sense_the_rythm

simfile.dart (4936B)

---

 import 'dart:io';
 
 import 'package:audioplayers/audioplayers.dart';
 
 enum Difficulty { Beginner, Easy, Medium, Hard, Challenge, Edit }
 
 // These are the standard note values:
 //
 //     0 – No note
 //     1 – Normal note
 //     2 – Hold head
 //     3 – Hold/Roll tail
 //     4 – Roll head
 //     M – Mine (or other negative note)
 //
 // Later versions of StepMania accept other note values which may not work in older versions:
 //
 //     K – Automatic keysound
 //     L – Lift note
 //     F – Fake note
 
 RegExp noteTypes = RegExp(r'^([012345MKLF]+)\s*([,;])?');
 
 class Chart {
   String? chartType;
   // Description/author
   String? author;
   // Difficulty (one of Beginner, Easy, Medium, Hard, Challenge, Edit)
   Difficulty? difficulty;
   // Numerical meter
   int? numericalMeter;
   // Groove radar values, generated by the program
   String? radarValues;
 
   List<List<String>>? measures;
 
   Map<double, String> beats = {};
 }
 
 class Simfile {
   String? directoryPath;
   String simfilePath;
   String? audioPath;
   String? bannerPath;
   String? lines;
 
   Duration? duration;
   // tags of simfile
   Map<String, String> tags = {};
 
   Chart? chartSimplest;
 
   Map<double, double> bpms = {};
   double offset = 0;
 
   Simfile(this.simfilePath);
 
   /// parses a chart tag with metadata [keys] and note data [value]
   void _parseChart({required List<String> keys, required String value}) {
     Chart chart = Chart();
     chart.chartType = keys[1];
     chart.author = keys[2];
     chart.difficulty = Difficulty.values.byName(keys[3]);
     chart.numericalMeter = int.parse(keys[4]);
     chart.radarValues = keys[5];
 
     // find simplest chart
     if (chartSimplest == null ||
         (chart.difficulty!.index <= chartSimplest!.difficulty!.index &&
             chart.numericalMeter! <= chartSimplest!.numericalMeter!)) {
       List<List<String>> measures = [];
       for (final measureRaw in value.split(',')) {
         List<String> measure = [];
         for (final noteRaw in measureRaw.split('\n')) {
           String note = noteRaw.trim();
           if (noteTypes.hasMatch(note)) {
             measure.add(note);
           }
         }
         measures.add(measure);
       }
 
       // for now only use the first bpm value
       double bpm = bpms.entries.first.value;
 
       // calculate timing for all notes based on offset, bpm and measure
       for (final (measureIndex, measure) in measures.indexed) {
         for (final (noteIndex, noteData) in measure.indexed) {
           double beat = measureIndex * 4.0 +
               (noteIndex.toDouble() / measure.length) * 4.0;
           double minutesPerBeat = 1.0 / bpm;
           double offsetMinutes = offset / 60.0;
           chart.beats[beat * minutesPerBeat + offsetMinutes] = noteData;
         }
       }
 
       chart.measures = measures;
       chartSimplest = chart;
     }
   }
 
   /// parse a tag based on a regex match [fieldData] and parsing the value based
   /// on the key
   void _parseTag(RegExpMatch fieldData) {
     List<String> keys =
         fieldData[1]!.split(':').map((key) => key.trim()).toList();
     String value = fieldData[2]!;
 
     if (keys[0] == "BPMS") {
       for (final pairRaw in value.split(',')) {
         List<String> pair = pairRaw.split('=');
         if (pair.length != 2) {
           continue;
         }
         double time = double.parse(pair[0]);
         double bpm = double.parse(pair[1]);
         bpms[time] = bpm;
       }
     }
 
     if (keys[0] == "OFFSET") {
       offset = double.parse(value);
     }
 
     if (keys[0] != "NOTES") {
       tags[keys[0]] = value;
       return;
     }
     _parseChart(keys: keys, value: value);
   }
 
   /// load the simfile
   Future<bool> load() async {
     directoryPath = File(simfilePath).parent.path;
     lines = File(simfilePath).readAsStringSync();
     
     // remove comments
     RegExp commentsRegExp = RegExp(r'//.*$');
     lines = lines?.replaceAll(commentsRegExp, '');
     // find all tags
     RegExp fieldDataRegExp = RegExp(r'#([^;]+):([^;]*);');
 
     // parse all tags
     for (final fieldData in fieldDataRegExp.allMatches(lines!)) {
       try {
         _parseTag(fieldData);
       } catch (err) {
         return false;
       }
     }
 
     // searching for audio and banned in the directory is more robust than using
     // values from metadata as they are wrong more often
     for (FileSystemEntity entity in Directory(directoryPath!).listSync()) {
       if (entity.path.endsWith('.ogg')) {
         audioPath = entity.path;
       }
       if (entity.path.endsWith('anner.png')) {
         bannerPath = entity.path;
       }
     }
 
     // dont use this simfile of files are missing
     if (audioPath == null) return false;
     if (bannerPath == null) return false;
 
     // get duration from audio
     AudioPlayer audioplayer = AudioPlayer();
     await audioplayer.setSource(DeviceFileSource(audioPath!));
     duration = await audioplayer.getDuration();
     audioplayer.dispose();
 
     return true;
   }
 }