/*
 * eslint.config.js  (ESLint 9 flat config)
 *
 * Lints static/js/**\/*.js as plain browser scripts (sourceType:'script').
 * All cross-file globals are declared here so no-undef works across the
 * multi-file global-scope architecture (no ES modules, no bundler).
 *
 * Load order and ownership of each global is documented in index.html.
 */

import js from '@eslint/js';
import globals from 'globals';

// ── Globals that cross file boundaries ──────────────────────────────────────
// Declared 'writable' if the variable itself is reassigned across files;
// 'readonly' if only the function/value is consumed by other files.
const appGlobals = {
  // state.js — mutable state shared across all modules
  S: 'writable',
  _plugins: 'writable',
  _batchState: 'writable',
  _batchWs: 'writable',
  _bnd: 'writable',
  _photoQueue: 'writable',
  _aiBlocksVisible: 'writable',
  _aiLog: 'writable',
  _aiLogWs: 'writable',

  // helpers.js
  esc: 'readonly',
  toast: 'readonly',
  isDesktop: 'readonly',

  // api.js
  req: 'readonly',

  // canvas-boundary.js
  parseBounds: 'readonly',
  parseBndPluginResults: 'readonly',
  setupDetailCanvas: 'readonly',
  drawBnd: 'readonly',

  // tree-render.js
  walkTree: 'readonly',
  removeNode: 'readonly',
  findNode: 'readonly',
  pluginsByCategory: 'readonly',
  pluginsByTarget: 'readonly',
  isLoading: 'readonly',
  vPluginBtn: 'readonly',
  vBatchBtn: 'readonly',
  vAiIndicator: 'readonly',
  candidateSugRows: 'readonly',
  _STATUS_BADGE: 'readonly',
  getBookStats: 'readonly',
  vAiProgressBar: 'readonly',
  vApp: 'readonly',
  mainTitle: 'readonly',
  mainHeaderBtns: 'readonly',

  // detail-render.js
  vDetailBody: 'readonly',
  aiBlocksShown: 'readonly',

  // canvas-crop.js
  startCropMode: 'readonly',

  // editing.js
  attachEditables: 'readonly',
  initSortables: 'readonly',

  // photo.js
  collectQueueBooks: 'readonly',
  renderPhotoQueue: 'readonly',
  triggerPhoto: 'readonly',

  // init.js
  render: 'readonly',
  renderDetail: 'readonly',
  connectBatchWs: 'readonly',
  connectAiLogWs: 'readonly',
  loadTree: 'readonly',

  // CDN (SortableJS loaded via <script> in index.html)
  Sortable: 'readonly',
};

export default [
  {
    files: ['static/js/**/*.js'],
    languageOptions: {
      ecmaVersion: 'latest',
      sourceType: 'script', // browser scripts, not ES modules
      globals: {
        ...globals.browser,
        ...appGlobals,
      },
    },
    rules: {
      ...js.configs.recommended.rules,

      // Catch typos and missing globals
      'no-undef': 'error',

      // builtinGlobals:false — only catch intra-file re-declarations, not globals
      // from appGlobals which are intentionally re-defined in their owning file.
      'no-redeclare': ['error', { builtinGlobals: false }],

      // Unused variables: allow leading-underscore convention for intentional ignores
      'no-unused-vars': [
        'error',
        { argsIgnorePattern: '^_', varsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' },
      ],

      // Require strict equality
      eqeqeq: ['error', 'always', { null: 'ignore' }],

      // Disallow var; prefer const/let
      'no-var': 'error',
      'prefer-const': ['error', { destructuring: 'all' }],

      // Warn on console usage (intentional debug left-ins)
      'no-console': 'warn',
    },
  },
  {
    // Test files run in Node.js, not the browser
    files: ['tests/js/**/*.js'],
    languageOptions: {
      ecmaVersion: 'latest',
      sourceType: 'module',
      globals: globals.node,
    },
    rules: {
      ...js.configs.recommended.rules,
      'no-undef': 'error',
      'no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
    },
  },
];