#!/usr/bin/env dart
// ignore_for_file: avoid_print

// find unused i18n strings

import 'dart:convert';
import 'dart:io';
import 'package:path/path.dart' as p;

void main(List<String> args) {
  final rootDir = findFlutterRoot();
  if (rootDir == null) {
    print('❌ Could not find a Flutter project root (no pubspec.yaml found).');
    exit(2);
  }

  final arbPath = args.isNotEmpty
      ? args[0]
      : p.join(rootDir.path, 'lib', 'l10n', 'app_en.arb');
  final sourceDir = args.length > 1 ? args[1] : p.join(rootDir.path, 'lib');

  final arbFile = File(arbPath);
  if (!arbFile.existsSync()) {
    print('❌ ARB file not found: $arbPath');
    exit(2);
  }

  final arbContent =
      jsonDecode(arbFile.readAsStringSync()) as Map<String, dynamic>;
  final keys = arbContent.keys.where((k) => !k.startsWith('@')).toList();
  print(
      '🗝  Found ${keys.length} keys in ${p.relative(arbPath, from: rootDir.path)}\n');

  // Collect all Dart files except those in lib/l10n/
  final dartFiles = Directory(sourceDir)
      .listSync(recursive: true)
      .whereType<File>()
      .where((f) =>
          f.path.endsWith('.dart') &&
          !f.path.contains(
              RegExp(r'lib[\/\\]l10n[\/\\]'))) // ignore localization files
      .toList();

  print('📁 Scanning ${dartFiles.length} Dart files (excluding lib/l10n/)\n');

  // Patterns that allow newlines and spaces between symbols (multiline-safe)
  final rawPatterns = <String>[
    r'\bS\.of\([^)]*\)\s*\.\s*{}',
    r'\bS\.of\([^)]*\)\s*!\s*\.\s*{}',
    r'\bAppLocalizations\.of\([^)]*\)\s*\.\s*{}',
    r'\bAppLocalizations\.of\([^)]*\)\s*!\s*\.\s*{}',
    r'\bcontext\.l10n\s*\.\s*{}',
    r'\bl10n\([^)]*\)\s*\.\s*{}',
    r'\.\s*{}', // fallback
  ];

  final unused = <String>[];
  final usedDetails = <String, List<String>>{};

  for (final key in keys) {
    final matches = <String>[];
    final regexes = rawPatterns
        .map((p) => RegExp(p.replaceAll('{}', RegExp.escape(key)),
            multiLine: true, dotAll: true))
        .toList();

    for (final file in dartFiles) {
      final content = file.readAsStringSync();
      if (regexes.any((r) => r.hasMatch(content))) {
        matches.add(p.relative(file.path, from: rootDir.path));
      }
    }

    if (matches.isEmpty) {
      unused.add(key);
    } else {
      usedDetails[key] = matches;
    }
  }

  // Summary
  print('✅ Used keys: ${usedDetails.length}');
  print('🧹 Unused keys: ${unused.length}\n');

  if (unused.isNotEmpty) {
    print('=== Unused keys ===');
    for (final k in unused) {
      print(' - $k');
    }
  }

  // Write report file
  final out = File(p.join(rootDir.path, 'i10n_usage_report.txt'));
  final buffer = StringBuffer()
    ..writeln('i10n usage report')
    ..writeln('Project root: ${rootDir.path}')
    ..writeln('ARB: ${p.relative(arbPath, from: rootDir.path)}')
    ..writeln(
        'Scanned Dart files under: ${p.relative(sourceDir, from: rootDir.path)} (excluding lib/l10n/)\n');

  buffer.writeln('USED KEYS:\n');
  usedDetails.forEach((k, files) {
    buffer.writeln('$k -> ${files.length} files');
    for (final f in files) {
      buffer.writeln('  - $f');
    }
  });

  buffer.writeln('\nUNUSED KEYS:\n');
  for (final k in unused) {
    buffer.writeln('- $k');
  }

  out.writeAsStringSync(buffer.toString());
  print('\n📄 Detailed report written to ${out.path}');
}

/// Walks upward from the current working directory to find a folder containing pubspec.yaml.
Directory? findFlutterRoot() {
  var dir = Directory.current;
  while (true) {
    final pubspec = File(p.join(dir.path, 'pubspec.yaml'));
    if (pubspec.existsSync()) return dir;
    final parent = dir.parent;
    if (parent.path == dir.path) return null;
    dir = parent;
  }
}