<?php
/*
 * Copyright (C) 2017 Champs Libres Cooperative <info@champs-libres.coop>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
namespace Chill\MainBundle\Export\Formatter;

use Symfony\Component\HttpFoundation\Response;
use Chill\MainBundle\Export\FormatterInterface;
use Symfony\Component\Translation\TranslatorInterface;
use Symfony\Component\Form\FormBuilderInterface;
use Chill\MainBundle\Export\ExportManager;
use Symfony\Component\Form\Extension\Core\Type\FormType;
use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;

/**
 *
 *
 * @author Julien Fastré <julien.fastre@champs-libres.coop>
 */
class SpreadSheetFormatter implements FormatterInterface
{
    /**
     *
     * @var TranslatorInterface
     */
    protected $translator;

    /**
     *
     * @var ExportManager
     */
    protected $exportManager;

    /**
     * The result, as returned by the export
     *
     * replaced when `getResponse` is called.
     *
     * @var type
     */
    protected $result;

    /**
     *
     * replaced when `getResponse` is called.
     *
     * @var type
     */
    protected $formatterData;

    /**
     * The export
     *
     * replaced when `getResponse` is called.
     *
     * @var \Chill\MainBundle\Export\ExportInterface
     */
    protected $export;

    /**
     *
     * replaced when `getResponse` is called.
     *
     * @var type
     */
    //protected $aggregators;

    /**
     * array containing value of export form
     *
     * replaced when `getResponse` is called.
     *
     * @var array
     */
    protected $exportData;

    /**
     * an array where keys are the aggregators aliases and
     * values are the data
     *
     * replaced when `getResponse` is called.
     *
     * @var type
     */
    protected $aggregatorsData;

    /**
     *
     * replaced when `getResponse` is called.
     *
     * @var array
     */
    protected $filtersData;

    /**
     *
     * replaced when `getResponse` is called.
     *
     * @var array
     */
    //protected $labels;

    /**
     * temporary file to store spreadsheet
     *
     * @var string
     */
    protected $tempfile;

    /**
     * cache for displayable result.
     *
     * This cache is reset when `getResponse` is called.
     *
     * The array's keys are the keys in the raw result, and
     * values are the callable which will transform the raw result to
     * displayable result.
     *
     * @var array
     */
    private $cacheDisplayableResult;

    /**
     * Whethe `cacheDisplayableResult` is initialized or not.
     *
     * @var boolean
     */
    private $cacheDisplayableResultIsInitialized = false;

    public function __construct(TranslatorInterface $translatorInterface, ExportManager $exportManager)
    {
        $this->translator = $translatorInterface;
        $this->exportManager = $exportManager;
    }


    public function buildForm(
        FormBuilderInterface $builder,
        $exportAlias,
        array $aggregatorAliases
    ) {
        // choosing between formats
        $builder->add('format', ChoiceType::class, array(
            'choices' => array(
                'OpenDocument Format (.ods) (LibreOffice, ...)' => 'ods',
                'Microsoft Excel 2007-2013 XML (.xlsx) (Microsoft Excel, LibreOffice)' => 'xlsx',
                'Comma separated values (.csv)' => 'csv'
            ),
            'placeholder' => 'Choose the format'
        ));

        // ordering aggregators
        $aggregators = $this->exportManager->getAggregators($aggregatorAliases);
        $nb = count($aggregatorAliases);

        foreach ($aggregators as $alias => $aggregator) {
            $builderAggregator = $builder->create($alias, FormType::class, array(
               'label' => $aggregator->getTitle(),
               'block_name' => '_aggregator_placement_spreadsheet_formatter'
            ));
            $this->appendAggregatorForm($builderAggregator, $nb);
            $builder->add($builderAggregator);
        }
    }

    /**
     * append a form line by aggregator on the formatter form.
     *
     * This form allow to choose the aggregator position (row or column) and
     * the ordering
     *
     * @param FormBuilderInterface $builder
     * @param string $nbAggregators
     */
    private function appendAggregatorForm(FormBuilderInterface $builder, $nbAggregators)
    {
        $builder->add('order', ChoiceType::class, array(
           'choices' => array_combine(
                 range(1, $nbAggregators),
                 range(1, $nbAggregators)
                 ),
           'multiple' => false,
           'expanded' => false
        ));

    }

    public function getName()
    {
        return 'SpreadSheet (xlsx, ods)';
    }

    public function getResponse(
        $result,
        $formatterData,
        $exportAlias,
        array $exportData,
        array $filtersData,
        array $aggregatorsData
    ) {
        // store all data when the process is initiated
        $this->result = $result;
        $this->formatterData = $formatterData;
        $this->export = $this->exportManager->getExport($exportAlias);
        $this->exportData = $exportData;
        $this->filtersData = $filtersData;
        $this->aggregatorsData = $aggregatorsData;

