import { describe, expect, it } from 'vitest';

import { selectFilings } from './index-csv.js';

const HEADER =
  'RETURN_ID,FILING_TYPE,EIN,TAX_PERIOD,SUB_DATE,TAXPAYER_NAME,RETURN_TYPE,DLN,OBJECT_ID,XML_BATCH_ID';

function row(fields: {
  returnId?: string;
  filingType?: string;
  ein: string;
  taxPeriod: string;
  subDate?: string;
  taxpayerName?: string;
  returnType: string;
  dln?: string;
  objectId: string;
  batchId: string;
}): string {
  return [
    fields.returnId ?? '1',
    fields.filingType ?? 'EFILE',
    fields.ein,
    fields.taxPeriod,
    fields.subDate ?? '20270301',
    fields.taxpayerName ?? 'SOME FOUNDATION',
    fields.returnType,
    fields.dln ?? '93000000000000',
    fields.objectId,
    fields.batchId,
  ].join(',');
}

describe('selectFilings', () => {
  it('keeps only RETURN_TYPE === "990PF" rows', () => {
    const csv = [
      HEADER,
      row({
        ein: '020123456',
        taxPeriod: '202612',
        returnType: '990PF',
        objectId: '111',
        batchId: 'BATCH1',
      }),
      row({
        ein: '020654321',
        taxPeriod: '202612',
        returnType: '990',
        objectId: '222',
        batchId: 'BATCH1',
      }),
    ].join('\n');

    const targetEins = new Set(['020123456', '020654321']);
    const filings = selectFilings(csv, targetEins);
    expect(filings).toHaveLength(1);
    expect(filings[0]?.ein).toBe('020123456');
  });

  it('filters to the target EIN set', () => {
    const csv = [
      HEADER,
      row({
        ein: '020999999',
        taxPeriod: '202612',
        returnType: '990PF',
        objectId: '333',
        batchId: 'BATCH1',
      }),
    ].join('\n');

    expect(selectFilings(csv, new Set(['020123456']))).toEqual([]);
  });

  it('zero-pads a short EIN before matching against the target set', () => {
    const csv = [
      HEADER,
      row({
        ein: '20123456', // 8 digits
        taxPeriod: '202612',
        returnType: '990PF',
        objectId: '444',
        batchId: 'BATCH1',
      }),
    ].join('\n');

    const filings = selectFilings(csv, new Set(['020123456']));
    expect(filings).toHaveLength(1);
    expect(filings[0]?.ein).toBe('020123456');
  });

  it('keeps only the LATEST TAX_PERIOD per EIN within the file', () => {
    const csv = [
      HEADER,
      row({
        ein: '020123456',
        taxPeriod: '202512',
        returnType: '990PF',
        objectId: 'OLD',
        batchId: 'BATCH1',
      }),
      row({
        ein: '020123456',
        taxPeriod: '202612',
        returnType: '990PF',
        objectId: 'NEW',
        batchId: 'BATCH2',
      }),
    ].join('\n');

    const filings = selectFilings(csv, new Set(['020123456']));
    expect(filings).toHaveLength(1);
    expect(filings[0]?.objectId).toBe('NEW');
    expect(filings[0]?.batchId).toBe('BATCH2');
  });

  it('skips rows with a blank OBJECT_ID or XML_BATCH_ID', () => {
    const csv = [
      HEADER,
      row({
        ein: '020123456',
        taxPeriod: '202612',
        returnType: '990PF',
        objectId: '',
        batchId: 'BATCH1',
      }),
    ].join('\n');

    expect(selectFilings(csv, new Set(['020123456']))).toEqual([]);
  });

  it('returns an empty array for a header-only file', () => {
    expect(selectFilings(HEADER, new Set(['020123456']))).toEqual([]);
  });

  it('throws when required columns are missing from the header', () => {
    expect(() => selectFilings('FOO,BAR\n1,2', new Set(['020123456']))).toThrow(
      /missing required column/i,
    );
  });
});