funkblubber/lib/parsing/parser.dart

import 'package:funkblubber/funkentity.dart';
import 'package:funkblubber/console.dart' as console;
import 'package:funkblubber/parsing/parsing_stage.dart';

enum Action {
  download,
  upload,
}

class StageResult {
  StageResult({required this.result, required this.stage});
  final ParseResult result;
  final ParsingStage stage;
}

class ParseResult {
  ParseResult({
    required this.success,
    required this.action,
    this.object,
    this.localPath,
  });

  final FunkObject? object;
  final String? localPath;
  final Action action;
  final bool success;
}

ParseResult extract(final List<String> args) {
  ParseResult result = ParseResult(
    success: false,
    action: Action.download,
  );

  if (args.isEmpty) {
    console.error('no arguments provided');
    return result;
  }

  ParsingStage currentStage = ParsingStage.nothing;

  for (final String arg in args) {
    switch (currentStage) {
      case ParsingStage.nothing:
        final stageResult = _onNothingStage(arg, result, currentStage);
        currentStage = stageResult.stage;
        result = stageResult.result;
        break;

      case ParsingStage.album:
        final stageResult = _onEntityStage(
          arg,
          result,
          currentStage,
          FunkEntity.album,
        );
        currentStage = stageResult.stage;
        result = stageResult.result;
        break;

      case ParsingStage.artist:
        final stageResult = _onEntityStage(
          arg,
          result,
          currentStage,
          FunkEntity.artist,
        );
        currentStage = stageResult.stage;
        result = stageResult.result;
        break;

      case ParsingStage.domain:
        final stageResult = _onDomainStage(arg, result, currentStage);
        currentStage = stageResult.stage;
        result = stageResult.result;
        break;

      case ParsingStage.path:
        final stageResult = _onPathStage(arg, result, currentStage);
        currentStage = stageResult.stage;
        result = stageResult.result;
        break;

      default:
        console.error('not implemented yet');
        break;
    }
  }

  return result;
}

StageResult _onEntityStage(
  final String arg,
  final ParseResult previousResult,
  final ParsingStage previousStage,
  final FunkEntity kind,
) {
  ParsingStage currentStage = previousStage;
  ParseResult result = previousResult;

  if (int.tryParse(arg) != null) {
    currentStage = ParsingStage.nothing;
    result = ParseResult(
      action: previousResult.action,
      success: true,
      object: FunkObject(
        domain: previousResult.object?.domain ?? '',
        id: arg,
        kind: kind,
      ),
    );
  }

  return StageResult(result: result, stage: currentStage);
}

StageResult _onDomainStage(
  final String arg,
  final ParseResult previousResult,
  final ParsingStage previousStage,
) {
  ParsingStage currentStage = previousStage;
  ParseResult result = previousResult;

  try {
    final Uri uri = Uri.parse(arg);
    currentStage = ParsingStage.nothing;
    result = ParseResult(
      action: previousResult.action,
      success: true,
      object: FunkObject(
        domain: uri.toString(),
        id: previousResult.object?.id ?? '',
        kind: previousResult.object?.kind ?? FunkEntity.album,
      ),
    );
  } catch (e) {
    console.error(e.toString());
  }

  return StageResult(result: result, stage: currentStage);
}

String _cutTrailingDash(final String path) =>
    path.endsWith('/') ? path.substring(0, path.length - 1) : path;

StageResult _onPathStage(
  final String arg,
  final ParseResult previousResult,
  final ParsingStage previousStage,
) {
  ParsingStage currentStage = previousStage;
  ParseResult result = previousResult;

  currentStage = ParsingStage.nothing;
  result = ParseResult(
    localPath: _cutTrailingDash(arg),
    action: previousResult.action,
    success: true,
    object: previousResult.object,
  );

  return StageResult(result: result, stage: currentStage);
}

StageResult _onNothingStage(
  final String arg,
  final ParseResult previousResult,
  final ParsingStage previousStage,
) {
  ParsingStage currentStage = previousStage;
  ParseResult result = previousResult;
  switch (arg) {
    case '-A':
    case '--artist':
      currentStage = ParsingStage.artist;
      break;
    case '-a':
    case '--album':
      currentStage = ParsingStage.album;
      break;
    case '-u':
    case '--upload':
      currentStage = ParsingStage.upload;
      break;
    case '-p':
    case '--path':
      currentStage = ParsingStage.path;
      break;
    case '-d':
    case '--domain':
      currentStage = ParsingStage.domain;
      break;
    default:
      try {
        final Uri uri = Uri.parse(arg);

        final segments = uri.pathSegments;
        for (int i = 0; i < segments.length; ++i) {
          switch (segments[i]) {
            case 'artists':
              result = ParseResult(
                action: Action.download,
                success: true,
                object: FunkObject(
                  kind: FunkEntity.artist,
                  id: segments[i + 1],
                  domain: uri.host,
                ),
              );
              ++i;
              break;

            case 'albums':
              result = ParseResult(
                action: Action.download,
                success: true,
                object: FunkObject(
                  kind: FunkEntity.album,
                  id: segments[i + 1],
                  domain: uri.host,
                ),
              );
              ++i;
              break;
          }
        }
      } catch (e) {
        console.error(e.toString());
        currentStage = ParsingStage.nothing;
      }
      break;
  }

  return StageResult(result: result, stage: currentStage);
}