import 'dart:async';
import 'dart:io';

import 'package:file_selector/file_selector.dart';
import 'package:flutter/services.dart';

import 'platform_environment.dart';
import 'runtime_models.dart';

abstract class SkillDirectoryAccessService {
  bool get isSupported;
  Future<String> resolveUserHomeDirectory();

  Future<List<AuthorizedSkillDirectory>> authorizeDirectories({
    List<String> suggestedPaths = const <String>[],
  }) async {
    final suggestedPath = suggestedPaths.isNotEmpty ? suggestedPaths.first : '';
    final granted = await authorizeDirectory(suggestedPath: suggestedPath);
    return granted == null
        ? const <AuthorizedSkillDirectory>[]
        : <AuthorizedSkillDirectory>[granted];
  }

  Future<AuthorizedSkillDirectory?> authorizeDirectory({
    String suggestedPath = '',
  });

  Future<SkillDirectoryAccessHandle?> openDirectory(
    AuthorizedSkillDirectory directory,
  );
}

class SkillDirectoryAccessHandle {
  SkillDirectoryAccessHandle({
    required this.path,
    required Future<void> Function() onClose,
    this.refreshedBookmark = '',
  }) : _onClose = onClose;

  final String path;
  final String refreshedBookmark;
  final Future<void> Function() _onClose;

  Future<void> close() => _onClose();
}

SkillDirectoryAccessService createSkillDirectoryAccessService() {
  final isFlutterTest = Platform.environment.containsKey('FLUTTER_TEST');
  if (Platform.isMacOS && !isFlutterTest) {
    return MacOsSkillDirectoryAccessService();
  }
  if (Platform.isLinux || Platform.isWindows || isFlutterTest) {
    return FileSelectorSkillDirectoryAccessService();
  }
  return UnsupportedSkillDirectoryAccessService();
}

class UnsupportedSkillDirectoryAccessService
    implements SkillDirectoryAccessService {
  @override
  bool get isSupported => false;

  @override
  Future<String> resolveUserHomeDirectory() async {
    return _fallbackUserHomeDirectory();
  }

  @override
  Future<List<AuthorizedSkillDirectory>> authorizeDirectories({
    List<String> suggestedPaths = const <String>[],
  }) async {
    return const <AuthorizedSkillDirectory>[];
  }

  @override
  Future<AuthorizedSkillDirectory?> authorizeDirectory({
    String suggestedPath = '',
  }) async {
    return null;
  }

  @override
  Future<SkillDirectoryAccessHandle?> openDirectory(
    AuthorizedSkillDirectory directory,
  ) async {
    return null;
  }
}

class FileSelectorSkillDirectoryAccessService
    implements SkillDirectoryAccessService {
  @override
  bool get isSupported => true;

  @override
  Future<String> resolveUserHomeDirectory() async {
    return _fallbackUserHomeDirectory();
  }

  @override
  Future<List<AuthorizedSkillDirectory>> authorizeDirectories({
    List<String> suggestedPaths = const <String>[],
  }) async {
    final initialDirectory = _initialDirectoryForSuggestion(
      suggestedPaths.isNotEmpty ? suggestedPaths.first : '',
    );
    final directoryPaths = await getDirectoryPaths(
      initialDirectory: initialDirectory.isEmpty ? null : initialDirectory,
    );
    return normalizeAuthorizedSkillDirectories(
      directories: directoryPaths
          .whereType<String>()
          .map(
            (path) => AuthorizedSkillDirectory(
              path: normalizeAuthorizedSkillDirectoryPath(path),
            ),
          )
          .where((directory) => directory.path.isNotEmpty),
    );
  }

  @override
  Future<AuthorizedSkillDirectory?> authorizeDirectory({
    String suggestedPath = '',
  }) async {
    final directoryPath = await getDirectoryPath(
      initialDirectory: _initialDirectoryForSuggestion(suggestedPath),
    );
    final normalized = normalizeAuthorizedSkillDirectoryPath(
      directoryPath ?? '',
    );
    if (normalized.isEmpty) {
      return null;
    }
    return AuthorizedSkillDirectory(path: normalized);
  }

  @override
  Future<SkillDirectoryAccessHandle?> openDirectory(
    AuthorizedSkillDirectory directory,
  ) async {
    final normalized = normalizeAuthorizedSkillDirectoryPath(directory.path);
    if (normalized.isEmpty) {
      return null;
    }
    return SkillDirectoryAccessHandle(
      path: normalized,
      refreshedBookmark: directory.bookmark,
      onClose: () async {},
    );
  }
}

class MacOsSkillDirectoryAccessService implements SkillDirectoryAccessService {
  static const MethodChannel _channel = MethodChannel(
    'plus.svc.xworkmate/skill_directory_access',
  );
  final FileSelectorSkillDirectoryAccessService _fallbackService =
      FileSelectorSkillDirectoryAccessService();

