $options);
    }

    public function getSelect()
    {
        return $this->select;
    }

    public function setSelect(Zend_Db_Select $select)
    {
        $alias = key($select->getPart(Zend_Db_Select::FROM));
        $tableName = $select->getPart(Zend_Db_Select::FROM)[$alias]['tableName'];
        $this->table = new Qs_Db_Table(['name' => $tableName]);
        $select->reset(Zend_Db_Select::COLUMNS)->columns([
            'id',
            'expired' => new Zend_Db_Expr(
                "IFNULL(`{$alias}`.`pdfCreatedAt`, '1980-01-01 00:00:00') < `{$alias}`.`changed`"
            )
        ]);
        $select->reset(Zend_Db_Select::LIMIT_COUNT);
        $select->reset(Zend_Db_Select::LIMIT_OFFSET);

        $this->select = $select;
        return $this;
    }

    public function getTargetDir()
    {
        return $this->targetDir;
    }

    public function setTargetDir($targetDir)
    {
        if (empty($targetDir)) {
            throw new Exception('Empty target dir');
        }
        if (!file_exists($targetDir) && false === mkdir($targetDir, 0755, true)) {
            throw new Exception('Can not create target dir: ' . $targetDir);
        }
        $this->targetDir = $targetDir;
        return $this;
    }

    public function getExportFile()
    {
        return $this->getTargetDir() . '/' . $this->getExportFileName();
    }

    private function getExportFileName()
    {
        $select = ''. $this->getSelect();
        return md5($select) . '.' . $this->getResultType();
    }

    public function getResultType()
    {
        return $this->resultType;
    }

    public function setResultType($resultType)
    {
        $this->resultType = $resultType;
        return $this;
    }

    private function getPidFile()
    {
        return $this->getTargetDir() . '/process.pid';
    }

    private function getStoredPid()
    {
        $pid = 0;
        $file = $this->getPidFile();
        if (file_exists($file)) {
            $pid = file_get_contents($file);
        }
        return $pid;
    }

    private function savePid($pid)
    {
        $file = $this->getPidFile();
        if (false === file_put_contents($file, $pid)) {
            throw new Exception('Failed write to file: ' . $file);
        }
        return $this;
    }

    public function isInProcess()
    {
        $pid = $this->getStoredPid();
        return $pid && posix_getsid($pid);
    }

    protected function start()
    {
        if ($this->isInProcess()) {
            return false;
        }
        $myPid = getmypid();
        $this->savePid($myPid);
        return true;
    }

    protected function clearStoredPid()
    {
        $this->savePid(0);
        return $this;
    }

    public function getItemFileName()
    {
        return $this->itemFileName;
    }

    public function setItemFileName($itemFileName)
    {
        $this->itemFileName = $itemFileName;
        return $this;
    }

    public function getPdfFactoryCallback()
    {
        return $this->pdfFactoryCallback;
    }

    public function setPdfFactoryCallback($pdfFactoryCallback)
    {
        $this->pdfFactoryCallback = $pdfFactoryCallback;
        return $this;
    }

    /**
     * @return void
     */
    protected function runForever()
    {
        ini_set('max_execution_time', '0');
        ini_set('ignore_user_abort', '1');
    }

    public function export()
    {
        $this->runForever();
        $this->start() || exit;
        $this->createPdfFiles();
        $this->createZipArchive();
        $this->clearStoredPid();
    }

    private function createPdfFiles()
    {
        foreach ($this->getSelect()->query() as $item) {
            $file = $this->getTargetDir() . '/' . $this->getPdfItemFileName($item['id']);
            if (!file_exists($file) || $item['expired']) {
                call_user_func($this->getPdfFactoryCallback(), $item['id'], $file);
                $this->table->updateDataByKey(['pdfCreatedAt' => date('Y-m-d H:i:s')], $item['id']);
            }
        }
        return $this;
    }

    private function getPdfItemFileName($id)
    {
        return Qs_String::fill($this->getItemFileName(), compact('id'));
    }

    private function createZipArchive()
    {
        $currentDir = getcwd();
        $dir = $this->getTargetDir();
        chdir($dir);

        $zip = $this->getExportFileName();
        $cmd = 'zip ' . escapeshellarg($zip);
        $item = null;
        foreach ($this->getSelect()->query() as $item) {
            $cmd .= ' ' . escapeshellarg($this->getPdfItemFileName($item['id']));
        }
        if (null === $item) {
            chdir($currentDir);
            return false;
        }
        $output = [];
        $return = 0;
        exec($cmd, $output, $return);
        if (0 !== $return) {
            throw new Exception("Failed to create zip file. \nCommand {$cmd}\nOutput: " . join(PHP_EOL, $output));
        }
        chdir($currentDir);
        return $dir . '/' . $zip;
    }

    public function download($fileName, $displayName = null)
    {
        $file = $this->getTargetDir() . '/' . $fileName;
        if (!file_exists($file)) {
            throw new Exception('File not found. Try to export again.');
        }
        if (false === ($handle = fopen($file, 'r'))) {
            throw new Exception('Failed to open file ' . $file);
        }
        header('Content-Type: application/' . $this->getResultType());
        if ($displayName) {
            $disabledCharacters = ['<', '>', '\\', '"', '/', ':', '|', '?', '*'];
            $displayName = str_replace('{date}', date('m-d-y_g-i-A', filemtime($file)), $displayName);
            $displayName = str_replace($disabledCharacters, '', $displayName);
            header('Content-Disposition: attachment; filename="' . $displayName . '"');
        }
        fpassthru($handle);
        fclose($handle);
        exit;
    }
}