/**
 * Handelsware — API-Client (quick-261002-fm5). Konsumiert
 * `/modules/handelsware-datev`. Die Excel-Datei geht als Multipart-Feld `file`;
 * beim Export zusaetzlich `buchungsdatum` und `newAccounts` (JSON-Text der von
 * der Vorschau gemeldeten neuen Konten) — die API liest alle Zeilen erneut aus
 * derselben Datei, damit die TXT nicht von der Arbeitsmappe abweichen kann.
 */

import { accountingRequest, type FileResponse } from '@/lib/accounting-request';

export type { FileResponse } from '@/lib/accounting-request';
export { AccountingRequestError as HandelswareRequestError } from '@/lib/accounting-request';

const BASE = '/modules/handelsware-datev';

export interface HandelswareSettings {
  erloeskonto: number | null;
  startGegenkonto: number | null;
  configured: boolean;
}

export interface HandelswareSettingsInput {
  erloeskonto: number;
  startGegenkonto: number;
}

export interface HandelswareAccount {
  id: string;
  name: string;
  gegenkonto: number;
  erloeskonto: number;
}

export interface HandelswareAccountInput {
  name: string;
  gegenkonto: number;
  erloeskonto: number;
}

export interface NewAccount {
  name: string;
  gegenkonto: number;
  erloeskonto: number;
}

export interface PreviewRow {
  line: number;
  buchungstext: string;
  umsatz: string;
  sollHaben: 'S' | 'H';
  gegenkonto: number;
  erloeskonto: number;
  isNew: boolean;
}

export interface RowError {
  line: number;
  code: string;
  message: string;
}

export interface HandelswarePreview {
  headerText: string;
  suggestedBuchungsdatum: string;
  exportFilename: string;
  rows: PreviewRow[];
  newAccounts: NewAccount[];
  rowErrors: RowError[];
}

export type HandelswareExportResult = FileResponse & { createdCount: number };

const DAYS_PER_MONTH = [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

/** TTMM: vier Ziffern, Monat 1-12, Tag passend zum Monat (Februar bis 29) — wie die API. */
export function isValidBuchungsdatum(ttmm: string): boolean {
  if (!/^\d{4}$/.test(ttmm)) return false;
  const day = Number.parseInt(ttmm.slice(0, 2), 10);
  const month = Number.parseInt(ttmm.slice(2, 4), 10);
  if (month < 1 || month > 12) return false;
  return day >= 1 && day <= DAYS_PER_MONTH[month - 1];
}

function fileForm(file: File): FormData {
  const form = new FormData();
  form.append('file', file);
  return form;
}

export function getHandelswareSettings(): Promise<HandelswareSettings> {
  return accountingRequest(`${BASE}/settings`);
}

export function saveHandelswareSettings(
  input: HandelswareSettingsInput,
): Promise<HandelswareSettings> {
  return accountingRequest(`${BASE}/settings`, { method: 'PUT', json: input });
}

export function previewHandelsware(file: File): Promise<HandelswarePreview> {
  return accountingRequest(`${BASE}/preview`, { method: 'POST', form: fileForm(file) });
}

export function exportHandelsware(
  file: File,
  buchungsdatum: string,
  newAccounts: NewAccount[],
): Promise<HandelswareExportResult> {
  const form = fileForm(file);
  form.append('buchungsdatum', buchungsdatum);
  form.append('newAccounts', JSON.stringify(newAccounts));
  return accountingRequest(`${BASE}/export`, { method: 'POST', form });
}

export function listAccounts(): Promise<HandelswareAccount[]> {
  return accountingRequest(`${BASE}/accounts`);
}

export function createAccount(input: HandelswareAccountInput): Promise<HandelswareAccount> {
  return accountingRequest(`${BASE}/accounts`, { method: 'POST', json: input });
}

export function updateAccount(
  id: string,
  input: HandelswareAccountInput,
): Promise<HandelswareAccount> {
  return accountingRequest(`${BASE}/accounts/${encodeURIComponent(id)}`, {
    method: 'PUT',
    json: input,
  });
}

export function deleteAccount(id: string): Promise<{ deleted: true }> {
  return accountingRequest(`${BASE}/accounts/${encodeURIComponent(id)}`, { method: 'DELETE' });
}

export function importAccountsCsv(file: File): Promise<{ count: number }> {
  return accountingRequest(`${BASE}/accounts/import-csv`, { method: 'POST', form: fileForm(file) });
}

export function exportAccountsCsv(): Promise<FileResponse> {
  return accountingRequest(`${BASE}/accounts/export-csv`);
}