MyFirstMAUI/MyFirstMauiApp/UseRestService/Data/PartManager.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Json;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;

namespace UseRestService.Data
{
    public static class PartsManager
    {
        // TODO: Add fields for BaseAddress, Url, and authorizationKey
        static readonly string BaseAddress = "https://mslearnpartsserver425916999.azurewebsites.net";
        static readonly string Url = $"{BaseAddress}/api/";

        static HttpClient client;

        static string authorizationKey;

        private static async Task<HttpClient> GetClient()
        {
            if (client != null)
                return client;

            client = new HttpClient();

            if (string.IsNullOrEmpty(authorizationKey))
            {
                authorizationKey = await client.GetStringAsync($"{Url}login");
                authorizationKey = JsonSerializer.Deserialize<string>(authorizationKey);
            }

            client.DefaultRequestHeaders.Add("Authorization", authorizationKey);
            client.DefaultRequestHeaders.Add("Accept", "application/json");

            return client;
        }

        public static async Task<IEnumerable<Part>> GetAll()
        {
            if (Connectivity.Current.NetworkAccess != NetworkAccess.Internet)
                return new List<Part>();

            var client = await GetClient();
            string result = await client.GetStringAsync($"{Url}parts");

            return JsonSerializer.Deserialize<List<Part>>(result, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true,
            });
        }

        public static async Task<Part> Add(string partName, string supplier, string partType)
        {
            if (Connectivity.Current.NetworkAccess != NetworkAccess.Internet)
                return new Part();

            var part = new Part()
            {
                PartName = partName,
                Suppliers = new List<string>(new[] { supplier }),
                PartID = string.Empty,
                PartType = partType,
                PartAvailableDate = DateTime.Now.Date
            };

            var msg = new HttpRequestMessage(HttpMethod.Post, $"{Url}parts");
            msg.Content = JsonContent.Create<Part>(part);

            var response = await client.SendAsync(msg);
            response.EnsureSuccessStatusCode();

            var returnedJson = await response.Content.ReadAsStringAsync();

            var insertedPart = JsonSerializer.Deserialize<Part>(returnedJson, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true,
            });

            return insertedPart;
        }

        public static async Task Update(Part part)
        {
            if (Connectivity.Current.NetworkAccess != NetworkAccess.Internet)
                return;

            HttpRequestMessage msg = new(HttpMethod.Put, $"{Url}parts/{part.PartID}");
            msg.Content = JsonContent.Create<Part>(part);

            var client = await GetClient();
            var response = await client.SendAsync(msg);
            response.EnsureSuccessStatusCode();
        }

        public static async Task Delete(string partID)
        {
            if (Connectivity.Current.NetworkAccess != NetworkAccess.Internet)
                return;

            HttpRequestMessage msg = new(HttpMethod.Delete, $"{Url}parts/{partID}");

            var client = await GetClient();
            var response = await client.SendAsync(msg);
            response.EnsureSuccessStatusCode();
        }
    }
}