calculate.dart

import 'dart:developer' as dev;
import 'dart:math';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:location/location.dart';
import 'package:url_launcher/url_launcher.dart';

import '../../models/sick_model.dart';

class CalculatePage extends StatefulWidget {
  const CalculatePage({Key? key}) : super(key: key);

  @override
  State<CalculatePage> createState() => _CalculatePageState();
}

class _CalculatePageState extends State<CalculatePage> {
  double currentLat = 0.0;
  double currentLng = 0.0;

  List<PatienPath> listPatientPathTmp = [];
  List<PatienPath> listPatientPath = [];
  List<SickModel> listPatient = [];

  @override
  void initState() {
    super.initState();
    findLat1Lng1();
  }

  @override
  void dispose() {
    super.dispose();
  }

  List<PatienPath> buildlistPatientPathTmp(double currentLat, double currentLng) {
    List<PatienPath> _listPatientPathTmp = [];
    // calculate distance from current location
    dev.log('patient total = ${listPatient.length}');
    for (int i = 0; i < listPatient.length; i++) {
      var lat1 = currentLat;
      var lng1 = currentLng;
      var lat2 = listPatient[i].lat;
      var lng2 = listPatient[i].lng;

      // calculate distance
      var distance = calculateDistance(lat1, lng1, lat2, lng2);
      dev.log('${listPatient[i].name} - ${listPatient[i].idCard} - $distance');
      // add to temp path list
      _listPatientPathTmp.add(PatienPath(docId: listPatient[i].idCard, distance: distance));
    }

    return _listPatientPathTmp;
  }

  List<SickModel> listPatientData = [];

  readAllSick() async {
    // read all patient to list
    FirebaseFirestore.instance.collection('sick').get().then((value) {
      // set data to patient list
      for (var doc in value.docs) {
        SickModel patient = SickModel.fromMap(doc.data());
        //dev.log('name = ${patient.name}');
        listPatient.add(patient);
        listPatientData.add(patient);
      }

      dev.log('total patient ${listPatient.length}');

      // calculate paths
      while (listPatient.length > 0) {
        // build pateint path list
        if (listPatientPath.length <= 0) {
          dev.log('currentLat = $currentLat, currentLng = $currentLng');
          listPatientPathTmp = buildlistPatientPathTmp(currentLat, currentLng);
        } else {
          // get lat, lon from patial list
          // dev.log('total patient = ${listPatient.length}');
          // dev.log('last patient path = ${listPatientPath.last.docId}');
          final item = listPatientData.firstWhere((element) => element.idCard == listPatientPath.last.docId);
          dev.log('currentLat = ${item.lat}, currentLng = ${item.lng}');
          listPatientPathTmp = buildlistPatientPathTmp(item.lat, item.lng);
        }

        // sort tmp path list
        listPatientPathTmp.sort((a, b) => a.distance.compareTo(b.distance));
        dev.log('shortes path is ${listPatientPathTmp.first.docId} , ${listPatientPathTmp.first.distance} ');

        // set data to patient path list
        listPatientPath
            .add(PatienPath(docId: listPatientPathTmp.first.docId, distance: listPatientPathTmp.first.distance));

        // remove patient in list patient
        listPatient.removeWhere((element) => element.idCard == listPatientPathTmp.first.docId);

        // remove first patient in temp
        listPatientPathTmp.removeAt(0);

        dev.log('list Patient Path Tmp length = ${listPatientPathTmp.length}');

        // dev.log('list patient length = ${listPatient.length}');
        // dev.log('list patient path length = ${listPatientPath.length}');
      }

      dev.log('list patient path = ${listPatientPath.length}');

      setState(() {});
    });
  }

  Future<Null> findLat1Lng1() async {
    findLocationData().then((value) {
      // setState(() {
      currentLat = value?.latitude ?? 0.0;
      currentLng = value?.longitude ?? 0.0;
      dev.log('currentLat = $currentLat, currentLng = $currentLng');
      readAllSick();
      //});
    });
  }

  double calculateDistance(double lat1, double lng1, double lat2, double lng2) {
    double distance = 0;

    var p = 0.017453292519943295;
    var c = cos;
    var a = 0.5 - c((lat2 - lat1) * p) / 2 + c(lat1 * p) * c(lat2 * p) * (1 - c((lng2 - lng1) * p)) / 2;
    distance = 12742 * asin(sqrt(a));

    return distance;
  }

  Future<LocationData?> findLocationData() async {
    Location location = Location();
    try {
      return await location.getLocation();
    } catch (e) {
      return null;
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: (listPatientPath.isEmpty)
          ? Center(child: CircularProgressIndicator())
          : Container(
              child: ListView.builder(
                itemCount: listPatientPath.length,
                itemBuilder: (context, index) {
                  // get patient data
                  final patient =
                      listPatientData.firstWhere((element) => element.idCard == listPatientPath[index].docId);
                  return ListTile(
                    title: Text(patient.name),
                  );
                },
              ),
            ),
    );
  }
 
}

class PatienPath {
  String docId;
  double distance;
  PatienPath({
    required this.docId,
    required this.distance,
  });
}