  @override
  bool get isSupported => true;

  @override
  Future<String> resolveUserHomeDirectory() async {
    try {
      final response = await _channel.invokeMethod<String>(
        'resolveUserHomeDirectory',
      );
      final trimmed = response?.trim() ?? '';
      return trimmed.isEmpty ? _fallbackUserHomeDirectory() : trimmed;
    } on MissingPluginException {
      return _fallbackUserHomeDirectory();
    }
  }

  @override
  Future<List<AuthorizedSkillDirectory>> authorizeDirectories({
    List<String> suggestedPaths = const <String>[],
  }) async {
    try {
      final response = await _channel.invokeMethod<List<dynamic>>(
        'authorizeDirectories',
        <String, dynamic>{'suggestedPaths': suggestedPaths},
      );
      if (response == null) {
        return const <AuthorizedSkillDirectory>[];
      }
      return normalizeAuthorizedSkillDirectories(
        directories: response
            .whereType<Map<Object?, Object?>>()
            .map(
              (item) => AuthorizedSkillDirectory(
                path: normalizeAuthorizedSkillDirectoryPath(
                  item['path']?.toString() ?? '',
                ),
                bookmark: item['bookmark']?.toString().trim() ?? '',
              ),
            )
            .where((directory) => directory.path.isNotEmpty),
      );
    } on MissingPluginException {
      return _fallbackService.authorizeDirectories(
        suggestedPaths: suggestedPaths,
      );
    }
  }

  @override
  Future<AuthorizedSkillDirectory?> authorizeDirectory({
    String suggestedPath = '',
  }) async {
    try {
      final response = await _channel.invokeMapMethod<String, dynamic>(
        'authorizeDirectory',
        <String, dynamic>{'suggestedPath': suggestedPath},
      );
      if (response == null) {
        return null;
      }
      final normalized = normalizeAuthorizedSkillDirectoryPath(
        response['path']?.toString() ?? '',
      );
      if (normalized.isEmpty) {
        return null;
      }
      return AuthorizedSkillDirectory(
        path: normalized,
        bookmark: response['bookmark']?.toString().trim() ?? '',
      );
    } on MissingPluginException {
      return _fallbackService.authorizeDirectory(suggestedPath: suggestedPath);
    }
  }

  @override
  Future<SkillDirectoryAccessHandle?> openDirectory(
    AuthorizedSkillDirectory directory,
  ) async {
    final bookmark = directory.bookmark.trim();
    final normalizedPath = normalizeAuthorizedSkillDirectoryPath(
      directory.path,
    );
    if (bookmark.isEmpty) {
      if (normalizedPath.isEmpty) {
        return null;
      }
      return SkillDirectoryAccessHandle(
        path: normalizedPath,
        refreshedBookmark: directory.bookmark,
        onClose: () async {},
      );
    }
    try {
      final response = await _channel.invokeMapMethod<String, dynamic>(
        'startDirectoryAccess',
        <String, dynamic>{'bookmark': bookmark},
      );
      if (response == null) {
        return null;
      }
      final accessId = response['accessId']?.toString().trim() ?? '';
      final resolvedPath = normalizeAuthorizedSkillDirectoryPath(
        response['path']?.toString() ?? normalizedPath,
      );
      if (accessId.isEmpty || resolvedPath.isEmpty) {
        return null;
      }
      final refreshedBookmark =
          response['bookmark']?.toString().trim().isNotEmpty == true
          ? response['bookmark'].toString().trim()
          : directory.bookmark;
      return SkillDirectoryAccessHandle(
        path: resolvedPath,
        refreshedBookmark: refreshedBookmark,
        onClose: () async {
          await _channel.invokeMethod<void>(
            'stopDirectoryAccess',
            <String, dynamic>{'accessId': accessId},
          );
        },
      );
    } on MissingPluginException {
      return _fallbackService.openDirectory(directory);
    }
  }
}

String _fallbackUserHomeDirectory() {
  return resolveUserHomeDirectory();
}

String _initialDirectoryForSuggestion(String suggestedPath) {
  final trimmed = normalizeAuthorizedSkillDirectoryPath(suggestedPath);
  if (trimmed.isEmpty) {
    return '';
  }
  final directory = Directory(trimmed);
  if (directory.existsSync()) {
    return directory.parent.path;
  }
  return directory.parent.path;
}