class ItemListCSV
{
    /**
     * Upload CSV Combo-sets
     *
     * @var array
     */
    private $combosets = [];

    /**
     * Registers hooks
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return void
     */
    public function init() {
        $opts = SettingsPage::getOptions();
        if ($opts[SettingsPage::ENABLE_ITEMCSV_OPT] === 'no') {
            return;
        }
        add_filter('usces_filter_downloadcsv_add_header', [get_class(), 'addHeaders']);
        add_filter('dlseller_filter_downloadcsv_add_header', [get_class(), 'addHeaders']);
        add_filter('usces_filter_downloadcsv_add_skuvalue', [get_class(), 'addComboSetCells'], 10, 2);
        add_filter('dlseller_filter_downloadcsv_add_skuvalue', [get_class(), 'addComboSetCells'], 10, 2);
        add_filter('usces_filter_uploadcsv_add_min_field_num', [get_class(), 'incrementUploadCSVFieldCount']);
        add_filter('dlseller_filter_uploadcsv_add_min_field_num', [get_class(), 'incrementUploadCSVFieldCount']);
        add_action('dlseller_after_uploadcsv_line_processed', [$this, 'prepareComboSet']);
        add_action('usces_after_uploadcsv_line_processed', [$this, 'prepareComboSet']);
        add_action('dlseller_after_uploadcsv_lines_processed', [$this, 'insertComboSets']);
        add_action('usces_after_uploadcsv_lines_processed', [$this, 'insertComboSets']);
    }

    /**
     * Returns list of Combo-set headers for exported CSV
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return string[]
     */
    public static function getHeaders() {
        return [
            __('COMBO-SET', 'wcexics'),
        ];
    }

    /**
     * Increments upload CSV field count by the number of columns required by Combo-set
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param int $fieldnum
     * @return int
     */
    public static function incrementUploadCSVFieldCount($fieldnum) {
        return $fieldnum + count(self::getHeaders());
    }

    /**
     * Adds Combo-set headers to exported CSV
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param string $line
     * @return string
     */
    public static function addHeaders($line) {
        $th_h = ',"';
        $th_f = '"';

        foreach (self::getHeaders() as $header) {
            $line .= $th_h . $header . $th_f;
        }

        return $line;
    }

    /**
     * Adds Combo-set cells to exported CSV
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param string $line_sku
     * @param array  $sku
     * @return mixed
     */
    public static function addComboSetCells($line_sku, $sku) {
        $td_h = ',"';
        $td_f = '"';

        $skumetaid = $sku['meta_id'];
        $comboset = ComboSet::getComboSetBySkuMetaId($skumetaid);
        if ($comboset instanceof GenericError) {
            for ($i = 0; $i < count(self::getHeaders()); $i++) {
                $line_sku .= $td_h . $td_f;
            }

            return $line_sku;
        }

        $jsona = $comboset->getJson();
        $jsona['groups'] = [];
        foreach ($comboset->getGroups() as $group) {
            $groupjson = $group->jsonSerialize();
            $items = [];
            foreach ($group->getItems() as $item) {
                $sku = wel_get_sku_by_id($item->getSkuMetaId());
                $ijson = $item->getJson();
                $ijson['skucode'] = $sku['code'];
                $ijson['postId'] = $item->getPostId();
                $items[] = $ijson;
            }
            $groupjson['items'] = $items;
            $jsona['groups'][] = $groupjson;
        }

        // output up to 5MB is kept in memory, if it becomes bigger it will automatically be written to a temporary file
        $csv = fopen('php://temp/maxmemory:' . (5 * 1024 * 1024), 'r+');

        fputcsv($csv, [json_encode($jsona)]);

        rewind($csv);

        // put it all in a variable
        $output = stream_get_contents($csv);

        $line_sku .= ',' . trim($output);

        return $line_sku;
    }

    /**
     * Prepare combo-set data and append to combo-sets array for later processing
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @return void
     */
    public function prepareComboSet($args) {
        if (empty($args['sku']) || empty($args['post_id'])) {
            return;
        }
        $sku = wel_get_sku($args['post_id'], $args['sku']['code']);
        if (empty($sku)) {
            return;
        }
        $offset = 0;
        if (defined('WCEX_DLSELLER')) {
            $offset = 1;
        }
        $csi = $offset + USCES_COL_SKU_APPLICABLE_TAXRATE + count(self::getHeaders());
        $comboset = !empty($args['datas'][$csi]) ? (string)$args['datas'][$csi] : '[]';
        $comboset = json_decode($comboset, true);
        if (empty($comboset)) {
            return;
        }

        $comboset['skuMetaId'] = $sku['meta_id'];
        $this->combosets[] = $comboset;
    }

    /**
     * Inserts upload CSV combo-sets
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @return void
     */
    public function insertComboSets() {
        foreach ($this->combosets as $comboset) {
            $this->insertComboSet($comboset);
        }
    }

    /**
     * Inserts a single upload CSV row combo-set
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @global \wpdb $wpdb
     * @param array $comboset
     * @return void
     */
    public function insertComboSet($comboset) {
        global $wpdb;

        $wpdb->query('START TRANSACTION');
        $cs = (new REST\ComboSet())->create(['skuMetaId' => $comboset['skuMetaId']], $comboset);
        if ($cs instanceof GenericError) {
            return;
        }
        foreach ($comboset['groups'] as $group) {
            $gres = (new REST\ComboGroup())->create(['comboSetId' => $cs->getId()], $group);
            if ($gres instanceof GenericError) {
                $wpdb->query('ROLLBACK');
                return;
            }

            foreach ($group['items'] as $item) {
                if (empty($item['skucode']) || empty($item['postId'])) {
                    continue;
                }
                $sku = wel_get_sku($item['postId'], $item['skucode']);
                if (empty($sku)) {
                    continue;
                }

                $res = (new REST\GroupItem())->create(
                    ['groupId' => $gres->getId()],
                    array_merge($item, ['welitemSkuMetaId' => $sku['meta_id']])
                );
                if ($res instanceof GenericError) {
                    $wpdb->query('ROLLBACK');
                    return;
                }
            }
        }
        $wpdb->query('COMMIT');
    }
}