cloudsolutions-atoms/lib/controllers/providers/api/parts_provider.dart

import 'dart:convert';

import 'package:test_sa/controllers/api_routes/urls.dart';
import 'package:test_sa/models/part.dart';
import 'package:test_sa/models/user.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart';

class PartsProvider extends ChangeNotifier{

  // number of items call in each request
  final pageItemNumber = 50;

  //reset provider data
  void reset(){
    _parts = null;
    _stateCode = null;
  }

  // state code of current request to defied error message
  // like 400 customer request failed
  // 500 service not available
  int _stateCode;
  int get stateCode => _stateCode;

  // true if there is next page in product list and false if not
  bool _nextPage = true;
  bool get nextPage => _nextPage;

  // contain user data
  // when user not login or register _user = null
  List<Part> _parts;
  List<Part> get parts => _parts;

  // when categories in-process _loading = true
  // done _loading = true
  // failed _loading = false
  bool _loading;
  bool get isLoading => _loading;
  set isLoading(bool isLoading){
    _loading = isLoading;
    notifyListeners();
  }

  /// return -2 if request in progress
  /// return -1 if error happen when sending request
  /// return state code if request complete may be 200, 404 or 403
  /// for more details check http state manager
  /// lib\controllers\http_status_manger\http_status_manger.dart
  Future<int> getParts ({String host,User user,String title}) async {
    if(_loading == true)
      return -2;
    _loading = true;
    notifyListeners();
    Response response;
    try{
      response = await get(
          Uri.parse(
       host + URLs.getPartNumber
          + "?page=${(_parts?.length ?? 0) ~/pageItemNumber}"
          + ( title == null || title.isEmpty ? "" : "&name=$title" )
          ),
        headers: {
          "Content-Type":"application/json; charset=utf-8"
        }
      );
      _stateCode = response.statusCode;
      if(response.statusCode >= 200 && response.statusCode < 300) {
        // client's request was successfully received
        List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
        List<Part>  _page = categoriesListJson.map((part) => Part.fromJson(part)).toList();
        if(parts == null)
          _parts = [];

        _parts.addAll(_page);
        if(_page.length >= pageItemNumber){
          _nextPage = true;
        }else{
          _nextPage = false;
        }
      }
      _loading = false;
      notifyListeners();
      return response.statusCode;
    } catch(error) {
      _loading = false;
      _stateCode = -1;
      notifyListeners();
      return -1;
    }

  }

  /// return -2 if request in progress
  /// return -1 if error happen when sending request
  /// return state code if request complete may be 200, 404 or 403
  /// for more details check http state manager
  /// lib\controllers\http_status_manger\http_status_manger.dart
  Future<List<Part>> getPartsList ({String host,User user,String title}) async {
    Response response;
    try{

      response = await get(
          Uri.parse(
          host + URLs.getPartNumber
              + ( title == null || title.isEmpty ? "" : "?name=$title" )
          ),
          headers: {
            "Content-Type":"application/json; charset=utf-8"
          }
      );
      List<Part>  _page = [];
      if(response.statusCode >= 200 && response.statusCode < 300) {
        // client's request was successfully received
        List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
        _page = categoriesListJson.map((part) => Part.fromJson(part)).toList();
      }
      return _page;
    } catch(error) {
      return [];
    }

  }

}