module.exports = {
  extends: [
    require.resolve('eslint-config-airbnb-base'),
    require.resolve('./src/eslint-plugin-wc-export'),
  ],
  parser: 'babel-eslint',
  env: {
    browser: true,
    mocha: true,
  },
  plugins: ['lit', 'html', 'no-only-tests', 'babel'],
  rules: {
    'arrow-parens': ['error', 'as-needed', { requireForBlockBody: true }],
    'no-underscore-dangle': 'off',
    // air bnb restricts for of loops, which we want to allow. we can't cherry pick it out, so we have to copy over the existing rules
    'no-restricted-syntax': [
      'error',
      {
        selector: 'ForInStatement',
        message:
          'for..in loops iterate over the entire prototype chain, which is virtually never what you want. Use Object.{keys,values,entries}, and iterate over the resulting array.',
      },
      {
        selector: 'LabeledStatement',
        message:
          'Labels are a form of GOTO; using them makes code confusing and hard to maintain and understand.',
      },
      {
        selector: 'WithStatement',
        message:
          '`with` is disallowed in strict mode because it makes code impossible to predict and optimize.',
      },
    ],
    'no-only-tests/no-only-tests': 'error',
    'import/extensions': ['error', 'always', { ignorePackages: true }],
    'import/prefer-default-export': 'off',
    'import/no-extraneous-dependencies': [
      'error',
      {
        devDependencies: [
          '**/test/**/*.js',
          '**/stories/**/*.js',
          '**/demo/**/*.js',
          '**/*.config.js',
          '**/*.conf.js',
        ],
      },
    ],
    'class-methods-use-this': [
      'error',
      {
        exceptMethods: [
          // web components life cycle
          'connectedCallback',
          'disconnectedCallback',

          // LitElement life cycle
          'performUpdate',
          'shouldUpdate',
          'firstUpdated',
          'update',
          'updated',
          'createRenderRoot',
          'render',
        ],
      },
    ],

    // Currently, eslint doesn't support optional chaining,
    // so switching to a babel rule for now.
    // https://github.com/eslint/eslint/issues/12642
    'no-unused-expressions': 'off',
    'babel/no-unused-expressions': 'error',

    // eslint-plugin-lit
    'lit/no-template-bind': 'error',
    'lit/no-duplicate-template-bindings': 'error',
    'lit/no-useless-template-literals': 'error',
    'lit/attribute-value-entities': 'error',
    'lit/binding-positions': 'error',
    'lit/no-invalid-html': 'error',
    'lit/no-value-attribute': 'error',
    'lit/no-invalid-escape-sequences': 'error',
    'lit/no-legacy-template-syntax': 'error',
    'lit/no-private-properties': 'error',
  },
  overrides: [
    {
      files: ['**/test/**/*.js', '**/demo/**/*.js', '**/stories/**/*.js'],
      rules: {
        'no-console': 'off',
        'no-unused-expressions': 'off',
        'babel/no-unused-expressions': 'off',
        'class-methods-use-this': 'off',

        // loosen templating restrictions in tests and demos
        'lit/no-template-bind': 'off',
        'lit/no-duplicate-template-bindings': 'off',
        'lit/no-useless-template-literals': 'off',
        'lit/binding-positions': 'off',
        'lit/no-invalid-html': 'off',
        'lit/no-private-properties': 'off',
      },
    },
  ],
};