        // reset cache
        $this->cacheDisplayableResult = array();
        $this->cacheDisplayableResultIsInitialized = false;

        $response = new Response();
        $response->headers->set('Content-Type',
            $this->getContentType($this->formatterData['format']));

        $this->tempfile = \tempnam(\sys_get_temp_dir(), '');
        $this->generatecontent();

        $f = \fopen($this->tempfile, 'r');
        $response->setContent(\stream_get_contents($f));
        fclose($f);

        // remove the temp file from disk
        \unlink($this->tempfile);

        return $response;
    }

    /**
     * Generate the content and write it to php://temp
     */
    protected function generateContent()
    {
        list($spreadsheet, $worksheet) = $this->createSpreadsheet();

        $this->addTitleToWorkSheet($worksheet);
        $line = $this->addFiltersDescription($worksheet);

        // at this point, we are going to sort retsults for an easier manipulation
        list($sortedResult, $exportKeys, $aggregatorKeys, $globalKeys) =
            $this->sortResult();

        $line = $this->addHeaders($worksheet, $globalKeys, $line);

        $line = $this->addContentTable($worksheet, $sortedResult, $line);

        switch ($this->formatterData['format'])
        {
            case 'ods':
                $writer = \PhpOffice\PhpSpreadsheet\IOFactory
                    ::createWriter($spreadsheet, 'Ods');
                break;
            case 'xlsx':
                $writer = \PhpOffice\PhpSpreadsheet\IOFactory
                    ::createWriter($spreadsheet, 'Xlsx');
                break;
            case 'csv':
                $writer = \PhpOffice\PhpSpreadsheet\IOFactory
                    ::createWriter($spreadsheet, 'Csv');
                break;
            default:
                // this should not happen
                // throw an exception to ensure that the error is catched
                throw new \LogicException();
        }

        $writer->save($this->tempfile);
    }

    /**
     * Create a spreadsheet and a working worksheet
     *
     * @return array where 1st member is spreadsheet, 2nd is worksheet
     */
    protected function createSpreadsheet()
    {
        $spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();
        $worksheet = $spreadsheet->getActiveSheet();

        // setting the worksheet title and code name
        $worksheet
            ->setTitle($this->getTitle())
            ->setCodeName('result');

        return [$spreadsheet, $worksheet];
    }

    /**
     * Add the title to the worksheet and merge the cell containing
     * the title
     *
     * @param Worksheet $worksheet
     */
    protected function addTitleToWorkSheet(Worksheet &$worksheet)
    {
        $worksheet->setCellValue('A1', $this->getTitle());
        $worksheet->mergeCells('A1:G1');
    }

    /**
     * Add filter description since line 3.
     *
     * return the line number after the last description
     *
     * @param Worksheet $worksheet
     * @return int the line number after the last description
     */
    protected function addFiltersDescription(Worksheet &$worksheet)
    {
        $line = 3;

        foreach ($this->filtersData as $alias => $data) {
            $filter = $this->exportManager->getFilter($alias);
            $description = $filter->describeAction($data, 'string');

            if (is_array($description)) {
                $description = $this->translator
                    ->trans(
                        $description[0],
                        isset($description[1]) ? $description[1] : []
                        );
            }

            $worksheet->setCellValue('A'.$line, $description);
            $line ++;
        }

        return $line;
    }

    /**
     * sort the results, and return an array where :
     *  - 0 => sorted results
     *  - 1 => export keys
     *  - 2 => aggregator keys
     *  - 3 => global keys (aggregator keys and export keys)
     *
     *
     * Example, assuming that the result contains two aggregator keys :
     *
     * array in result :
     *
     * ```
     * array(
     *  array( //row 1
     *      'export_result' => 1,
     *      'aggregator_1'  => 2,
     *      'aggregator_2'  => 3
     *  ),
     *  array( // row 2
     *      'export_result' => 4,
     *      'aggregator_1'  => 5,
     *      'aggregator_2'  => 6
     *  )
     * )
     * ```
     *
     * the sorted result will be :
     *
     * ```
     * array(
     *  array( 2, 3, 1 ),
     *  array( 5, 6, 4 )
     * )
     * ```
     *
     */
    protected function sortResult()
    {
        // get the keys for each row
        $exportKeys = $this->export->getQueryKeys($this->exportData);
        $aggregatorKeys = $this->getAggregatorKeysSorted();

        $globalKeys = \array_merge($aggregatorKeys, $exportKeys);

        $sortedResult = \array_map(function ($row) use ($globalKeys) {
                $newRow = array();

                foreach ($globalKeys as $key) {
                    $newRow[] = $this->getDisplayableResult($key, $row[$key]);
                }

                return $newRow;
            }, $this->result);

