import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:path/path.dart' as p;
import 'package:yaml/yaml.dart';

/// Thin wrapper around the raw project YAML.
///
/// Feature packages extend this class via Dart extension methods to expose
/// typed configuration (e.g. [KanbanDewConfig.kanban], [McpDewConfig.mcp]).
/// This keeps feature-specific config classes out of core.
class DewConfig {
  final YamlMap raw;
  const DewConfig({required this.raw});
  factory DewConfig.fromYaml(YamlMap yaml) => DewConfig(raw: yaml);
}

/// Path helper for well-known directories under a project root.
///
/// Feature packages extend this via extension methods to expose their own
/// directories (e.g. [KanbanDirs.kanban]).
class ProjectDirs {
  final String _root;
  const ProjectDirs(this._root);

  /// The workspace root (where `.project/` lives).
  String get workspace => _root;

  /// `.project/` directory.
  String get project => p.join(_root, '.project');
}

/// Locates the nearest project root and exposes the parsed [DewConfig].
class ProjectContext {
  final String root;
  final DewConfig config;
  final FileSystem fs;

  const ProjectContext({required this.root, required this.config, required this.fs});

  /// Typed path helpers for this project's well-known directories.
  ProjectDirs get dirs => ProjectDirs(root);

  /// Walks up from [from] (defaults to [fs.currentDirectory]) until a
  /// `.project/dew.yaml` is found.
  static Future<ProjectContext> find({
    FileSystem fs = const LocalFileSystem(),
    Directory? from,
  }) async {
    var dir = from ?? fs.currentDirectory;
    while (true) {
      final configFile = fs.file(p.join(dir.path, '.project', 'dew.yaml'));
      if (await configFile.exists()) {
        final yaml = loadYaml(await configFile.readAsString()) as YamlMap;
        return ProjectContext(
          root: dir.path,
          config: DewConfig.fromYaml(yaml),
          fs: fs,
        );
      }
      final parent = dir.parent;
      if (parent.path == dir.path) {
        throw StateError(
          'Could not find .project/dew.yaml. '
          'Run "dew init ." to initialise a project here.',
        );
      }
      dir = parent;
    }
  }
}