import js from '@eslint/js'
import globals from 'globals'
import reactHooks from 'eslint-plugin-react-hooks'
import reactRefresh from 'eslint-plugin-react-refresh'
import tseslint from 'typescript-eslint'
import { defineConfig, globalIgnores } from 'eslint/config'

export default defineConfig([
  globalIgnores(['dist', 'build', 'html', 'coverage', 'aStableBuild']),
  // ── CommonJS config files (Node.js) ──
  {
    files: ['postcss.config.js', 'tailwind.config.js'],
    extends: [js.configs.recommended],
    languageOptions: {
      ecmaVersion: 2020,
      globals: globals.node,
      sourceType: 'commonjs',
    },
  },
  // ── Node.js scripts (ESM with __dirname via import.meta) ──
  {
    files: ['scripts/**/*.js'],
    extends: [js.configs.recommended],
    languageOptions: {
      ecmaVersion: 2022,
      globals: globals.node,
      sourceType: 'module',
    },
    rules: {
      'no-console': 'off',
    },
  },
  // ── Test files ──
  {
    files: ['src/__tests__/**/*.{js,jsx}', 'src/i18n/test-*.js'],
    extends: [js.configs.recommended],
    languageOptions: {
      ecmaVersion: 2020,
      globals: { ...globals.browser, ...globals.node },
      parserOptions: {
        ecmaVersion: 'latest',
        ecmaFeatures: { jsx: true },
        sourceType: 'module',
      },
    },
    rules: {
      'no-unused-vars': ['error', { varsIgnorePattern: '^[A-Z_]', argsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' }],
      'no-console': 'off',
    },
  },
  // ── Main source code ──
  {
    files: ['src/**/*.{js,jsx}'],
    ignores: ['src/__tests__/**', 'src/i18n/test-*.js'],
    extends: [
      js.configs.recommended,
      reactHooks.configs['recommended-latest'],
      reactRefresh.configs.vite,
    ],
    languageOptions: {
      ecmaVersion: 2020,
      globals: globals.browser,
      parserOptions: {
        ecmaVersion: 'latest',
        ecmaFeatures: { jsx: true },
        sourceType: 'module',
      },
    },
    rules: {
      'no-unused-vars': ['error', { varsIgnorePattern: '^[A-Z]', argsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' }],
      'no-alert': 'error',
      'no-debugger': 'error',
      'eqeqeq': ['warn', 'smart'],
      'no-console': ['warn', { allow: ['warn', 'error'] }],
      'react-refresh/only-export-components': 'off',
    },
  },
  // ── TypeScript source code ──
  {
    files: ['src/**/*.{ts,tsx}', 'scripts/**/*.ts'],
    extends: [
      js.configs.recommended,
      ...tseslint.configs.recommended,
      reactHooks.configs['recommended-latest'],
    ],
    languageOptions: {
      ecmaVersion: 'latest',
      sourceType: 'module',
      globals: { ...globals.browser, ...globals.node },
      parserOptions: {
        ecmaFeatures: { jsx: true },
      },
    },
    rules: {
      // Permissive baseline during the gradual migration. Tightened in Phase 6.
      'no-unused-vars': 'off', // handled by @typescript-eslint version
      '@typescript-eslint/no-unused-vars': ['warn', { argsIgnorePattern: '^_', varsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' }],
      '@typescript-eslint/no-explicit-any': 'warn',
      '@typescript-eslint/no-empty-object-type': 'off',
      'no-alert': 'error',
      'no-debugger': 'error',
      'eqeqeq': ['warn', 'smart'],
      'no-console': ['warn', { allow: ['warn', 'error'] }],
    },
  },
  // ── Server (Express, deployed as Vercel serverless functions) ──
  {
    files: ['server/**/*.ts', 'api/**/*.ts'],
    extends: [
      js.configs.recommended,
      ...tseslint.configs.recommended,
    ],
    languageOptions: {
      ecmaVersion: 'latest',
      sourceType: 'module',
      globals: globals.node,
    },
    rules: {
      'no-unused-vars': 'off', // handled by @typescript-eslint version
      '@typescript-eslint/no-unused-vars': ['warn', { argsIgnorePattern: '^_', varsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' }],
      '@typescript-eslint/no-explicit-any': 'warn',
      '@typescript-eslint/no-empty-object-type': 'off',
      'eqeqeq': ['warn', 'smart'],
      'no-console': 'off', // console.* is the actual logging mechanism (Vercel function logs)
    },
  },
])