        \array_multisort($sortedResult);

        return array($sortedResult, $exportKeys, $aggregatorKeys, $globalKeys);
    }

    /**
     * get an array of aggregator keys. The keys are sorted as asked
     * by user in the form.
     *
     * @return string[] an array containing the keys of aggregators
     */
    protected function getAggregatorKeysSorted()
    {
        // empty array for aggregators keys
        $keys = array();
        // this association between key and aggregator alias will be used
        // during sorting
        $aggregatorKeyAssociation = array();

        foreach ($this->aggregatorsData as $alias => $data) {
            $aggregator = $this->exportManager->getAggregator($alias);
            $aggregatorsKeys = $aggregator->getQueryKeys($data);
            // append the keys from aggregator to the $keys existing array
            $keys = \array_merge($keys, $aggregatorsKeys);
            // append the key with the alias, which will be use later for sorting
            foreach ($aggregatorsKeys as $key) {
                $aggregatorKeyAssociation[$key] = $alias;
            }
        }

        // sort the result using the form
        usort($keys, function ($a, $b) use ($aggregatorKeyAssociation) {
            $A = $this->formatterData[$aggregatorKeyAssociation[$a]]['order'];
            $B = $this->formatterData[$aggregatorKeyAssociation[$b]]['order'];

            if ($A === $B) {
                return 0;
            } elseif ($A > $B) {
                return 1;
            } else {
                return -1;
            }

        });

        return $keys;
    }

    /**
     * add headers to worksheet
     *
     * return the line number where the next content (i.e. result) should
     * be appended.
     *
     * @param Worksheet $worksheet
     * @param array $aggregatorKeys
     * @param array $exportKeys
     * @param int $line
     * @return int
     */
    protected function addHeaders(
        Worksheet &$worksheet,
        array $globalKeys,
        $line
    ) {
        // get the displayable form of headers
        $displayables = array();
        foreach ($globalKeys as $key) {
            $displayables[] = $this->translator->trans(
                $this->getDisplayableResult($key, '_header')
                );
        }

        // add headers on worksheet
        $worksheet->fromArray(
            $displayables,
            NULL,
            'A'.$line);

        return $line + 1;
    }

    protected function addContentTable(Worksheet $worksheet,
        $sortedResults,
        $line
    ) {
        $worksheet->fromArray(
            $sortedResults,
            NULL,
            'A'.$line);

        return $line + count($sortedResults) + 1;
    }

    protected function getTitle()
    {
        return $this->translator->trans($this->export->getTitle());
    }

    /**
     * Get the displayable result.
     *
     * @param string $key
     * @param string $value
     * @return string
     */
    protected function getDisplayableResult($key, $value)
    {
        if ($this->cacheDisplayableResultIsInitialized === false) {
            $this->initializeCache($key);
        }

        return call_user_func($this->cacheDisplayableResult[$key], $value);
    }

    protected function initializeCache($key)
    {
        /*
         * this function follows the following steps :
         *
         * 1. associate all keys used in result with their export element
         *    (export or aggregator) and data;
         * 2. associate all keys used in result with all the possible values :
         *    this array will be necessary to call `getLabels`
         * 3. store the `callable` in an associative array, in cache
         */
        // 1. create an associative array with key and export / aggregator
        $keysExportElementAssociation = array();
        // keys for export
        foreach ($this->export->getQueryKeys($this->exportData) as $key) {
            $keysExportElementAssociation[$key] = [$this->export,
                $this->exportData];
        }
        // keys for aggregator
        foreach ($this->aggregatorsData as $alias => $data) {
            $aggregator = $this->exportManager->getAggregator($alias);

            foreach ($aggregator->getQueryKeys($data) as $key) {
                $keysExportElementAssociation[$key] = [$aggregator, $data];
            }
        }

        // 2. collect all the keys before iteration
        $keys = array_keys($keysExportElementAssociation);

        $allValues = array();
        // store all the values in an array
        foreach ($this->result as $row) {
            foreach ($keys as $key) {
                $allValues[$key][] = $row[$key];
            }
        }

        // 3. iterate on `keysExportElementAssociation` to store the callable
        // in cache
        foreach ($keysExportElementAssociation as $key => list($element, $data)) {
            $this->cacheDisplayableResult[$key] =
                $element->getLabels($key, \array_unique($allValues[$key]), $data);
        }

        // the cache is initialized !
        $this->cacheDisplayableResultIsInitialized = true;
    }

    protected function getContentType($format)
    {
        switch ($format)
        {
            case 'csv':
                return 'text/csv';
            case 'ods':
                return 'application/vnd.oasis.opendocument.spreadsheet';
            case 'xlsx':
                return 'application/vnd.openxmlformats-officedocument.'
                . 'spreadsheetml.sheet';
        }
    }

    public function getType()
    {
        return 'tabular';
    }
}