import 'dart:collection';

import 'package:sheetless/sheet.dart';

enum ChangeType {
  sheetNameChange,
  composerNameChange,
  addTagChange,
  removeTagChange,
}

class Change {
  final ChangeType type;
  final String sheetUuid;
  final String value;

  Change({required this.type, required this.sheetUuid, required this.value});

  Map<String, dynamic> toMap() => {
    "type": type.index,
    "sheetUuid": sheetUuid,
    "value": value,
  };

  factory Change.fromMap(Map<dynamic, dynamic> map) {
    return Change(
      type: ChangeType
          .values[map["type"]], // TODO: this will create problems if new enums are added
      sheetUuid: map["sheetUuid"],
      value: map["value"],
    );
  }
}

class ChangeQueue {
  // Queue with oldest change first
  final Queue<Change> queue = Queue();

  ChangeQueue() {}

  void addChange(Change change) {
    queue.addLast(change);
  }

  int length() {
    return queue.length;
  }

  void applyToSheets(List<Sheet> sheets) {
    for (Change change in queue) {
      var sheet = sheets.where((sheet) => sheet.uuid == change.sheetUuid).first;
      switch (change.type) {
        case ChangeType.sheetNameChange:
          sheet.name = change.value;
        case ChangeType.composerNameChange:
          sheet.composerName = change.value;
        case ChangeType.addTagChange:
          // TODO: Handle this case.
          throw UnimplementedError();
        case ChangeType.removeTagChange:
          // TODO: Handle this case.
          throw UnimplementedError();
      }
    }
  }
}