/**
 * @file attributeAutomat.js
 * @description Manages catalog product attributes and their discrete values
 * (e.g. Color, Size) 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`: Calls `actions.load()` upon receiving an `'attributename'` SSE event.
 * - UI / Dialogs: Mutating actions (`createAttribute`, `updateAttribute`,
 *   `deleteAttribute`, `addValue`, `deleteValue`, `reorderValues`).
 */

import { Automat } from 'react-automat';
import { attributename as attributenameApi, attributevalue as attributevalueApi } from '../api';
import authAutomat from './authAutomat';

/**
 * @typedef {Object} AttributeValue
 * @property {number} id
 * @property {number} attributeId
 * @property {string} value
 * @property {number} sort
 */

/**
 * @typedef {Object} AttributeName
 * @property {number} id
 * @property {string} name
 * @property {number} sort
 * @property {boolean} exclusive
 * @property {AttributeValue[]} values
 */

/**
 * @typedef {Object} AttributeState
 * @property {AttributeName[]} attributes
 * @property {'idle'|'loading'|'succeeded'|'failed'} status
 * @property {string|null} error
 */

/** @type {AttributeState} */
const initialState = {
  attributes: [],
  status: 'idle',
  error: null,
};

function sortValues(values) {
  if (!Array.isArray(values)) return [];
  return [...values].sort((a, b) => {
    const sDiff = (a.sort ?? 0) - (b.sort ?? 0);
    if (sDiff !== 0) return sDiff;
    return (a.id ?? 0) - (b.id ?? 0);
  });
}

function normalizeAttributes(attributes) {
  if (!Array.isArray(attributes)) return [];
  return [...attributes]
    .map((attr) => ({
      ...attr,
      exclusive: Boolean(attr.exclusive),
      values: sortValues(attr.values),
    }))
    .sort((a, b) => {
      const sDiff = (a.sort ?? 0) - (b.sort ?? 0);
      if (sDiff !== 0) return sDiff;
      return (a.id ?? 0) - (b.id ?? 0);
    });
}

let attributeAutomat;

const actions = {
  /** Load all attribute names and their values for the selected company. */
  async load() {
    attributeAutomat.setState({ status: 'loading', error: null });
    try {
      const res = await attributenameApi.list();
      const attributes = normalizeAttributes(res.attributenames);
      attributeAutomat.setState({ attributes, status: 'succeeded' });
      return attributes;
    } catch (err) {
      attributeAutomat.setState({ status: 'failed', error: err?.message ?? String(err) });
      throw err;
    }
  },

  /**
   * Create an attribute name.
   * @param {{ name: string, sort?: number, exclusive?: boolean }} body
   */
  async createAttribute(body) {
    const res = await attributenameApi.create(body);
    await actions.load();
    return res.attributename;
  },

  /**
   * Update an attribute name.
   * @param {number} id
   * @param {{ name?: string, sort?: number, exclusive?: boolean }} body
   */
  async updateAttribute(id, body) {
    const res = await attributenameApi.update(id, body);
    await actions.load();
    return res.attributename;
  },

  /**
   * Delete an attribute name.
   * @param {number} id
   */
  async deleteAttribute(id) {
    await attributenameApi.delete(id);
    await actions.load();
  },

  /**
   * Delete multiple attribute names.
   * @param {number[]} ids
   */
  async deleteAttributes(ids) {
    for (const id of ids) {
      await attributenameApi.delete(id);
    }
    await actions.load();
  },

  /**
   * Reorder attribute names.
   * @param {number[]} attributenameIds
   */
  async reorderAttributes(attributenameIds) {
    await attributenameApi.order(attributenameIds);
    await actions.load();
  },

  /**
   * Create a value for an attribute.
   * @param {number} attributeId
   * @param {{ value: string, sort?: number }} body
   */
  async createValue(attributeId, body) {
    const res = await attributevalueApi.create(attributeId, body);
    await actions.load();
    return res.attributevalue;
  },

  /**
   * Update an attribute value.
   * @param {number} id
   * @param {{ value?: string, sort?: number }} body
   */
  async updateValue(id, body) {
    const res = await attributevalueApi.update(id, body);
    await actions.load();
    return res.attributevalue;
  },

  /**
   * Delete an attribute value.
   * @param {number} id
   */
  async deleteValue(id) {
    await attributevalueApi.delete(id);
    await actions.load();
  },

  /**
   * Delete multiple attribute values.
   * @param {number[]} ids
   */
  async deleteValues(ids) {
    for (const id of ids) {
      await attributevalueApi.delete(id);
    }
    await actions.load();
  },

  /**
   * Reorder values of an attribute.
   * @param {number} attributeId
   * @param {number[]} attributevalueIds
   */
  async reorderValues(attributeId, attributevalueIds) {
    await attributevalueApi.order(attributeId, attributevalueIds);
    await actions.load();
  },

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

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

// Selectors
export function selectAttributes() {
  return attributeAutomat.state.attributes;
}

export function selectAttributeStatus() {
  return attributeAutomat.state.status;
}

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

export default attributeAutomat;