/**
 * @file brandAutomat.js
 * @description Manages catalog brands and manufacturers for the active company.
 *
 * Upstream Triggers:
 * - `authAutomat`: Subscribes to auth state changes — calls `actions.load()` on
 *   `'authed'` with a `selectedCompanyId`, and `actions.reset()` on `'anon'`.
 * - `sseAutomat`: Subscribes to the single `'brand'` event carrying
 *   `{ sender, brandId }` — any create/rename/delete/picture change triggers
 *   `actions.load(true)`, which silently re-fetches the list. Subscribed views
 *   (e.g. `ArtikelMarkenPage` via `brandAutomat.subscribe(...)`) then
 *   re-render from the updated state. Events sent by this tab (matching `sender`)
 *   are ignored.
 * - UI / Settings: Mutating actions (`create`, `rename`, `remove`, `addImage`, `deleteImage`).
 */

import { Automat } from 'react-automat';
import { brand as brandApi } from '../api';
import authAutomat from './authAutomat';
import sseAutomat, { getSseClientId } from './sseAutomat';

/**
 * @typedef {Object} BrandState
 * @property {Array<object>} brands All brands (full list, decoupled from page UI).
 * @property {Array<object>} filteredBrands Filtered brands according to active filter query.
 * @property {string} filter Active search/filter string.
 * @property {'idle'|'loading'|'succeeded'|'failed'} status
 * @property {string|null} error
 */

/** @type {BrandState} */
const initialState = {
  brands: [],
  filteredBrands: [],
  filter: '',
  status: 'idle',
  error: null,
};

const sortBrands = (brands) =>
  [...brands].sort((a, b) => String(a.name ?? '').localeCompare(String(b.name ?? ''), 'de'));

const applyFilter = (brands, filter) => {
  const query = String(filter ?? '').trim().toLowerCase();
  return query ? brands.filter((b) => String(b.name ?? '').toLowerCase().includes(query)) : brands;
};

let brandAutomat;
let inflightLoad = null;
const FETCH_PAGE_SIZE = 100;
// #region fetch
async function fetchAllBrands() {
  let offset = 0, total = Infinity;
  const collected = [];
  while (offset === 0 || collected.length < total) {
    const res = await brandApi.list({ offset, limit: FETCH_PAGE_SIZE });
    if (offset === 0) total = Number(res.total ?? res.brands?.length ?? 0);
    const page = Array.isArray(res.brands) ? res.brands : [];
    collected.push(...page);
    offset += page.length;
    if (page.length === 0) break;
  }
  return { brands: sortBrands(collected) };
}

const updateStateWithBrands = (brands, extra = {}) => {
  const filteredBrands = applyFilter(brands, brandAutomat.state.filter);
  brandAutomat.setState({ brands, filteredBrands, ...extra });
  return brands;
};

const actions = {
  /** Sets the active brand search filter and updates filteredBrands. */
  filter(query) {
    const filter = String(query ?? '');
    brandAutomat.setState({ filter, filteredBrands: applyFilter(brandAutomat.state.brands, filter) });
  },

  /**
   * Load all brands for the selected company (pages through the API).
   * @param {boolean} [silent=false] If true, re-fetches without setting status to 'loading'.
   */
  async load(silent = false) {
    if (inflightLoad) return inflightLoad;
    if (!silent) {
      brandAutomat.setState({ status: 'loading', error: null });
    }
    return (inflightLoad = fetchAllBrands()
      .then(({ brands }) => updateStateWithBrands(brands, { status: 'succeeded', error: null }))
      .catch((err) => {
        const error = err?.message ?? String(err);
        brandAutomat.setState(silent ? { error } : { status: 'failed', error });
        throw err;
      })
      .finally(() => { inflightLoad = null; }));
  },
  // #region add
  async create(body) {
    const res = await brandApi.create(body);
    const row = res.brand;
    updateStateWithBrands(sortBrands([...brandAutomat.state.brands.filter((b) => b.id !== row.id), row]));
    return row;
  },
  // #region rename
  async rename(id, body) {
    const res = await brandApi.rename(id, body);
    const updated = res.brand ?? { id: res.id, name: res.name, gsprpinfo: res.gsprpinfo };
    updateStateWithBrands(sortBrands(brandAutomat.state.brands.map((b) => (b.id === id ? { ...b, ...updated } : b))));
    return res;
  },
  // #region del
  async remove(id) {
    await brandApi.delete(id);
    updateStateWithBrands(brandAutomat.state.brands.filter((b) => b.id !== id));
  },
  async removeBrands(ids) {
    const idSet = new Set(ids);
    for (const id of ids) {
      await brandApi.delete(id);
    }
    updateStateWithBrands(brandAutomat.state.brands.filter((b) => !idSet.has(b.id)));
    await actions.load(true);
  },
  // #region addPic
  async addImage(id, file) {
    const res = await brandApi.addImage(id, file);
    await brandAutomat.actions.load(true);
    return res.brand;
  },
  // #region delPic
  async deleteImage(id) {
    const res = await brandApi.deleteImage(id);
    const updated = res.brand ?? { pics: [] };
    updateStateWithBrands(brandAutomat.state.brands.map((b) => (b.id === id ? { ...b, ...updated, pics: [] } : b)));
    return res.brand;
  }
};

/**
 * Global brand state container.
 * @type {Automat<BrandState>}
 */
brandAutomat = new Automat(initialState, actions, { name: 'brand' });

authAutomat.subscribe((auth) => {
  const companyId = auth.user?.selectedCompanyId;
  if (auth.status === 'authed' && companyId) void brandAutomat.actions.load();
  else if (auth.status === 'anon') brandAutomat.setState(initialState);
});

// #region onSse
sseAutomat.actions.on('brand', (event) => {
  try {
    const payload = JSON.parse(event?.data ?? '{}');
    if (payload?.sender && payload.sender === getSseClientId()) return;
  } catch { }
  void brandAutomat.actions.load(true).catch(() => { });
});

export default brandAutomat;