<?php

declare(strict_types=1);

namespace KupShop\FeedsBundle\Formatter;

use KupShop\FeedsBundle\Dto\FeedItem;

class StreamedCSVFormatter implements StreamedFormatterInterface
{
    public static function getType(): string
    {
        return 'csv';
    }

    public static function getContentType(): string
    {
        return 'text/csv';
    }

    /**
     * @param \Generator<int, FeedItem> $data
     */
    public function process(array $configuration, \Generator $data): void
    {
        $file = new \SplFileObject('php://output', 'w');

        // backward compatibility with old CsvFormat
        $separator = $configuration['separator'] ?? ',';
        $header = $configuration['header'] ?? false;
        $enclosureCustom = $configuration['enclosure-custom'] ?? false;
        $enclosure = $configuration['enclosure'] ?? '"';
        $escape = $configuration['escape'] ?? '\\';

        if ($timestamp = $configuration['timestamp'] ?? false) {
            $file->fwrite('# timestamp '.$timestamp.PHP_EOL);
        }

        foreach ($this->getFlattenedGenerator($configuration, $data) as $key => $item) {
            if (empty($item)) {
                continue;
            }

            // add header
            if ($header && $key === 0) {
                if ($enclosureCustom) {
                    $file->fwrite(implode($separator, array_map([$this, 'encodeValue'], array_keys($item)))."\r\n");
                } else {
                    $file->fputcsv(array_keys($item), $separator, $enclosure, $escape);
                }
            }

            // add data row
            if ($enclosureCustom) {
                $file->fwrite(implode($separator, $item)."\r\n");
            } else {
                $file->fputcsv($item, $separator, $enclosure, $escape);
            }
        }
    }

    protected function getFlattenedGenerator(array $configuration, \Generator $data): \Generator
    {
        foreach ($data as $item) {
            yield $this->prepareItem(
                $configuration,
                $item,
                $this->toFlattenArray($item->asSimpleArray())
            );
        }
    }

    /**
     * Converts multi-dimensional array to simple flatten array.
     */
    private function toFlattenArray(array $data): array
    {
        $flattened = [];

        foreach ($data as $key => $value) {
            if (is_array($value)) {
                $flattened[$key] = $this->formatArrayAsMultilineString($value);
            } else {
                $flattened[$key] = $value === null ? '' : $value;
            }
        }

        return $flattened;
    }

    private function formatArrayAsMultilineString(array $array): string
    {
        $formatted = [];

        foreach ($array as $item) {
            if (is_array($item)) {
                $lines = [];
                foreach ($item as $value) {
                    $lines[] = is_array($value) ? $this->formatArrayAsMultilineString($value) : $value;
                }
                $formatted[] = implode("\n\n", $lines);
            } else {
                $formatted[] = $item;
            }
        }

        return implode("\n", $formatted);
    }

    /**
     * Prepares item by its configuration in attributes.
     */
    private function prepareItem(array $configuration, FeedItem $original, array $item): array
    {
        $newItem = [];

        $enclosureCustom = $configuration['enclosure-custom'] ?? false;

        foreach ($item as $key => $value) {
            $attributes = $original->getAttributes($key);

            // replace key by `override-name` attribute
            if (!empty($attributes['override-name'])) {
                $key = $attributes['override-name'];
            }

            $forceEnclosure = $attributes['enclosure'] ?? false;
            $doubleQuotesWithoutEscaping = $attributes['double-quotes-without-escaping'] ?? false;
            $tripleQuotesWithoutEscaping = $attributes['triple-quotes-without-escaping'] ?? false;

            if ($enclosureCustom && ($forceEnclosure || $forceEnclosure === '') && !empty($value)) {
                if ($doubleQuotesWithoutEscaping || $doubleQuotesWithoutEscaping === '') {
                    $value = $this->doubleQuotesWithoutEscaping($value);
                } elseif ($tripleQuotesWithoutEscaping || $tripleQuotesWithoutEscaping === '') {
                    $value = $this->tripleQuotesWithoutEscaping($value);
                } else {
                    $value = $this->encodeValue($value);
                }
            }

            $newItem[$key] = $value;
        }

        return $newItem;
    }

    protected function doubleQuotesWithoutEscaping(string $value): string
    {
        // remove any ESCAPED double quotes within string.
        $value = str_replace('\\"', '"', $value);
        // then replace double quotes with two double quotes
        $value = str_replace('"', '""', $value);

        // force wrap value in quotes and return
        return '"'.$value.'"';
    }

    private function tripleQuotesWithoutEscaping(string $value): string
    {
        // remove any ESCAPED double quotes within string.
        $value = str_replace('\\"', '"', $value);
        // then replace double quotes with triple double quotes
        $value = str_replace('"', '"""', $value);

        // force wrap value in quotes and return
        return '"'.$value.'"';
    }

    private function encodeValue(string $value): string
    {
        // remove any ESCAPED double quotes within string.
        $value = str_replace('\\"', '"', $value);
        // then force escape these same double quotes And Any UNESCAPED Ones.
        $value = str_replace('"', '\"', $value);

        // force wrap value in quotes and return
        return '"'.$value.'"';
    }
}