/**
 * @file companyAutomat.js
 * @description Manages configuration details of the currently selected company
 * (tax rates, currency, language, legal details, and root category ID).
 *
 * Upstream Triggers:
 * - `authAutomat`: Subscribes to auth state changes — triggers `actions.load()`
 *   when status is `'authed'` with a `selectedCompanyId`, and `actions.reset()` on `'anon'`.
 * - UI / Settings: Calls `update(payload)` or manual `load()`.
 *
 * Downstream Triggers:
 * - `categoryAutomat`: Subscribes to `companyAutomat` — triggers `actions.loadTree()`
 *   whenever `company.current.id` or `rootCategoryId` changes/becomes available;
 *   resets when company is unset.
 * - `posterminalAutomat`: Reads `companyAutomat.state.current?.id` as a fallback company ID.
 */

import { Automat } from 'react-automat';
import { company as companyApi } from '../api';
import authAutomat from './authAutomat';
import { normalizeCompany } from '../utils/companyForm';

/**
 * @typedef {Object} CompanyState
 * @property {object|null} current  Normalized company object for the selected company.
 * @property {'idle'|'loading'|'succeeded'|'failed'} status
 * @property {string|null} error
 */

/** @type {CompanyState} */
const initialState = {
  current: null,
  status: 'idle',
  error: null,
};

let companyAutomat;

const actions = {
  /**
   * Load the company data for the currently selected company.
   * @returns {Promise<object|null>}
   */
  async load() {
    const companyId = authAutomat.state.user?.selectedCompanyId;
    if (!companyId) return null;
    companyAutomat.setState({ status: 'loading', error: null });
    try {
      const data = await companyApi.getById(companyId);
      const normalized = normalizeCompany(data.company);
      companyAutomat.setState({ current: normalized, status: 'succeeded' });
      return normalized;
    } catch (err) {
      companyAutomat.setState({ status: 'failed', error: err?.message ?? String(err) });
      throw err;
    }
  },

  /**
   * Update company details and refresh cached data.
   * @param {object} payload
   */
  async update(payload) {
    const companyId = authAutomat.state.user?.selectedCompanyId;
    if (!companyId) throw new Error('Kein Unternehmen ausgewählt.');
    companyAutomat.setState({ status: 'loading', error: null });
    try {
      await companyApi.update(companyId, payload);
      const data = await companyApi.getById(companyId);
      const normalized = normalizeCompany(data.company, payload);
      companyAutomat.setState({ current: normalized, status: 'succeeded' });
      return normalized;
    } catch (err) {
      companyAutomat.setState({ status: 'failed', error: err?.message ?? String(err) });
      throw err;
    }
  },

  /** Reset to idle (called on logout / company switch). */
  reset() {
    companyAutomat.setState(initialState);
  },
};

/**
 * Global company state container.
 * Loads automatically when authAutomat reaches 'authed' with a selectedCompanyId.
 *
 * @type {Automat<CompanyState>}
 */
companyAutomat = new Automat(initialState, actions, { name: 'company' });

// Subscribe to auth changes — load when authed, reset when logged out / anon
authAutomat.subscribe((auth) => {
  const companyId = auth.user?.selectedCompanyId;
  if (auth.status === 'authed' && companyId) {
    void companyAutomat.actions.load();
  } else if (auth.status === 'anon') {
    companyAutomat.actions.reset();
  }
});

// Selectors (plain functions for use outside React)
export const selectCurrentCompany = () => companyAutomat.state.current;
export const selectCompanyId = () => companyAutomat.state.current?.id ?? null;
export const selectCompanyStatus = () => companyAutomat.state.status;
export const selectCompanyName = () => companyAutomat.state.current?.name;
export const selectCompanyIso639 = () => companyAutomat.state.current?.iso639;
export const selectCompanyLanguageId = () => companyAutomat.state.current?.languageId ?? null;
export const selectCompanyTaxrate = () => companyAutomat.state.current?.taxrate ?? null;
export const selectCompanyReducedTaxrate = () => companyAutomat.state.current?.reducedtaxrate ?? null;
export const selectCompanyTaxfreerate = () => companyAutomat.state.current?.taxfreerate ?? null;
export const selectCompanyRootCategoryId = () => companyAutomat.state.current?.rootCategoryId ?? null;

export default companyAutomat;