// ignore_for_file: file_names

import 'dart:math';

class PerhitunganKNN {
  List<List<double>> features;
  List<String> labels;

  PerhitunganKNN(this.features, this.labels);

  Map<String, dynamic> classify(List<double> newPoint, int k) {
    List<Map<String, dynamic>> distances = [];

    // Hitung jarak dari newPoint ke setiap titik dalam features
    for (int i = 0; i < features.length; i++) {
      double dist = euclideanDistance(features[i], newPoint);
      distances.add({'index': i, 'distance': dist});
    }

    // Urutkan berdasarkan jarak
    distances.sort((a, b) => a['distance'].compareTo(b['distance']));

    // Pilih K tetangga terdekat
    Map<String, int> votes = {};
    List<String> nearestNeighbors = [];
    for (int i = 0; i < k; i++) {
      String label = labels[distances[i]['index']];
      nearestNeighbors.add(label);
      votes[label] = votes.containsKey(label) ? votes[label]! + 1 : 1;
    }

    // Tentukan mayoritas kelas dari K tetangga terdekat
    String majorityLabel =
        votes.entries.reduce((a, b) => a.value > b.value ? a : b).key;

    return {
      'result': majorityLabel,
      'nearestNeighbors': nearestNeighbors,
      'distances': distances
    };
  }

  double euclideanDistance(List<double> p1, List<double> p2) {
    double sum = 0.0;
    for (int i = 0; i < p1.length; i++) {
      sum += pow((p1[i] - p2[i]), 2);
    }
    return sqrt(sum);
  }
}