import { exportFile, QTableColumn, useQuasar } from 'quasar';
import { storeToRefs } from 'pinia';
import { unparse } from 'papaparse';
import { useI18n } from 'vue-i18n';
import { api } from 'src/services';
import { useDashboardStore } from 'src/stores/main';

/**
 * TABLE EXPORT (CSV / JSON).
 *
 * Server-mode tables — every table whose rows live in wp_vtables_source —
 * never ship their rows to the browser
 * (fetch_table blanks source.rows and sends only first_page), so exporting from
 * memory produced an empty file. Those go through the streaming export endpoint
 * instead. Only legacy tables, whose rows really are in source.rows, keep the
 * client-side path.
 *
 * Either way the export is the full table.
 */
export type ExportFormat = 'csv' | 'json' | 'xlsx';

export function useTableExport() {
  const { selectedTable } = storeToRefs(useDashboardStore());
  const { t } = useI18n();
  const $q = useQuasar();

  function download(type: ExportFormat) {
    const table = selectedTable.value;
    if (!table) {
      return;
    }

    // xlsx is always built server-side — there is no client-side writer, and
    // the endpoint handles legacy tables too via its source-blob fallback.
    if (type === 'xlsx' || table.server_mode) {
      // A plain navigation, not XHR: the response is an attachment, so the
      // browser hands it straight to the download manager and never buffers
      // the whole dataset in JS.
      window.location.href = api.exportRowsUrl(table.id, type);
      return;
    }

    const {
      title,
      source: { columns, rows },
    } = table;

    const name = `${title}.${type}`;
    let content = '';

    if (type === 'csv') {
      // Build the matrix explicitly instead of patching a header line into
      // unparse(rows) output: that assumed the object key order matched the
      // column order, and injected the labels unquoted, so any label holding a
      // comma corrupted the header row.
      const cols: QTableColumn[] = Array.isArray(columns) ? columns : [];
      content = cols.length
        ? unparse({
            fields: cols.map((col) => col.label ?? col.name),
            data: (rows ?? []).map((row: Record<string, unknown>) =>
              cols.map((col) => row[col.name] ?? '')
            ),
          })
        : unparse(rows ?? []);
    } else {
      content = JSON.stringify(rows ?? []);
    }

    const status = exportFile(name, content);

    if (!status) {
      $q.notify({
        type: 'negative',
        message: t('failed'),
      });
    }
  }

  return { download };
}