import js from '@eslint/js';
import prettier from 'eslint-config-prettier';
import globals from 'globals';
import tseslint from 'typescript-eslint';

/**
 * Formatting is Prettier's job – `eslint-config-prettier` switches every stylistic rule off,
 * so a rule here always means "this is a mistake", never "this looks different".
 */
export default tseslint.config(
  // `rpgmz/` is gitignored: a copy of the RPG Maker MZ runtime kept next to the project to read the
  // autotile tables from (#118). It is nobody's source, so it is not linted either.
  { ignores: ['dist/**', 'data/**', 'node_modules/**', 'rpgmz/**', 'wiki/**', 'index.html', 'play.html'] },

  // Type-aware linting for everything the tsconfig covers (src, tests, vite.config.ts).
  {
    files: ['src/**/*.ts', 'tests/**/*.ts', 'vite.config.ts'],
    extends: [js.configs.recommended, ...tseslint.configs.recommendedTypeChecked],
    languageOptions: {
      parserOptions: { projectService: true, tsconfigRootDir: import.meta.dirname },
      globals: globals.browser,
    },
    rules: {
      // The duplicate `import` statements the last refactoring round had to find by hand.
      'no-duplicate-imports': 'error',
      // `tsc` already reports unused locals; keep ESLint quiet about the same thing.
      '@typescript-eslint/no-unused-vars': 'off',
      // Off by design: the codebase builds objects from closures (`createFieldRow` returns
      // `{ setValue }`, test fixtures return `{ sceneOf, object }`). Those have no `this`,
      // but the rule cannot tell them from class methods and fired ~50 times on them.
      '@typescript-eslint/unbound-method': 'off',
      // A `?? []` on something that is never nullish hides that the type says otherwise.
      '@typescript-eslint/no-unnecessary-condition': 'error',
      '@typescript-eslint/no-unnecessary-type-assertion': 'error',
      '@typescript-eslint/consistent-type-imports': ['error', { fixStyle: 'inline-type-imports' }],
      '@typescript-eslint/no-import-type-side-effects': 'error',
      // Async work that nobody awaits silently swallows its rejection.
      '@typescript-eslint/no-floating-promises': 'error',
      '@typescript-eslint/no-misused-promises': ['error', { checksVoidReturn: false }],
      eqeqeq: ['error', 'always', { null: 'ignore' }],
      'no-console': ['error', { allow: ['warn', 'error'] }],
      'prefer-const': 'error',
      'object-shorthand': ['error', 'properties'],
    },
  },

  // Node scripts: plain JavaScript, no type information available.
  {
    files: ['tools/**/*.mjs'],
    extends: [js.configs.recommended],
    languageOptions: {
      ecmaVersion: 2023,
      sourceType: 'module',
      globals: globals.node,
    },
    rules: {
      'no-duplicate-imports': 'error',
      eqeqeq: ['error', 'always', { null: 'ignore' }],
      'prefer-const': 'error',
    },
  },

  // Editor plugins: browser modules that get everything through `api`, so they import nothing.
  {
    files: ['plugins/**/*.js'],
    extends: [js.configs.recommended],
    languageOptions: {
      ecmaVersion: 2023,
      sourceType: 'module',
      globals: globals.browser,
    },
    rules: {
      'no-restricted-syntax': [
        'error',
        { selector: 'ImportDeclaration', message: 'A plugin gets everything through `api`.' },
      ],
      eqeqeq: ['error', 'always', { null: 'ignore' }],
      'prefer-const': 'error',
    },
  },

  prettier,
);