funkblubber/lib/parser.dart

import 'package:funkblubber/funkentity.dart';
import 'package:funkblubber/console.dart' as console;
import 'package:funkblubber/string_utils.dart' as utils;

enum Action {
  download,
  upload,
}

enum ParsingStage {
  nothing,
  album,
  artist,
  track,
  path,
  upload,
  domain,
}

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.track:
        final stageResult = _onEntityStage(
          arg,
          result,
          currentStage,
          FunkEntity.track,
        );
        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;
}

void _onHelpStage() {
  final String help = '''
usage: funkblubber [[-OPTIONS|URL]...]

    A simple CLI for interaction with your Funkwhale account.

    Options:
      [-a|--album ID] Provide with album ID to download it. 

      [-A|--artist ID] Provide with artist ID to download their albums.

      [-t|--track ID] Provide with track ID to download a single track entity.

      [-p|--path PATH] Provide to explicitly define download directory.
                       Assumed '.'.

      [-d|--domain DOMAIN] Provide to explicitly define the host where your
                           Funkwhale instance is. Required with -a, -A, and -u.
                           Is not required if you download by a full URL.

      Examples:
        funkblubber https://my.funkwhale/library/tracks/10244/
        Download album by URL to current folder.

        funkblubber https://my.funkwhale/library/tracks/10244/ -p music
        Download album by URL to local ./music folder.

        funkblubber -A 152 -d my.funkwhale -p media/music/
        Download everything by artist with ID 152 from a funkwhale instance
        with my.funkwhale domain and save it to local ./media/music folder.

        funkblubber --album 1423 -d my.funkwhale
        Download album with ID 1423 from a funkwhale instance
        with my.funkwhale domain and save it to current folder.

  ''';

  console.info(help);
}

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);
}

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

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

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

ParseResult _makeParseResultFromEntityInfo(
  final FunkEntity kind,
  final String host,
  final String id,
) =>
    ParseResult(
      action: Action.download,
      success: true,
      object: FunkObject(
        kind: kind,
        id: id,
        domain: host,
      ),
    );

ParseResult _parseUrl(final String url, final ParseResult previousResult) {
  ParseResult result = previousResult;
  try {
    final Uri uri = Uri.parse(url);

    final segments = uri.pathSegments;
    for (int i = 0; i < segments.length; ++i) {
      switch (segments[i]) {
        case 'artists':
          result = _makeParseResultFromEntityInfo(
            FunkEntity.artist,
            uri.host,
            segments[i + 1],
          );
          ++i;
          break;

        case 'tracks':
          result = _makeParseResultFromEntityInfo(
            FunkEntity.track,
            uri.host,
            segments[i + 1],
          );
          ++i;
          break;

        case 'albums':
          result = _makeParseResultFromEntityInfo(
            FunkEntity.album,
            uri.host,
            segments[i + 1],
          );
          ++i;
          break;
      }
    }
  } catch (e) {
    console.error(e.toString());
  }

  return result;
}

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 '-t':
    case '--track':
      currentStage = ParsingStage.track;
      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;
    case '-h':
    case '--help':
      _onHelpStage();
      currentStage = ParsingStage.nothing;
      break;
    default:
      result = _parseUrl(arg, result);
      break;
  }

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